AS1310

AS1310
Ultra Low Quiescent Current,
Hysteretic DC-DC Step-Up Converter
General Description
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
ams Datasheet
[v1-11] 2015-Jan-28
Page 1
Document Feedback
AS1310 − General Description
Benefits
Features
Over – temperature protection and
shutdown
Integrated temperature monitoring
Early power-fail warning
Adjustable low battery detection
• No external diode or transistor required
• 8-pin TDFN (2mm x 2mm)
Cost effective, small package
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
L1
6.8μH
3
VIN
0.7V to 3.6V
C1
22μF
8
VIN
1
LBI
On
Off
Low Battery Detect
6
LBO
R1
R2
AS1310
R3
VOUT
1.8V to 3.3V
4
VOUT
C2
22μF
5
7
REF
EN
2
Page 2
Document Feedback
LX
CREF
100nF
GND
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Pin Assignment
Pin Assignment
Figure 3:
Pin Diagram (Top View)
LBI
1
8
VIN
GND
2
7
EN
6
LBO
5
REF
AS1310
LX
3
VOUT
4
Exposed pad
Figure 4:
Pin Description
Pin Number
Pin Name
Description
1
LBI
Low Battery Comparator Input. 0.6V Threshold. May not be left floating. If
connected to GND, LBO is working as Power Output OK.
2
GND
3
LX
4
VOUT
Output Voltage. Decouple VOUT with a ceramic capacitor as close as
possible to VOUT and GND.
5
REF
Reference Pin. Connect a 100nF ceramic capacitor to this pin.
6
LBO
Low Battery Comparator Output. Open-drain output.
7
EN
Enable Pin. Logic controlled shutdown input.
1 = Normal operation;
0 = Shutdown; shutdown current <100nA.
8
VIN
Battery Voltage Input. Decouple VIN with a 22μF ceramic capacitor as
close as possible to VIN and GND.
9
NC
Exposed Pad. This pad is not connected internally. Can be left floating or
connect to GND to achieve an optimal thermal performance.
ams Datasheet
[v1-11] 2015-Jan-28
Ground
External Inductor Connector
Page 3
Document Feedback
AS1310 − Absolute Maximum Ratings
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
Junction Temperature
Storage Temperature Range
-55
Package Body Temperature
Humidity non-condensing
Moisture Sensitive Level
Page 4
Document Feedback
5
1
ºC/W
+125
ºC
+125
ºC
+260
ºC
85
%
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 maximum floor life
time of unlimited
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Electrical Characteristics
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, C REF = 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
TAMB
Parameter
Conditions
Max
Units
-40
+85
°C
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
Operating Temperature
Range
Min
Typ
Input
VIN
Input Voltage Range
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
IQ
ISHDN
ams Datasheet
[v1-11] 2015-Jan-28
0.8
1
Page 5
Document Feedback
AS1310 − Electrical Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Units
Switches
NMOS
PMOS
IPEAK
0.35
Ω
0.5
Ω
VOUT = 3V
RON
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 Bias Current
IREF
REF Input Bias Current
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
0.6
25
ILBI
LBI Leakage Current
LBI = 3.6V, TAMB = +25°C
VLBO
LBO Voltage Low (2)
ILBO = 1mA
ILBO
LBO Leakage Current
LBO = 3.6V, TAMB = +25°C
Power-OK Threshold
LBI = 0V, Falling Edge
20
90
92.5
mV
100
nA
100
mV
100
nA
95
%
Thermal Protection
Thermal Shutdown
10°C Hysteresis
150
°C
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 V OUT is below 92.5% of its nominal value.
Page 6
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Typical Operating Characteristics
Typical Operating
Characteristics
TAMB = +25°C, unless otherwise specified.
Figure 7:
Efficiency vs. Output Current; VOUT = 1.8V
90
L1: XPL2010-682M
85
Efficiency (%)
80
75
70
65
60
55
50
Vin = 0.9V
Vin = 1.2V
45
Vin = 1.5V
40
0.01
0.1
1
10
100
1000
Output Current (mA)
Figure 8:
Efficiency vs. Output Current; VOUT = 1.8V
90
85
L1: XPL7030-682M
Efficiency (%)
80
75
70
65
60
55
50
Vin = 0.9V
Vin = 1.2V
45
40
0.01
Vin = 1.5V
0.1
1
10
100
1000
Output Current (mA)
ams Datasheet
[v1-11] 2015-Jan-28
Page 7
Document Feedback
AS1310 − Typical Operating Characteristics
Figure 9:
Efficiency vs. Output Current; VOUT = 3.0V
100
95
L1: XPL2010-682M
Efficiency (%)
90
85
80
75
70
65
60
Vin = 0.9V
55
50
Vin = 1.2V
Vin = 1.5V
Vin = 1.8V
45
Vin = 2.4V
40
0.01
0.1
1
10
100
1000
Output Current (mA)
Figure 10:
Efficiency vs. Output Current; VOUT = 3.0V
100
95
L1: XPL7030-682M
Efficiency (%)
90
85
80
75
70
65
60
Vin = 0.9V
55
50
Vin = 1.2V
Vin = 1.5V
Vin = 1.8V
45
40
0.01
Vin = 2.4V
0.1
1
10
100
1000
Output Current (mA)
Page 8
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Typical Operating Characteristics
Figure 11:
Efficiency vs. Input Voltage; VOUT = 1.8V
100
L1: XPL2010-682M
95
Efficiency (%)
90
85
80
75
70
65
60
Iout = 1mA
Iout=10mA
55
Iout=50mA
50
0.7
0.9
1.1
1.3
1.5
1.7
1.9
Input Voltage (V)
Figure 12:
Maximum Output Current vs. Input Voltage
180
Output Current (mA) .
160
140
120
100
80
60
40
Vout = 1.8V
20
Vout = 3.0V
0
0
0.5
1
1.5
2
2.5
3
Input Voltage (V)
ams Datasheet
[v1-11] 2015-Jan-28
Page 9
Document Feedback
AS1310 − Typical Operating Characteristics
Figure 13:
Start-up Voltage vs. Output Current
1
Start-up Voltage (V)
0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0
1
2
3
4
5
6
7
8
9
10
Output Current (mA)
Figure 14:
RON vs. Temperature
1
0.9
0.8
0.7
R ON (Ω)
0.6
0.5
0.4
0.3
0.2
PM OS
0.1
0
-40
NM OS
-15
10
35
60
85
Temperature (°C)
Page 10
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Typical Operating Characteristics
100mV/Div
VOUT (AC)
ILX
200mA/Div
VLX
2V/Div
Figure 15:
Output Voltage Ripple; VIN = 2V, VOUT = 3V,Rload = 100Ω
5μs/Div
ams Datasheet
[v1-11] 2015-Jan-28
Page 11
Document Feedback
AS1310 − Detailed Description
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 V OUT ).
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.
Page 12
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Detailed Description
Figure 16:
Simplified Boost DCDC Architecture
L1
SW2
VIN
VOUT
Q
CIN
SW1
Q
FB
COUT
RLOAD
IPK
GND
0V
0V
ON time of the power switch (Faraday’s Law) is given by:
(EQ1)
LI PK
T ON = -------------------------------------------------------------------- sec [volts, amps, ohms, Henry]
V IN – ( I PK R SW1 + I PK R L1 )
Applying Min and Max values and neglecting the resistive
voltage drop across L1 and SW1;
(EQ2)
(EQ3)
ams Datasheet
[v1-11] 2015-Jan-28
TON _ MIN =
TON _ MAX =
LMIN I PK _ MIN
V IN _ MAX
LMAX I PK _ MAX
V IN _ MIN
Page 13
Document Feedback
AS1310 − Detailed Description
Figure 17:
Simplified Voltage and Current Waveforms
V
0.99VOUT_NOM
VOUT Ripple
VOUT
VIND_TOFF
B
B
VIN
VIND_TON
C
D
A
C
D
0
T
TOFF
IL
TWAIT
TON
SW1_on
SW2_off
TOFF
TWAIT
IPK
0
SW2_on
SW1_off
T
T
T
Another important relationship is the “volt-seconds” law.
Expressed as following:
(EQ4)
V ON T ON = V OFF T OFF
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:
(EQ5)
T ON
V OUT – V IN
------------ = ----------------------------V IN
T OFF
The time segment called T WAIT in Figure 17 is a measure of the
“hold-up” time of the output capacitor. While the output
voltage is above the threshold (0.99xV OUT ), the output is
assumed to be in regulation and no further switching occurs.
Page 14
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Detailed Description
Inductor Choice Example
For the AS1310 V IN_MIN = 0.9V, V OUT_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, L MAX 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 V IN.
Energy stored during the ON time is given by:
(EQ6)
2
E = 0.5L ( I PK ) Joules (Region A in Figure 17)
If the overall time period (TON + TOFF) is T, the power taken from
the input is:
2
(EQ7)
0.5L ( I PK )
P IN = --------------------------- Watts
T
Assume output power is 0.8 PIN to establish an initial value of
operating period T.
T WAIT is determined by the time taken for the output voltage to
fall to 0.99xV OUT. The longer the wait time, the lower will be the
supply current of the converter. Longer wait times require
increased output capacitance. Choose T WAIT = 10% T as a
minimum starting point for maximum energy transfer. For very
low power load applications, choose T WAIT ≥ 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):
(EQ8)
T
I
PK OFF
- ------------PREGION_C = V IN -------
2
T
Output power is also composed of the inductor component
(Region B in Figure 17), neglecting efficiency loss:
ams Datasheet
[v1-11] 2015-Jan-28
Page 15
Document Feedback
AS1310 − Detailed Description
(EQ9)
0.5L ( I
T
)
2
PK
PREGION_B = ---------------------------
Total power delivered to the load is the sum of EQ 8 and EQ 9:
2
(EQ10)
I PK T OFF 0.5L ( I PK )
P TOTAL = V IN -------- ------------- + --------------------------2 T
T
From EQ 3 (using nominal values) peak current is given by:
(EQ11)
T ON V IN
I PK = --------------------L
Substituting EQ 11 into EQ 10 and re-arranging:
2
(EQ12)
V IN T ON
P TOTAL = ----------------------- ( 0.9T )
2TL
0.9T incorporates a wait time T WAIT = 10% T
Output power in terms of regulated output voltage and load
resistance is:
2
(EQ13)
V OUT
P OUT = -----------------R LOAD
Combining EQ 12 and EQ 13:
2
(EQ14)
2
V IN T ON
V OUT
----------------- = ---------------------- ( 0.9T )η
R LOAD
2TL
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.
(EQ15)
I PEAK T ON
C IN = -------------------------V RIPPLE
Using TON = 1μs, and I PEAK = 480mA, and V RIPPLE = 50mV, EQ 15
yields:
CIN = 9.6μF
Nearest preferred would be 10μF.
(EQ16)
Page 16
Document Feedback
V PK _ RIPPLE _ ESR = I PK R ESR
ams Datasheet
[v1-11] 2015-Jan-28
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.
(EQ17)
COUT =
I LOAD (TON + TWAIT )
(1 − 0.99)VOUT _ NOM
Note(s): There is also a ripple component due to the equivalent
series resistance (ESR) of the capacitor.
Summary
User Application Defines:
V INmin, V INmax, VOUTmin, V OUTmax, I LOADmin, I LOADmax
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 V IN 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 T WAIT via EQ 6 or EQ 13, and use EQ 16 to find the
value.
ams Datasheet
[v1-11] 2015-Jan-28
Page 17
Document Feedback
AS1310 − Application Information
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
VIN 0.7V to 3.6V
LX
Zero
Crossing
Detector
L1 6.8µF
VOUT
VOUT 1.8V to 3.3V
COUT
22µF
LBI
R3
+
ON
OFF
EN
VIN
100mV
LBO
+
-
CIN
22µF
-
Startup
Circuit ry
Driver &
Control
Logic
0.6V
92.5% VREF
+
Imax
Detection
-
REF
VREF
GND
CREF
100nF
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 V IN or V OUT, as long as it is
limited to less than 3.6V.
Output Disconnect and Inrush Limiting. During shutdown
V OUT 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 V OUTNOM.
Page 18
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
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 V OUT 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
V IN = 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 R 3 from pin LBO to pin V OUT. 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 R 2 and then calculate R 1 as:
(EQ18)
V IN
R 1 = R 2 ⋅  ------------ – 1
 V LBI

Where: V LBI is 0.6V ±30mV
ams Datasheet
[v1-11] 2015-Jan-28
Page 19
Document Feedback
AS1310 − Application Information
Figure 19:
Typical Application with Adjustable Battery Monitoring
VIN
0.7V to 3.6V
L1
6.8µH
LX
LBO
Low Battery
Detect
AS1310
CIN
22µF
ON
VIN
OUT
LBI
REF
EN
GND
VOUT
1.8V to 3.3V
CREF
100nF
COUT
22µF
OFF
0V
Figure 20:
Typical Application with LBO working as Power-OK
VIN
0.7V to 3.6V
L1
6.8µH
LX
LBO
Power OK
Output
AS1310
CIN
22µF
ON
VIN
OUT
LBI
REF
EN
GND
VOUT
1.8V to 3.3V
CREF
100nF
COUT
22µF
OFF
0V
Page 20
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
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
vias in the printed circuit board. It’s also recommended to solder
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
100
90
L1: XPL2010-682M
Efficiency (%)
80
70
60
50
40
30
20
Vin = 1.1V
10
0
0.001
Vin = 1.5V
0.01
0.1
1
10
100
Output Current (mA)
ams Datasheet
[v1-11] 2015-Jan-28
Page 21
Document Feedback
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
L
DCR
Current
Rating
Dimensions
(L/W/T)
XPL2010-682M
6.8μH
421mΩ
0.62A
2.0x1.9x1.0 mm
EPL2014-682M
6.8μH
287mΩ
0.59A
2.0x2.0x1.4 mm
LPS3015-682M
6.8μH
300mΩ
0.86A
3.0x3.0x1.5 mm
LPS3314-682M
6.8μH
240mΩ
0.9A
3.3x3.3x1.3 mm
LPS4018-682M
6.8μH
150mΩ
1.3A
3.9x3.9x1.7 mm
XPL7030-682M
6.8μH
59mΩ
9.4A
7.0x7.0x3.0 mm
LQH32CN6R8M53L
6.8μH
250mΩ
0.54A
3.2x2.5x1.55 mm
LQH3NPN6R8NJ0L
6.8μH
210mΩ
0.7A
3.0x3.0x1.1 mm
LQH44PN6R8MJ0L
6.8μH
143mΩ
0.72A
4.0x4.0x1.1 mm
Page 22
Document Feedback
Manufacturer
Coilcraft
www.coilcraft.com
Murata
www.murata.com
ams Datasheet
[v1-11] 2015-Jan-28
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 V IN capacitor should be
22μF. The V OUT 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
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.
Figure 24:
Recommended Capacitors for REF
Part Number
C
TC
Code
Insulation
Resistance
Rated
Voltage
Dimensions
(L/W/T)
GRM188R71C104KA01
100nF
X7R
>5GΩ
16V
0603,
T=0.8mm
GRM31CR61C226KE15
100nF
X7R
>5GΩ
50V
0805,
T=1.25mm
Manufacturer
Murata
www.murata.com
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, V IN
and GND pins should be minimized. Similarly, the output loop
formed by C2, V OUT and GND should also be minimized. Ideally
both loops should connect to GND in a “star” fashion. Finally, it
is important to return C REF to the GND pin directly.
ams Datasheet
[v1-11] 2015-Jan-28
Page 23
Document Feedback
AS1310 − Package Drawings & Mark ings
Package Drawings & Markings
The device is available in a TDFN (2x2) 8-pin package.
Figure 25:
Drawings and Dimensions
XXX
A2
Green
RoHS
Symbol
Min
Nom
Max
A
A1
A3
L
b
D
E
e
D2
E2
aaa
bbb
ccc
ddd
eee
fff
N
0.51
0.00
0.55
0.02
0.15 REF
0.325
0.25
2.00 BSC
2.00 BSC
0.50 BSC
1.60
0.90
0.15
0.10
0.10
0.05
0.08
0.10
8
0.60
0.05
0.225
0.18
1.45
0.75
-
0.425
0.30
1.70
1.00
-
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.
Page 24
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Ordering & Contact Information
Ordering & Contact Information
The device is available as the standard products shown in
Figure 26.
Figure 26:
Ordering Information
Delivery
Form
Package
1.8V
Tape and Reel
TDFN (2x2) 8-pin
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 Code
Marking
Output
AS1310-BTDT-18
A2
AS1310-BTDT-20
Description
Ultra Low Quiescent
Current,
Hysteretic DC-DC
Step-Up Converter
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:
[email protected]
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
ams Datasheet
[v1-11] 2015-Jan-28
Page 25
Document Feedback
AS1310 − RoHS Compliant & ams Green Statement
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.
Page 26
Document Feedback
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Copyrights & Disclaimer
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.
ams Datasheet
[v1-11] 2015-Jan-28
Page 27
Document Feedback
AS1310 − Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Page 28
Document Feedback
Product Status
Definition
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
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
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
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
ams Datasheet
[v1-11] 2015-Jan-28
AS1310 − Revision Information
Revision Information
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
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.
ams Datasheet
[v1-11] 2015-Jan-28
Page 29
Document Feedback
AS1310 − Content Guide
Content Guide
Page 30
Document Feedback
1
1
2
General Description
Key Benefits & Features
Applications
3
4
5
7
Pin Assignment
Absolute Maximum Ratings
Electrical Characteristics
Typical Operating Characteristics
12
12
12
15
15
16
17
17
Detailed Description
Hysteretic Boost Converter
Input Loop Timing
Inductor Choice Example
Output Loop Timing
Input Capacitor Selection
Output Capacitor Selection
Summary
18
18
19
21
21
22
22
23
23
Application Information
AS1310 Features
Power-OK and Low-Battery-Detect Functionality
Thermal Shutdown
Always ON Operation
Component Selection
Inductor Selection
Capacitor Selection
Layout Considerations
24
25
26
27
28
29
Package Drawings & Markings
Ordering & Contact Information
RoHS Compliant & ams Green Statement
Copyrights & Disclaimer
Document Status
Revision Information
ams Datasheet
[v1-11] 2015-Jan-28