AS1331
300mA Buck-Boost Synchronous DC/DC Converters
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 1 - 16
Datasheet
1 General Description
This special device is a synchronous buck-boost DC/DC
converter which can handle input voltages above, below ,
or equal to the output voltage.
Due to the internal structure of the AS1331 which is
working continuously through all operation modes this
device is ideal for dual or triple cell alkaline/NiCad/NiMH
as well as single cell Li-Ion battery applications.
Because of the implemented Power Save Mode, the
solution footprint and the component count is minimized
and also over a wide range of load currents a high
conversion efficiency is provided.
The device includes two N-channel MOSFET switches
and two P-channel switches. Also following features are
implemented: a quiescent current of typically 22µA
(ideal for battery power applications), a shutdown
current less than 1µA, current limiting, thermal shutdown
and output disconnect.
The AS1331 is available in a 10-p in 3x3mm TDF N
package with fixed and adjustable output voltage.
2 Key Features
! Input Voltage Range: 1.8V to 5.5V
! Output Voltages:
- Fixed: 2.5V, 3.0V, 3.3V
- Adjustable: 2.5V to 3.3V
! Output Current: 300mA @ 3.3V
! Up to 90% efficiency
! Power Good
! Output Disconnection in Shutdown
! Automatic transition between Buck and Boost mode
! Ultra Low Quiescent Current: 22µA, Shutdown Cur-
rent <1µA (Active Low)
! Short-Circuit Protection
! Low Battery detection
! Over Temperature Protection
! 10-pin 3x3mm TDFN package
3 Applications
The AS1331 is an ideal solution for handheld
computers, handheld instruments, portable musi c
players and PDA s. Two and three cell Alkaline, NiCd or
NiMH or single cell Li battery powered products.
Figure 1. AS1331 - Typical Application Diagram
1.8V to 5.5V
AS1331-AD C2
22µF
R2
R1
On
Off
C1
10µF
PGND
3
SW2
2
VOUT
2.5V to 3.3V
6
EN
10
FB
5
VIN
1
VOUT
SW1
4
L1
6.8µH
8
LBO
7
LBI
GND
9
R3
Low Battery Detect
R4
R5
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 2 - 16
AS1331
Datasheet - Pin A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
Pin Descriptions
Table 1. Pin Descriptions
Pin
Name Pin
Number Description
VOUT 1Output of the Buck/Boos t Converter.
SW1 2Buck/Boost Switch Pin. Connect the inductor from SW1 to SW2
PGND 3Power Ground. Both GND pins must be connected.
SW2 4Buck/Boost Switch Pin. Connect the inductor from SW1 to SW2. An
optional Schottky diode can be connected between this pin and VOUT to
increase efficiency.
VIN 5Input Supply Pin. A minimum 2.2µF capacitor should be placed between
VIN and GND.
EN 6 Enable Pin. Logic controlled shutdown input.
1 = Normal operation;
0 = Shutdo w n ; qu i escent current <1µA.
LBI 7 Low Battery Comperator Input. 1.25V Threshold. May no t be left floating.
If connected to GND LBO is working as Output Power okay.
LBO 8 Low Battery Comperator Outp ut . This open-drain output is low when the
voltage on LBI is less than 1.25V.
GND 9 Ground. Both GND pins must be connected.
FB 10
Feedback Pin. Feedback input for the adjustable version. Connect a
resistor divider tap to this pin. The output voltage can be adjusted from 2.5V
to 3.3V by: VOUT = 1.25V[1 + (R1/R2)]
Note: For the fixed Output Voltage Version contact this pin to VOUT.
NC 11 Exposed Pad. This pad is not connected internally. It can be used for
ground connection between GND and PGND.
AS1331
SW2 2
SW1 4
VOUT 1
PGND 3
LBI
7
LBO
8
GND
9
FB
10
11
VIN 5EN
6
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AS1331
Datasheet - Ab so lu te Ma xi mu m R at in gs
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 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 on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter Min Max Units Notes
SW1, SW2, VIN, VOUT, EN -0.3 +7 V
PGND to GND -0.3 +0.3 V
SW1, SW2 -0.3 +7 V
ESD 4 kV HBM MIL-Std. 883E 3015.7 methods
Thermal Resistance θJA +33 ºC/W
Junction Temperature +150 ºC
Operating Temperature Range -40 85 ºC
Storage Temperature Range -65 +125 ºC
Package Body Temperature +260 ºC
The reflow peak soldering temperature
(body temperature) specified is in
accordance with IPC/JEDEC J-STD-
020D “Moisture/Reflow Sensitivity
Classification for Non-Hermetic So lid
State Surfa ce Mount Devices”.
The lead finish for Pb-free leaded
packages is matte tin (100% Sn).
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 4 - 16
AS1331
Datasheet - Ele c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
VIN = 3.6V, VOUT = 3.3V, TAMB = -40°C to +85ºC. Typical values are at TAMB = +25ºC. Unless otherwise specified.
Table 3. Electrical Characteristics
Symbol Parameter Conditions Min Typ Max Units
Input
VIN Input Voltage Range 1.8 5.5 V
Minimum Startup Voltage ILOAD < 1mA 1.6 1.8 V
VUV Undervoltage Lockout
Threshold1VIN decreasing 1.5 1.6 1.7 V
Regulation
VOUT
Output Voltage Adjustable
Version 2.50 3.30 V
Output Voltage 3.3V
No Load
3.201 3.3 3.399 V
Output Voltage 3.0V 2.910 3.0 3.090 V
Output Voltage 2.5V 2.425 2.5 2.575 V
VFB FB Voltage Adjustable version No Load 1.212 1.25 1.288 V
IFB FB Input Current Adjustable
Version VFB = 1.3V, TAMB = 25°C 1 100 nA
VOUT Lockout Threshold2Rising Edge 2.0 2.15 2.3 V
Operating Current
IQQuiescent Current VIN VIN = 5V 26µA
Quiescent Current VOUT VIN = 5V, VOUT = 3.6V, VFB = 1.3V 20 32 µA
ISHDN Shutdown Current EN = 0V, VOUT = 0V, TAMB = +25ºC 0.01 1 µA
Switches
IMOS MOS Switch Leakage VIN = 5V, TAMB=25°C, Switches A-D 0.01 1 µA
RON
NMOS B, C VIN = 5V 0.13 Ω
PMOS A VIN = 5V 0.17 Ω
PMOS D VOUT = 3.3V 0.21 Ω
IPEAK Peak Cur ren t Li mi t L = 6.8µH, VIN = 5V 450 600 750 mA
Enable
VENH EN Input High 1.4 V
VENL EN Input Low 0.4 V
IEN EN Input Current EN = 5.5V, TAMB = 25°C 1 100 nA
Low Battery & Power-OK
VLBI LBI Threshold Falling Edge 1.212 1.25 1.288 V
LBI Hysteresis 10 mV
LBI Leakage Current LBI = 5.5V, TAMB = 25°C 1 100 nA
LBO Voltage Low3ILBO = 1mA 0.05 0.2 V
LBO Leakage Current LBO = 5.5V, TAMB = 25°C 1 100 nA
Power-OK Threshold LBI = 0V, Falling Edge 90 92.5 95 %
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 5 - 16
AS1331
Datasheet - Ele c t r i c a l C h a r a c t e r i s t i c s
Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or
SQC (Statistical Quality Control) methods.
Thermal Protection
Thermal Shutdown 10°C Hysteresis 145 °C
1. If the input voltage falls below this value during normal operation the device goes in startup mode.
2. The regulator is in startup mode until this voltage is reached. Caution: Do not apply full load current until the
device output > 2.3V
3. LBO goes low in startup mode as well as during normal opera tion if:
1) The voltage at the LBI pin is below LBI threshold.
2) The voltage at the LBI pin is below 0.1V and VOUT is below 92.5% of its nominal value.
Table 3. Electrical Characteristics
Symbol Parameter Conditions Min Typ Max Units
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AS1331
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
7 Typical Operating Characteristics
Circuit of Figure 24 on page 12, VIN = 2.4V, VOUT = 3.3V, TAMB = +25°C, unless otherwise specified.
Figure 3. Efficiency vs. Output Current; VOUT = 2.5V Figure 4. Efficiency vs. Output Current; VOUT = 3.0V
30
40
50
60
70
80
90
100
0.1 1 10 100 1000
Output Current (mA )
Efficiency (%)
Vin = 1.8V
Vin = 3.6V
Vin = 5.5V
30
40
50
60
70
80
90
100
0.1 1 10 100 1000
Output Current (mA )
Efficiency (%)
Vin = 1.8V
Vin = 3.6V
Vin = 5.5V
Figure 5. Efficiency vs. Output Current; VOUT = 3.3V Figure 6. Efficiency vs. Input Voltage
30
40
50
60
70
80
90
100
0.1 1 10 100 1000
Output Current (mA )
Efficiency (%)
Vin = 1.8V
Vin = 3.6V
Vin = 5.5V
30
40
50
60
70
80
90
100
1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4
Input Volt age ( V)
Efficiency (%)
Iout = 10m A
Iout = 100m A
Iout = 300m A
Figure 7. IOUT max vs. Input Voltage Figure 8. Sleep Currents vs. Input Voltage
0
100
200
300
400
500
1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4
Input Volt age ( V)
O ut put Current max (mA)
0
5
10
15
20
25
30
1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4
I n put Voltage (V)
Sleep Current (µA)
IVIN
IVOUT
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AS1331
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 9. IIN Short Circuit vs. Input Voltage Figure 10. VOUT Ripple vs. Input Voltage
0
5
10
15
20
25
30
1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4
I n put Voltage (V)
I nput Current (mA)
0
50
100
150
200
250
1.5 2 2.5 3 3.5 4 4.5 5 5.5
Input Volt age ( V)
Vout Ripple V olt age ( m V )
10uF / Vpp
22uF / Vpp
47uF / Vpp
Figure 11. Load Regulation vs. Load Current Figure 12. VOUT Regulation vs. Tempera tu r e
3.24
3.26
3.28
3.3
3.32
3.34
3.36
3.38
0.1 1 10 100 1000
Load Cur rent (mA)
Output Voltage ( V )
Vout - 10uF
Vout - 22uF
Vout - 47uF 2
2.25
2.5
2.75
3
3.25
3.5
-45 -30 -15 0 15 30 45 60 75 90
T emperat ur e (° C)
Output Voltage ( V )
VOUT = 3.3V
VOUT = 3.0V
VOUT = 2.5V
Figure 13. IFB vs. Temperature; VIN = 5V Figure 14. EN Pin Threshold
-0.2
-0.1
0
0.1
0.2
0.3
0.4
-45 -30 -15 0 15 30 45 60 75 90
Temper ature (°C)
F B Input Current (µA)
3.6V
5.0V
5.5V
0.6
0.7
0.8
0.9
1
-45 -30 -15 0 15 30 45 60 75 90
Temper ature ( °C)
Thres hold V oltage ( V )
up-ON
down-OFF
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AS1331
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 15. VIN = 4.4V, VOUT = 3.3V, IOUT = 200mA Figure 16. VIN = 4.4V, VOUT = 3.3V, IOUT = 50mA
5µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
5µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
Figure 17. VIN = 3.6V, VOUT = 3.3V, IOUT = 200mA Figure 18. VIN = 3.6V, VOUT = 3.3V, IOUT = 50mA
5µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
5µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
Figure 19. VIN = 2.5V, VOUT = 3.3V, IOUT = 200mA Figure 20. VIN = 2.5V, VOUT = 3.3V, IOUT = 50mA
5µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
5µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
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AS1331
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 21. Shorted Output; VIN = 3.6V Figure 22. Startup; VIN = 3.6V, Rload = 3.3kΩ
1µs/Div
5V/Div
200mV/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
500µs/Div
5V/Div
2V/Div
SW2
ICOIL SW1VOUT
5V/Div
200mA/Div
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AS1331
Datasheet - D et a i l e d De s c r i p t i o n
8 Detailed Description
The synchronous buck-boost converter AS1331 uses a Power Save Mode control technique to reach a high efficiency
over a wide dynamic range of load currents. The output voltage is monit ored by a comparator with 3% accuracy. The
Power Save Mode puts the device into “sleep mode” when VOUT is above its programmed reference thresh old.
Meaning, the switching is stopped and only quiescent current is drawn from the power source. The switching is started
again when VOUT drops below the referen c e threshold and the out put capacitor is charged again.
The numbers of current pulses which are necessary to load the output capacitor are set by the value of the output
capacitor, the load current, and the comparator hysteresis (~1%).
Figure 23. AS1331 - Block Diagram - Fixed Output Voltage
Modes of Operation
When VOUT drops below the reference threshold, the AS1331 switches on the transist ors SW A and SW C until the
inductor current reaches app roximately 400mA. In the next step SW A and SW D are closed and depending on the
difference between VIN and VOUT the inductor current raises, falls or stays constant.
VIN > VOUT: The inductor current is going up to 600mA.
VIN ~ VOUT: The device stops after 2µs.
VIN < VOUT: The inductor current falls down to 0mA.
If the inductor current is not 0mA, the transistors SW B and SW D are closed to ramp down the current to zero. If VOUT
is still below the threshold voltage the next cycle is started. If I MAX (600mA) wasn’t reached in the previous cycle, SW A
and SW D are closed until the inductor current is 600mA.
Note: The 4-switch-mode (SW A+SW C => SW B+SW D => SW A + SW C...) and also the buck-mode (SW A+SW D
=> SW B+SW D => SW A+SW D...) are never used.
Start-Up Mode
At start-up the switch SW D is disabled and its diode is used to transfer current to the output capacitor until VOUT
reaches approximately 2.15V. The inductor current is controlled by an alternate algorithm during start-up.
Note: Do not apply loads >1mA until VOUT = 2.3V is reached.
VIN
SW1 SW2
SW A
SW B
SW C
SW D
VIN
VIN
1.6V
600mA
VOUT
PGND GND
EN
Peak
Current
Limit
UVLO
State
Machine
and
Logic
VBEST
Gate Drivers
and
Anticross
Conduction IZERO
Detect
1.25V
Thermal Shutdown
Shutdown
VOUT
VBEST
R1
R2
FB
VOUT
Comp
AS1331
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AS1331
Datasheet - D et a i l e d De s c r i p t i o n
Other AS1331 Features
Shutdown
The part is in shutdown mode while the voltage at pin EN is below 0.4V and is active when the voltage is higher than
1.4V.
Note: EN can be driven above VIN or VOUT, as long as it is limited to less than 5.5V.
Output Disconnect and Inrush Limiting
During shutdown VOUT is going to 0V so that no current from the input source is running thru the device. The inrush
current is also limited at turn-on mode to minimize the surge currents seen by the input supply. These features of the
AS1331 are realized by opening both P-channel MOSFETs of the rectifiers, allowing a t ru e output disconnect.
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 thresho ld (1.25V). This can be used to monitor the battery voltage.
- LBI pin is connected to GND and VOUT is belo w 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
1.25V 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 realised with no addition al external components.
The Power-OK feature is not active during shutdown and provides a power-on-reset function that can operate down to
VIN = 1.8V. 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 from pin LBO to pin VOUT. Larger values for this resistor will help to minimize current
consumption; a 100k Ω resist or is perf ect for most applications (see Figure 25 on page 12).
For the circuit shown in the left of Figure 24 on page 12, 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 defin ed resistor for R5 and then calculate R 4 as:
Where:
VLBI (the internal sense reference voltage) is 1.25V.
In case of the LBI pin is connecte d to GND, an internal re sistor-devider network is act ivated and compares the output
voltage with a 92.5% voltage threshold. For this particular Power-OK application, no external resistive components are
necessary.
Thermal Shutdown
To prevent the AS1331 from short-term misuse and overload conditi ons the chip includes a thermal overl oad
protection. To block the normal operation mode all switches will be turned off. The device is in thermal shutdown when
the junction temperature exceeds 145°C. To resume the normal operation the temperature has to drop below 135°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 AS1331 at its useable maximal power. To dissipate as much heat as possible away from the package
into a copper plane with as much area as possible, it’s recommended to use multiple vias in the prin ted circuit board.
It’s also recommended to solder the Exposed Pad (pin 11) to the GND plane.
Note: Continuing operation in t hermal overload conditions may damage the device and is considered bad practice.
(EQ 1)
R4R5VIN
VLBI
----------- 1
⎝⎠
⎛⎞
=
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 12 - 16
AS1331
Datasheet - D et a i l e d De s c r i p t i o n
Output Voltage Selection
The AS1331 is available in two versions (see Ordering Information on page 15). One version can only operate at one
fixed output voltage (see Figure 25) and the other version can operate with user-adjustable output voltages from 2.5V
to 3.3V by connecting a voltage divider between the pins VOUT and FB (see Figure 24).
Figure 24. LiIon to Adjustable Output Voltage
The output voltage can be adjusted by select ing different values for R1 and R2.
Calculate VOUT by:
Where:
VFB = 1.25V, VOUT = 2.5V to 3.3V;
R2 (the predefined resistor in th e resistor devider) should be 270kΩ.
R3 (the Pull-up resistor for the LBO pin) should be ~100k Ω.
Figure 25. LiIon to 3.3V with POK - Fixed Output Voltage
LiIon Battery
AS1331-AD C2
22µF
R2
R1
On
Off
C1
10µF
PGND
3
SW2
2
VOUT
2.5V to 3.3V
6
EN
10
FB
5
VIN
1
VOUT
SW1
4
L1
6.8µH
8
LBO
7
LBI
GND
9
R3
R4
R5
(EQ 2)
VOUT VFB 1R1
R2
------
+
⎝⎠
⎛⎞
×=
LiIon Battery
AS1331-
3.3V C2
22µF
On
Off
C1
10µF
PGND
3
SW2
2
VOUT
3.3V
300mA
6
EN
5
VIN
1
VOUT
SW1
4
L1
6.8µH
8
LBO
7
LBI
GND9
10
FB
R3
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AS1331
Datasheet - App l i c a t i o n I n f o r m a t i o n
9 Application Information
Component Selection
Only three power components are required to complete the design of the buck-boost converter. For the adjustable
version VOUT programming resistors are needed. The high operating frequency and low peak currents of the AS1331
allow the use of low value, low prof ile 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 >600mA current rating and <400mΩ DCR is recommended.
Capacitor Selection
The buck-boost convertor requires two capacitors. Ceramic X5 R or X7R types will minimize ESL and ESR while
maintaining capacitance at rated voltage over temperature. The VIN capacitor should be at least 2.2µF. The VOUT
capacitor should be between 10µF and 47µF. A larger output capacitor should be used if lower peak to peak out put
voltage ripple is desired. A larger outpu t capacitor will also improve load regulation on VOUT. See Table 5 for a list of
capacitors for input and output capacitor selection.
Table 4. Recommended Inductors
Part Number LDCR Current Rating Dimensions (L/W/T) Manufacturer
LPS3015-682M 6.8µH 300mΩ0.89A 3.0x3.0x1.5mm Coilcraft
www.coilcraft.com
EPL2014-682M 6.8µH 287mΩ0.80A 2.0x2.0x1.4mm
XPL2010-682M 6.8µH 336mΩ0.73A 2.0x1.9x1.0mm
Table 5. Recommended Input Capacitor
Part Number CTC Code Rated Voltage Dimensions (L/W/T) Manufacturer
GRM188R61A225KE34 2.2µF X5R 10V 0603, T=0.87mm Murata
www.murata.com
GRM188R60J475KE19 4.7µF X5R 6.3V 0603, T=0.87mm
GRM219R60J106KE19 10µF X5R 6.3V 0805, T=0.95mm
Table 6. Recommended Output Capacitor
Part Number CTC Code Rated Voltage Dimensions (L/W/T) Manufacturer
GRM21BR61A106KE19 10µF X5R 10V 0805, T=1.35mm Murata
www.murata.com
GRM319R61A106KE19 10µF X5R 10V 1206, T=0. 95mm
GRM319R61A106KE19 10µF X5R 10V 1210, T=0. 95mm
GRM31CR61C226KE15 22µF X5R 16V 1206, T=1.8mm
GRM31CR60J475ME19 47µF X5R 6.3V 1206, T=1.75mm
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AS1331
Datasheet - Pa ck ag e D ra wi ng s a nd Markin gs
10 Package Drawings and Markings
The device is available in a 10-pin 3x3mm TDFN package.
Figure 26. 10-pin 3x3mm TDFN package Diagram
Note:
1. Figure 26 is shown for illustration only.
2. All dimensions are in millimeters, angle is in degrees.
3. Dimensioning and toleran c ing conform to ASME Y14.5M-1994.
4. N is the total number of terminals.
5. Terminal #1 identifier and terminal numbering convention shall conform to JESD 95-1 SPP-012. Details of ter-
minal #1 identifier are optional, but must be located within the area indicated. The terminal #1 identifier may be
either a mold, embedded metal or mark feature.
6. Dimension b applies to metallized terminal and is measured between 0.15 and 0.30mm from te rminal tip.
7. ND refers to the maximum number of terminals on D side.
8. Unilateral coplanarity zone applies to the exposed heat sink sl ug as well as the terminals.
Table 7. 10-pin 3x3mm TDFN package Dimensions
Symbol Min Typ Max Symbol Min Typ Max
A 0.70 0.75 0.80 D BSC 3.00
A1 0.00 0.02 0. 05 E BSC 3.00
A3 0.20 REF D2 2.20 2.70
L1 0.03 0.15 E2 1.40 1.75
L2 0.13 L 0.30 0.40 0.50
aaa 0.15 K 0.20
bbb 0.10 b 0.18 0.25 0.30
ccc 0.10 e 0.50
ddd 0.05 N 10
eee 0.08 ND 5
ggg 0.10 θ0°14°
SEE
DETAIL B
PIN 1 INDEX AREA
(D/2 xE/2)
BTM VIEW
N-1N
b
bb
ddd
D2
D2/2
b
(D/2 xE/2)
2x
2x
TOP VIEW
aaa C
aaa C
E
PIN 1 INDEX AREA
D
ccc C
A
SIDE VIEW
(ND-1) X e
e
0.08 C
A1
A
B
L
C A B
C
E2
E2/2
SEATING
PLANE
A3
K
C
DETAIL B
Datum A or B
Terminal Tip
e
ODD T ERMINA L SIDE
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 15 - 16
AS1331
Datasheet - O r d e r i n g I n f o r m a t i o n
11 Ordering Information
The device is available as the standard products shown in Table 8.
* on request
Note: All products are RoHS compliant and Pb-free.
Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
For further info rmation and requests, please contact us mailto:sales@austriamicrosystems.com
or find your local distribu tor at http://www.austriamicrosystems.com/distributor
Table 8. Ordering Information
Ordering Code Marking Output Description Delivery Form Package
AS1331-BTDT-AD ASRP adjustable 300mA Buck-Boost
Synchronous DC/DC Converters Tape and Reel 10-pin 3x3mm TDFN
AS1331-BTDT-25* ASRR 2.5V 300mA Buck-Boost
Synchronous DC/DC Converters Tape and Reel 10-pin 3x3mm TDFN
AS1331-BTDT-30* ASRT 3.0V 300mA Buck-Boost
Synchronous DC/DC Converters Tape and Reel 10-pin 3x3mm TDFN
AS1331-BTDT-33 ASRU 3.3V 300mA Buck-Boost
Synchronous DC/DC Converters Tape and Reel 10-pin 3x3mm TDFN
www.austriamicrosystems.com/DC-DC_Buck-Boost/AS1331 Revision 1.04 16 - 16
AS1331
Datasheet
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