AIC1553
Compact 500KHz PWM/PFM, Step-Down DC/DC
Converters
Analog Integrations Corporation
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
DS-1553-P2 061402
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
1
FEATURES
Tiny 5-Lead SOT-23 package
Uses Tiny Capacitors and Inductor
High Frequency Operation: 500KHz
High Output Current: 500mA
Low R
DS(ON)
Internal Switch: 0.6
High Efficiency: Up to 90%
Current Mode Operation for Excellent Line and
Load Transient Response
Short-Circuit Protected
Low Quiescent Current: 22
A
Low Dropout Operation: 100% Duty Cycle
Ultralow Shutdown Current: I
Q
< 1
A
Peak Inductor Current Independent of Inductor
Value
Low Output Voltages: Down to 0.75V
APPLICATIONS
Cellular Phones.
PDAs and Handy-Terminals.
CPU I/O Supplies.
Cordless Phones.
Notebook Chipset Supplies.
Handheld Equipment
DESCRIPTION
The AIC1553 is a step-down, current mode,
DC/DC converter. It operates from 2.5V to 5.5V
input voltage range and switches at 500KHz,
allowing the use of tiny, low cost capacitors and
inductors. The output voltage is adjustable from
0.75V to 5V. A built-in 0.6
switch allows up to
0.5A of output current at high efficiency.
The AIC1553 operates continuously to very low
load currents to provide low ripple at the
expense of light load efficiency. With no load,
the AIC1553 draws only 22
A. In shutdown
mode, it draws less than 1
A, making it ideal for
current sensitive applications.
The tiny 5-lead SOT-23 package makes it
easy to save the layout area.
TYPICAL APPLICATION CIRCUIT
SW 1
GND 2
VFB 3
VIN
5
SD
4
U1
AIC1553
V
IN
+
C1
10
F
L1
6.8
H
R2
560K
R1
240K
C2
47
F
C3
D1
SS12
C4
4.7
F
V
OUT
ON/OFF
2.5V
2.5V~5.5V
22pF
2.5V/500mA Step-Down Converter
AIC1553
2
ORDERING INFORMATION
PIN CONFIGURATION
FRONT VIEW
Example: AIC1553CVTR
In SOT-23-5 Package & Tape &
Reel Packing Type
VIN
GND
SW
3
2
1
4
5
VFB
SD
AIC1553CXXX XX
PACKING TYPE
TR: TAPE & REEL
BG: BAG
PACKING TYPE
TR: TAPE & REEL
BG: BAG
PACKAGE TYPE
V: SOT-23-5
SOT-23-5 MARKING
Part No.
Marking
AIC1553CV EP01
ABSOLUTE MAXIMUM RATINGS
(Voltage Referred to GND Pin)
VIN Pin Voltage
- 0.3 to + 6V
SD Voltage (Pin 4)
- 0.3 to + 6V
V
FB
Voltage (Pin 3)
- 0.3 to + 6V
VIN SW (Max Switch Voltage)
7.0V to - 0.3V
Operating Temperature Range
-40
C ~ 85C
Junction Temperature Range
125
C
Storage Temperature Range
- 65
C ~ 150C
TEST CIRCUIT
Refer to TYPICAL APPLICATION CIRCUIT.
AIC1553
3
ELECTRICAL CHARACTERISTICS
(V
IN
=3.6V, T
A
=25
C, unless otherwise
specified.)
PARAMETER SYMBOL
TEST
CONDITIONS
MIN
TYP
MAX
UNIT
Operating Voltage Range
V
IN
2.5 5.5 V
Feedback Pin Input Current
I
FB
0.1
A
Feedback Voltage
V
FB
0.75 V
Reference Voltage Line
Regulation
V
LINE REG
V
IN
=2.5V to 5V, I
LOAD
=200mA
5
15
mV
Output Voltage Load
Regulation
V
LOAD REG
I
LOAD
=100mA to 500mA
5
20
mV
Quiescent Current
I
Q
22
A
Shutdown Mode Input DC
Supply Current
0.25 1
A
Shutdown Threshold High
Shutdown Threshold Low
V
SD
0.3
1.4
0.6
1.6
V
Peak Switch Current
Threshold
I
SW(PEAK)
V
FB
= 0V
0.7
1.1
A
Switch ON Resistance
R
DS(ON)
V
IN
= 3.3V, V
FB
= 0V
0.6
AIC1553
4
TYPICAL PERFORMANCE CHARACTERISTICS
-50
0
50
100
150
0.730
0.735
0.740
0.745
0.750
0.755
0.760
0.765
0.770
V
IN
=3.6V
Fig. 2 Reference Voltage vs. Temperature
Reference V
o
lt
age (V)
Temperature (
C)
Frequency (KH
z
)
-50
0
50
100
150
400
425
450
475
500
525
550
575
600
V
IN
=3.6V
Fig. 2 Frequency vs. Temperature
Temperature (
C)
2
3
4
5
6
400
450
500
550
600
650
Fig. 3 Switch Resistance vs. Supply Voltage
O
N
R
e
sist
ance (m
)
Supply Voltage (V)
Ef
ficiency (%)
1
10
100
1000
40
45
50
55
60
65
70
75
80
85
90
95
100
Fig. 4 Efficiency vs. Load Current
Load Current (mA)
V
OUT
=1.5V
V
IN
=2.5V
V
IN
=3.3V
V
IN
=5V
Fig. 5 Efficiency vs. Load Current
Ef
ficiency (%)
Load Current (mA)
1
10
100
1000
65
70
75
80
85
90
95
100
V
OUT
=2.5V
V
IN
=3.3V
V
IN
=3.3V
V
IN
=5V
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