AIC1580/L
Step-Down DC/DC Controller with Shutdown
Analog Integrations Corporation
4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan
DS-1580-01 012102
TEL: 886-3-5772500
FAX: 886-3-5772510
www.analog.com.tw
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FEATURES
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Operation Voltage up to 15V.
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Simple Voltage-Mode PWM Control.
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Fast Transient Response.
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2V and 1.3V
2% Feedback Voltage Reference
Option.
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Adjustable Current Limit without External Sense
Resistors.
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200KHz Switching Oscillator.
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Short-Circuit Protection with Low Short Circuit
Output Current.
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Low Shutdown Current
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Built-in Soft Start.
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APPLICATIONS
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Power Supply for Motherboard V
GTL
(1.5V Output)
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Power Supply for Motherboard V
I/O
.
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High-Power 5V to 3.xV DC/DC Regulators.
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Low-Voltage Distributed Power Supplies.
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DESCRIPTION
The AIC1580 is a high-power, high-efficiency
voltage-mode switching regulator controller for
motherboard V
I/O
power supply applications.
Designed to drive a N-channel MOSFET in a
standard buck topology, the AIC1580 features a
high voltage CMOS output driver, short-circuit
protection, and 8-pin package.
An external 4-bit Digital-to-Analog Converter
(DAC) can be used along with the AIC1580 to
adjust the output voltage from 2.0V to 3.5V in
0.1V increments. Table 1 on the following page
specifies the corresponding output voltage for
16 combinations of DAC inputs as in the typical
application circuit.
The 200KHz switching frequency allows for
using small external components while
maintaining high conversion efficiency. The
11MHz bandwidth and 6V/
S slew rate of the
error amplifier ensures high converter
bandwidth and fast transient response.
The AIC1580 provides adjustable overcurrent
and short-circuit protections by sensing the
output current across the on resistance of the
external N-channel MOSFET rather than an
external low value sense resistor.
The AIC1580L provides lower reference voltage
(1.30V) than the default (2.00V, AIC1580) for
lower V
OUT
requirement.
AIC1580/L
2
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ORDERING INFORMATION
PIN CONFIGURATION
SO-8
TOP VIEW
*AIC1580: 2.00V
AIC1580L: 1.30V
PHASE
1
3
4
2
VCC
SD
COMP
FB*
UGATE
GND
8
6
5
7
OCSET
PACKING TYPE
TR: TAPE & REEL
TB: TUBE
PACKAGING TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
REFERENCE
VOLTAGE
DEFAULT: 2.00V
L: 1.30V
AIC1580XCXXX
Example: AIC1580CSTR
2.00V in SO-8 Package & Taping
& Reel Packing Type
(CN is not available in TR packing)
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TYPICAL APPLICATION CIRCUIT
R2
2K2
C9
1nF
C 7
33P
C6
1nF
R6
90.9K
R 9
4K7
OCSET
1
SD
2
COMP
3
FB
4
GND
5
PHASE
6
UGATE
7
VCC 8
U1
AIC1580
M1
CEB6030L
L2
7
H
L1
1.5
H
D1
SB1020
+
C 4
1000
F*6
V
OUT
V
I N
1
R1
10
C1
1
F
V
IN
2
12V
R 5
3.01K
R7
6.04K
R8
30.1k
R4
15K
R3
7.5K
SW0VID0
SW1 VID1
SW2 VID2
SW3 VID3
Optional Circuit
+
C 3
1000
F*2
*C1 must be very close to VCC pin
5V
Supply DC-DC Step Down Circuit
AIC1580/L
3
Table 1. Output Voltage Program
VID3
VID2
VID1
VID0
VOUT
1
1
1
1
2.00V
1
1
1
0
2.10V
1
1
0
1
2.20V
1
1
0
0
2.30V
1
0
1
1
2.40V
1
0
1
0
2.50V
1
0
0
1
2.60V
1
0
0
0
2.70V
0
1
1
1
2.80V
0
1
1
0
2.90V
0
1
0
1
3.00V
0
1
0
0
3.10V
0
0
1
1
3.20V
0
0
1
0
3.30V
0
0
0
1
3.40V
0
0
0
0
3.50V
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ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
CC
....... ...... ... ... ............................... ... ... ... ......................................... 15V
Input, Output, or I/O Voltage .................. ... ... ... ... ... ....... ... ......... GND - 0.3V to VCC+0.3V
ESD Classification ................................ ... ... ... ........ ... ................. ... ......................... Class 2
Recommended Operating Conditions
Supply Voltage, V
CC
....... ......................... ... ... ... .......... ... ... .................................. 12V
10%
Ambient Temperature Range .... ................................... ... ... ... .... ... ... .................. 0
C~70
C
Junction Temperature Range ....... ............... ... ... ............ ..... ... ......................... 0
C~ 100
C
Thermal Information
Thermal Resistance,
JA
(Typical, Note 1)
SOIC Package .................................. ... ... ... ... ... ... ... ... ..... ... ... ... ... ........... . 100
C/W
SOIC Package (with 3 in
2
of Copper) ... ... ... ... ... ... ... ... ... ... ... ... ... ... ......... .. 90
C/W
Maximum Junction Temperature (Plastic Package) ... ... ... .... ... ..... ... ... ................... 150
C
Maximum Storage Temperature Range ... ... ... ... ..... ... ... ... ......... ... .... ......... 65
C~150
C
Maximum Lead Temperature (Soldering 10 Sec) ... ... ... ... ... ... ... ...... ... ......... ......... 300
C
Note 1:
JA
is measured with the component mounted on an evaluation PC board in free air.
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TEST CIRCUIT
Refer to TYPICAL APPLICATION CIRCUIT.
AIC1580/L
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ELECTRICAL CHARACTERISTICS
(VCC=12V, T
A
=25
C, unless otherwise
specified.)
PARAMETER
TEST CONDITIONS
SYMBOL
MIN.
TYP.
MAX.
UNIT
VCC Supply Current
Nominal Supply
UGATE Open
I
VCC
2
mA
Power-On Reset
V
CC
Threshold
V
OCSET
=4.5V
9.5
V
Oscillator
Frequency
200
KHz
Duty Cycle
88
%
Internal Reference Voltage
Reference Voltage
AIC1580
AIC1580L
1.96
1.27
2.00
1.30
2.04
1.33
V
Error Amplifier
DC Gain
76
dB
Gain-Bandwidth Product
GBW
11
MHz
Slew Rate
Comp=10pF
SR
6
V/
S
Gate Driver
Upper Gate Source
R
UGATE
7
Upper Gate Sink
R
UGATE
5
Protection
OCSET Current Source
V
OCSET
=4.5VDC
I
OCSET
200
A
SS Current
I
SS
10
A
Shutdown
Shutdown Low Input
V
IN
L
0.35
V
Shutdown High Input
V
IN
H
2
V
Shutdown Mode Current
1
A
AIC1580/L
5
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TYPICAL PERFORMANCE CHARACTERISTICS
1
2
3
4
5
6
7
8
9
10
11
30
40
50
60
70
80
90
100
Vo=3.5V
Vo=2.0V
Vo=1.3V
Efficiency (%)
I
OUT
(A)
Fig. 1 Efficiency vs. Load Current
O
CSET
(
A)
Temperature (
C)
Fig. 2 OCSET Current vs. Temperature
-40
-20
0
20
40
60
80
100
120
140
160
192
194
196
198
200
Tc=134ppm/ C@ 0~100
C
Fig. 3 Over-Current Operation
Fig. 4 Output Clamped by Built-In Soft Start
Fig. 5 Transient Response
V
OUT
NOISE
AIC1580/L
6
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BLOCK DIAGRAM
-
+
-
+
SD
Oscillator
PWM Comparator
Error AMP
COMP
FB
REF
VCC
PHASE
OCSET
UGATE
GND
200
A
Over Current
Built-In Soft Start
Gate Control
Power-On
Reset
-
+
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PIN DESCRIPTIONS
PIN 1: OCSET - Current limit sense pin. Connect
a resistor R
OCSET
from this pin to
the drain of the external
MOSFET. R
OCSET
, an internal
200
A current source (I
OCSET
),
and the external MOSFET on-
resistance (R
DS(ON)
) jointly set
the
overcurrent trip point
according to the following
equation:
I
I
R
R
PEAK
OCSET
OCSET
DS(ON
=
)
If FB pin voltage is sensed to be
below 50% of the internal
voltage reference VDAC, the
overcurrent comparator cycles
the soft-start function.
PIN 2:
SD
- Shutdown pin. Connect this pin
to ground for shutdown.
PIN 3:COMP
- External compensation pin. This
pin is connected to error
amplifier output and PWM
comparator. A RC network is
connected to FB pin to
compensate the voltage-control
feedback loop of the converter.
PIN 4: FB
- The error amplifier inverting
input pin. The FB pin and COMP
pin are used to compensate the
voltage-control feedback loop.
PIN 5: GND
- Ground pin.
PIN 6: PHASE - Overcurrent detection pin.
Connect the PHASE pin to
source of the external N-
MOSFET. This pin detects the
voltage drop across the
MOSFET R
DS(ON)
for overcurrent
protection.
PIN 7: UGATE - External MOSFET gate drive pin.
Connect this pin to gate of the
external MOSFET.
PIN 8: VCC
- The chip power supply pin.
Recommended supply voltage is
12V.
AIC1580/L
7
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APPLICATION CIRCUIT
AIC1580L
*C1
1
F
C7
33P
C6
1000P
C9
1000P
+
C4
1000
F*6
+
C3
1000
F*3
R7
13K
R5
2K
R9
4K7
R6
90.9K
R1
10
R2
2.2K
L2
7
F
L1
1.5
F
D1
SB1020
M1
CEB6030L
1.5V/10A
*C1 must be very close
to VCC PIN
V
OUT
5V
12V
OCSET
VCC
SD
COMP
FB
UGATE
PHASE
GND
*V
OUT
=1.3V(R5+R7)/R7
Fig. 6 DC/DC Step Down Circuit
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PHYSICAL DIMENSIONS
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8 LEAD PLASTIC SO (unit: mm)
SYMBOL
MIN
MAX
A
1.35
1.75
A1
0.10
0.25
B
0.33
0.51
C
0.19
0.25
D
4.80
5.00
E
3.80
4.00
e
1.27(TYP)
H
5.80
6.20
L
0.40
1.27
D
H
e
A
B
A1
C
E
L
AIC1580/L
8
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8 LEAD PLASTIC DIP (unit: mm)
SYMBOL
MIN
MAX
A1
0.381
--
A2
2.92
4.96
b
0.35
0.56
C
0.20
0.36
D
9.01
10.16
E
7.62
8.26
E1
6.09
7.12
e
2.54 (TYP)
eB
--
10.92
b
e
L
A2
A1
eB
E
C
E1
D
L
2.92
3.81
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