AIC1620/AIC1621/AIC1622
High Efficiency Synchronous Step-Up DC/DC
Converter
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FEATURES
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DESCRIPTION
The AIC1620/AIC1621/AIC1622 are high effi-
ciency step up DC-DC converter. The start-up
voltage is as low as 0.8V and operate with an
input voltage down to 0.7V. Consuming only
20µA of quiescent current. These devices offer
a built-in synchronous rectifier that reduces
size and cost by eliminating the need for an ex-
ternal Schottky diode and improves overall effi-
ciency by minimizing losses.
The switching frequency depends on the load
and the input voltage can range up to 500KHz.
The peak current of the internal switch is fixed
at 0.8A (AIC1620), at 0.45A (AIC1621), or is
selectable (AIC1622) for design flexibility. Rip-
ple does not exceed the product of the switch
current limit and the filter capacitor equivalent
series resistance (ESR). The AIC1622 also fea-
tures a circuit that eliminates noise due to in-
ductor ringing.
High Efficiency 93% (V
IN
=2.4V, V
OUT
=3.3V,
I
OUT
=200mA).
20µA Quiescent Supply Current.
Power-Saving Shutdown Mode (0.1µA typical).
Internal Synchronous Rectifier ( no external
diode )
Selectable Current Limit for Reduced Ripple
( AIC1622 ).
Low Noise , Anti-Ringing Feature ( AIC1622 )
On-Chip Low Battery Detector.
Low Battery Hysteresis
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APPLICATIONS
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Palmtop & Notebook Computers.
PDAs
Wireless Phones
Pocket Organizers.
Cameras.
1 to 2-Cell Hand-Held Devices
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TYPICAL APPLICATION CIRCUIT
V
IN
+
100µF
OFF
SHDN
AIC1620
AIC1621
AIC1622
LX
OUT
22µH
Output 3.3V, or
Adj. (1.8V to 4.0V)
up to 300mA
ON
+
220µF
Low-Battery
Detect In
LBI
REF
0.1µF
LBO
FB
LBO
GND
FB
Low-Battery
Detect Out
Analog Integrations Corporation
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
DS-1620-00 032502
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AIC1620/AIC1621/AIC1622
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ORDERING INFORMATION
AIC1620CX XX
AIC1621C X XX
AIC1622C X XX
PACKING TYPE
TR: TAPE & REEL
PACKAGING TYPE
O: MSOP8 (for AIC1620/1)
O: MSOP10 (for AIC1622)
PIN CONFIGURATION
(MSOP8)
FB 1
LBI 2
LBO 3
REF 4
TOP VIEW
8
OUT
LX
GND
SHDN
AIC1620
AIC1621
7
6
5
(MSOP10)
FB 1
TOP VIEW
10
OUT
Example: AIC1620COTR
à
In MSO8 Package & Taping &
Reel Packing Type
LBI 2
LBO 3
CLSEL 4
REF 5
9 LX
AIC1622
8
7
6
GND
BATT
SHDN
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ABSOLUTE MAXIMUM RATINGS
Supply Voltage (OUT to GND)
Switch Voltage (LX to GND)
Battery Voltage (Batt to GND)
SHDN , LBO to GND
LBI, REF, FB, CLSEL to GND
Switch Current (LX)
Output Current (OUT)
Operating Temperature Range
Storage Temperature Range
8.0V
V
OUT
+ 0.3V
6.0V
6.0V
V
OUT
+0.3V
-1.5A to +1.5A
-1.5A to +1.5A
-40°C ~ +85°C
-65°C ~150°C
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TEST CIRCUIT
Refer to Typical Application Circuit.
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AIC1620/AIC1621/AIC1622
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ELECTRICAL CHARACTERISTICS
(V
T
A
=25°C, unless otherwise specified.)
BATT
=2.0V,
V
OUT
=3.3V (FB=V
OUT
), R
L
=∝,
PARAMETER
Minimum Input Voltage
Operating Voltage
Start-Up Voltage
Start-Up Voltage Tempco
Output Voltage Range
Output Voltage
Steady State Output Current
(Note 2)
Reference Voltage
Reference Voltage Tempco
Reference Load Regulation
Reference Line Regulation
FB , LBI Input Threshold
Internal switch On-Resistance
LX Switch Current Limit
TEST CONDITIONS
MIN.
TYP.
0.7
MAX.
UNIT
V
1.1
R
L
=3KΩ (Note1)
0.8
-2
1.8
FB = V
OUT
FB=OUT
AIC1620
AIC1622 (CLSEL=OUT)
AIC1622 (CLSEL=GND)
I
REF
= 0
3.17
300
150
1.199
3.3
400
4.0
1.1
V
V
mV/°C
4.0
3.43
V
(
V
OUT
=3.3V) AIC1621
mA
220
1.23
0.024
1.261
V
mV/°C
30
10
1.261
mV
mV/V
V
Ω
1.0
A
0.6
1
35
µA
µA
I
REF
= 0 to 100
µA
V
OUT
= 1.8V to 4V
1.199
I
LX
= 100mA
AIC1620,AIC1622(CLSEL = OUT)
AIC1621,AIC1622(CLSEL = GND)
0.6
0.3
10
5
1.23
0.3
0.8
0.45
0.05
20
LX Leakage Current
Operating Current into OUT
(Note 3)
Shutdown Current into OUT
Efficiency
V
LX
=0V, 4V; V
OUT
=4V
V
FB
= 1.4V , V
OUT
= 3.3V
SHDN = GND
V
OUT
= 3.3V ,I
LOAD
= 200mA
V
OUT
= 2V ,I
LOAD
= 1mA
0.1
90
1
µA
%
85
2
0.6
4
0.9
0.03
7
1.3
50
µS
µS
nA
LX Switch On-Time
LX Switch Off-Time
FB Input Current
V
FB
=1V , V
OUT
= 3.3V
V
FB
=1V , V
OUT
= 3.3V
V
FB
= 1.4V
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AIC1620/AIC1621/AIC1622
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ELECTRICAL CHARACTERISTICS
(Continued)
PARAMETER
LBI Input Current
CLSEL Input Current
TEST CONDITIONS
V
LBI
= 1.4V
AIC1622 , CLSEL = OUT
V
SHDN
= 0 or V
OUT
V
LBI
= 0, I
SINK
= 1mA
V
LBO
= 5.5V, V
LBI
= 5.5V
MIN.
TYP.
1
1.4
0.07
0.2
0.07
50
MAX.
50
3
50
0.4
1
UNIT
nA
µA
nA
µA
SHDN
Input Current
LBO
Low Output Voltage
LBO
Off Leakage Current
LBI Hystereisis
Damping Switch Resistance
mV
100
0.2V
OUT
Ω
V
AIC1622, V
BATT
= 2V
50
SHDN
Input Voltage
0.8V
OUT
0.2V
OUT
CLSEL Input Voltage
0.8V
OUT
V
Note 1:
Start-up voltage operation is guaranteed without the addition of an external Schottky diode between the in-
put and output.
Note 2:
Steady-state output current indicates that the device maintains output voltage regulation under load.
Note 3:
Device is bootstrapped (power to the IC comes from OUT). This correlates directly with the actual battery
supply.
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TYPICAL PERFORMANCE CHARACTERISTICS
100
90
80
160
140
120
100
80
60
40
20
0 0.0
Efficiency (%)
70
60
50
40
30
20
10
0
0.01
0.1
1
V
IN
=2.4V
V
IN
=1.2V
Input Battery Current (
µ
A)
I_limit=0.8A , V
OUT
=3.3V
I_limit=0.45A , V
OUT
=3.3V
0.5
1.0
1.5
2.0
2.5
3.0
10
100
1000
Loading (mA)
Input battery voltage (V)
Fig. 1
V
OUT
=3.3V
CLSEL=OUT (0.8A)
Fig. 2
No-Load Battery Current vs. Input Battery Voltage
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AIC1620/AIC1621/AIC1622
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TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
100
1.8
1.6
90
80
Start-up Voltage (V)
1.4
1.2
1.0
0.8
0.6
0.4
Efficiency (%)
V
IN
=2.4V
70
Without Diode
V
IN
=1.2V
60
With Diode
50
0.2
40
0.01
0.1
1
10
100
1000
0.0
0.01
0.1
1
10
100
Loading (mA)
Fig. 3 V
OUT
=3.3V CLSEL=GND (0.45A)
0.10
0.08
2.2
2.0
Load Current (mA)
Fig. 4 Start-up Voltage vs. Load Current
Shutdown Current (µA)
0.06
0.04
0.02
0.00
-0.02
-0.04
-0.06
-0.08
-0.10
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Shutdown Threshold (V)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Fig. 5
800
V
OUT
(V)
Shutdown Current vs. V
OUT
Output Voltage (V)
Fig. 6
Shutdown Threshold vs. Output Voltage
Maximum Output Current (mA)
700
600
V
OUT
=3.3V
CLSEL=OUT
LX pin waveform
500
400
300
200
100
0
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
V
OUT
AC Couple
CLSEL=GND
Inductor Current
V
IN
=2.4V
V
OUT
=3.3V
Input Voltage (V)
Fig. 7
Maximum Output Current vs. Input Voltage
Fig. 8 Heavy Load Waveform
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