AIC1562
High-Efficiency, Bootstrapped DC/DC Converter
Analog Integrations Corporation
4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
www.analog.com.tw
DS-1562-00 Jan 30, 01
TEL: 886-3-5772500
FAX: 886-3-5772510
1
FEATURES
3V to 20V Input Voltage Operation.
Internal 800mA Switch.
Bootstrapped Driver for N-Channel MOSFET.
High Efficiency (up to 90%).
Fast Transient Response.
Internal
2% Reference.
Low Quiescent Current at 1.6mA.
Frequency Operation from 200Hz to 200KHz.
APPLICATIONS
CPU Power Supplies for Mother Boards.
DC/DC Converters for CPU VRMs.
Step-Down DC-DC Converter Module.
DESCRIPTION
The AIC1562 is a high performance monolithic
DC/DC converter drive IC with output-
bootstrapping capability, designed specifically for
driving N-channel MOSFET to achieve maximum
possible power conversion efficiency. The device
consists of an internal temperature compensated
reference, comparator, controlled duty cycle
oscillator, bootstrapped driver and a 800mA output
switch. Working with the AIC1741, a low power
adjustable regulator, the AIC1562 works at 100%
duty cycle under heavy load transient conditions to
minimize transient response time, making it an idea
precision switching power solution to stringent
requirements on computer mother boards.
TYPICAL APPLICATION CIRCUIT
+
+
V
IN
5V
V
OUT
: 2.5V~3.5V/10A
12V
BYV
1
1
8
AIC1741
VOUT
GND
FB
VIN
1000
F/6.3Vx2
C8, C9
M
T
D
20N
03D
H
Q1
2N
2907
A
Q2
BST
SE
AIC1562
SC
C1
47
F
+
P5
MICROPROCESSOR
CPU
1000
F/6.3V
x5
C12
0.1
F
x2
1000
F
+
FB
GND
R8
10K
C2
220pF
R2
VCC
TC
0.022
F
C4
R1
1K
C3
0.1
F
D3
D1
L1
7.5
F
R7
470
C5
0.1
F
R8
1K
R9
1K
R10
D2
1N4148
1N4148
Z1
5.1V
C11
0.1
F
x2
C10
C13
C11, C12: Ceramic Capacitor
L1: Iron Powder Core
V
OUT
= (1+R10/1K)x1.235V
24K
CPU Power Supply for P5 Mother Board
AIC1562
2
ORDERING INFORMATION
AIC1562 XX
ORDER NUMBER
AIC1562CN
(PLASTIC DIP)
PIN CONFIGURATION
AIC1562CS
(PLASTIC SO)
TOP VIEW
VCC
BST
SE
TC
GND
NC
FB
SC 1
3
4
2
8
6
5
7
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
TEMPERATURE
C: 0
C~+70C
ABSOLUTE MAXIMUM RATINGS
Supply Voltage ........................................................................................................... 20V
Comparator Input Voltage Range ...................................................................... -0.3V~20V
Switch Collector Voltage
............................................................................................ 20V
Switch Emitter Voltage
.............................................................................................. 20V
Switch Collector to Emitter Voltage
........................................................................... 20V
Driver Collector Voltage
............................................................................................ 20V
Switch Current ............................................................................................................. 1A
Power Dissipation and Thermal Characteristics
DIP Package
Ta=
25
C
....................................................................... 1.0W
Thermal
Resistance .................................................. 100
C/W
SO Package
Ta=
25
C ................................................................... 625mW
Thermal
Resistance .................................................. 160
C/W
Operating Junction Temperature
............................................................................ 125
C
Operating Ambient Temperature Range
........................................................... 0
C~70C
Storage Temperature Range................................................................... - 65
C ~ 150C
TEST CIRCUIT
AIC1562
3
BST
AIC1562
NC
8
7
6
5
4
3
2
1
FB
VCC
SC
SE
TC
GND
R1
1K
C
T
1nF
0.8A
Current Source
VCC
1.275V
1.225V
VCC
40mA
Current Source
2V/0V
I
DISCHARG
/ I
CHG
AIC1562
4
ELECTRICAL CHARACTERISTICS
(VCC= 5V, Ta=25
C unless otherwise specified.)
PARAMETER
TEST CONDITIONS
SYMBOL
MIN.
TYP.
MAX.
UNIT
Oscillator
Charging Current
5.0V
VCC20V
I
CHG
15
25
35
A
Discharge Current
5.0
VCC20V
I
DISCHG
120
150
180
A
Voltage Swing
PIN 3
V
OSC
0.6
V
Discharge to Charge Current
Ratio
V
IS
=VCC
I
DISCHG
/ I
CHG
6.0
Output Switch
Saturation Voltage, Emitter
Follower Connection
I
SE
=0.8A;
V
BST
=V
SC
= VCC
V
CE(SAT)
1.6
2.0
V
Saturation Voltage
I
SC
=0.8A; I
BST
=40mA,
(Forced
20)
V
CE (SAT)
0.5
0.8
V
DC Current Gain
I
SC
=0.8A; V
CE
=5.0V
h
FE
35
120
Collector Off-State Current
V
CE
=20V
I
C(OFF)
10
nA
Comparactor
Threshold Voltage
Ta=25
C
0
C Ta 70C
V
FB
1.225
1.21
1.25
1.275
1.29
V
V
Threshold Voltage Line
Regulation
3.0V
VCC20V
REG
LINE
0.1
0.5
mV/V
Input Bias Current
V
IN
=0V
I
IB
0.4
2
A
Supply current
V
IS
=VCC, pin 5>V
FB
5.0V
VCC20V
C
T
=1nF
PIN 2=GND
Remaining pins open
I
CC
1.6
3
mA
AIC1562
5
TYPICAL PERFORMANCE CHARACTERISTICS
CT, Oscillator Timing Capacitor (nF)
t
O
N
-
O
FF
Ou
t
p
u
t
S
w
it
ch
ON
-OF
F
T
i
m
e
(
S)
Output Switch ON-OFF Time vs. Oscillator Timing
Capacitor
0.1
1
10
100
1
10
ON TIME
VCC=5V
V
IPK
=VCC
PIN 5=GND
100
1000
OFF TIME
I
CC
S
u
pp
l
y
C
u
r
r
ent
(
m
A
)
0
5
10
15
20
0
0.4
0.8
1.2
1.8
2
VCC, Supply Voltage (V)
Standby Supply Current vs. Supply Voltage
C
T
=1nF
V
IS
=VCC
PIN 2=GND
V
FB
,
,
T
h
r
e
s
h
ol
d V
o
l
t
ag
e
(
V
)
Temperature (
C)
0
10
20
30
40
50
60
70
80
1.2
1.22
1.24
1.26
1.28
1.3
V
FB
, Threshold Voltage vs Temperature
VCC=5V
C
T
=1nF
PIN 2=GND
Emitter Follower Configuration Output Switch
Saturation Voltage vs. Emitter Current
IE, Emitter Current Current (A)
V
C
E
(SAT
),
Sa
tu
ra
t
i
o
n
Vo
l
t
a
g
e
(
V
)
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
VCC=5V
PIN 1, 7, 8= VCC
PIN 3, 5= GND
0
0
0.2
0.4
0.6
0.8
1
0
0.2
0.4
0.6
V
C
E
(SAT
)
,
S
a
t
u
r
a
t
i
on V
o
l
t
ag
e (
V
)
Temperature (
C)
Common Emitter Configuration Output Switch
Saturation Voltage vs. Collector Current
VCC=5V
PIN 7=VCC
PIN 2, 3, 5=GND
Forced Beta = 20
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