AIC AIC1341-CS Datasheet
AIC1341
High Performance, Triple-Output, Auto-
Tracking Com bo Controller
Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
www.analog.com.tw
DS-1341-00 May 24, 01 TEL: 886-3-5772500 FAX: 886-3-5772510 1
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FEATURES
l Provide Triple Accurate Regulated Voltages
l Optimized Voltage-Mode PWM Control
l Dual N-Channel MOSFET Synchronous Drivers
l Fast Transient Response
l Adjustable Over Current Protection using R
DS(ON)
.
No External Current Sense Resistor Required.
l Programmable Softstart Function
l 200KHz Free-Running Oscillator
l Robust Output s Auto-Tracking Characteristics
l Sink and Source Capabilities with External Circuit
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APPLICATIONS
l Advanced PC Mboards
l Information PCs
l Servers and Workstations
l Internet Appliances
l PC Add-On Cards
l DDR Termination
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GENERAL DESCRIPTION
The AIC1341 combines a synchronous voltage
mode PWM controller with two linear controllers
as well as the monitoring and protection functions
in this chip. The PWM controller regulates the
output voltage with a synchronous rectified stepdown converter. The built-in N-Channel MOSFET
drivers also help to simplify the design of stepdown converter. It is able to power CPUs, GPUs,
memories, chipset s and multi-voltage applications.
The PWM controller features over current protection using R
DS(ON)
. It improves efficiency and saves
cost, as there is no expensive current sense resistor required.
Two built-in adjustable linear controllers drive an
external MOSFETs to form two linear regulators
that regulates power for multiple system I/O. Output voltage of both linear regulators can also be
adjusted by means of the external resistor divider.
Both linear regulators feature current limit. For a
system I/O requires current less than 500mA, the
AIC1340 is recommended for saving one external
MOSFET.
The programmable soft-start design provodes a
controlled output voltage rise, which limits the current rate during power on time.
The shutdown function is also provided for disabling the combo controller.
AIC1341
2
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TYPICAL APPLICATION CIRCUIT
+
+
UGATE
PHASE
VIN2
LGATE
GATE3
PGNDFB3
GATE2
FB2
COMP1
SS
GND
+5VIN
VCC
+12VIN
15
OCSET
4
7
11
8
6
VOUT2
VOUT3
+3.3VIN
12
13
16
1
2
14
14
VOUT1
+
5
GND
FB1
3
SD
10
+
+3.3VIN
AIC1341CS
Q1
Q2
Typical Triple-Output Application
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ORDERING INFORMATION
ORDER NUMBER
PIN CONFIGURATIONAIC1341-XX
AIC1341CS
(SO 16)
PACKAGING TYPE
S: SMALL OUTLINE
TEMPERATURE RANGE
C: O°C~+70°C
1
3
4
2
5
7
68FB2
UGATE
SD
VCC
PHASE
SS
VIN2
GATE2
OCSET
LGATE
PGND
FB3
FB1
COMP1
GATE3
GND
16
14
15
13
12
11
9
10
AIC1341
3
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ABSOLUTE MAXIMUM RATING
Absolute Maximum Ratings
Supply Voltage (VCC) .............................................................................................................. 15V
UGATE....................................................................................................GND - 0.3V to VCC + 0.3V
LGATE ....................................................................................................GND - 0.3V to VCC + 0.3V
Input Output and I/O Voltage .................................................................................GND - 0.3V to 7V
Operating Conditions
Ambient Temperature Range ........................................................................................0° C to 85°C
Maximum Operating Junction Temperature ............................................................................. 100°C
Supply Voltage, VCC .......................................................................................................15V±10%
Thermal Information
Thermal Resistance θJA (°C/W)
SOIC Package.......................................................................................................100°C/W
Maximum Junction Temperature (Plastic Package).................................................................. 150°C
Maximum Storage Temperature Range .......................................................................-65°C to 150°C
Maximum Lead Temperature (Soldering 10s)........................................................................... 300°C
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TEST CIRCUIT
Refer to APPLICATION CIRCUIT.
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ELECTRICAL CHARACTERISTICS
(Vcc=12V, TJ=25°C, Unless otherwise
specified)
PARAMETER TEST CONDITIONS SYMBOL MIN. TYP. MAX. UNIT
VCC SUPPLY CURRENT
Supply Current UGATE, LGATE, GATE2 and
GATE3 open
I
CC
1.8 5 mA
POWER ON RESET
Rising VCC Threshold V
OCSET
=4.5V VCC
THR
8.6 9.5 10.4 V
Falling VCC Threshold V
OCSET
=4.5V VCC
THF
8.2 9.2 10.2 V
Rising VIN2 Under-Voltage
Threshold
VIN2
THR
2.5 2.6 2.7 V
VIN2 Under-Voltage Hysteresis
VIN2
HYS
130 mV
Rising V
OCSET1
Threshold V
OCSETH
1.3 V
AIC1341
4
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ELECTRICAL CHARACTERISTICS
(Continued)
PARAMETER TEST CONDITIONS
SYMBOL
MIN. TYP. MAX. UNIT
OSCILLATOR and REFERENCE
Free Running Frequency F 170 200 230 KHz
FB2 Reference Voltage V
REF2
1.245 1.270 1.295 V
FB3 Reference Voltage V
REF3
1.250 1.275 1.300 V
LINEAR CONTROLLER
Regulation 0 < I
GATE2/3
< 10mA -2.5 +2.5 %
Under-Voltage Level FB2/3 falling FB2/3
UV
70 80 %
PWM CONTROLLER ERROR AMPLIFIER
DC GAIN 76 dB
Gain Bandwidth Product GBWP 11 MHz
Slew Rate COMP1=10pF SR 6 V/µS
PWM CONTROLLER GATE DRIVER
Upper Drive Source VCC=12V, V
UGATE
=11V R
UGH
5.2 6.5 Ω
Upper Drive Sink VCC=12V, V
UGATE
=1V R
UGL
3.3 5 Ω
Lower Drive Source VCC=12V, V
LGATE
=11V R
LGH
4.1 6 Ω
Lower Drive Sink VCC=12V, V
LGATE
=1V R
LGL
3 5 Ω
PROTECTION
Soft-Start Current I
SS
11 µA
Chip Shutdown Soft Start
Threshold
1.0 V
AIC1341
5
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PIN DESCRIPTIONS
Pin 1: PHASE: Over-current detection pin. Con-
nect the PHASE pin to source of
the external high-side NMOSFET. This pin detects the
voltage drop across the high-side
N-MOSFET R
DS(ON)
for over-
current protection.
Pin 2: UGATE: External high-side N-MOSFET
gate drive pin. Connect UGATE
to gate of the external high-side
N-MOSFET.
Pin 3: SD: To shut down the system, active
high or floating. If connecting a
resistor to ground, keep the re-
sistor less than 4.7K Ω
Pin 4: VCC: The chip power supply pin. It also
provides the gate bias charge for
all the MOSFETs controlled by
the IC. Recommended supply
voltage is 12V.
Pin 5: SS: Soft-start pin. Connect a capaci-
tor from this pin to ground. This
capacitor, along with an internal
10µA (typically) current source,
sets the soft-start interval of the
converter.
Pulling this pin low will shut down
the IC.
Pin 6: FB2: Connect this pin to a resistor di-
vider to set the linear regulator
output voltage.
Pin 7: VIN2: This pin supplies power to the
internal regulator. Connect this
pin to a suitable 3.3V source.
Additionally, this pin is used to
monitor the 3.3V supply. If, following a start-up cycle, the voltage drops below 2.6V (typically),
the chip shuts down. A new softstart cycle is initiated upon re-
turn of the 3.3V supply above
the under-voltage thres hold.
Pin 8: GATE2: Linear Controller output drive pin.
This pin can drive either a Darlington NPN transistor or a Nchannel MOSFET.
Pin 9: GND: Signal GND for IC. All voltage
levels are measured with respect
to this pin.
Pin 10: GATE3: Linear Controller output drive pin.
This pin can drive either a Darlington NPN transistor or an Nchannel MOSFET.
Pin 11: FB3 Negative feedback pin for the
linear controller error amplifier
connect this pin to a resistor divider to set the linear controller
output voltage.
Pin 12: COMP1 External compensation pin. This
pin is connected to error amplifier output and PWM comparator.
A RC network is connected to
FB1 to compensate the voltage
control feedback loop of the converter.
Pin 13: FB1 The error amplifier inverting input
pin. The FB1 pin and COMP1 pin
are used to compensate the voltage-control feedback loop.
Pin 14: OCSET: Current limit sense pin. Connect
a resistor R
OCSET
from this pin to
the drain of the external high-side
N-MOSFET. R
OCSET
, an internal
200µA current source (I
OCSET
),
and the upper N-MOSFET onresistance (R
DS(ON)
) set the overcurrent trip point according to the
following equation:
I
I R
R
PEAK
OCSET OCSET
DS(ON)
=
×
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