AIC1638
1-Cell, 3-Pin, Step-Up DC/DC Converter
Analog Integrations Corporation
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
DS-1638-01 012102
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
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FEATURES
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A Guaranteed Start-Up from less than 0.9 V.
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High Efficiency.
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Low Quiescent Current.
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Less Number of External Components needed.
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Low Ripple and Low Noise.
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Fixed Output Voltage: 2.7V, 3.0V, 3.3V, and 5V.
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Space Saving Packages: SOT-89 and TO-92.
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APPLICATIONS
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Pagers.
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Cameras.
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Wireless Microphones.
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Pocket Organizers.
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Battery Backup Suppliers.
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Portable Instruments.
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DESCRIPTION
The AIC1638 is a high efficiency step-up DC/DC
converter for applications using 1 to 4 NiMH
battery cells. Only three external components are
required to deliver a fixed output voltage of 2.7V,
3.0V, 3.3V, or 5V. The AIC1638 starts up from less
than 0.9V input with 1mA load. Pulse Frequency
Modulation scheme brings optimized performance
for applications with light output loading and low
input voltages. The output ripple and noise are
lower compared with the circuits operating in PSM
mode.
The PFM control circuit operating in 100KHz (max.)
switching rate results in smaller passive
components. The space saving SOT-89 and TO-
92 packages make the AIC1638 an ideal choice of
DC/DC converter for space conscious applications,
like pagers, electronic cameras, and wireless
microphones.
TYPICAL APPLICATION CIRCUIT
D1
GS SS12
VOUT
SW
GND
AIC1638-27
AIC1638-30
AIC1638-33
AIC1638-50
C2
47
F
+
V
OUT
L1
100
H
V
IN
+ C1
22
F
One Cell Step-Up DC/DC Converter
AIC1638
2
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ORDERING INFORMATION
PACKING TYPE
TR: TAPE & REEL
BG: BAG
PACKAGE TYPE
X: SOT-89
Z: TO-92
OUTPUT VOLTAGE
27: 2.7V
30: 3.0V
33: 3.3V
50: 5.0V
AIC1638-XXCXXX
Example: AIC1638-27CXTR
2.7V Version, in SOT-89 Package
& Tape & Reel Packing Type
TO-92
TOP VIEW
1: GND
2: VOUT
3: SW
1
2
3
1
2
3
SOT-89
TOP VIEW
1: GND
2: VOUT
3: SW
PIN CONFIGURATION
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ABSOLUATE MAXIMUM RATINGS
Supply Voltage (VOUT pin)... ... .... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .12V
SW pin Voltage ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... ... ... ... ... ... ... ... ... ... ... ... ... ... .12V
SW pin Switch Current ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 0.6A
Operating Temperature Range ... ... ... ... ... ... ... ... ... ... ... ... ..... ... ... ... ... .... .-40
C to 85
C
Storage Temperature Range ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... -65
C to 150
C
Lead Temperature (Soldering 10 Sec.) ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 260
C
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TEST CIRCUIT
2.5V
FOUT
AIC1638
VOUT
SW
100
GND
Oscillator Test Circuit
AIC1638
3
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ELECTRICAL CHARACTERISTICS
(T
A
=25
C, I
OUT
=10mA, Unless otherwise
specified)
PARAMETER
TEST CONDITIONS
SYMBOL
MIN.
TYP.
MAX.
UNIT
Output Voltage
AIC1638-27 V
IN
=1.8V
AIC1638-30 V
IN
=1.8V
AIC1638-33 V
IN
=2.0V
AIC1638-50 V
IN
=3.0V
V
OUT
2.633
2.925
3.218
4.875
2.700
3.000
3.300
5.000
2.767
3.075
3.382
5.125
V
Input Voltage
Normal Operation
V
IN
8
V
Start-Up Voltage
I
OUT
=1mA, V
IN
:0
2V
V
START
0.8
0.9
V
Min. Hold-on Voltage
I
OUT
=1mA, V
IN
:2
0V
V
HOLD
0.7
V
No-Load Input Current
I
OUT
=0mA
I
IN
15
A
Supply Current
AIC1638-27
AIC1638-30
AIC1638-33
AIC1638-50
EXT at no load, V
IN
=V
OUT
x 0.95
Measurement of the IC input
current (VOUT pin)
I
DD1
42
50
60
90
A
Supply Current
AIC1638-27
AIC1638-30
AIC1638-33
AIC1638-50
V
IN
=V
OUT
+ 0.5V
Measurement of the IC input
current (VOUT pin)
I
DD2
7
7
7
7
A
SW Leakage Current
V
SW
=10V, V
IN
=V
OUT
+ 0.5V
0.5
A
SW Switch-On
Resistance
AIC1638-27
AIC1638-30
AIC1638-33
AIC1638-50
V
IN
=V
OUT
x 0.95, V
SW
=0.4V
R
ON
1.3
1.2
1.1
1
Oscillator Duty Cycle
V
IN
=V
OUT
x 0.95
Measurement of the SW pin
waveform
DUTY
65
75
85
%
Max. Oscillator Freq.
V
IN
=V
OUT
x 0.95
Measurement of the SW pin
waveform
F
OSC
80
105
130
KHz
Efficiency
85
%
AIC1638
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TYPICAL PERFORMANCE CHARACTERISTICS
(Refer to Typical Application)
Capacitor (C2) : 47
F (Tantalum Type)
Diode (D1) : 1N5819 Schottky Type
Fig. 1 AIC1638-27 Load Regulation (L=100
H CD54)
0
20
40
60
80
100
120
140
160
180
2.2
2.3
2.4
2.5
2.6
2.7
2.8
V
IN
=
2.0V
V
IN
=1.8V
V
IN
=1.5V
V
IN
=1.2V
V
IN
=0.9V
Output
V
oltage (V)
Output Current (mA)
Fig. 2 AIC1638-27 Efficiency (L=100
H CD54)
0
20
40
60
80
100
120
140
160
180
55
60
65
70
75
80
85
V
IN
=2.0V
V
IN
=1.8V
V
IN
=1.5V
V
IN
=1.2V
V
IN
=0.9V
Efficiency (%)
Output current (mA)
Fig. 3 AIC1638-27 Load Regulation (
L=47
H CD54)
0
20
40
60
80
100 120
140
160
180
200 220
240
2.3
2.4
2.5
2.6
2.7
2.8
V
IN
=2.0V
V
IN
=1.8V
V
IN
=1.5V
V
IN
=1.2V
V
IN
=0.9V
Output
V
oltage (V)
Output Current (mA)
240
85
Fig. 4 AIC1638-27 Efficiency (L=47
H CD54)
Efficiency (%)
Output current (mA)
0
20
40
60
80
100 120
140 160
180 200
220
50
55
60
65
70
75
80
V
IN
=2.0V
V
IN
=1.8V
V
IN
=1.5V
V
IN
=1.2V
V
IN
=0.9V
Fig. 5 AIC1638-27 Start-Up & Hold-ON Voltage (L=47
H CD54)
0
2
4
6
8
10
12
14
16
18
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Start up
Hold on
Input Voltage (V)
Output Current (mA)
Fig. 6 AIC1638-27
Start-Up & Hold-ON Voltage
(L=100
H CD54)
0
2
4
6
8
10
12
14
16
18
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Start up
Hold on
Input Voltage (V)
Output Current (mA)
AIC1638
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TYPICAL PERFORMANCE CHARACTERISTICS
(Continued)
Temperature (
C)
-40
-20
0
20
40
60
80
100
2.62
2.64
2.66
2.68
2.70
2.72
2.74
2.76
2.78
Fig. 7 AIC1638-27 Output Voltage vs. Temperature
No Load
Output Voltage
V
OUT
(V)
-40
-20
0
20
40
60
80
100
20
40
60
80
100
120
140
160
Fig. 8 AIC1638-27 Switching Frequency vs. Temperature
Switching Frequency (kHz)
Temperature (
C)
-40
-20
0
20
40
60
80
100
66
68
70
72
74
76
78
80
82
Fig. 9 AIC1638-27 Maximum Duty Cycle vs. Temperature
Maximum Duty Cycle (%
)
Temperature (
C)
-40
-20
0
20
40
60
80
100
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Fig. 10 AIC1638-27 SW Turn On Resistance vs. Temperature
SW Turn On Resistance (
)
Temperature (
C)
-40
-20
0
20
40
60
80
100
20
24
28
32
36
40
44
48
52
Fig. 11 AIC1638-27 Supply Current vs. Temperature
Supply Current I
DD1
(
A)
Temperature (
C)
0
10
20
30
40
50
60
70
80
90
100 110 120 130 140
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
V
IN
=2.0V
V
IN
=1.8V
V
IN
=1.5V
V
IN
=1.2V
V
IN
=0.9V
Fig. 12 AIC1638-30 Load Regulation (L=100
H, CD54)
Output voltage
V
OUT
(V)
Output Current (mA)
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