AIC AIC1579CN

AIC1579/L
Step-Down Switching Regulator Controller
FEATURES
DESCRIPTION
Operation Voltage up to 15V.
The AIC1579 is a high-power, high-efficiency
Simple Voltage-Mode PWM Control.
voltage-mode switching regulator controller for
Fast Transient Response.
motherboard VI/O power supply applications.
2V and 1.3V ± 2% Feedback Voltage Reference
Designed to drive an N-channel MOSFET in a
Option.
standard buck topology, the AIC1579 features a
Adjustable Current Limit without External Sense
high voltage CMOS output driver, short-circuit
Resistors.
protection, and 8-pin package.
200KHz Free-Running Oscillator.
Short-Circuit Protection with Low Short Circuit
An external 4-bit Digital-to-Analog Converter
Output Current.
(DAC) can be used along with the AIC1579 to
adjust the output voltage from 2.0V to 3.5V in
0.1V increments. Table 1 on the following page
APPLICATIONS
Power Supply for Motherboard VGTL (1.5V Output)
Power Supply for Motherboard VI/O.
High-Power 5V to 3.xV DC/DC Regulators.
Low-Voltage Distributed Power Supplies.
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/µS slew rate of the
error
amplifier
ensures
high
converter
bandwidth and fast transient response.
The AIC1579 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 AIC1579L provides lower reference voltage
(1.30V) than the default (2.00V, AIC1579) for
lower VOUT requirement.
Analog Integrations Corporation
4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
DS-1579-01
TEL: 886-3-5772500
Nov 9, 00
FAX: 886-3-5772510
www.analog.com.tw
1
AIC1579/L
ORDERING INFORMATION
AIC1579 XXX
AIC1579CN
AIC1579LCN
(PLASTIC DIP)
TEMPERATURE RANGE
C=0°C~+70°C
TOP VIEW
8 VCC
OCSET 1
AIC1579CS
AIC1579LCS
(PLASTIC SO)
REFERENCE VOLTAGE
DEFAULT: 2.00V
L: 1.30V
PIN CONFIGURATION
ORDER NUMBER
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
SS 2
7 UGATE
COMP 3
6 PHASE
FB* 4
5 GND
*AIC1579: 2.00V
AIC1579L: 1.30V
TYPICAL APPLICATION CIRCUIT
C2
*C1 MUST BE VERY CLOSE TO VCC PIN
10Ω
R8
1000pF
R1
2.2K 1%
C5
OCSET
0.1µF
SS
R2
33P
VCC
5V
L1
1µH
M1
UGATE
RFP45N03L
+
COMP PHASE
FB
GND
C6
12V
C1*
1µF
C3
1000µFx2
3.3V/10A
VOUT
AIC1579
C7
90.9K 1% 1000pF
D1
L2
7µH
+
C4
1000µ F x 6
BYV118
R4
VID0
60.4K 1%
R5
VID1
30.1K 1%
R6
VID2
15.0K 1%
R7
VID3
7.5K 1%
R3
3.01K 1%
Switching Regulator for Pentium VCORE Supply
2
AIC1579/L
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
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC ....…...………............................…………......................................... 15V
Input, Output, or I/O Voltage ...............………………....……......... GND - 0.3V to VCC+0.3V
ESD Classification .............................………….....……..............……......................... Class 2
Recommended Operating Conditions
Supply Voltage, VCC ....…......................………….......……….................................. 12V ±10%
Ambient Temperature Range .…................................………….……….................. 0°C~70°C
Junction Temperature Range ....…............……….........…..……......................... 0°C~ 100°C
Thermal Information
Thermal Resistance, θJA (Typical, Note 1)
SOIC Package ...............................………………………..……………........…. 100°C/W
SOIC Package (with 3 in2 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: θJA is measured with the component mounted on an evaluation PC board in free air.
TEST CIRCUIT
Refer to TYPICAL APPLICATION CIRCUIT.
3
AIC1579/L
ELECTRICAL CHARACTERISTICS
specified.)
PARAMETER
TEST CONDITIONS
(VCC= 12V, Ta=25°°C, unless otherwise
SYMBOL
MIN.
TYP.
MAX.
UNIT
VCC Supply Current
Nominal Supply
UGATE Open
IVCC
2.3
mA
Power-On Reset
VCC Threshold
VOCSET=4.5V
10.4
V
240
KHz
100
%
2.04
1.33
V
Oscillator
Frequency
160
200
Max. Duty Cycle
Internal Reference Voltage
Reference Voltage
AIC1579
AIC1579L
1.96
1.27
2.00
1.30
Error Amplifier
DC Gain
76
dB
GBW
11
MHz
SR
6
V/µS
Upper Gate Source
RUGATE
8
12
Ω
Upper Gate Sink
RUGATE
5.5
10
Ω
200
230
µA
Gain-Bandwidth Product
Slew Rate
Gate Driver
Protection
OCSET Current Source
VOCSET =4.5VDC
IOCSET
SS Current
170
ISS
µA
10
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs. Load Current
OCSET Current vs. Temperature
100
Vo=3.5V
80
200
Vo=2.0V
Clset (µA)
Efficiency (%)
90
70
Vo=1.3V
60
50
198
Tc=134ppm/ [email protected] 0~100°C
196
194
40
192
30
1
2
3
4
5
6
IOUT (A)
7
8
9
10
11
-40
-20
0
20
40
60
80
100
Temperature (°C)
120
140
160
4
AIC1579/L
TYPICAL PERFORMANCE CHARACTERISTICS(Continued)
SS Current vs. Temperature
Over-Current Operation
9.9
Soft Start (µA)
9.8
9.7
9.6
Tc = 306 ppm/°C @ 0~100°C
9.5
9.4
9.3-40
-20
0
20
40
60
80
100
120
140
160
Temperature (°C)
Soft Start Initiates Output
Transient Response
5
AIC1579/L
BLOCK DIAGRAM
SS
-
PHASE
+
OCSET
Over Current
10µA
200µA
Power-ON Reset
Soft
Start
VCC
4V
PWM Comparator
REF.
+
Error
AMP
FB
Gate
Control
-
UGATE
GND
Oscilator
COMP
PIN DESCRIPTIONS
PIN 1: OCSET - Current limit sense pin. Connect
a resistor ROCSET from this pin to
the drain of the external
MOSFET. ROCSET, an internal
200µA current source (IOCSET),
and the external MOSFET onresistance (RDS(ON)) jointly set the
overcurrent trip point according
to the following equation:
IPEAK
IOCSET × ROCSET
=
RDS(ON)
comparator. A RC network is
connected to FB pin to
compensate the voltage-control
feedback loop of the converter.
PIN 4: FB
PIN 5: GND-
Ground pin.
PIN 6: PHASE-
Overcurrent
detection
pin.
Connect the PHASE pin to
source of the external NMOSFET. This pin detects the
voltage
drop
across
the
MOSFET RDS(ON) for overcurrent
protection.
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: SS
- Soft start pin. Connect a
capacitor from this pin to ground.
An internal 10µA current source
provides soft start function for
the converter.
PIN 3: COMP - External compensation pin. This
pin is connected to error
amplifier output and PWM
- The error amplifier inverting
input pin. The FB pin and COMP
pin are used to compensate the
voltage-control feedback loop.
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.
6
AIC1579/L
APPLICATION CIRCUIT
*C1 MUST BE VERY CLOSE TO VCC PIN
C2
10Ω
R8
1000pF
R1
2.2K 1%
C5
VCC
OCSET
0.01µF
C6
33P
R2
90.9K 1%
12V
C1*
1µF
SS
UGATE
COMP
FB
PHASE
5V
L1
1µH
M1
RFP45N03L
GND
+
C3
1000µFX2
AIC1579L
1.5V/10A
VOUT
L2
C7
7µH
D1
1000pF
R3
1%
13K
R4
+
C4
1000µF x 6
BYV118
1%
2K
*VOUT=1.3V x (1+ R3/R4)
PHYSICAL DIMENSIONS
8 LEAD PLASTIC SO (unit: mm)
D
H
E
e
C
B
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
A
A1
1.27(TYP)
H
5.80
6.20
L
0.40
1.27
L
7
AIC1579/L
8 LEAD PLASTIC DIP (unit: mm)
D
E1
E
A2
A1
C
L
eB
b
e
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
L
2.92
3.81
8