Datasheet

AS1340
5 0 V, M i c r o p o w e r, D C - D C B o o s t C o n v e r t e r
1 General Description
2 Key Features
The AS1340 boost converter contains a 1.4A internal switch in a tiny
TDFN-8 3x3mm package. The device operates from a 2.7 to 5.5V
supply, and can boost voltages up to 50V output.
The output voltage can easily be adjusted by an external resistor
divider.
2.7V to 50V Adjustable Output Voltage
2.7V to 50V Input Voltage Range
2.7V to 5.5V Supply Voltage Range
High Output Currents:
The AS1340 uses a unique control scheme providing the highest
efficiency over a wide range of load conditions. An internal 1.4A
MOSFET reduces external component count, and a fixed high
switching frequency (1MHz) allows for tiny surface-mount
components.
- 100mA @ 12V from 3.3V VIN
- 50mA @ 24V from 3.3V VIN
- 30mA @ 36V from 3.3V VIN
Efficiency: Up to 93%
The AS1340 also features power-OK circuitry which monitors the
output voltage.
Switching Frequency: 1MHz
Additionally the AS1340 features a low quiescent supply current and
a shutdown mode to save power. During shutdown an output
disconnect switch separates the input from the output.
The AS1340 is ideal for LCD or OLED panels with low current
requirements and can also be used in a wide range of other
applications.
Output Disconnect
Power-OK Output
Operating Supply Current: 30µA
Shutdown Current: 0.1µA
TDFN-8 3x3mm Package
The device is available in a low-profile TDFN-8 3x3mm package.
3 Applications
The device is ideal for OLED display power supply, LED power
supply, LCD bias generators, mobile/cordless phones, palmtop
computers, PDAs and organizers, handy terminals or any other
portable, battery-powered device.
Figure 1. AS1340 - Typical Application Diagram
L1
4.7µH
3
VIN = 2.7V
to 5.5V
CIN
SWVIN
5
AS1340
1
EN
R1
COUT
8
FB
R2
7, 9
6
VOUT
LX
VCC
VOUT = > VIN to 50V
LX
POK
On
Off
SWOUT
VCC
3
VIN = 2.7V to
5.5V
6
2
4
L1
VIN = 2.7V to
~VOUT
L1
3
VIN = 2.7V to
5.5V
VCC
GND
6
VOUT
LX
If not needed the output disconnect switch can be left unconnected which will also increase the efficiency.
Additionally the supply of the chip can be split to allow higher supply voltages for the coil. In this case the output disconnect switch must not be used.
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AS1340
Datasheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
EN 1
8 FB
VCC 2
7 GND
AS1340
SWVIN 3
POK 4
6 SWOUT
GND 9
5 LX
4.1 Pin Descriptions
Table 1. Pin Descriptions
Pin Number
Pin Name
1
EN
2
3
VCC
SWVIN
4
POK
5
LX
6
7
SWOUT
GND
8
FB
9
GND
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Description
Active-High Enable Input. A logic low on this pin shuts down the device and reduces the supply
current to 0.1µA.
Note: Connect to VCC for normal operation.
+2.7V to +5.5V Supply Voltage. Bypass this pin to GND with a 1µF capacitor.
Shutdown Disconnect Switch In
Power-OK.
0 = VOUT < 90% of VOUTNOM.
1 = VOUT > 90% of VOUTNOM.
Inductor. The drain of the internal N-channel MOSFET.
Note: This pin is high impedance in shutdown.
Shutdown Disconnect Switch Out. Disconnects the input from the output during shutdown.
Ground. This pin and pin 9 must be connected to GND to ensure normal operation.
Feedback Pin. Feedback input to the gm error amplifier. Connect a resistor divider tap to this pin. The
output voltage can be adjusted from VIN to 50V by:
VOUT = 1.25V[1 + (R1/R2)]
Ground. This pin and pin 7 must be connected to GND to ensure normal operation.
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AS1340
Datasheet - A b s o l u t e M a x i m u m R a t i n g s
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
VCC, FB, EN to GND
-0.3
7
SWVIN, SWOUT to GND
-0.3
7
Units
Comments
Electrical Parameters
LX to GND
Input Current (latch-up immunity)
V
55
-100
100
mA
Norm: JEDEC 78
1.5
kV
Norm: MIL 883 E method 3015
36.7
ºC/W
on PCB
Electrostatic Discharge
Electrostatic Discharge HBM
Temperature Ranges and Storage Conditions
Thermal Resistance JA
Junction Temperature
Storage Temperature Range
-55
Package Body Temperature
Humidity non-condensing
Moisture Sensitive Level
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5
+150
ºC
+125
ºC
+260
ºC
85
%
1
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).
Represents a max. floor life time of unlimited
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AS1340
Datasheet - E l e 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
VCC = EN = 2.7V, TAMB = -40 to +85ºC (unless otherwise specified). Typical values are at TAMB = +25ºC.
Table 3. Electrical Characteristics
Symbol
Parameter
TAMB
Operating Temperature Range
VCC
Max
Unit
-40
+85
°C
Supply Voltage
2.7
5.5
V
VIN
Inductor Input Voltage Range
2.7
50
V
VOUT
Output Voltage Range
2.7
50
V
ICC
Quiescent Supply Current
VFB = 1.3V, VIN = 5V
30
50
µA
Enable Supply Current
EN = GND
0.1
1
µA
VCC Line Regulation
VOUT = 18V, ILOAD = 1mA, VIN = 5.5V,
VCC = 2.7 to 5.5V
0.3
%/V
VIN Line Regulation
VOUT = 18V, ILOAD = 1mA,
VCC = 5V, VIN = 2.7 to 5.5V
0.25
%/V
VLDR
Load Regulation
VOUT = 18V, VCC = VIN = 5V, ILOAD = 0 to
20mA
0.02
%/mA

Efficiency
L1 = 10µH, VIN = 5.5V, VOUT = 20V, ILOAD =
100mA
88
%
VFB
Feedback Set Point
IFB
Feedback Input Bias Current
VLNR
Condition
Min
1.225
Typ
1.25
1.275
V
VFB = 1.3V
5
100
nA
VOUT max
VIN = 5.5V, ILOAD = 0mA
50
V
ILX(MAX)
LX Switch Current Limit
VIN = 5.5V, ILOAD > 20mA
1.41
A
RLX
LX On-Resistance
VCC = 5.5V, ILX = 100mA
0.6
RP_ON
Switch On-Resistance
VIN = 5.5V, PMOS
0.2
ILX_LEAK
LX Leakage Current
VLX = 50V
2
IP_LEAK
Switch Leakage Current
VIN = 5.5V, PMOS
0.5
DC-DC Switches

µA
Control Inputs
VIH
EN Input Threshold
2.7V VCC  5.5V
EN Input Bias Current
VCC = 5.5V, VEN = 0 to 5.5V
POK Output Low Voltage
POK sinking 1mA
POK Output High Leakage Current
POK = 5.5V
POK Threshold
Rising edge, referenced to VOUT(NOM)
0.8 x
VCC
0.2 x
VCC
VIL
IEN
-1
V
+1
µA
0.01
0.2
V
100
500
nA
87
90
93
%
Oscillator Frequency
0.85
1
1.15
MHz
Maximum Duty Cycle
85
90
95
%
POK Output
VOL
Oscillator
fCLK
Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality
Control) methods.
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AS1340
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
Parts used for measurements: 4.7µH (LPS4018-472ML) Inductor, 10µF (GRM32DR71C106KA01) CIN and 1µF (GRM31MR71H105KA88)
COUT.
Figure 4. Efficiency vs. Output Current; VOUT = 24V
100
100
90
90
80
80
70
70
Efficiency (%)
Efficiency (%)
Figure 3. Efficiency vs. Output Current; VOUT = 36V
60
50
40
30
60
50
40
30
20
20
Vi n = 2.7V
10
Vi n = 2.7V
Vi n = 3.3V
Vi n = 3.3V
10
Vi n = 5.5V
0
Vi n = 5.5V
0
0.1
1
10
100
0.1
1
Output Current (mA)
Figure 5. Efficiency vs. Output Current; VOUT = 12V
100
90
90
80
80
70
70
60
50
40
30
60
50
40
30
20
20
Vi n = 2.7V
Vi n = 2.7V
Vi n = 3.3V
10
Vi n = 3.3V
10
Vi n = 5.5V
0
Vi n = 5.5V
0
0.1
1
10
100
0.1
1
Output Current (mA)
100
Figure 8. Efficiency vs. VIN; IOUT = 10mA
100
90
90
Efficiency (%)
100
80
70
60
50
10
Output Current (mA)
Figure 7. Efficiency vs. VIN; VOUT=18V, Split Supplies
Efficiency (%)
100
Figure 6. Efficiency vs. Output Current; VOUT = 6V
100
Efficiency (%)
Efficiency (%)
10
Output Current (mA)
Iout = 1mA
Iout = 5mA
Iout = 10mA
Iout = 20mA
80
70
60
50
Iout = 50mA
Vout = 6V
Vout = 12V
Vout = 18V
Vout = 24V
Vout = 30V
Vout = 36V
Vout = 48V
40
40
2
4
6
8
10
12
2.7
Input Voltage (V)
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3.1
3.5
3.9
4.3
4.7
5.1
5.5
Input Voltage (V)
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AS1340
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. Output Voltage vs. Temperature;
VOUT = 18V
Figure 10. Output Voltage vs. Load Current;
VOUT = 18V, VIN = 3.3V
18.5
18.5
Iout=1mA
18.4
Iout=5mA
Iout=10mA
18.3
18.3
Iout=20mA
18.2
Output Voltage (V) .
Output Voltage (V) .
18.4
Iout=50mA
18.1
18
17.9
17.8
18.2
18.1
18
17.9
17.8
17.7
17.7
17.6
17.6
17.5
-45 -30 -15
17.5
0
15
30
45
60
75
90
0
Temperature (C°)
20
30
Figure 12. Output Voltage vs. Input Voltage;
VOUT = 18V
18.5
18.4
18.4
18.3
18.3
Output Voltage (V)
18.5
18.2
18.1
18
17.9
17.8
17.7
Iout = 1mA
17.6
Iout = 10mA
Iout = 5mA
18.2
18.1
18
17.9
17.8
17.7
Iout = 1mA
17.6
Iout = 10mA
Iout = 5mA
Iout = 20mA
Iout = 20mA
17.5
17.5
2
3
4
5
6
7
8
9
10
11 12
2.7
3.1
3.5
Input Voltage (V)
3.9
4.3
4.7
5.1
5.5
5.1
5.5
Input Voltage (V)
Figure 13. Output Current vs. VIN; Split Supplies
Figure 14. Output Current vs. VIN
500
500
450
Vout = 12V
Vout = 18V
Vout = 24V
Vout = 30V
450
Vout = 36V
Vout = 12V
Vout = 18V
Vout = 24V
Vout = 30V
Vout = 36V
400
Output Current (mA)
Output Current (mA)
40
Output Current (mA)
Figure 11. Output Voltage vs. Input Voltage;
VOUT = 18V, Split Supplies
Output Voltage (V)
10
350
300
250
200
150
400
350
300
250
200
150
100
100
50
50
0
0
2
3
4
5
6
7
8
9
10 11
12
2.7
Input Voltage (V)
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3.1
3.5
3.9
4.3
4.7
Input Voltage (V)
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AS1340
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 16. Input Current vs. Input Voltage;
IOUT = 0mA, switching
5.5
1
5
0.9
4.5
0.8
Vout = 6V
Vout = 12V
Input Current (mA)
4
3.5
3
2.5
2
1.5
1
0.5
Vout = 6V
Vout = 12V
Vout = 18V
Vout = 24V
Vout = 30V
Vout = 36V
Vout = 18V
Vout = 24V
0.7
Vout = 30V
0.6
0.5
0.4
0.3
0.2
0.1
0
0
0
5
10
15
20
25 30
35
40
45
50
2.7
3.1
3.5
Output Current (mA)
Figure 17. Input Current vs. Output Current;
VOUT = 12V
4.3
4.7
5.1
5.5
60
70
Figure 18. Input Current vs. Output Current;
VOUT = 18V
600
600
Vi n = 2.4V
Vi n = 2.4V
Vi n = 2.7V
500
Vi n = 2.7V
500
Vi n = 3.3V
Vi n = 5.5V
Input Current (mA)
400
300
200
100
Vi n = 3.3V
Vi n = 5.5V
400
300
200
100
0
0
10
20
30
40
50
60
70
0
Output Current (mA)
30
40
50
VOUT
POK
EN
500mA/DIV
5V/Div
Figure 20. Startup Waveform - POK
10V/Div
EN
LX
VOUT
20
Output Current (mA)
Figure 19. Startup Waveform
200µs/Div
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10
5V/Div
0
5V/DIV
Input Current (mA)
3.9
Input Voltage (V)
2V/Div
Start-Up Voltage (V)
Figure 15. Startup Voltage vs. Output Current;
VIN = 2.7 to 5.5V
50µs/Div
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AS1340
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
500µs/Div
Figure 23. Output Voltage Ripple;
VOUT = 18V, IOUT = 1mA
Figure 24. Output Voltage Ripple;
VOUT = 18V, IOUT = 20mA
VIN = 2.7V
VIN = 2.7V
2ms/Div
1µs/Div
1mA 20mA
VOUT(AC)
IOUT
1mA 20mA
VOUT(AC)
IOUT
200mV/Div
Figure 26. Fixed Frequency vs. Powersave Operation;
VIN = 2.7V, VOUT = 18V
200mV/Div
Figure 25. Load Transient Response;
VIN = 5.5V, VOUT = 18V
2ms/Div
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VIN = 3.3V
200mV/Div
VOUT
VIN = 5.5V
200mV/Div
VOUT
VIN = 5.5V
VIN = 3.3V
200mV/Div
VOUT(AC)
VIN
500µs/Div
2V/DIV
200mV/Div
Figure 22. Transient Line Regulation;
VOUT = 18V, ILOAD = 20mA
2V/DIV
VIN
VOUT(AC)
Figure 21. Transient Line Regulation;
VOUT = 18V, ILOAD = 1mA
2ms/Div
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AS1340
Datasheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1340 features a current limiting circuitry, a fixed-frequency PWM architecture, power-OK circuitry, thermal protection, and an automatic
powersave mode in a tiny package, and maintains high efficiency at light loads.
Figure 27. AS1340 - Block Diagram with Shutdown Disconnect Switch
3
VIN = 2.7V
to 5.5V
SWVIN
6
L1
4.7µH
SWOUT
4
POK
5
LX
2
–
VOUT
Good
VCC
CIN
1µF
PWM
Control
Sync Drive
Control
1 MHz
Spread
Spectrum
Ramp Generator
Slope
Compensator
1
Shutdown
Control
Powersave
Shutdown
Powersave
Operation
Control
VIN to 50V
+
0.9
CFF*
Current
Sense

R1
AS1340
+
PWM –
Comp
–
EN
1.13V
VC
RC
COUT
8
–
gm Error
Amp
+
FB
CP2
CC
1.25V
Ref
R2
7,9 GND
* Optional
Automatic powersave mode regulates the output and also reduces average current flow into the device, resulting in high efficiency at light loads.
When the output increases sufficiently, the powersave comparator output remains high, resulting in continuous operation.
For each oscillator cycle, the power switch is enabled. A voltage proportional to switch current is added to a stabilizing ramp and the resulting
sum is delivered to the positive terminal of the PWM comparator.
The error amplifier compares the voltage at FB with the internal 1.25V reference and generates an error signal (VC). When VC is below the
powersave mode threshold voltage the automatic powersave-mode is activated and the hysteretic comparator disables the power circuitry, with
only the low-power circuitry still active (total current consumption is minimized).
When a load is applied, VFB decreases; VC increases and enables the power circuitry and the device starts switching. In light loads, the output
voltage (and the voltage at FB) will increase until the powersave comparator disables the power circuitry, causing the output voltage to decrease
again. This cycle is repeated resulting in low-frequency ripple at the output.
The POK output indicates whether the output voltage is within 90% of the nominal output voltage level or not. When EN is low, the circuit is not
active and POK gives a high signal when connected to VCC by a pull-up resistor. When EN goes high, POK goes low after approximately 50µs
and will go high when the output reaches 90% of the nominal output voltage (see Figure 20 on page 7). When input and output voltage are
almost the same, it may happen that the POK Signal does not go low because VOUT reaches 90% before the delay has expired. The open-drain
POK output sinks current, when EN is high and the output voltage is below 90% of the nominal output voltage.
Thermal protection circuitry shuts down the device when its temperature reaches 145ºC.
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AS1340
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
9.1 Power Supply Concept
The AS1340 has an operating voltage range from 2.7 to 5.5V. If the inductor is supplied from the same source the battery disconnect switch can
be used as well (see Figure 1 on page 1). In case that a input voltage source is higher than 5.5V, the inductor can be supplied separately up to
50V (see Figure 28), but then the battery disconnect switch cannot be used, because its operating voltage range is limited to 5.5V.
9.2 Shutdown
A logic low on pin EN shuts down the AS1340 and a logic high on EN powers on the device.
In shutdown mode the supply current drops to below 1µA to maximize battery life. In case that the battery disconnect switch is used, the battery
is disconnected from the output during shutdown.
Note: Pin EN should not be left floating. If the shutdown feature is not used, connect EN to VIN.
9.3 Battery Disconnect
The AS1340 has an integrated switch that can be used to disconnect the battery during shutdown. The operation voltage of this switch is limited
to 5.5V. When EN is high, the switch is closed and supplies the inductor. Due to the RON resistance the efficiency is slightly lower if the battery
disconnect switch is used.
PLOSS = IIN² x RON
(EQ 1)
9.4 Setting Output Voltage
Output voltage can be adjusted by connecting a voltage divider between pins LX and FB (see Figure 28).
Figure 28. Typical Application (SWVIN and SWOUT not in use)
Supply
2.7V to VOUT
L1
4.7µH
CIN
10µF
3
2
VIN = 2.7V
to 5.5V
C1
0.1µF
SWVIN
6
SWOUT
5
VCC
D1
VOUT = 18V
LX
R1
2.2M
4
AS1340
POK
On
1
Off
EN
COUT
1µF
8
FB
R2
165k
7,9
GND
The output voltage can be adjusted by selecting different values for R1 and R2. For R2, select a value between 10k and 200k.
Calculate R1 by:
V OUT
R 1 = R 2   ------------- – 1
 V FB

(EQ 2)
Where:
VOUT = VIN to 50V, VFB = 1.25V
The input bias current of FB has a maximum value of 100nA which allows for large-value resistors. For less than 1% error, the current through R2
should be 100 times the feedback input bias current (IFB).
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AS1340
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9.5 LED Power Supply Application
The AS1340 can also be used for driving LEDs. Just simply connect the LEDs between the pins LX and FB. (see Figure 29).
Figure 29. LED Supply Application
L1
4.7µH
3
VIN = 2.7V
to 5.5V
2
C1
0.1µF
SWVIN
6
SWOUT
5
VCC
4
LX
AS1340
POK
On
1
Off
EN
D1
COUT
1µF
8
FB
ILED
R2
100
7,9
GND
The output voltage is adjusted automatically to the required voltage of the LEDs. This voltage depends on the forward voltage (VF) of the used
LEDs and the Feedback Voltage VFB.
Calculate VOUT by:
V OUT = V F  I LED   n + V FB
(EQ 3)
Note: The brightness of the LEDs can directly be adjusted by setting the current ILED via the corresponding R2.
Calculate R2 by:
V FB
I LED = ---------R2
(EQ 4)
Where:
VFB = 1.25V
n .... number of LED’s
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AS1340
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9.6 Inductor Selection
For the external inductor, a 6.8µH inductor is recommended. Minimum inductor size is dependant on the desired efficiency and output current.
Inductors with low core losses and small DCR at 1MHz are recommended.
Table 4. Recommended Inductors
Part Number
LPS4018-472ML_
L
4.7µH
DCR
Current Rating
0.125
Dimensions (L/W/T)
1.9A
4.4x4.4x1.7mm
ME3220-472ML_
4.7µH
0.190
1.5A
3.2x2.8x2mm
MOS6020-472ML_
4.7µH
0.050
1.94A
6.8x6x2.4mm
MSS6122-472ML_
4.7µH
0.065
1.82A
6.1x6.1x6mm
LPS4018-682ML_
6.8µH
0.150
1.3A
4.4x4.4x1.7mm
ME3220-682ML_
6.8µH
0.270
1.2A
3.2x2.8x2mm
MOS6020-682ML_
6.8µH
0.078
1.72A
6.8x6x2.4mm
MSS6122-682ML_
6.8µH
0.100
1.50A
6.1x6.1x6mm
Manufacturer
Coilcraft
www.coilcraft.com
100
100
90
90
80
80
70
70
Efficiency (%) .
Efficiency (%) .
Figure 30. Efficiency Comparison of Different Inductors, VIN = 3.3V, VOUT = 18V
60
50
40
30
20
LPS4018-472
10
ME3220-472
LPS4018-682
ME3220-682
0
60
50
40
30
20
MOS6020-472
10
MSS6122-472
MOS6020-682
MSS6122-682
0
1
10
100
1
Output Current (mA)
10
100
Output Current (mA)
100
100
90
90
80
80
70
70
Efficiency (%) .
Efficiency (%) .
Figure 31. Efficiency Comparison of Different Inductors, VIN = 5.5V, VOUT = 18V
60
50
40
30
20
LPS4018-472
10
ME3220-472
LPS4018-682
ME3220-682
0
60
50
40
30
20
MOS6020-472
10
MSS6122-472
MOS6020-682
MSS6122-472
0
1
10
100
1
Output Current (mA)
www.ams.com/DC-DC_Step-Up/AS1340
10
100
Output Current (mA)
Revision 1.20
12 - 17
AS1340
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9.7 Capacitor Selection
A 4.7µF capacitor is recommended for CIN as well as a 2µF for COUT. Small-sized ceramic capacitors are recommended. X5R and X7R
ceramic capacitors are recommend as they retain capacitance over wide ranges of voltages and temperatures.
9.7.1
Output Capacitor Selection
Low ESR capacitors should be used to minimize VOUT ripple. Multi-layer ceramic capacitors are recommended since they have extremely low
ESR and are available in small footprints. A 2.2 to 10µF output capacitor is sufficient for most applications. Larger values up to 22µF may be
used to obtain extremely low output voltage ripple and improve transient response.
X5R and X7R dielectric materials are recommended due to their ability to maintain capacitance over wide voltage and temperature ranges.
Table 5. Recommended Output Capacitor
Part Number
C
TC Code
Rated Voltage
GRM31MR71H105KA88
1µF
GRM32ER71H475KA88
4.7µF
X7R
50V
C1210
C1206C105K5RAC
1µF
X7R
50V
C1206
C1206C225K5RAC
2.2µF
X7R
50V
C1210
1206C105KAT2A
1µF
X7R
50V
C1206
9.7.2
X7R
50V
Dimensions (L/W/T)
C1206
Manufacturer
Murata
www.murata.com
Kemet
www.kemet.com
AVX
www.avx.com
Input Capacitor Selection
Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. Ceramic capacitors are
recommended for input decoupling and should be located as close to the device as is practical. A 4.7µF input capacitor is sufficient for most
applications. Larger values may be used without limitations.
Table 6. Recommended Input Capacitor
Part Number
C
TC Code
Rated Voltage
Dimensions (L/W/T)
GRM21BR71C105KA01
1µF
X7R
16V
C0805
GRM21BR61C225KA88
2.2µF
X7R
16V
C0805
GRM32DR71C106KA01
10µF
X7R
16V
C1210
9.7.3
Manufacturer
Murata
www.murata.com
Diode Selection
A Schottky diode must be used to carry the output current for the time it takes the PMOS synchronous rectifier to switch on.
Note: Do not use ordinary rectifier diodes, since the slow recovery times will compromise efficiency.
Table 7. Recommended Diodes
Part Number
Reverse Voltage
Forward Current
Package
Manufacturer
PMEG4010BEA
40V
1A
SOD123
Philips
www.nxp.com
MBR0540
40V
500mA
SOD123
MBR0560
60V
500mA
SOD123
MCC
www.mccsemi.com
9.8 Thermal Protection
To protect the device from short circuit or excessive power dissipation of the auxiliary NPNs, the integrated thermal protection switches off the
device when the junction temperature (TJ) reaches 145ºC (typ). When TJ decreases to approximately 125ºC, the device will resume normal
operation. If the thermal overload condition is not corrected, the device will switch on and off while maintaining TJ within the range between
125ºC and 145ºC.
www.ams.com/DC-DC_Step-Up/AS1340
Revision 1.20
13 - 17
AS1340
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
10 Package Drawings and Markings
Figure 32. TDFN-8 3x3mm Marking
Package Code:
XXXX - encoded Datecode
www.ams.com/DC-DC_Step-Up/AS1340
Revision 1.20
14 - 17
AS1340
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
Figure 33. TDFN-8 3x3mm Package
www.ams.com/DC-DC_Step-Up/AS1340
Revision 1.20
15 - 17
AS1340
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.
Table 8. Ordering Information
Ordering Code
Marking
Description
Delivery Form
Package
AS1340A-BTDT-10
ASM3
50V, Micropower, DC-DC Boost Converter,
Automatic Power Save, 1MHz
Tape and Reel
TDFN-8 3x3mm
Note: All products are RoHS compliant.
Buy our products or get free samples online at ICdirect: http://www.ams.com/ICdirect
Technical Support is found at http://www.ams.com/Technical-Support
For further information and requests, please contact us mailto:[email protected]
or find your local distributor at http://www.ams.com/distributor
www.ams.com/DC-DC_Step-Up/AS1340
Revision 1.20
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AS1340
Datasheet
Copyrights
Copyright © 1997-2010, ams AG, Tobelbaderstrasse 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.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. ams AG makes no
warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described
devices from patent infringement. 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 normal
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. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard
production flow, such as test flow or test location.
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Tobelbaderstrasse 30
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Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
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Revision 1.20
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