ams Datasheet Page 1
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AS1310
Ultra Low Quiescent Current,
Hysteretic DC-DC Step-Up Converter
The AS1310 is an ultra low quiescent current hysteretic step-up
DC-DC converter optimized for light loads (60mA), where it
achieves efficiencies of up to 92%.
AS1310 operates from a 0.7V to 3.6V supply and supports
output voltages between 1.8V and 3.3V. Besides the available
AS1310 standard variants any variant with output voltages in
50mV steps are available.
If the input voltage exceeds the output voltage the device is in
a feed-through mode and the input is directly connected to the
output voltage.
In light load operation, the device enters a sleep mode when
most of the internal operating blocks are turned OFF in order
to save power. This mode is active approximately 50μs after a
current pulse provided that the output is in regulation.
In order to save power the AS1310 features a shutdown mode,
where it draws less than 100nA. During shutdown mode the
battery is disconnected from the output.
The AS1310 also offers adjustable low battery detection. If the
battery voltage decreases below the threshold defined by two
external resistors on pin LBI, the LBO output is pulled to logic
low.
The AS1310 is available in a TDFN (2x2) 8-pin package.
Ordering Information and Content Guide appear at end of
datasheet.
Key Benefits & Features
The benefits and features of AS1310, Ultra Low Quiescent
Current, Hysteretic DC-DC Step-Up Converter are listed below:
Figure 1:
Added Value of Using AS1310
Benefits Features
Ideal for single Li-Ion battery powered
applications
• Wide Input Voltage Range (0.7V to 3,6V)
• Feed through mode when VIN > VOUT
Extended battery life
• High Efficiency up to 92%
• Low Quiescent Current of typ. 1uA
• Low Shutdown Current of less than 100nA
Supports a variety of end applications
• Fixed output voltage range (1.8V to 3.3V)
• Output Disconnect in shutdown
• Output current: 60mA @ VIN=0.9V, VOUT=1.8V
General Description
Page 2 ams Datasheet
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AS1310 − General Description
Applications
The AS1310 is an ideal solution for single and dual cell powered
devices as blood glucose meters, remote controls, hearing aids,
wireless mouse or any light-load application.
Figure 2:
Typical Application Diagram
Over – temperature protection and
shutdown Integrated temperature monitoring
Early power-fail warning Adjustable low battery detection
Cost effective, small package • No external diode or transistor required
• 8-pin TDFN (2mm x 2mm)
Benefits Features
VIN
0.7V to 3.6V
AS1310 C2
22μF
On
Off
C1
22μF
GND
2
VOUT
1.8V to 3.3V
7
EN
8
VIN
4
VOUT
6
LBO
1
LBI
R3
Low Battery Detect
R1
R2
L1
6.8μH
LX
3
CREF
100nF
5
REF
ams Datasheet Page 3
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AS1310 − Pin Assignment
Figure 3:
Pin Diagram (Top View)
Figure 4:
Pin Description
Pin Number Pin Name Description
1LBI
Low Battery Comparator Input. 0.6V Threshold. May not be left floating. If
connected to GND, LBO is working as Power Output OK.
2GNDGround
3LXExternal Inductor Connector
4VOUT
Output Voltage. Decouple VOUT with a ceramic capacitor as close as
possible to VOUT and GND.
5REFReference Pin. Connect a 100nF ceramic capacitor to this pin.
6LBOLow Battery Comparator Output. Open-drain output.
7EN
Enable Pin. Logic controlled shutdown input.
1 = Normal operation;
0 = Shutdown; shutdown current <100nA.
8VIN
Battery Voltage Input. Decouple VIN with a 22μF ceramic capacitor as
close as possible to VIN and GND.
9NC
Exposed Pad. This pad is not connected internally. Can be left floating or
connect to GND to achieve an optimal thermal performance.
Pin Assignment
AS1310
1
2
4
3
8
7
5
6
LBI
GND
VOUT
LX
VIN
EN
REF
LBO
Exposed pad
Page 4 ams Datasheet
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AS1310 − Absolute Maximum Ratings
Stresses beyond those listed in Absolute Maximum Ratings may
cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any
other conditions beyond those indicated in Electrical
Characteristics is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device
reliability.
Figure 5:
Absolute Maximum Ratings
Parameter Min Max Units Comments
Electrical Parameters
VIN, VOUT, EN, LBI, LBO to GND -0.3 +5 V
LX, REF to GND -0.3 VOUT + 0.3 V
Input Current (latch-up
immunity) -100 100 mA Norm: JEDEC 78
Electrostatic Discharge
Electrostatic Discharge HBM ±2 kV Norm: MIL 883 E method 3015
Temperature Ranges and Storage Conditions
Thermal Resistance θJA 58 ºC/W
Junction Temperature +125 ºC
Storage Temperature Range -55 +125 ºC
Package Body Temperature +260 ºC
The reflow peak soldering
temperature (body temperature)
specified is in accordance with
IPC/JEDEC J-STD-020“Moisture/Reflow
Sensitivity Classification for
Non-Hermetic Solid State Surface
Mount Devices”.
The lead finish for Pb-free leaded
packages is matte tin (100% Sn).
Humidity non-condensing 5 85 %
Moisture Sensitive Level 1 Represents a maximum floor life
time of unlimited
Absolute Maximum Ratings
ams Datasheet Page 5
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AS1310 − Electrical Characteristics
All limits are guaranteed. The parameters with Min and Max
values are guaranteed by production tests or SQC (Statistical
Quality Control) methods.
VIN = 1.5V, C1 = C2 = 22μF, CREF = 100nF, Typical values are at
TAMB = +25ºC (unless otherwise specified). All limits are
guaranteed. The parameters with min and max values are
guaranteed with production tests or SQC (Statistical Quality
Control) methods.
Figure 6:
Electrical Characteristics
Symbol Parameter Conditions Min Typ Max Units
TAMB Operating Temperature
Range -40 +85 °C
Input
VIN Input Voltage Range 0.7 3.6 V
Minimum Startup Voltage ILOAD = 1mA, TAMB = +25°C 0.7 0.8 V
Regulation
VOUT Output Voltage Range 1.8 3.3 V
Output Voltage Tolerance
ILOAD = 10 mA, TAMB = +25°C -2 +2 %
ILOAD = 10mA -3 +3 %
VOUT Lockout Threshold(1) Rising Edge 1.55 1.65 1.75 V
Operating Current
IQ
Quiescent Current VIN
VOUT = 1.02xVOUTNOM,
REF = 0.99xVOUTNOM,
TAMB = +25°C
100 nA
Quiescent Current VOUT
VOUT = 1.02xVON, REF =
0.99xVON,
No load, TAMB = +25°C
0.8 1 1.2 μA
ISHDN Shutdown Current TAMB = +25ºC 100 nA
Electrical Characteristics
Page 6 ams Datasheet
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AS1310 − Electrical Characteristics
Note(s) and/or Footnote(s):
1. The regulator is in startup mode until this voltage is reached. Caution: Do not apply full load current until the device output > 1.75V.
2. LBO goes low in startup mode as well as during normal operation if:
- The voltage at the LBI pin is below LBI threshold.
- The voltage at the LBI pin is below 0.1V and VOUT is below 92.5% of its nominal value.
Switches
RON
NMOS VOUT = 3V 0.35 Ω
PMOS 0.5 Ω
NMOS maximum On-time 3.6 4.2 4.8 μs
IPEAK Peak Current Limit 320 400 480 mA
Zero Crossing Current 5 20 35 mA
Enable, Reference
VENH EN Input Voltage High 0.7 V
VENL EN Input Voltage Low 0.1 V
IEN EN Input Bias Current EN = 3.6V, TAMB = +25°C 100 nA
IREF REF Input Bias Current REF = 0.99xVOUTNOM,
TAMB = +25°C 100 nA
Low Battery & Power-OK
VLBI LBI Threshold Falling Edge 0.57 0.6 0.63 V
LBI Hysteresis 25 mV
ILBI LBI Leakage Current LBI = 3.6V, TAMB = +25°C 100 nA
VLBO LBO Voltage Low (2) ILBO = 1mA 20 100 mV
ILBO LBO Leakage Current LBO = 3.6V, TAMB = +25°C 100 nA
Power-OK Threshold LBI = 0V, Falling Edge 90 92.5 95 %
Thermal Protection
Thermal Shutdown 10°C Hysteresis 150 °C
Symbol Parameter Conditions Min Typ Max Units
ams Datasheet Page 7
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AS1310 − Typical Operating Characteristics
TAMB = +25°C, unless otherwise specified.
Figure 7:
Efficiency vs. Output Current; VOUT = 1.8V
Figure 8:
Efficiency vs. Output Current; VOUT = 1.8V
Typical Operating
Characteristics
40
45
50
55
60
65
70
75
80
85
90
0.01 0.1 1 10 100 1000
Output Cur r ent ( mA)
Ef f iciency (%)
Vin = 0.9V
Vi n = 1.2V
Vi n = 1.5V
L1: XPL2010-682M
40
45
50
55
60
65
70
75
80
85
90
0.01 0.1 1 10 100 1000
Output Cur r ent ( mA)
Ef f iciency (%)
Vin = 0.9V
Vi n = 1.2V
Vi n = 1.5V
L1: XPL7030-682M
Page 8 ams Datasheet
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AS1310 − Typical Operating Characteristics
Figure 9:
Efficiency vs. Output Current; VOUT = 3.0V
Figure 10:
Efficiency vs. Output Current; VOUT = 3.0V
40
45
50
55
60
65
70
75
80
85
90
95
100
0.01 0.1 1 10 100 1000
Output Cur r ent ( mA)
Ef f iciency (%)
Vin = 0.9V
Vi n = 1.2V
Vin = 1.5V
Vi n = 1.8V
Vin = 2.4V
L1: XPL2010-682M
40
45
50
55
60
65
70
75
80
85
90
95
100
0.01 0.1 1 10 100 1000
Output Cur r ent ( mA)
Ef f iciency (%)
Vin = 0.9V
Vi n = 1.2V
Vin = 1.5V
Vi n = 1.8V
Vin = 2.4V
L1: XPL7030-682M
ams Datasheet Page 9
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AS1310 − Typical Operating Characteristics
Figure 11:
Efficiency vs. Input Voltage; VOUT = 1.8V
Figure 12:
Maximum Output Current vs. Input Voltage
50
55
60
65
70
75
80
85
90
95
100
0.7 0.9 1.1 1.3 1.5 1.7 1.9
Input Voltage ( V)
Ef f iciency (%)
Iou t = 1mA
Iout=10mA
Iout=50mA
L1: XPL2010-682M
0
20
40
60
80
100
120
140
160
180
0 0.5 1 1.5 2 2.5 3
Input Voltage ( V)
O ut put Current (mA) .
Vout = 1.8 V
Vout = 3.0V
Page 10 ams Datasheet
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AS1310 − Typical Operating Characteristics
Figure 13:
Start-up Voltage vs. Output Current
Figure 14:
RON vs. Temperature
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
012345678910
Output Cur r ent ( mA)
S tar t - up V oltage ( V )
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
-40 -15 10 35 60 85
Temperature (°C)
RON ( )
PM OS
NM OS
Ω
Page 12 ams Datasheet
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AS1310 − Detailed Description
Hysteretic Boost Converter
Hysteretic boost converters are so called because comparators
are the active elements used to determine ON-OFF timing via
current and voltage measurements. There is no continuously
operating fixed oscillator, providing an independent timing
reference. As a result, a hysteretic or comparator based
converter has a very low quiescent current. In addition, because
there is no fixed timing reference, the operating frequency is
determined by external component (inductor and capacitors)
and also the loading on the output.
Ripple at the output is an essential operating component. A
power cycle is initiated when the output regulated voltage
drops below the nominal value of VOUT (0.99 x VOUT).
Inductor current is monitored by the control loop, ensuring that
operation is always dis-continuous.
The application circuit shown in Figure 2 will support many
requirements. However, further optimization may be useful,
and the following is offered as a guide to changing the passive
components to more closely match the end requirement.
Input Loop Timing
The input loop consists of the source DC supply, the input
capacitor, the main inductor, and the N-channel power switch.
The ON timing of the N-channel switch is determined by a peak
current measurement or a maximum ON time. In the AS1310,
peak current is 400mA (typ) and maximum ON time is 4.2μs
(typ). Peak current measurement ensures that the ON time
varies as the input voltage varies. This imparts line regulation
to the converter.
The fixed ON-time measurement is something of a safety
feature to ensure that the power switch is never permanently
ON. The fixed on-time is independent of input voltage changes.
As a result, no line regulation exists.
Detailed Description
ams Datasheet Page 13
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AS1310 − Detailed Description
Figure 16:
Simplified Boost DCDC Architecture
ON time of the power switch (Faraday’s Law) is given by:
sec [volts, amps, ohms, Henry]
Applying Min and Max values and neglecting the resistive
voltage drop across L1 and SW1;
SW1
SW2
CIN COUT
L1
RLOAD
VIN VOUT
0V 0V
QQ
FB
GND
IPK
(EQ1)
TON LIPK
VIN IPKRSW1 IPKRL1
+()–
--------------------------------------------------------------------
=
(EQ2)
MAXIN
MINPKMIN
MINON V
IL
T
_
_
_=
(EQ3)
MININ
MAXPKMAX
MAXON V
IL
T
_
_
_=
Page 14 ams Datasheet
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AS1310 − Detailed Description
Figure 17:
Simplified Voltage and Current Waveforms
Another important relationship is the “volt-seconds” law.
Expressed as following:
Voltages are those measured across the inductor during each
time segment. Figure 17 shows this graphically with the shaded
segments marked “A & B”. Re-arranging EQ 4:
The time segment called TWAIT in Figure 17 is a measure of the
“hold-up” time of the output capacitor. While the output
voltage is above the threshold (0.99xVOUT), the output is
assumed to be in regulation and no further switching occurs.
IPK
T
T
VOUT
VIN
0
0
TWAIT
TOFF
TON
TWAIT
TOFF SW1_on
SW2_off
SW1_off
SW2_on
V
IL
VIND_TON
VIND_TOFF
T
C
BB
A
T
C DD
VOUT Ripple
0.99VOUT_NOM
(EQ4)
VONTON VOFFTOFF
=
(EQ5)
TON
TOFF
-------------VOUT VIN
–
VIN
------------------------------
=
ams Datasheet Page 15
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AS1310 − Detailed Description
Inductor Choice Example
For the AS1310 VIN_MIN = 0.9V, VOUT_MAX = 3.3V, EQ 5 gives
TON=2.66TOFF.
Let the maximum operating on-time = 1μs.
Note that this is shorter than the minimum limit ON-time of
3.6μs. Therefore from EQ 5, TOFF = 0.376μs. Using EQ 3, LMAX is
obtained:
LMAX = 1.875μH. The nearest preferred value is 2.2μH.
This value provides the maximum energy storage for the chosen
fixed ON-time limit at the minimum VIN.
Energy stored during the ON time is given by:
Joules (Region A in Figure 17)
If the overall time period (TON + TOFF) is T, the power taken from
the input is:
Watts
Assume output power is 0.8 PIN to establish an initial value of
operating period T.
TWAIT is determined by the time taken for the output voltage to
fall to 0.99xVOUT. The longer the wait time, the lower will be the
supply current of the converter. Longer wait times require
increased output capacitance. Choose TWAIT = 10% T as a
minimum starting point for maximum energy transfer. For very
low power load applications, choose TWAIT ≥ 50% T.
Output Loop Timing
The output loop consists of the main inductor, P-channel
synchronous switch (or diode if fitted), output capacitor and
load. When the input loop is interrupted, the voltage on the LX
pin rises (Lenz’s Law). At the same time a comparator enables
the synchronous switch, and energy stored in the inductor is
transferred to the output capacitor and load. Inductor peak
current supports the load and replenishes the charge lost from
the output capacitor. The magnitude of the current from the
inductor is monitored, and as it approaches zero, the
synchronous switch is turned ON. No switching action
continues until the output voltage falls below the output
reference point (0.99 x VOUT).
Output power is composed of the DC component (Region C in
Figure 17):
PREGION_C =
Output power is also composed of the inductor component
(Region B in Figure 17), neglecting efficiency loss:
(EQ6)
E0.5LI
PK
()
2
=
(EQ7)
PIN 0.5L IPK
()
2
T
---------------------------
=
(EQ8)
VINIPK
2
-------- TOFF
T
-------------
Page 16 ams Datasheet
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AS1310 − Detailed Description
PREGION_B =
Total power delivered to the load is the sum of EQ 8 and EQ 9:
From EQ 3 (using nominal values) peak current is given by:
Substituting EQ 11 into EQ 10 and re-arranging:
0.9T incorporates a wait time TWAIT = 10% T
Output power in terms of regulated output voltage and load
resistance is:
Combining EQ 12 and EQ 13:
Symbol η reflects total energy loss between input and output
and is approximately 0.8 for these calculations. Use EQ 14 to
plot duty cycle (TON/T) changes for various output loadings and
changes to VIN.
Input Capacitor Selection
The input capacitor supports the triangular current during the
ON-time of the power switch, and maintains a broadly constant
input voltage during this time. The capacitance value is
obtained from choosing a ripple voltage during the ON-time of
the power switch. Additionally, ripple voltage is generated by
the equivalent series resistance (ESR) of the capacitor. For worst
case, use maximum peak current values from the datasheet.
Using TON = 1μs, and IPEAK = 480mA, and VRIPPLE = 50mV, EQ 15
yields:
CIN = 9.6μF
Nearest preferred would be 10μF.
(EQ9)
0.5L IPK
()
2
T
---------------------------
(EQ10)
PTOTAL VINIPK
2
-------- TOFF
T
-------------0.5L IPK
()
2
T
---------------------------
+=
(EQ11)
IPK TONVIN
L
---------------------
=
(EQ12)
PTOTAL V2INTON
2TL
----------------------- 0.9T()=
(EQ13)
POUT V2OUT
RLOAD
------------------
=
(EQ14)
V2OUT
RLOAD
------------------V2INTON
2TL
----------------------- 0.9T()η=
(EQ15)
CIN IPEAKTON
VRIPPLE
--------------------------
=
(EQ16)
ESRPKESRRIPPLEPK RIV =
__
ams Datasheet Page 17
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AS1310 − Detailed Description
Typically, the ripple due to ESR is not dominant. ESR for the
recommended capacitors (Murata GMR), ESR = 5mΩ to 10mΩ.
For the AS1310, maximum peak current is 480mA. Ripple due
to ESR is 2.4mV to 4.8mV.
Ripple at the input propagates through the common supply
connections, and if too high in value can cause problems
elsewhere in the system. The input capacitance is an important
component to get right.
Output Capacitor Selection
The output capacitor supports the triangular current during the
OFF-time of the power switch (inductor discharge period), and
also the load current during the wait time (Region D in
Figure 17) and ON-time (Region A in Figure 17) of the power
switch.
Note(s): There is also a ripple component due to the equivalent
series resistance (ESR) of the capacitor.
Summary
User Application Defines:
VINmin, VINmax, VOUTmin, VOUTmax, ILOADmin, ILOADmax
Inductor Selection:
Select Max on-time = 0.5μs to 3μs for AS1310. Use EQ 3 to
calculate inductor value.
Use EQ 5 to determine OFF-time.
Use EQ 6 to check that power delivery matches load
requirements assume 70% conversion efficiency.
Use EQ 13 to find overall timing period value of T at min VIN and
max VOUT for maximum load conditions.
Input Capacitor Selection:
Choose a ripple value and use EQ 14 to find the value.
Output Capacitor Selection:
Determine TWAIT via EQ 6 or EQ 13, and use EQ 16 to find the
value.
(EQ17)
NOMOUT
WAITONLOAD
OUT VTTI
C
_
)99.01( )(
−
+
=
Page 18 ams Datasheet
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AS1310 − Application Information
The AS1310 is available with fixed output voltages from 1.8V to
3.3V in 50mV steps.
Figure 18:
AS1310 Block Diagram
AS1310 Features
Shutdown. The part is in shutdown mode while the voltage at
pin EN is below 0.1V and is active when the voltage is higher
than 0.7V.
Note(s): EN can be driven above VIN or VOUT, as long as it is
limited to less than 3.6V.
Output Disconnect and Inrush Limiting. During shutdown
VOUT is going to 0V and no current from the input source is
running through the device. This is true as long as the input
voltage is higher than the output voltage.
Feedthrough Mode. If the input voltage is higher than the
output voltage the supply voltage is connected to the load
through the device. To guarantee a proper function of the
AS1310 it is not allowed that the supply exceeds the maximum
allowed input voltage (3.6V).
In this feedthrough mode the quiescent current is 35μA (typ.).
The device goes back into step-up mode when the oputput
voltage is 4% (typ.) below VOUTNOM.
Application Information
V
IN
0.7V to 3.6V
Driver &
Con trol
Logic
Imax
Detection
Zero
Crossing
Detector
Startup
Circuitry
+
-
+
-
VREF
C
IN
22µF
GND
REF
C
REF
100nF
LX
L1 6.8µF
LBI
VIN
V
OUT
1.8V to 3.3V
VOUT
LBO
R3
C
OUT
22µF
+
-
AS1310
ON
OFF
EN
0.6V
92. 5% VREF
100mV
ams Datasheet Page 19
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AS1310 − Application Information
Power-OK and Low-Battery-Detect Functionality
LBO goes low in startup mode as well as during normal
operation if:
• The voltage at the LBI pin is below LBI threshold (0.6V).
This can be used to monitor the battery voltage.
• LBI pin is connected to GND and VOUT is below 92.5% of
its nominal value. LBO works as a power-OK signal in this
case.
The LBI pin can be connected to a resistive-divider to monitor
a particular definable voltage and compare it with a 0.6V
internal reference. If LBI is connected to GND an internal
resistive-divider is activated and connected to the output.
Therefore, the Power-OK functionality can be realized with no
additional external components.
The Power-OK feature is not active during shutdown and
provides a power-ON-reset function that can operate down to
VIN = 0.7V. A capacitor to GND may be added to generate a
power-ON-reset delay. To obtain a logic-level output, connect
a pull-up resistor R3 from pin LBO to pin VOUT. Larger values for
this resistor will help to minimize current consumption; a 100kΩ
resistor is perfect for most applications (see Figure 20).
For the circuit shown in the left of Figure 19, the input bias
current into LBI is very low, permitting large-value
resistor-divider networks while maintaining accuracy. Place the
resistor-divider network as close to the device as possible. Use
a defined resistor for R2 and then calculate R1 as:
Where: VLBI is 0.6V ±30mV
(EQ18)
R1R2VIN
VLBI
------------ 1–
⋅=
Page 20 ams Datasheet
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AS1310 − Application Information
Figure 19:
Typical Application with Adjustable Battery Monitoring
Figure 20:
Typical Application with LBO working as Power-OK
LBI
OUT
EN
L1
6.8µH
C
REF
100nF
REF
LX
ON
OFF
V
IN
0.7V to 3.6V
AS1310 V
OUT
1.8V to 3.3V
0V
VIN
GND C
OUT
22µF
C
IN
22µF
LBO Low Battery
Detect
LBI
OUT
EN
L1
6.8µH
C
REF
100nF
REF
LX
ON
OFF
V
IN
0.7V to 3.6V
AS1310 V
OUT
1.8V to 3.3V
0V
VIN
GND C
OUT
22µF
C
IN
22µF
LBO Power OK
Output
ams Datasheet Page 21
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AS1310 − Application Information
Thermal Shutdown
To prevent the AS1310 from short-term misuse and overload
conditions the chip includes a thermal overload protection. To
block the normal operation mode all switches will be turned
OFF. The device is in thermal shutdown when the junction
temperature exceeds 150°C. To resume the normal operation
the temperature has to drop below 140°C.
A good thermal path has to be provided to dissipate the heat
generated within the package. Otherwise it’s not possible to
operate the AS1310 at its usable maximal power. To dissipate
as much heat as possible from the package into a copper plane
with as much area as possible, it’s recommended to use multiple
v i as i n t he p ri n t e d c i r cu i t b o a rd . I t ’s a l s o r e c om m e n d ed t o s ol d e r
the Exposed Pad (pin 9) to the GND plane.
Note(s): Continuing operation in thermal overload conditions
may damage the device and is considered bad practice.
Always ON Operation
In battery powered applications with long standby times as
blood glucose meters, remote controls, soap dispensers, etc., a
careful battery management is required. Normally a complex
power management control makes sure that the DCDC is only
switched ON, when it is really needed. With AS1310 this
complex control can be saved completely, since the AS1310 is
perfectly suited to support always-ON operations of the
application. The efficiency at standby currents of e.g. 2μAs is
around 45% (see Figure 21).
Figure 21:
Efficiency vs. Output Current for Always ON Operation;
VOUT=3.3V
0
10
20
30
40
50
60
70
80
90
100
0.001 0.01 0.1 1 10 100
Output Cur r ent ( mA)
Ef f iciency (%)
V in = 1.1V
Vin = 1.5V
L1: XPL2010-682M
Page 22 ams Datasheet
Document Feedback [v1-11] 2015-Jan-28
AS1310 − Application Information
Component Selection
Only four components are required to complete the design of
the step-up converter. The low peak currents of the AS1310
allow the use of low value, low profile inductors and tiny
external ceramic capacitors.
Inductor Selection
For best efficiency, choose an inductor with high frequency core
material, such as ferrite, to reduce core losses. The inductor
should have low DCR (DC resistance) to reduce the I²R losses,
and must be able to handle the peak inductor current without
saturating. A 6.8μH inductor with a >500mA current rating and
<500mΩ DCR is recommended.
Figure 22:
Recommended Inductors
Part Number LDCR Current
Rating Dimensions
(L/W/T) Manufacturer
XPL2010-682M 6.8μH 421mΩ0.62A 2.0x1.9x1.0 mm
Coilcraft
www.coilcraft.com
EPL2014-682M 6.8μH 287mΩ0.59A 2.0x2.0x1.4 mm
LPS3015-682M 6.8μH 300mΩ0.86A 3.0x3.0x1.5 mm
LPS3314-682M 6.8μH 240mΩ0.9A 3.3x3.3x1.3 mm
LPS4018-682M 6.8μH 150mΩ1.3A 3.9x3.9x1.7 mm
XPL7030-682M 6.8μH 59mΩ9.4A 7.0x7.0x3.0 mm
LQH32CN6R8M53L 6.8μH 250mΩ0.54A 3.2x2.5x1.55 mm
Murata
www.murata.com
LQH3NPN6R8NJ0L 6.8μH 210mΩ0.7A 3.0x3.0x1.1 mm
LQH44PN6R8MJ0L 6.8μH 143mΩ0.72A 4.0x4.0x1.1 mm
ams Datasheet Page 23
[v1-11] 2015-Jan-28 Document Feedback
AS1310 − Application Information
Capacitor Selection
The convertor requires three capacitors. Ceramic X5R or X7R
types will minimize ESL and ESR while maintaining capacitance
at rated voltage over temperature. The VIN capacitor should be
22μF. The VOUT capacitor should be between 22μF and 47μF. A
larger output capacitor should be used if lower peak to peak
output voltage ripple is desired. A larger output capacitor will
also improve load regulation on VOUT. See Figure 23 for a list of
capacitors for input and output capacitor selection.
Figure 23:
Recommended Input and Output Capacitors
On the pin REF a 10nF capacitor with an Insulation resistance
>1GΩ is recommended.
Figure 24:
Recommended Capacitors for REF
Layout Considerations
Relatively high peak currents of 480mA (max) circulate during
normal operation of the AS1310. Long printed circuit tracks can
generate additional ripple and noise that mask correct
operation and prove difficult to “de-bug” during production
testing. Referring to Figure 2, the input loop formed by C1, VIN
and GND pins should be minimized. Similarly, the output loop
formed by C2, VOUT and GND should also be minimized. Ideally
both loops should connect to GND in a “star” fashion. Finally, it
is important to return CREF to the GND pin directly.
Part Number CTC
Code Rated
Voltage Dimensions
(L/W/T) Manufacturer
GRM21BR60J226ME99 22μF X5R 6.3V 0805, T=1.25mm
Murata
www.murata.com
GRM31CR61C226KE15 22μF X5R 16V 1206, T=1.6mm
GRM31CR60J475KA01 47μF X5R 6.3V 1206, T=1.6mm
Part Number CTC
Code Insulation
Resistance Rated
Voltage Dimensions
(L/W/T) Manufacturer
GRM188R71C104KA01 100nF X7R >5GΩ16V 0603,
T=0.8mm Murata
www.murata.com
GRM31CR61C226KE15 100nF X7R >5GΩ50V 0805,
T=1.25mm
Page 24 ams Datasheet
Document Feedback [v1-11] 2015-Jan-28
AS1310 − Package Drawings & Markings
The device is available in a TDFN (2x2) 8-pin package.
Figure 25:
Drawings and Dimensions
Note(s) and/or Footnote(s):
1. Dimensioning & tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. Coplanarity applies to the exposed heat slug as well as the terminal.
4. Radius on terminal is optional.
5. N is the total number of terminals.
Package Drawings & Markings
Symbol Min Nom Max
A 0.51 0.55 0.60
A1 0.00 0.02 0.05
A3 0.15 REF
L 0.225 0.325 0.425
b 0.18 0.25 0.30
D2.00 BSC
E2.00 BSC
e0.50 BSC
D2 1.45 1.60 1.70
E2 0.75 0.90 1.00
aaa - 0.15 -
bbb - 0.10 -
ccc 0.10 -
ddd - 0.05 -
eee - 0.08 -
fff - 0.10 -
N8
X X X
A2
Green
RoHS
ams Datasheet Page 25
[v1-11] 2015-Jan-28 Document Feedback
AS1310 − Ordering & Contact Information
The device is available as the standard products shown in
Figure 26.
Figure 26:
Ordering Information
Note(s) and/or Footnote(s):
1. On request
2. Non-standard devices are available between 1.8V and 3.3V in 50mV steps.
Buy our products or get free samples online at:
www.ams.com/ICdirect
Technical Support is available at:
www.ams.com/Technical-Support
Provide feedback about this document at:
www.ams.com/Document-Feedback
For further information and requests, e-mail us at:
ams_sales@ams.com
For sales offices, distributors and representatives, please visit:
www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
Ordering Code Marking Output Description Delivery
Form Package
AS1310-BTDT-18 A2 1.8V
Ultra Low Quiescent
Current,
Hysteretic DC-DC
Step-Up Converter
Tape and Reel TDFN (2x2) 8-pin
AS1310-BTDT-20 A8 2.0V Tape and Reel TDFN (2x2) 8-pin
AS1310-BTDT-25 A9 2.5V Tape and Reel TDFN (2x2) 8-pin
AS1310-BTDT-27 A7 2.7V Tape and Reel TDFN (2x2) 8-pin
AS1310-BTDT-30 A6 3.0V Tape and Reel TDFN (2x2) 8-pin
AS1310-BTDT-33(1) tbd 3.3V Tape and Reel TDFN (2x2) 8-pin
AS1310-BTDT-xx(2) tbd tbd Tape and Reel TDFN (2x2) 8-pin
Ordering & Contact Information
Page 26 ams Datasheet
Document Feedback [v1-11] 2015-Jan-28
AS1310 − RoHS Compliant & ams Green Statement
RoHS: The term RoHS compliant means that ams AG products
fully comply with current RoHS directives. Our semiconductor
products do not contain any chemicals for all 6 substance
categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to
be soldered at high temperatures, RoHS compliant products are
suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br): ams Green
defines that in addition to RoHS compliance, our products are
free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous
material).
Important Information: The information provided in this
statement represents ams AG knowledge and belief as of the
date that it is provided. ams AG bases its knowledge and belief
on information provided by third parties, and makes no
representation or warranty as to the accuracy of such
information. Efforts are underway to better integrate
information from third parties. ams AG has taken and continues
to take reasonable steps to provide representative and accurate
information but may not have conducted destructive testing or
chemical analysis on incoming materials and chemicals. ams AG
and ams AG suppliers consider certain information to be
proprietary, and thus CAS numbers and other limited
information may not be available for release.
RoHS Compliant & ams Green
Statement
ams Datasheet Page 27
[v1-11] 2015-Jan-28 Document Feedback
AS1310 − Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141
Unterpremstaetten, Austria-Europe. Trademarks Registered. All
rights reserved. The material herein may not be reproduced,
adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent
indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied,
or by description regarding the information set forth herein.
ams AG reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing
this product into a system, it is necessary to check with ams AG
for current information. This product is intended for use in
commercial applications. Applications requiring extended
temperature range, unusual environmental requirements, or
high reliability applications, such as military, medical
life-support or life-sustaining equipment are specifically not
recommended without additional processing by ams AG for
each application. This product is provided by ams AG “AS IS”
and any express or implied warranties, including, but not
limited to the implied warranties of merchantability and fitness
for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any
damages, including but not limited to personal injury, property
damage, loss of profits, loss of use, interruption of business or
indirect, special, incidental or consequential damages, of any
kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation
or liability to recipient or any third party shall arise or flow out
of ams AG rendering of technical or other services.
Copyrights & Disclaimer
Page 28 ams Datasheet
Document Feedback [v1-11] 2015-Jan-28
AS1310 − Document Status
Document Status Product Status Definition
Product Preview Pre-Development
Information in this datasheet is based on product ideas in
the planning phase of development. All specifications are
design goals without any warranty and are subject to
change without notice
Preliminary Datasheet Pre-Production
Information in this datasheet is based on products in the
design, validation or qualification phase of development.
The performance and parameters shown in this document
are preliminary without any warranty and are subject to
change without notice
Datasheet Production
Information in this datasheet is based on products in
ramp-up to full production or full production which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade
Datasheet (discontinued) Discontinued
Information in this datasheet is based on products which
conform to specifications in accordance with the terms of
ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and
should not be used for new designs
Document Status
ams Datasheet Page 29
[v1-11] 2015-Jan-28 Document Feedback
AS1310 − Revision Information
Note(s) and/or Footnote(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Changes from 1-10 (2014-Nov-11) to current revision 1-11 (2015-Jan-28) Page
Updated Figure 18 18
Updated Figures 19 & 20 20
Revision Information
Page 30 ams Datasheet
Document Feedback [v1-11] 2015-Jan-28
AS1310 − Content Guide
1 General Description
1 Key Benefits & Features
2 Applications
3 Pin Assignment
4Absolute Maximum Ratings
5 Electrical Characteristics
7 Typical Operating Characteristics
12 Detailed Description
12 Hysteretic Boost Converter
12 Input Loop Timing
15 Inductor Choice Example
15 Output Loop Timing
16 Input Capacitor Selection
17 Output Capacitor Selection
17 Summary
18 Application Information
18 AS1310 Features
19 Power-OK and Low-Battery-Detect Functionality
21 Thermal Shutdown
21 Always ON Operation
22 Component Selection
22 Inductor Selection
23 Capacitor Selection
23 Layout Considerations
24 Package Drawings & Markings
25 Ordering & Contact Information
26 RoHS Compliant & ams Green Statement
27 Copyrights & Disclaimer
28 Document Status
29 Revision Information
Content Guide
