AIC1568
4-bit DAC, Step-Down PWM Power Controller
Analog Integrations Corporation 4F, 9 Industry E. 9th Rd, Science-Based Industrial Park, Hsinchu, Taiwan DS-1568-01 012102
TEL: 886-3-5772500 FAX: 886-3-5772510 www.analog.com.tw
1
n FEATURE
l Compatible with HIP6008.
l Simple Voltage-Mode PWM Control.
l Fast Transient Response.
l ±1.5% 4-Bit Digital-to-Analog Output Voltage.
l Adjustable Current Limit without External Sense
Resistors.
l Full 0% to 100% Duty Ratio.
l 200KHz Free-Running Oscillator, Programmable
up to 350KHz.
l Power-Good Output Voltage Monitor.
l Short Circuit Protection with Low Short Circuit
Output Current.
l TTL Compatible 4-bit Digital-to-Analog Core
Output Voltage Selection, with range from 2.0V to
3.5V in 0.1V increments.
n APPLICATIONS
l Power Supply for Pentium, Pentium Pro, Power
PC and Alpha Microprocessors.
l High-Power 5V to 3.xV DC/DC Regulators.
l Low-Voltage Distributed Power Supplies.
n DESCRIPTION
The AIC1568 is a high power, high efficiency
switching controller optimized for high
performance microprocessor applications. It is
designed to drive an N-channel MOSFET in a
standard buck topology. Featuring a digitally
programmable switching regulator, the AIC1568
includes monitoring and protection capabilities in
addition to all the essential PWM control
functions.
The internal 4-bit Digital-to-Analog Converter
(DAC) adjusts the output voltage from 2.0V to
3.5V in 0.1V increments. The precision reference
and voltage-mode control can provide output
regulation within ±1.5% over temperature and line
voltage shifts.
The AIC1568 includes an internal 200KHz free-
running oscillator that can be adjusted up to
350KHz. The resulting PWM duty ratio ranges
from 0% to 100%. The error amplifier features a
11MHz bandwidth and 6V/
µ
S slew rate, which
enables high converter bandwidth for fast
transient response.
The AIC1568 provides adjustable over current
and short circuit protections. It senses the output
current by using the RDS(ON) of the N-channel
MOSFET without an external low value sense
resistor. It also monitors the output voltage with a
window comparator and issues a power good
signal when the output is within 10% of the rated
output voltage.
AIC1568
2
n TYPICAL APPLICATION CIRCUIT
C1
1
µ
F
C2
0.1
µ
F
C6
1000P
C5
0.1
µ
F
C8
0.1
µ
F
C9
1000P
+
C3
1000
µ
F x 2
R4
15K
R3
47K
R6
90.9K
R1
R2
2.2K
L1
1
µ
H
L2
D1
BYV118
RFP45N03L
M1
AIC1568
OC
SET
COMP
FB
SS
VID0
VID1
VID2
VID3
R7
1.2M
+
JUMPER
C4
1000
µ
F x 6
12V
2.0V
≤
V
OUT
≤
3.5V
at 10A
5V
BOOT
GND
PHASE
RT/OVP
UDRI
VCC
VSEN
PGOOD
C7
33P
7
µ
H
10
V
IN
V
DRI
R5
3.01K
Switching DC/DC Converter
n ORDERING INFORMATION
PIN CONFIGURATION
SO-16
TOP VIEW VSEN
RT/OVP
VCC
BOOT
UGATE
PHASE
PGOOD
GND
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
OCSET
SS
VID0
VID1
VID2
VID3
COMP
FB
AIC1568CXXX
PACKING TYPE
TR: TAPE & REEL
TB: TUBE
PACKAGING TYPE
S: SMALL OUTLINE
Example: AIC1568CSTR
à in SO-16 Package & Taping &
Reel Packing Type
AIC1568
3
n ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC ....…...............................................……………............................. 15V
Boot Voltage, VBOOT ……….......................…...........…………........................................ 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
Maximum Operating Junction Temperature..........…......…..........…………................... 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.
n TEST CIRCUIT
Refer to TYPICAL APPLICATION CIRCUIT.
AIC1568
4
n ELECTRICAL CHARACTERISTICS (VCC= 12V, TA=25°C, unless otherwise specified.)
PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT
VCC Supply Current
Nominal Supply UGATE Open IVCC 2 mA
Power-On Reset
VCC Threshold VOCSET=4.5V 7 8.5 V
Rising VOCSET Threshold 1.26 V
Oscillator
Free Running Frequency RT Open 170 200 230 KHz
Total Variation 6KΩ<RT<200KΩ -20 +20 %
Ramp Amplitude RT Open ∆VOSC 1.5 VP-P
DAC Output Voltage
DAC Output Voltage Accuracy -1.5 +1.5 %
Error Amplifier
DC Gain 76 dB
Gain-Bandwidth Product GBW 11 MHz
Slew Rate SR 6 V/
µ
S
Gate Driver
Upper Gate Source R
UGATE
8 12 Ω
Upper Gate Sink R
UGATE
5.5 10 Ω
Protection
Over-Voltage Trip (V
VSEN
/VDAC) 106 115 125 %
OCSET Current Source VOCSET =4.5VDC IOCSET 170 200 230
µ
A
OVP Sourcing Current VVSEN =5.5V, VOVP=0V IOVP 30 mA
SS Current ISS 10
µ
A
SS Sink Current under
Current Limit VVSEN =VDAC, VOCSET=5.0V,
V
PHASE
=0V, V
FB
=V
DAC
- 50mV 130
µ
A
SS Sink Current under Hard
Current Limit
VVSEN=0, VOCSET =5.0V,
VPHASE =0V, VFB=0V 65 mA
Power Good
Upper Threshold (V
VSEN
/VDAC) VVSEN rising 106 114 %
Lower Threshold (V
VSEN
/VDAC) VVSEN falling 84 94 %
Hysteresis (VVSEN /VDAC) Upper and lower threshold 2 %
PGOOD Voltage Low IPGOOD=5mA V
PGOOD
0.5 V
AIC1568
5
n BLOCK DIAGRAM
PHASE
GND
BOOT
UGATE
OVER
CURRENT
VSEN
OCSET
+
−
SOFT
SATRT
1
µ
A
4V
FB
IOCSET
200µA
CONTROL
LOGIC
OVP
POWER-ON
RESET
VCC
-
+
50%
POWER GOOD
SS
-
+
PGOOD
-
+
-
+
ERROR
AMP
OSCILLATOR
PWM
COMPARATOR
REFERENCE
RT/OVP
VID0
VID1
VID2
VID3
COMP
4BITS
DAC
-
++
−
+
VDAC
90%
110%
115%
1
11
13
1
14
10
3
5
2
16
4
6
7
8
12
9
15
n 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 200
µ
A current source (IOCSET), and
the external MOSFET on-
resistance (RDS(ON)) jointly set the
over current trip point according
to the following equation:
IIR
R
PEAK OCSET OCSET
DS(ON
=×
)
If FB pin voltage is sensed to be
below 50% of the internal
voltage reference VDAC, the
over current comparator cycles
the soft-start function.
PIN 2: SS -Soft start pin. Connect a
capacitor from this pin to ground.
An internal 10
µ
A current source
provides soft start function for
the converter.
PIN 3: VID0
PIN 4: VID1
PIN 5: VID2
PIN 6: VID3 -4-bit DAC voltage select pin. TTL
inputs used to set the internal
voltage reference VDAC. When
left open, these pins are
internally pulled up to 5V and
provide logic ones. The level of
VDAC sets the converter output
voltage as well as the PGOOD
and OVP thresholds.
Table 1 specifies the VDAC
voltage for the 16 combinations
of DAC inputs.
AIC1568
6
Table 1. Output Voltage Program
VID0 VID1 VID2 VID3 VDAC
0 0 0 0 3.5V
1 0 0 0 3.4V
0 1 0 0 3.3V
1 1 0 0 3.2V
0 0 1 0 3.1V
1 0 1 0 3.0V
0 1 1 0 2.9V
1 1 1 0 2.8V
0 0 0 1 2.7V
1 0 0 1 2.6V
0 1 0 1 2.5V
1 1 0 1 2.4V
0 0 1 1 2.3V
1 0 1 1 2.2V
0 1 1 1 2.1V
1 1 1 1 2.0V
PIN 7: COMP -External compensation pin. This
pin is connected to error
amplifier output and PWM
comparator. An RC network is
connected to FB pin to
compensate the voltage-control
feedback loop of the converter.
PIN 8: FB -The error amplifier inverting
input pin. The FB pin and COMP
pin are used to compensate the
voltage-control feedback loop.
PIN 9: GND -Signal GND. It also serves as
the power GND for the upper
gate driver.
PIN 10: PGOOD-Power good indicator pin.
PGOOD is an open drain output.
This pin is pulled low when the
converter output is ±10% out of
the VDAC reference voltage.
PIN 11: PHASE -Over current detection pin. Connect
the PHASE pin to source of the
external MOSFET. This pin detects
the voltage drop across the MOSFET
RDS(ON) for over-current protection.
PIN 12: UGATE- External MOSFET gate drive pin.
Connect this pin to gate of the
external MOSFET.
PIN 13: BOOT -External MOSFET driver power
supply pin. To convert 5V main power
to VCORE power by driving N-channel
MOSFET, supply voltage of no higher
than 12V is recommended since the
negative power terminal of the
internal driver is internally tied to
GND.
PIN 14: VCC -The chip power supply pin.
Recommended supply voltage is 12V.
PIN 15: RT/OVP- Frequency adjustment and
overvoltage indicator pin. This pin is
multiplexed to provide two functions.
The first function is oscillator
switching frequency adjustment.
Connecting a resistor (RT) from this
pin to GND increases the frequency
according to the following equation:
FKHzS≅ + ×
200 5105
log RT
The second function for this pin is to
drive an external SCR in the event of
an over voltage fault.
PIN 16: VSEN -Converter output voltage sense pin.
Connect this pin to the converter
output. The PGOOD and OVP
comparator circuits use this signal to
report output voltage status and
perform overvoltage protection
function.
AIC1568
7
n PHYSICAL DIMENSION
l 16 LEAD PLASTIC SO (150 mil) (unit: mm)
SYMBOL MIN MAX
A1.35 1.75
A1 0.10 0.25
B0.33 0.51
C0.19 0.25
D9.80 10.00
E3.80 4.00
e1.27 (TYP)
H5.80 6.20
L0.40 1.27
E
e
D
B
C
A
A1
L
H
