AMSCO AS1310

Data sheet
AS1310
U l t r a L o w Q u i e s c e n t C u r r e n t , H y s te r e t i c D C - D C S t e p - U p C o n v e r t e r
1 General Description
2 Key Features
Input Voltage Range: 0.7V to 3.6V
The AS1310 is an ultra low IQ hysteretic step-up DC-DC converter
optimized for light loads (60mA), where it achieves efficiencies of up
to 92%.
Fixed Output Voltage Range: 1.8V to 3.3V
Output Current: 60mA @ VIN=0.9V, VOUT=1.8V
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. See Ordering Information on page 14 for more information.
Quiescent Current: 1µA (typ.)
Shutdown Current: < 100nA
Up to 92% efficiency
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.
Output Disconnect in Shutdown
Feedthrough Mode when VIN > VOUT
Adjustable Low Battery detection
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.
No external diode or transistor required
Over Temperature Protection
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.
TDFN (2x2) 8-pin package
3 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 1. AS1310 - Typical Application Diagram
L1
6.8µH
3 LX
VIN
0.7V to 3.6V
C1
22µF
8
6
VIN
R1
1
LBI
R2
On
Off
LBO
AS1310
Low Battery Detect
R3
4
VOUT
C2
22µF
5
7
REF
EN
VOUT
1.8V to 3.3V
CREF
100nF
2 GND
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AS1310
Datasheet - P i n A s s i g n m e n t s
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
LBI 1
GND 2
LX 3
VOUT 4
8 VIN
AS1310
7 EN
6 LBO
9
5 REF
Pin Descriptions
Table 1. Pin Descriptions
Pin Number
Pin Name
1
LBI
2
3
GND
LX
4
VOUT
5
6
REF
LBO
7
EN
8
VIN
9
NC
Description
Low Battery Comparator Input. 0.6V Threshold. May not be left floating. If connected to GND, LBO is
working as Power Output OK.
Ground
External Inductor Connector.
Output Voltage. Decouple VOUT with a 22µF ceramic capacitor as close as possible to VOUT and
GND.
Reference Pin. Connect a 100nF ceramic capacitor to this pin.
Low Battery Comparator Output. Open-drain output.
Enable Pin. Logic controlled shutdown input.
1 = Normal operation;
0 = Shutdown; shutdown current <100nA.
Battery Voltage Input. Decouple VIN with a 22µF ceramic capacitor as close as possible to VIN and
GND.
Exposed Pad. This pad is not connected internally. Can be left floating or connect to GND to achieve
an optimal thermal performance.
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AS1310
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
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
kV
Norm: MIL 883 E method 3015
Electrostatic Discharge
Electrostatic Discharge HBM
+/- 2
Temperature Ranges and Storage Conditions
Thermal Resistance θJA
+33
Junction Temperature
Storage Temperature Range
-55
Package Body Temperature
Humidity non-condensing
Moisture Sensitive Level
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5
ºC/W
+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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AS1310
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
VIN = 1.5V, C1 = C2 = 22µF, CREF = 100nF, TAMB = -40°C to +85ºC. Typical values are at TAMB = +25ºC. Unless otherwise specified.
Table 3. Electrical Characteristics
Symbol
TAMB
Parameter
Conditions
Min
Typ
Max
Units
Operating Temperature Range
-40
85
°C
Input Voltage Range
0.7
3.6
V
0.8
V
1.8
3.3
V
ILOAD = 10 mA, TAMB = +25°C
-2
+2
%
ILOAD = 10mA
-3
+3
%
1.75
V
100
nA
1.2
µA
100
nA
Input
VIN
Minimum Startup Voltage
ILOAD = 1mA, TAMB = +25°C
0.7
Regulation
VOUT
Output Voltage Range
Output Voltage Tolerance
VOUT Lockout Threshold
1
Rising Edge
1.55
1.65
Operating Current
Quiescent Current VIN
VOUT = 1.02xVOUTNOM, REF =
0.99xVOUTNOM, TAMB = +25°C
Quiescent Current VOUT
VOUT = 1.02xVON, REF = 0.99xVON, no
load, TAMB = +25°C
Shutdown Current
TAMB = +25ºC
NMOS
VOUT = 3V
0.35
Ω
PMOS
VOUT = 3V
0.5
Ω
IQ
ISHDN
0.8
1
Switches
RON
IPEAK
NMOS maximum On-time
3.6
4.2
4.8
µs
Peak Current Limit
320
400
480
mA
5
20
35
mA
Zero Crossing Current
Enable, Reference
VENH
EN Input Voltage High
VENL
EN Input Voltage Low
IEN
EN Input BiasCurrent
IREF
REF Input BiasCurrent
0.7
V
0.1
V
EN = 3.6V, TAMB = +25°C
100
nA
REF = 0.99xVOUTNOM, TAMB = +25°C
100
nA
0.63
V
Low Battery & Power-OK
VLBI
LBI Threshold
Falling Edge
0.57
LBI Hysteresis
ILBI
0.6
25
LBI Leakage Current
2
LBI = 3.6V, TAMB = +25°C
VLBO
LBO Voltage Low
ILBO = 1mA
ILBO
LBO Leakage Current
LBO = 3.6V, TAMB = +25°C
Power-OK Threshold
LBI = 0V, Falling Edge
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92.5
mV
100
nA
100
mV
100
nA
95
%
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AS1310
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
Table 3. Electrical Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Thermal Protection
Thermal Shutdown
10°C Hysteresis
150
°C
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:
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.
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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AS1310
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
TAMB = +25°C, unless otherwise specified.
Figure 3. Efficiency vs. Output Current; VOUT = 1.8V
90
90
L1: XPL2010-682M
85
L1: XPL7030-682M
85
80
80
75
75
Efficiency (%)
Efficiency (%)
Figure 4. Efficiency vs. Output Current; VOUT = 1.8V
70
65
60
55
70
65
60
55
50
50
Vin = 0.9V
Vin = 1.2V
45
Vin = 1.5V
40
0.01
0.1
1
10
100
Vin = 0.9V
Vin = 1.2V
45
Vin = 1.5V
40
0.01
1000
0.1
Output Current (mA)
Figure 5. Efficiency vs. Output Current; VOUT = 3.0V
100
100
L1: XPL2010-682M
90
85
80
85
80
75
70
65
60
Vin = 0.9V
55
50
Vin = 1.2V
Vin = 1.8V
45
10
100
70
65
60
Vin = 0.9V
Vin = 1.2V
Vin = 1.5V
Vin = 1.8V
45
Vin = 2.4V
1
Vin = 2.4V
40
0.01
1000
0.1
Output Current (mA)
95
10
100
1000
Figure 8. Maximum Output Current vs. Input Voltage
180
L1: XPL2010-682M
160
Output Current (mA) .
90
Efficiency (%)
1
Output Current (mA)
Figure 7. Efficiency vs. Input Voltage; VOUT = 1.8V
100
1000
75
55
50
Vin = 1.5V
0.1
100
L1: XPL7030-682M
95
90
40
0.01
10
Figure 6. Efficiency vs. Output Current; VOUT = 3.0V
Efficiency (%)
Efficiency (%)
95
1
Output Current (mA)
85
80
75
70
65
60
Iout = 1mA
Iout=10mA
55
140
120
100
80
60
40
Vout = 1.8V
20
Vout = 3.0V
Iout=50mA
50
0
0.7
0.9
1.1
1.3
1.5
1.7
1.9
0
Input Voltage (V)
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0.5
1
1.5
2
2.5
3
Input Voltage (V)
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AS1310
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 10. RON vs. Temperature
1
1
0.95
0.9
0.9
0.8
0.85
0.7
0.8
0.6
R ON (Ω)
Start-up Voltage (V)
Figure 9. Start-up Voltage vs. Output Current
0.75
0.7
0.5
0.4
0.65
0.3
0.6
0.2
0.55
0.1
0.5
0
1
2
3
4
5
6
7
8
9
10
0
-40
Output Current (mA)
PM OS
NM OS
-15
10
35
60
85
Temperature (°C)
100mV/Div
VOUT (AC)
ILX
200mA/Div
VLX
2V/Div
Figure 11. Output Voltage Ripple; VIN = 2V, VOUT = 3V,
Rload = 100Ω
5µs/Div
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AS1310
Datasheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1310 is available with fixed output voltages from 1.8V to 3.3V in 50mV steps.
Figure 12. AS1310 - Block Diagram
0.7 to 3.6V
Input
CIN
22µF
6.8µH
1.8V to 3.3V
Output
Zero
Crossing
Detector
LX
COUT
22µF
Startup
Circuitry
Driver
and
Control
Logic
VIN
VOUT
R3
–
+
LBI
LBO
Imax
Detection
EN
AS1310
VREF
REF
CREF
100nF
GND
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: 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 feedtrough mode the quiescent current is 35µA (typ.). The device goes back into step-up mode when the oputput voltage is 4% (typ.)
below VOUTNOM.
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AS1310
Datasheet - D e t a i l e d D e s c r i p t i o n
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 realised
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 14 on page
10).
For the circuit shown in the left of Figure 13, 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:
V IN
R 1 = R 2 ⋅ ⎛ ----------- – 1⎞
⎝ V LBI
⎠
(EQ 1)
Where:
VLBI is 0.6V.
Figure 13. Typical Application with adjustable Battery Monitoring
L1
6.8µH
3 LX
VIN
0.7V to 3.6V
C1
22µF
8
6
VIN
R1
1
LBI
R2
On
Off
LBO
AS1310
Low Battery Detect
R3
4
VOUT
C2
22µF
5
7
REF
EN
VOUT
1.8V to 3.3V
CREF
100nF
2 GND
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AS1310
Datasheet - D e t a i l e d D e s c r i p t i o n
Figure 14. Typical Application with LBO working as Power-OK
L1
6.8µH
3 LX
VIN
0.7V to 3.6V
8
6
VIN
C1
22µF
1
LBI
On
Off
LBO
AS1310
Low Battery Detect
R3
4
VOUT
C2
22µF
5
7
REF
EN
VOUT
1.8V to 3.3V
CREF
100nF
2 GND
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 useable 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 vias in the printed circuit board. It’s also recommended to solder the Exposed Pad (pin 9) to the GND plane.
Note: Continuing operation in thermal overload conditions may damage the device and is considered bad practice.
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AS1310
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
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.
Table 4. Recommended Inductors
Part Number
L
DCR
Current Rating
Dimensions (L/W/T)
XPL2010-682M
6.8µH
421mΩ
0.62A
2.0x1.9x1.0mm
EPL2014-682M
6.8µH
287mΩ
0.59A
2.0x2.0x1.4mm
LPS3015-682M
6.8µH
300mΩ
0.86A
3.0x3.0x1.5mm
LPS3314-682M
6.8µH
240mΩ
0.9A
3.3x3.3x1.3mm
LPS4018-682M
6.8µH
150mΩ
1.3A
3.9x3.9x1.7mm
XPL7030-682M
6.8µH
59mΩ
9.4A
7.0x7.0x3.0mm
LQH32CN6R8M53L
6.8µH
250mΩ
0.54A
3.2x2.5x1.55mm
LQH3NPN6R8NJ0L
6.8µH
210mΩ
0.7A
3.0x3.0x1.1mm
LQH44PN6R8MJ0L
6.8µH
143mΩ
0.72A
4.0x4.0x1.1mm
Manufacturer
Coilcraft
www.coilcraft.com
Murata
www.murata.com
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 Table 5
for a list of capacitors for input and output capacitor selection.
Table 5. Recommended Input and Output Capacitors
Part Number
C
TC Code
Rated Voltage
Dimensions (L/W/T)
GRM21BR60J226ME99
22µF
X5R
6.3V
0805, T=1.25mm
GRM31CR61C226KE15
22µF
X5R
16V
1206, T=1.6mm
GRM31CR60J475KA01
47µF
X5R
6.3V
1206, T=1.6mm
Manufacturer
Murata
www.murata.com
On the pin REF a 10nF capacitor with an Insulation resistance >1GΩ is recommended.
Table 6. Recommended Capacitors for REF
Part Number
C
TC Code
Insulation
Resistance
Rated
Voltage
Dimensions (L/W/T)
Manufacturer
GRM188R71C104KA01
100nF
X7R
>5GΩ
16V
0603, T=0.8mm
GRM31CR61C226KE15
100nF
X7R
>5GΩ
50V
0805, T=1.25mm
Murata
www.murata.com
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AS1310
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 15. TDFN (2x2) 8-pin Marking
Package Code:
XXX - encoded Datecode
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AS1310
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 16. TDFN (2x2) 8-pin package Diagram
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AS1310
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 7.
Table 7. Ordering Information
Ordering Code
Marking
Output
Description
Delivery Form
Package
Tape and Reel
TDFN (2x2) 8-pin
AS1310-BTDT-18
A2
1.8V
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
AS1310-BTDT-20
A8
2.0V
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
Tape and Reel
TDFN (2x2) 8-pin
AS1310-BTDT-25
A9
2.5V
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
Tape and Reel
TDFN (2x2) 8-pin
AS1310-BTDT-27
A7
2.7V
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
Tape and Reel
TDFN (2x2) 8-pin
AS1310-BTDT-30
A6
3.0V
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
Tape and Reel
TDFN (2x2) 8-pin
1
tbd
3.3V
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
Tape and Reel
TDFN (2x2) 8-pin
2
tbd
tbd
Ultra Low Quiescent Current, Hysteretic DC-DC
Step-Up Converter
Tape and Reel
TDFN (2x2) 8-pin
AS1310-BTDT-33
AS1310-BTDT-xx
1. On request
2. Non-standard devices are available between 1.8V and 3.3V in 50mV steps.
Note: All products are RoHS compliant and austriamicrosystems green.
Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
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For further information and requests, please contact us mailto:sales@austriamicrosystems.com
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AS1310
Datasheet
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Contact Information
Headquarters
austriamicrosystems AG
Tobelbaderstrasse 30
A-8141 Unterpremstaetten, Austria
Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com/contact
www.austriamicrosystems.com/DC-DC_Step-Up/AS1310
Revision 1.04
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