TNY375-380
TinySwitch-PK Family
www.powerint.com May 2007
Energy-Efcient, Off-Line Switcher With
Enhanced Peak Power Performance
®
Output Power Table
Product3
230 VAC ± 15% 85-265 VAC
Adapter1Open
Frame2Peak Adapter1Open
Frame2Peak
TNY375 P 8.5 W 15 W 16.5 W 6 W 11.5 W 12.5 W
TNY376 P 10 W 19 W 22 W 7 W 15 W 17 W
TNY377 P 13 W 23.5 W 28 W 8 W 18 W 23 W
TNY378 P 16 W 28 W 34 W 10 W 21.5 W 27 W
TNY379 P 18 W 32 W 39 W 12 W 25 W 31 W
TNY380 P 20 W 36.5 W 45 W 14 W 28.5 W 35 W
Table 1. Output Power Table.
Notes:
1. Minimum continuous power in a typical non-ventilated enclosed adapter
measured at +50 °C ambient. Use of an external heatsink will increase power
capability.
2. Minimum continuous power in an open frame design (see Key Applications
Considerations).
3. Packages: P: DIP-8C. Available as lead free (with N suffix). See Part Ordering
Information.
Product Highlights
Lowest System Cost with Enhanced Flexibility
Simple ON/OFF control, no loop compensation needed
Unique Peak Mode feature extends power range without
increasing transformer size
Maximum frequency and current limit boosted at peak loads
Selectable current limit through BP/M capacitor value
Higher current limit further extends maximum power in open
frame applications
Lower current limit improves efficiency in enclosed adapter
applications
Allows optimum TinySwitch-PK choice by swapping devices
with no other circuit redesign
Tight I2f parameter tolerance reduces system cost:
Maximizes MOSFET and magnetics power delivery
ON time extension – typically extends low line regulation range/
hold-up time to reduce input bulk capacitance
Self-biased: no bias winding required for TNY375-376; winding
required for TNY377-380
Frequency jittering reduces EMI filter costs
Optimized pin out eases pcb/external heatsinking
Quiet source-connected heatsink pins for low EMI
Enhanced Safety and Reliability Features
Accurate hysteretic thermal shutdown with automatic recovery
provides complete system level overload protection and
eliminates need for manual reset
Auto-restart delivers <3% maximum power in short circuit and
open loop fault conditions
Output overvoltage shutdown with optional Zener
Line undervoltage detect threshold set using a single optional
resistor
Very low component count enhances reliability and enables
single sided printed circuit board layout
High bandwidth provides fast turn on with no overshoot and
excellent transient load response
Extended creepage between DRAIN and all other pins improves
field reliability
EcoSmart®– Extremely Energy Efficient
Easily meets all global energy efficiency regulations
No-load <170 mW at 265 VAC without bias winding, <60 mW
with bias winding
ON/OFF control provides constant efficiency down to very light
loads – ideal for mandatory CEC efficiency regulations and 1 W
PC standby requirements
Applications
Applications with high peak-to-continuous power demands –
DVDs, set-top decoders, active speakers (e.g. PC audio),
audio amplifiers, modems, photo printers
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Description
TinySwitch-PK incorporates a 700 V MOSFET, oscillator, high-
voltage switched current source, current limit (user selectable),
and thermal shutdown circuitry. A unique peak mode feature
boosts current limit and frequency for peak load conditions. The
boosted current limit provides the peak output power while the
increased peak mode frequency ensures the transformer can be
sized for continuous load conditions rather than peak power
demands.
PI-4266-010906
Wide-Range
HV DC Input D
S
EN/UV
BP/M
+
-
+
-
DC
Output
TinySwitch-PK
Figure 1. Typical Standby Application.
Rev. A 05/07
2
TNY375-380
www.powerint.com
Pin Functional Description
DRAIN (D) Pin:
This pin is the power MOSFET drain connection. It provides
internal operating current for both start-up and steady-state
operation.
BYPASS/MULTI-FUNCTION (BP/M) Pin:
This pin has multiple functions:
It is the connection point for an external bypass capacitor for
the internally generated 5.85 V supply.
It is a mode selector for the current limit value, depending on
the value of the capacitance added. Use of a 0.1 mF
capacitor results in the standard current limit value. Use of a
1 mF capacitor results in the current limit being reduced to
that of the next smaller device size (TNY376-380). Use of a
10 mF capacitor results in the current limit being increased to
that of the next larger device (TNY377-379).
It provides a shutdown function. When the current into the
bypass pin exceeds 7 mA, the device latches off until the
BP/M voltage drops below 4.9 V, during a power down or
when a line undervoltage is detected. This can be used to
provide an output overvoltage function with a Zener diode
connected from the BP/M pin to a bias winding supply.
1.
2.
3. ENABLE/UNDERVOLTAGE (EN/UV) Pin:
This pin has dual functions: enable input and line undervoltage
sense. During normal operation, switching of the power
MOSFET is controlled by this pin. MOSFET switching is
terminated when a current greater than a threshold current is
drawn from this pin. Switching resumes when the current being
PI-4550-121406
CLOCK
OSCILLATOR
5.85 V
4.9 V
SOURCE
(S)
S
R
Q
DCMAX
BYPASS/
MULTI-FUNCTION
(BP/M)
+
-
VILIMIT
FAULT
PRESENT
CURRENT LIMIT
COMPARATOR
ENABLE
LEADING
EDGE
BLANKING
THERMAL
SHUTDOWN
+
-
DRAIN
(D)
REGULATOR
5.85 V
BYPASS PIN
UNDER-VOLTAGE
1.0 V + VT
ENABLE/
UNDER-
VOLTAGE
(EN/UV) Q
115 mA 25 mA
LINE UNDER-VOLTAGE
RESET
AUTO-
RESTART
COUNTER
JITTER 2X
1.0 V
6.4 V
BYPASS
CAPACITOR
SELECT AND
CURRENT
LIMIT STATE
MACHINE
OVP
LATCH
RESET
Figure 2 Functional Block Diagram.
PI-4348-032806
DS
BP/M S
S
EN/UV
P Package (DIP-8C)
8
5
7
1
4
2
S
6
Figure 3. Pin Configuration.
Rev. A 05/07
3
TNY375-380
www.powerint.com
pulled from the pin drops to less than a threshold current. A
modulation of the threshold current reduces group pulsing.
The threshold current is between 75 mA and 115 mA.
The EN/UV pin also senses line undervoltage conditions
through an external resistor connected to the DC line voltage.
If there is no external resistor connected to this pin,
TinySwitch-PK detects its absence and disables the line under-
voltage function.
SOURCE (S) Pin:
This pin is internally connected to the output MOSFET source
for high voltage power return and control circuit common.
TinySwitch-PK Functional Description
TinySwitch-PK combines a high voltage power MOSFET switch
with a power supply controller in one device. Unlike
conventional PWM (pulse width modulator) controllers, it uses a
simple ON/OFF control to regulate the output voltage.
The controller consists of an oscillator, enable circuit (sense and
logic), current limit state machine, 5.85 V regulator, BYPASS/
MULTI-FUNCTION pin undervoltage, overvoltage circuit, and
current limit selection circuitry, over-temperature protection,
current limit circuit, leading edge blanking, and a 700 V power
MOSFET. TinySwitch-PK incorporates additional circuitry for
line undervoltage sense, auto-restart, adaptive switching cycle
on-time extension, and frequency jitter. Figure 2 shows the
functional block diagram with the most important features.
Oscillator
The typical oscillator frequency is internally set to an average of
264 kHz (at the highest current limit level). Two signals are
generated from the oscillator: the maximum duty cycle signal
(DCMAX) and the clock signal that indicates the beginning of
each cycle.
The oscillator incorporates circuitry that introduces a small
amount of frequency jitter, typically ±3% of the oscillator
frequency, to minimize EMI emission. The modulation rate of
the frequency jitter is set to 1 kHz to optimize EMI reduction for
both average and quasi-peak emissions. The frequency jitter
should be measured with the oscilloscope triggered at the
falling edge of the DRAIN waveform. The waveform in Figure 4
illustrates the frequency jitter with an oscillator frequency of
264 kHz.
Enable Input and Current Limit State Machine
The enable input circuit at the EN/UV pin consists of a low
impedance source follower output set at 1.2 V. The current
through the source follower is limited to 115 mA. When the
current out of this pin exceeds the threshold current, a low logic
level (disable) is generated at the output of the enable circuit
until the current out of this pin is reduced to less than the
threshold current. This enable circuit output is sampled at the
beginning of each cycle on the rising edge of the clock signal. If
high, the power MOSFET is turned on for that cycle (enabled). If
low, the power MOSFET remains off (disabled). Since the
sampling is done only at the beginning of each cycle,
subsequent changes in the EN/UV pin voltage or current during
the remainder of the cycle are ignored. When a cycle is
disabled, the EN/UV pin is sampled at 264 kHz. This faster
sampling enables the power supply to respond faster without
being required to wait for completion of the full period.
The current limit state machine reduces the current limit by
discrete amounts at light loads when TinySwitch-PK is likely to
switch in the audible frequency range. The lower current limit
raises the effective switching frequency above the audio range
and reduces the transformer flux density, including the
associated audible noise. The state machine monitors the
sequence of enable events to determine the load condition and
adjusts the current limit level accordingly in discrete amounts.
Under most operating conditions (except when close to no-
load), the low impedance of the source follower keeps the
voltage on the EN/UV pin from going much below 1.2 V in the
disabled state. This improves the response time of the
optocoupler that is usually connected to this pin.
5.85 V Regulator and 6.4 V Shunt Voltage Clamp
The 5.85 V regulator charges the bypass capacitor connected
to the BYPASS pin to 5.85 V by drawing a current from the
voltage on the DRAIN pin whenever the MOSFET is off. The
BYPASS/MULTI-FUNCTION pin is the internal supply voltage
node. When the MOSFET is on, the device operates from the
energy stored in the bypass capacitor. Extremely low power
consumption of the internal circuitry allows the TNY375 and
TNY376 to operate continuously from current taken from the
DRAIN pin. A bypass capacitor value of 0.1 mF is sufficient for
both high frequency decoupling and energy storage.
In addition, there is a 6.4 V shunt regulator clamping the
BYPASS/MULTI-FUNCTION pin at 6.4 V when current is
provided to the BYPASS/MULTI-FUNCTION pin through an
external resistor. This facilitates powering of TinySwitch-PK
externally through a bias winding as required for TNY377-380.
Powering the TinySwitch-PK externally in this way also
decreases the no-load consumption to well below 50 mW.
600
0 2.5 5
272 kHz
256 kHz
VDRAIN
Time (µs)
PI-4539-120406
500
400
300
200
100
0
Figure 4. Frequency Jitter.
Rev. A 05/07
4
TNY375-380
www.powerint.com
BYPASS/MULTI-FUNCTION Pin Undervoltage
The BYPASS/MULTI-FUNCTION pin undervoltage circuitry
disables the power MOSFET when the BYPASS/MULTI-
FUNCTION pin voltage drops below 4.9 V in steady state
operation. Once the BYPASS/MULTI-FUNCTION pin voltage
drops below 4.9 V in steady state operation, it must rise back to
5.85 V to enable (turn-on) the power MOSFET.
Over Temperature Protection
The thermal shutdown circuitry senses the die temperature.
The threshold is typically set at 142 °C with 75 °C hysteresis.
When the die temperature rises above this threshold, the power
MOSFET is disabled and remains disabled, until the die
temperature falls by 75 °C, at which point it is re-enabled. A
large hysteresis of 75 °C (typical) is provided to prevent
overheating of the PC board due to a continuous fault condition.
Current Limit
The current limit circuit senses the current in the power
MOSFET. When this current exceeds the internal threshold
(ILIMIT), the power MOSFET is turned off for the remainder of that
cycle. The current limit state machine reduces the current limit
threshold by discrete amounts under medium and light loads.
The leading edge blanking circuit inhibits the current limit
comparator for a short time (tLEB) after the power MOSFET is
turned on. This leading edge blanking time has been set so
that current spikes caused by typical capacitance and
secondary-side rectifier reverse recovery time will not cause
premature termination of the switching pulse.
Auto-Restart
In the event of a fault condition such as output overload, output
short circuit, or an open loop condition, TinySwitch-PK enters
into auto-restart operation. An internal counter clocked by the
oscillator is reset every time the EN/UV pin is pulled low. If the
EN/UV pin is not pulled low for 8192 switching cycles
(or 32 ms), the power MOSFET switching is normally disabled
for 1 second (except in the case of line undervoltage condition,
in which case it is disabled until the condition is removed). The
auto-restart alternately enables and disables the switching of
the power MOSFET until the fault condition is removed.
Figure 5 illustrates auto-restart circuit operation in the presence
of an output short circuit.
In the event of a line undervoltage condition, the switching of
the power MOSFET is disabled beyond its normal 1 second
until the line undervoltage condition ends.
Adaptive Switching Cycle On-Time Extension
Adaptive switching cycle on-time extension keeps the cycle on
until current limit is reached, instead of prematurely terminating
after the DCMAX signal goes low. This feature reduces the
minimum input voltage required to maintain regulation, typically
extending hold-up time and minimizing the size of bulk
capacitor required. The on-time extension is disabled during
the startup of the power supply, and after auto-restart, until the
power supply output reaches regulation.
Line Undervoltage Sense Circuit
The DC line voltage can be monitored by connecting an
external resistor from the DC line to the EN/UV pin. During
power-up or when the switching of the power MOSFET is
disabled in auto-restart, the current into the EN/UV pin must
exceed 25 mA to initiate switching of the power MOSFET.
During power-up, this is accomplished by holding the BYPASS/
MULTI-FUNCTION pin to 4.9 V while the line undervoltage
condition exists. The BYPASS/MULTI-FUNCTION pin then rises
from 4.9 V to 5.85 V when the line undervoltage condition goes
away. Once MOSFET switching is enabled, the DC line voltage
is ignored unless the power supply enters auto-restart mode in
the event of a fault condition. When the switching of the power
MOSFET is disabled in auto-restart mode and a line under-
voltage condition exists, the auto-restart counter is stopped.
This stretches the disable time beyond its normal 1 second until
the line undervoltage condition ends.
The line undervoltage circuit also detects when there is no
external resistor connected to the EN/UV pin (less than ~1 mA
into the pin). In this case the line undervoltage function is
disabled.
TinySwitch-PK Operation
TinySwitch-PK devices operate in the current limit mode.
When enabled, the oscillator turns the power MOSFET on at the
beginning of each cycle. The MOSFET is turned off when the
current ramps up to the current limit or when the DCMAX limit is
reached (applicable when On-Time Extension is disabled).
Since the highest current limit level and frequency of a
TinySwitch-PK design are constant, the power delivered to the
load is proportional to the primary inductance of the transformer
and peak primary current squared. Hence, designing the
supply involves calculating the primary inductance of the
transformer for the maximum output power required. If the
TinySwitch-PK is appropriately chosen for the power level, the
current in the calculated inductance will ramp up to current limit
before the DCMAX limit is reached.
PI-4320-030106
01000 2000
Time (ms)
0
5
0
10
100
200
300 VDRAIN
VDC-OUTPUT
Figure 5. Auto-Restart Operation.
Rev. A 05/07
5
TNY375-380
www.powerint.com
Enable Function
TinySwitch-PK senses the EN/UV pin to determine whether or
not to proceed with the next switching cycle. The sequence of
cycles is used to determine the current limit. Once a cycle is
started, it always completes the cycle (even when the EN/UV
pin changes state halfway through the cycle). This operation
results in a power supply in which the output voltage ripple is
determined by the output capacitor, amount of energy per
switch cycle, and the delay of the feedback.
The EN/UV pin signal is generated on the secondary by
comparing the power supply output voltage with a reference
voltage. The EN/UV pin signal is high when the power supply
output voltage is less than the reference voltage.
In a typical implementation, the EN/UV pin is driven by an
optocoupler. The collector of the optocoupler transistor is
connected to the EN/UV pin, and the emitter is connected to
the SOURCE pin. The optocoupler LED is connected in series
with a Zener diode across the DC output voltage to be
regulated. When the output voltage exceeds the target
regulation voltage level (optocoupler LED voltage drop plus
Zener voltage), the optocoupler LED will start to conduct,
pulling the EN/UV pin low. The Zener diode can be replaced by
a TL431 reference circuit for improved accuracy.
ON/OFF Operation with Current Limit State Machine
The internal clock of the TinySwitch-PK runs at all times. At the
beginning of each clock cycle, it samples the EN/UV pin to
decide whether or not to implement a switch cycle, and based
on the sequence of samples over multiple cycles, it determines
the appropriate current limit. At high loads, the state machine
sets the current limit to its highest value. With TinySwitch-PK,
when the state machine sets the current limit to its highest
value, the oscillator frequency is also doubled, providing the
unique peak mode operation. At lighter loads, the state
machine sets the current limit to reduced values. At these lower
current limit levels, the oscillator frequency returns to the
standard value.
At near maximum load, TinySwitch-PK will conduct during
nearly all of its clock cycles (Figure 6). At slightly lower load, it
will “skip” additional cycles in order to maintain voltage
regulation at the power supply output (Figure 7). At medium
loads, more cycles will be skipped, the current limit will be
V
DRAIN
V
EN
CLOCK
DC
DRAIN
I
MAX
PI-2749-082305
V
DRAIN
V
EN
CLOCK
DC
DRAIN
I
MAX
PI-2667-082305
Figure 6. Operation at Near Maximum Loading (fOSC 264 kHz).
Figure 7. Operation at Moderately Heavy Loading (fOSC 264 kHz).
PI-4540-050407
V
DRAIN
V
EN
CLOCK
DC
DRAIN
I
MAX
Figure 8. Operation at Medium Loading (fOSC 132 kHz).
Rev. A 05/07
6
TNY375-380
www.powerint.com
Figure 9. Operation at Very Light Load (fOSC 132 kHz).
01 2
Time (ms)
0
200
400
5
0
10
0
100
200
PI-2383-030801
VDC-INPUT
VBYPASS
VDRAIN
PI-2381-1030801
01 2
Time (ms)
0
200
400
5
0
10
0
100
200
VDC-INPUT
VBYPASS
VDRAIN
PI-2348-030801
0.5 1
Time (s)
0
100
200
300
0
100
200
400
VDC-INPUT
VDRAIN
PI-2395-030801
02.5 5
Time (s)
0
100
200
400
300
0
100
200
VDC-INPUT
VDRAIN
Figure 10. Power-up With Optional External UV Resistor (4 MW) Connected
to EN/UV Pin.
Figure 11. Power-up Without Optional External UV Resistor Connected
to EN/UV Pin.
Figure 12. Normal Power-down Timing (Without UV Resistor).
Figure 13. Slow Power-down Timing With Optional External (4 MW) UV Resistor
Connected to EN/UV Pin.
Rev. A 05/07
7
TNY375-380
www.powerint.com
reduced, and the clock frequency is reduced to half that at the
highest current limit level (Figure 8). At very light loads, the
current limit will be reduced even further (Figure 9). Only a small
percentage of cycles will occur to satisfy the power consumption
of the power supply. The response time of the ON/OFF control
scheme is very fast compared to PWM control. This provides
tight regulation and excellent transient response.
Power Up/Down
The TinySwitch-PK requires only a 0.1 mF capacitor on the
BYPASS/MULTI-FUNCTION pin to operate with standard
current limit. Because of its small size, the time to charge this
capacitor is kept to an absolute minimum, typically 0.6 ms. The
time to charge will vary in proportion to the BYPASS/MULTI-
FUNCTION pin capacitor value when selecting different current
limits. Due to the high bandwidth of the ON/OFF feedback,
there is no overshoot at the power supply output. When an
external resistor (4 MW) is connected from the power supply
positive DC input to the EN/UV pin, the power MOSFET
switching will be delayed during power-up until the DC line
voltage exceeds the threshold (100 V). Figures 10 and 11 show
the power-up timing waveform in applications with and without
an external resistor (4 MW) connected to the EN/UV pin.
During power-down, when an external resistor is used, the
power MOSFET will switch for 32 ms after the output loses
regulation. The power MOSFET will then remain off without any
glitches since the undervoltage function prohibits restart when
the line voltage is low.
Figure 12 illustrates a typical power-down timing waveform.
Figure 13 illustrates a very slow power-down timing waveform,
as in standby applications. The external resistor (4 MW) is
connected to the EN/UV pin in this case to prevent unwanted
restarts.
With the TNY375 and TNY376, no bias winding is needed to
provide power to the chip because it draws the power directly
from the DRAIN pin (see Functional Description above). This
eliminates the cost of a bias winding and associated
components. For the TNY377-380 or for applications that
require very low no-load power consumption (50 mW), a resistor
from a bias winding to the BYPASS/MULTI-FUNCTION pin can
provide the power to the chip. The minimum recommended
current supplied is IS2 + IDIS. The BYPASS/MULTI-FUNCTION
pin in this case will be clamped at 6.4 V. This method will
eliminate the power draw from the DRAIN pin, thereby reducing
the no-load power consumption and improving full-load
efficiency.
Current Limit Operation
Each switching cycle is terminated when the DRAIN current
reaches the current limit of the device. Current limit operation
provides good line ripple rejection and relatively constant power
delivery independent of input voltage.
BYPASS/MULTI-FUNCTION Pin Capacitor
The BYPASS/MULTI-FUNCTION pin can use a ceramic
capacitor as small as 0.1 mF for decoupling the internal power
supply of the device. A larger capacitor size can be used to
adjust the current limit. A 1 mF BP/M pin capacitor will select a
lower current limit equal to the standard current limit of the next
smaller device, and a 10 mF BP/M pin capacitor will select a
higher current limit equal to the standard current limit of the
next larger device. The TNY375 and TNY376 MOSFETs do not
have the capability to match the current limit of the next larger
devices in the family. The current limit is therefore increased to
the maximum capability of their respective MOSFETs. The
higher current limit level of the TNY380 is set to 1105 mA
typical. The smaller current limit of the TNY375 is set to
325 mA.
Rev. A 05/07
8
TNY375-380
www.powerint.com
Applications Examples
The circuit shown in Figure 14 is a low cost universal AC input,
four-output flyback power supply utilizing a TNY376. The
continuous output power is 7.5 W with a peak of 13 W. The
output voltages are 3.3 V, 5 V, 12 V, and –12 V.
The rectified and filtered input voltage is applied to the primary
winding of T1. The other side of the transformer’s primary is
driven by the integrated MOSFET in U4. Diode D5, C3, R1, R2,
and VR1 compose the clamp circuit, limiting the leakage
inductance turn-off voltage spike on the DRAIN pin to a safe
value. The use of a combination Zener clamp and parallel RC
optimizes both EMI and energy efficiency.
Both the 3.3 V and 5V outputs are sensed through resistors R6
and R7. The voltage across R8 is regulated to 2.5 V by reference
IC U3. If the voltage across R8 begins to exceed 02.5 V, then
current will flow in the LED inside the optocoupler U2, driven by
the cathode of U3. This will cause the transistor of the
optocoupler to sink current. When the current exceeds the
ENABLE pin threshold current, the next switching cycle is
inhibited. Conversely, when the voltage across resistor R13 falls
below 2.5 V, and the current out of the ENABLE pin is below the
threshold, a conduction cycle is allowed to occur. By adjusting
the number of enabled cycles, regulation is maintained. As the
load reduces, the number of enabled cycles decreases, lowering
the effective switching frequency and scaling switching losses
with load. This provides almost constant efficiency down to very
light loads, ideal for meeting energy efficiency requirements.
The input filter circuit (C1, L1 and C2) reduces conducted EMI.
To improve common mode EMI, this design makes use of
E-ShieldTM shielding techniques in the transformer. E-Shielding
thus reduces common mode displacement currents, reducing
EMI. These techniques, combined with the frequency jitter of
TNY376, give excellent EMI performance, with this design
achieving >10 dBmV of margin to EN55022 Class B conducted
EMI limits.
For design flexibility, the value of C4 can be selected to pick one
of the three current limit options in U4. Doing so allows the
designer to select the current limit appropriate for the application.
Standard current limit is selected with a 0.1 mF BP/M pin
capacitor and is the normal choice for typical applications.
When a 1 mF BP/M pin capacitor is used, the current limit is
reduced, offering reduced RMS device currents and therefore
improved efficiency, but at the expense of maximum power
capability. This is ideal for thermally challenging designs where
dissipation must be minimized.
When a 10 mF BP/M pin capacitor is used, the current limit is
increased, extending the power capability for applications
requiring higher peak power or continuous power where the
thermal conditions allow.
Further flexibility comes from the current limits between adjacent
TinySwitch-PK family members being compatible. The reduced
current limit of a given device is equal to the standard current
limit of the next smaller device, and the increased current limit is
equal to the standard current limit of the next larger device.
•
•
•
D9
UF4003
U1
TNY376P
U2A
LTV817A
U3
L431
2%
C1
22 MF
400 V
C2
22 MF
400 V C3
10 nF
1 kV
C4
10 MF
50 V
C11
47 MF
25 V
C14
100 nF
50 V
C13
10 MF
50 V
C9
1000 MF
10 V C5
220 MF
25 V
C10
470 MF
10 V
C8
470 MF
10 V
C6
100 MF
25 V
C7
1000 MF
25 V
C12
220 MF
25 V
U2B
LTV817A
JP1
JP2
C5
330 pF
250 VAC
R1
100 7
R4
200 7
1/2 W
R6
20 k7
1%
R5
1 k7
R7
6.34 k7
1%
R8
10 k7
1%
R9
3.3 k7
R2
47 7
R3
17
1/2 W
L1
5 mH
L2
3.3 MH
L3
3.3 MH
L4
3.3 MH
F1
3.15 A
85-265
VAC
+12 V, 0.64 A
+5.0 V, 0.6 A
+3.3 V, 0.6 A
RTN
-12 V, 0.03 A
L
N
D1
FR106
D2
FR106
D5
FR106
D6
UF4003
D7
1N5819
D8
SB340
VR1
P6KE180A
D3
1N4007
D4
1N4007
PI-4673-051107
T1
EEL19
1
N.C.
6
11
7
8,9,10
12
4
3
5
D
S
EN/UV
BP
TinySwitch-PK
Figure 14. TNY376P, Four Output, 7.5 W, 13 W Peak Universal Input Power Supply.
Rev. A 05/07
9
TNY375-380
www.powerint.com
Key Application considerations
TinySwitch-PK Design Considerations
Output Power Table
Data sheet maximum output power table (Table 1) represents
the maximum practical continuous output power level that can
be obtained under the following assumed conditions:
The minimum DC input voltage is 100 V or higher for 85 VAC
input, or 220 V or higher for 230 VAC input or 115 VAC with
a voltage doubler. The value of the input capacitance should
be sized to meet these criteria for AC input designs.
Efficiency of 75%.
Minimum datasheet value of I2f.
Transformer primary inductance tolerance of ±10%.
Reflected output voltage (VOR) of 135 V.
Voltage only output of 12 V with an ultrafast PN rectifier
diode
Continuous conduction mode operation with transient KP*
value of 0.25.
Increased current limit is selected for peak and open frame
power columns and standard current limit for adapter
columns.
The part is board mounted with SOURCE pins soldered to a
sufficient area of copper to keep the SOURCE pin
temperature at or below 110°C.
Ambient temperature of 50 °C for open frame designs and
40 °C for sealed adapters.
*KP. Below a value of 1, KP is the ratio of ripple to peak
primary current. A transient KP limit of ≥0.25 is recommended
to avoid premature termination of switching cycles due to initial
current limit (IINIT) being exceeded, which reduces maximum
output power capability.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
The values shown in Table 1 for peak power assume operation
in ILIMITPEAKinc. For reference, Table 2 provides peak output
powers for each family member at the three selectable current
limit modes.
For both Table 1 and Table 2, the peak output power values are
limited electronically, based on minimum device I2f. Stated
differently, with sufficient heatsinking, these values could be
delivered indefinitely, but in most cases this would be
impractical. Adapter and open frame power values are
thermally limited and represent the practical continuous (or
average) output power in two thermal environments.
Over Voltage Protection
The output overvoltage protection provided by TinySwitch-PK
uses an internal latch that is triggered by a threshold current of
approximately 7 mA into the BYPASS pin. In addition to an
internal filter, the BYPASS pin capacitor forms an external filter,
providing noise immunity from inadvertent triggering. For the
bypass capacitor to be effective as a high frequency filter, it
Peak Output Power Table
Product
230 VAC ± 15% 85-265 VAC
ILIMIT-
PEAKred
ILIMITPEAK
ILIMIT-
PEAKinc
ILIMIT-
PEAKred
ILIMITPEAK
ILIMIT-
PEAKinc
TNY375 P 8.5 W 14.5 W 16.5 W 5.5 W 11.5 W 12.5 W
TNY376 P 10 W 19 W 22 W 6 W 15 W 17 W
TNY377 P 13 W 23 W 28 W 8 W 18 W 23 W
TNY378 P 16 W 27.5 W 34 W 10 W 21.5 W 27 W
TNY379 P 18 W 31.5 W 39 W 12 W 25 W 31 W
TNY380 P 20 W 36 W 45 W 14 W 28 W 35 W
Table 2. Peak Output Power Capability vs Current Limit Mode Selection.
U1
TNY380P
C1
10 MF
400 V
C2
22 MF
400 V
L1
1 mH
R1
1 k7
R9
3.9 M7
R5
47 7
1/8 W
R3
2 k7
1/8 W
R4
20 7
R2
390 7
1/8 W
R6
21k 7
1%
R10
3.9 M7
C8
10 nF
1 kV
C7
1MF
50 V
C3
1000 MF
16 V
C4
1000 MF
16 V
C5
220 MF
16 V
C6
10 MF
50 V
U2
PC817A
VR2
1N5251B, 22 V
VR1
BZX55B11
11 V, 2%
C9
2.2 nF
250 VAC
R7
22 7
1/2 W
F1
3.15 A
185-265
VAC
+12 V
RTN
L
N
D1
1N4007
D2
1N4007
D7
FR106
D5
SB560
VR3
P6KE170A
D6
UF4004
D3
1N4007
D4
1N4007
PI-4674-042607
T1
EFD25 9,101
36,7,8
5
2
D
S
EN/UV
BP
TinySwitch-PK
L2
3.3 MH
Figure 15. Universal Input 20 W Continuous and 45 W Peak Power Supply Using TNY380P.
Rev. A 05/07
10
TNY375-380
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should be located as close as possible to the SOURCE and
BYPASS pins of the device.
For best performance of the OVP function, it is recommended
that a relatively high bias winding voltage is used, in the range
of 15 V-30 V. This minimizes the error voltage on the bias
winding due to leakage inductance and also ensures adequate
voltage during no-load operation from which to supply the IC
device consumption.
Selecting the zener diode voltage to be approximately 6 V
above the bias winding voltage (28 V for 22 V bias winding)
gives good OVP performance for most designs but can be
adjusted to compensate for variations in leakage inductance.
Adding additional filtering can be achieved by inserting a low
value (10 W to 47 W) resistor in series with the bias winding
diode and/or the OVP Zener, as shown by R4 and R5 in
Figure 15. The resistor in series with the OVP Zener also limits
the maximum current into the BYPASS pin.
Reducing No-load Consumption
With the exception of the TNY375 and TNY376, a bias winding
must be used to provide supply current for the IC. This has the
additional benefit of reducing the typical no-load consumption
to <60mW. Select the value of the resistor (R8 in Figure 15) to
provide the datasheet supply current equal to IS2 + |IDIS|.
Although in practice the bias voltage falls at low load, the
reduction in supply current through R8 is balanced against the
reduced IC consumption as the effective switching frequency
reduces with load.
Audible Noise
The cycle skipping mode of operation used in the TinySwitch-PK
devices can generate audio frequency components in the
transformer. To limit this audible noise generation, the
transformer should be designed such that the peak core flux
density is below 3000 Gauss (300 mT). Following this guideline,
and using the standard transformer production technique of dip
varnishing practically eliminates audible noise. Vacuum
impregnation of the transformer should not be used due to the
high primary capacitance and increased losses that results.
Higher flux densities are possible; however, careful evaluation of
the audible noise performance should be made using
production transformer samples before approving the design.
Ceramic capacitors that use dielectrics such as Z5U, when
used in clamp circuits, may also generate audio noise. If this is
the case, try replacing them with a capacitor having a different
dielectric or construction such as the film foil or metallized foil
type.
TinySwitch-PK Layout Considerations
Single Point Grounding
Use a single point ground connection from the input filter
capacitor to the area of copper connected to the SOURCE pins.
When used as an auxillary supply in a larger converter, a local
DC bus decoupling capacitor is recommended. A value of
100 nF is typical.
The bias winding should be returned directly to the input or
decoupling capacitor. This routes surge currents away from the
device during common mode line surge events.
Bypass Capacitor (CBP)
The BYPASS pin capacitor should be located as near as
possible to the BYPASS and SOURCE pins using a Kelvin
connection. No power current should flow through traces
connected to the BYPASS pin capacitor or optocoupler. If
using SMD components, a capacitor can be placed underneath
the package directly between BP and SOURCE pins.
When using a capacitor value of 1 mF or 10 mF to select the
reduced or increased current limit mode, it is recommended
that an additional 0.1 mF ceramic capacitor is placed directly
between BP and SOURCE pins.
Enable/Undervoltage Pin Node Connections
The EN/UV pin is a low-current, low-voltage pin, and noise
coupling can cause poor regulation and/or inaccurate line UV
levels. Traces connected to the EN/UV pin must be routed
away from any high current or high-voltage switching nodes,
including the drain pin and clamp components. This also
applies to the placement of the line undervoltage sense resistor
(RUV). Drain connected traces must not be routed underneath
this component.
TinySwitch-PK determines the presence of the UV resistor via a
~1 mA current into the EN/UV pin at startup. When the under-
voltage feature is not used ensure that leakage current into the
EN/UV pin is <<1mA. This prevents false detection of the
presence of a UV resistor which may prevent correct start-up.
As the use of no-clean flux may increase leakage currents (by
reducing surface resistivity) care should be taken to follow the
flux suppliers guidance, specifically avoiding flux contamination.
Placing a 100 kW, 5% resistor between BP and EN/UV pins
eliminates this requirement by feeding current >ILUV(MAX) into the
EN/UV pin.
Primary Loop Area
The area of the primary loop that connects the input filter
capacitor, transformer primary, and TinySwitch-PK device
should be kept as small as possible.
Primary Clamp Circuit
A clamp is used to limit peak voltage on the DRAIN pin at turn
off. This can be achieved by using an RCD clamp or a Zener
and diode clamp across the primary winding. In all cases, to
minimize EMI, care should be taken to minimize the loop length
from the clamp components to the transformer and the
TinySwitch-PK device.
Thermal Considerations
The four SOURCE pins are internally connected to the IC lead
frame and provide the main path to remove heat from the
device. Therefore all the SOURCE pins should be connected to
a copper area underneath the TinySwitch-PK integrated circuit
to act not only as a single point ground, but also as a heatsink.
As this area is connected to the quiet source node, it should be
Rev. A 05/07
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maximized for good heatsinking. Similarly, for axial output
diodes, maximize the PCB area connected to the cathode.
Y-Capacitor
The placement of the Y-capacitor should be directly from the
primary input filter capacitor positive terminal to the common/
return terminal of the transformer secondary. Such a placement
will route high magnitude common mode surge currents away
from the TinySwitch-PK device. Note – if an input π (C, L, C)
EMI filter is used, then the inductor in the filter should be placed
between the negative terminals on the input filter capacitors.
Optocoupler
Place the optocoupler physically close to the TinySwitch-PK
device to minimize the primary side trace lengths. Keep the
high current high voltage drain and clamp traces away from the
optocoupler to prevent noise pick up.
Output Diode
For best performance, the area of the loop connecting the
secondary winding, the Output Diode, and the Output Filter
Capacitor should be minimized. In addition, for axial diodes,
sufficient copper area should be provided at the anode and
cathode terminal of diode for heatsinking. A larger area is
preferred at the quiet cathode terminal. A large anode area can
increase high frequency radiated EMI.
Quick Design Checklist
As with any power supply design, all TinySwitch-PK designs
should be verified on the bench to make sure that component
specifications are not exceeded under worst case conditions.
The following minimum set of tests is strongly recommended:
Maximum drain voltage – Verify the VDS does not exceed
650 V at highest input voltage and peak (overload) output
power. The 50 V margin to the 700 V BVDSS specification
gives margin for design variation.
Maximum drain current – At maximum ambient temperature,
maximum input voltage, and peak output (overload) power,
verify drain current waveforms for any signs of transformer
saturation and excessive leading edge current spikes at
startup. Repeat under steady state conditions and verify that
the leading edge current spike event is below ILIMIT(Min) at the
end of the tLEB(Min). Under all conditions the maximum drain
current should be below the specified absolute maximum
ratings.
Thermal Check – At specified maximum output power,
minimum input voltage, and maximum ambient temperature,
verify that the temperature specifications are not exceeded
for TinySwitch-PK device, transformer, output diode, and
output capacitors. Enough thermal margin should be
allowed for part-to-part variation of the RDS(ON) of TinySwitch-
PK device as specified in the datasheet. Under low-line
maximum power, a maximum TinySwitch-PK device
SOURCE pin temperature of 110 °C is recommended to
allow for these variations.
Design Tools
Up-to-date information on design tools can be found at the
Power Integrations web site: www.powerint.com.
1.
2.
3.
Figure 16. Layout Considerations for TinySwitch-PK Using P Package.
TOP VIEW
PI-4675-050707
Opto-
coupler
+
-
HV
+ - DC
OUT
Input Filter Capacitor
Output
Rectifier
Safety Spacing
T
r
a
n
s
f
o
r
m
e
r
PRI
SEC
BIAS
BIAS
RUV
TinySwitch-PK
Bypass capacitor connection
to device should be short
Route connections to EN/UV pin
(including undervoltage resistor)
away from drain connected traces
Copper area for
heat sinking
Return bias winding
directly to input capacitor
Maximize hatched copper
areas ( ) for optimum
heatsinking
BP
EN/UV
Y1-
Capacitor
S
S
S
S
PRI
CBP
D
Rev. A 05/07
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TNY375-380
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Parameter Symbol
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
See Figure 14
(Unless Otherwise Specified)
Min Typ Max Units
Control Functions
Output Frequency
See Note A
fOSC
State Machine at
Highest Current
Limit Level
Average 248 264 280
kHz
pk-pk Jitter 16
fOSC-Low All Lower Current
Limit Levels
Average 124 132 140
pk-pk Jitter 8
Maximum Duty Cycle DCMAX S1 Open 62 65 %
EN/UV Pin Upper
Turnoff Threshold
Current
IDIS -150 -115 -90 mA
EN/UV Pin Voltage VEN
IEN/UV = 25 mA1.8 2.2 2.6 V
IEN/UV = -25 mA0.8 1.2 1.6
DRAIN Supply Current
IS1
EN/UV Current > IDIS (MOSFET Not
Switching) See Note B 290 mA
IS2
EN/UV Open
(MOSFET
Switching at fOSC)
See Note C
TNY375 385 520
TNY376 460 600
TNY377 570 710
TNY378 740 900
TNY379 870 1060
TNY380 1100 1350
Absolute Maximum Ratings(1,5)
DRAIN Voltage .............................................................................. -0.3 V to 700 V
DRAIN Peak Current: TNY375 .............................................................. 0.6 A
TNY376 ..............................................................0.8 A
TNY377 ...............................................................1.4 A
TNY378 ..............................................................2.2 A
TNY379 ..............................................................2.9 A
TNY380..............................................................4.3 A
EN/UV Voltage ................................................................................... -0.3 V to 9 V
EN/UV Current ........................................................... .................................. 100 mA
BP/M Voltage .................................................. ....................................-0.3 V to 9 V
Storage Temperature .............................................................-65 °C to 150 °C
Operating Junction Temperature(3) ............................... -40 °C to 150 °C
Lead Temperature(4) .....................................................................................260 °C
Notes:
1. All voltages referenced to SOURCE, TA = 25 °C.
2. Normally limited by internal circuitry.
3. 1/16 in. from case for 5 seconds.
4. Maximum ratings specified may be applied one at a time
without causing permanent damage to the product. Exposure
to Absolute Maximum Rating conditions for extended periods
of time may affect product reliability.
Thermal Impedance
Thermal Impedance: P Package:
(qJA) ................................................70 °C/W(2); 60 °C/W(3)
(qJC)(1) ............................................... ...........................11 °C/W
Notes:
1. Measured on the SOURCE pin close to plastic interface.
2. Soldered to 0.36 sq. in. (232 mm2), 2 oz. (610 g/m2) copper clad.
3. Soldered to 1 sq. in. (645 mm2), 2 oz. (610 g/m2) copper clad.
Rev. A 05/07
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TNY375-380
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Parameter Symbol
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
See Figure 14
(Unless Otherwise Specified)
Min Typ Max Units
Control Functions (cont.)
BP/M Pin Charge
Current
ICH1
VBP/M = 0 V,
TJ = 25 °C
See Note D, E
TNY375-379 -8.3 -5.4 -2.5
mA
TNY380 -9.7 -7.1 -3.9
ICH2
VBP/M = 4 V,
TJ = 25 °C
See Note D, E
TNY375-379 -5 -3.5 -1.5
TNY380 -6.6 -4.8 -2.1
BP/M Pin Voltage VBP/M See Note D 5.6 5.85 6.15 V
BP/M Pin Voltage
Hysteresis VBP/MH 0.80 0.95 1.20 V
BP/M Pin Shunt
Voltage VSHUNT IBP = 2 mA 6.0 6.4 6.7 V
EN/UV Pin Line Under-
voltage Threshold ILUV TJ = 25 °C 22.5 25 27.5 mA
Circuit Protection
Peak Current Limit
(BP/M Capacitor =
0.1 mF)
See Note E
ILIMITPEAK
TNY375
TJ = 25 °C
di/dt = 72 mA/ms
See Note F 330 355 380
mA
TNY376
TJ = 25 °C
di/dt = 91 mA/ms
See Note F 423 455 487
TNY377
TJ = 25 °C
di/dt = 117 mA/ms
See Note F 544 585 626
TNY378
TJ = 25 °C
di/dt = 143 mA/ms
See Note F 665 715 765
TNY379
TJ = 25 °C
di/dt = 169 mA/ms
See Note F 786 845 904
TNY380
TJ = 25 °C
di/dt = 195 mA/ms
See Note F 907 975 1043
Peak Current Limit
(BP/M Capacitor =
1 mF)
See Note E
ILIMITred
TNY375
TJ = 25 °C
di/dt = 72 mA/ms
See Note F 302 325 358
mA
TNY376
TJ = 25 °C
di/dt = 91 mA/ms
See Note F 330 355 391
TNY377
TJ = 25 °C
di/dt = 117 mA/ms
See Note F 423 455 501
TNY378
TJ = 25 °C
di/dt = 143 mA/ms
See Note F 544 585 644
TNY379
TJ = 25 °C
di/dt = 169 mA/ms
See Note F 665 715 787
TNY380
TJ = 25 °C
di/dt = 195 mA/ms
See Note F 786 845 930
Rev. A 05/07
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TNY375-380
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Parameter Symbol
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
See Figure 14
(Unless Otherwise Specified)
Min Typ Max Units
Circuit Protection (cont.)
Peak Current Limit
(BP/M Capacitor =
10 mF)
See Note E
ILIMITinc
TNY375
TJ = 25 °C
di/dt = 72 mA/ms
See Note F 349 375 413
mA
TNY376
TJ = 25 °C
di/dt = 91 mA/ms
See Note F 465 500 550
TNY377
TJ = 25 °C
di/dt = 117 mA/ms
See Note F 665 715 787
TNY378
TJ = 25 °C
di/dt = 143 mA/ms
See Note F 786 845 930
TNY379
TJ = 25 °C
di/dt = 169 mA/ms
See Note F 907 975 1073
TNY380
TJ = 25 °C
di/dt = 195 mA/ms
See Note F 1028 1105 1216
Power Coefficient I2f
I2f = ILIMITPEAK(TYP)
2 ×
fOSC(TYP)
BP/M Capacitor =
0.1 mF
0.9 ×
I2f I2f 1.12 ×
I2f
A2Hz
I2f = ILIMITPEAKred(TYP)
2 ×
fOSC(TYP)
BP/M Capacitor =
1 mF
0.9 ×
I2f I2f 1.16 ×
I2f
I2f = ILIMITPEAKinc(TYP)
2 ×
fOSC(TYP)
BP/M Capacitor =
10 mF
0.9 ×
I2fI2f1.16 ×
I2f
Initial Current Limit IINIT
See Figure 17
TJ = 25 °C, See Note G
0.75 ×
ILIMIT(MIN)
mA
Leading Edge Blanking
Time tLEB
TJ = 25 °C
See Note G 190 235 ns
Current Limit
Delay tILD
TJ = 25 °C
See Note G, H 200 ns
Thermal Shutdown
Temperature TSD 135 142 150 °C
Thermal Shutdown
Hysteresis TSDH 75 °C
BP/M Pin Shutdown
Threshold Current ISD 4 7 9 mA
BP/M Pin Power-Up
Reset Threshold
Voltage
VBP/M(RESET) 1.6 2.6 3.6 V
Rev. A 05/07
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TNY375-380
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Parameter Symbol
Conditions
SOURCE = 0 V; TJ = -40 to 125 °C
See Figure 14
(Unless Otherwise Specified)
Min Typ Max Units
Output
ON-State
Resistance RDS(ON)
TNY375
ID = 28 mA
TJ = 25 °C 19 22
W
TJ = 100 °C 29 33
TNY376
ID = 35 mA
TJ = 25 °C 14 16
TJ = 100 °C 21 24
TNY377
ID = 45 mA
TJ = 25 °C 7.8 9.0
TJ = 100 °C 11.7 13.5
TNY378
ID = 55 mA
TJ = 25 °C 5.2 6.0
TJ = 100 °C 7.8 9.0
TNY379
ID = 65 mA
TJ = 25 °C 3.9 4.5
TJ = 100 °C 5.8 6.7
TNY380
ID = 75 mA
TJ = 25 °C 2.6 3.0
TJ = 100 °C 3.9 4.5
OFF-State Drain
Leakage Current
IDSS1
VBP/M = 6.2 V
VEN/UV = 0 V
VDS = 560 V
TJ = 125 °C
See Note I
TNY375-376 50
mA
TNY377-378 100
TNY379-380 200
IDSS2
VBP/M = 6.2 V
VEN/UV = 0 V
VDS = 375 V,
TJ = 50 °C
See Note G, I
15
Breakdown
Voltage BVDSS
VBP = 6.2 V, VEN/UV = 0 V,
See Note J, TJ = 25 °C 700 V
DRAIN Supply Voltage 50 V
Auto-Restart
ON-Time At fOSC
tAR
TJ = 25 °C
See Note K 32 ms
Auto-Restart
Duty Cycle DCAR TJ = 25 °C 3 %
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NOTES:
For all BP/M pin capacitor values.
IS1 is an accurate estimate of device controller current consumption at no-load, since operating frequency is so low under these
conditions. Total device consumption at no-load is the sum of IS1 and IDSS2.
Since the output MOSFET is switching, it is difficult to isolate the switching current from the supply current at the DRAIN. An
alternative is to measure the BP/M pin current at 6.1 V.
BP/M pin is not intended for sourcing supply current to external circuitry.
To ensure correct current limit, it is recommended that nominal 0.1 mF / 1 mF / 10 mF capacitors are used. In addition, the BP/M
capacitor value tolerance should be equal to or better than indicated below across the ambient temperature range of the target
application. The minimum and maximum capacitor values are guaranteed by characterization.
For current limit at other di/dt values, refer to Figure 24. Measurements made with device self-biased.
This parameter is derived from characterization.
This parameter is derived from the change in current limit measured at 1X and 4X of the di/dt shown in the ILIMIT specification.
IDSS1 is the worst-case OFF state leakage specification at 80% of BVDSS and maximum operating junction temperature. IDSS2 is a
typical specification under worst-case application conditions (rectified 265 VAC) for no-load consumption calculations.
Breakdown voltage may be checked against minimum BVDSS specification by ramping the DRAIN pin voltage up to but not
exceeding minimum BVDSS.
Auto-restart on time has the same temperature characteristics as the oscillator (inversely proportional to frequency).
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
Nominal BP/M
Pin Cap Value
Tolerance Relative to Nominal
Capacitor Value
Min Max
0.1 mF-60% +100%
1 mF-50% +100%
10 mF-50% NA
Rev. A 05/07
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TNY375-380
www.powerint.com
PI-4079-080905
0.1 mF
10 V
50 V
470 W
5 W S2
470 W
NOTE: This test circuit is not applicable for current limit or output characteristic measurements.
S D
EN/UV
S
SBP/M
S
150 V
S1
2 MW
0.8
Figure 17. General Test Circuit.
Figure 18. Duty Cycle Measurement. Figure 19. Output Enable Timing.
Figure 20. Current Limit Envelope at fOSC = 132 kHz.
Rev. A 05/07
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TNY375-380
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1.1
1.0
0.9
-50 -25 0 25 50 75 100 125 150
Junction Temperature (°C)
Breakdown Voltage
(Normalized to 25 °C)
PI-2213-012301
1.2
1.0
0.8
0.6
0.4
0.2
0
-50 -25 0 25 50 75 100 125
Junction Temperature (°C)
PI-2680-012301
Output Frequency
(Normalized to 25 °C)
1
0.8
0.6
0.4
0.2
0
-50 0 50 100 150
Temperature (°C)
PI-4102-010906
1.2
Standard Current Limit
(Normalized to 25 °C)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
1 2 3 4
Normalized di/dt
PI-4268-042707
Normalized Current Limit
TNY375 72 mA/µs
TNY376 91 mA/µs
TNY377 117 mA/µs
TNY378 143 mA/µs
TNY379 169 mA/µs
TNY380 195 mA/µs
Normalized
di/dt = 1
Note: For the
normalized current
limit value, use the
typical current limit
specified for the
appropriate BP/M
capacitor.
DRAIN Voltage (V)
Drain Current (mA)
450
375
300
150
75
225
0
0 2 4 6 8 10
TCASE=25 °C
TCASE=100 °C
PI-4267-120406
TNY375 1.0
TNY376 1.33
TNY377 2.33
TNY378 3.67
TNY379 4.87
TNY380 7.33
Scaling Factors:
Drain Voltage (V)
Drain Capacitance (pF)
PI-4269-120406
0 100 200 300 400 500 600
1
10
100
1000
TNY375 1.0
TNY376 1.33
TNY377 2.33
TNY378 3.67
TNY379 4.87
TNY380 7.33
Scaling Factors:
Figure 21. Breakdown vs. Temperature. Figure 22. Frequency vs. Temperature.
Figure 23. Standard Current Limit vs. Temperature. Figure 24. Current Limit vs. di/dt.
Figure 25. Output Characteristics. Figure 26. COSS vs. Drain Voltage.
Rev. A 05/07
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TNY375-380
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150
90
120
30
60
0
0 200 400 600
DRAIN Voltage (V)
Power (mW)
PI-4270-120406
TNY375 1.0
TNY376 1.33
TNY377 2.33
TNY378 3.67
TNY379 4.87
TNY380 7.33
Scaling Factors:
1.2
1.0
0.8
0.6
0.4
0.2
0
-50 -25 0 25 50 75 100 125
Junction Temperature (°C)
PI-2698-012301
Under-Voltage Threshold
(Normalized to 25 °C)
Figure 27. Drain Capacitance Power. Figure 28. Undervoltage Threshold vs. Temperature.
Notes:
1. Package dimensions conform to JEDEC specification
MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP)
package with .300 inch row spacing.
2. Controlling dimensions are inches. Millimeter sizes are
shown in parentheses.
3. Dimensions shown do not include mold flash or other
protrusions. Mold flash or protrusions shall not exceed
.006 (.15) on any side.
4. Pin locations start with Pin 1, and continue counter-clock-
wise to Pin 8 when viewed from the top. The notch and/or
dimple are aids in locating Pin 1. Pin 3 is omitted.
5. Minimum metal to metal spacing at the package body for
the omitted lead location is .137 inch (3.48 mm).
6. Lead width measured at package body.
7. Lead spacing measured with the leads constrained to be
perpendicular to plane T.
.008 (.20)
.015 (.38)
.300 (7.62) BSC
(NOTE 7)
.300 (7.62)
.390 (9.91)
.367 (9.32)
.387 (9.83)
.240 (6.10)
.260 (6.60)
.125 (3.18)
.145 (3.68)
.057 (1.45)
.068 (1.73)
.120 (3.05)
.140 (3.56)
.015 (.38)
MINIMUM
.048 (1.22)
.053 (1.35)
.100 (2.54) BSC
.014 (.36)
.022 (.56)
-E-
Pin 1
SEATING
PLANE
-D-
-T-
P08C
DIP-8C
PI-3933-100504
D S .004 (.10)
⊕
T E D S .010 (.25) M
⊕
(NOTE 6)
.137 (3.48)
MINIMUM
Part Ordering Information
• TinySwitch Product Family
• Series Number
• Package Identifier
P Plastic DIP-8C
• Lead Finish
N Pure Matte Tim (Pb-Free)
TNY 378 P N
For the latest updates, visit our website: www.powerint.com
Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power
Integrations does not assume any liability arising from the use of any device or circuit described herein. POWER INTEGRATIONS MAKES
NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS.
Patent Information
The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered by
one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A
complete list of Power Integrations patentsmay be found at www.powerint.com. Power Integrations grants its customers a license under
certain patent rights as set forth at http://www.powerint.com/ip.htm.
Life Support Policy
POWER INTEGRATIONS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR
SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF POWER INTEGRATIONS. As used herein:
A Life support device or system is one which, (i) is intended for surgical implant into the body, or (ii) supports or sustains life, and (iii)
whose failure to perform, when properly used in accordance with instructions for use, can be reasonably expected to result in significant
injury or death to the user.
A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause
the failure of the life support device or system, or to affect its safety or effectiveness.
The PI logo, TOPSwitch, TinySwitch, LinkSwitch, DPA-Switch, PeakSwitch, EcoSmart, Clampless, E-Shield, Filterfuse, StakFET, PI Expert
and PI FACTS are trademarks of Power Integrations, Inc. Other trademarks are property of their respective companies.
©2007, Power Integrations, Inc.
1.
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Revision Notes Date
A Release Final Datasheet 5/07