AIC3842 Datasheet, PDF (1/7 Pages) Analog Intergrations Corporation – Current-Mode PWM Controller

PRELIMINARY
AIC3842
Current-Mode PWM Controller
n FEATURES
l Low Start-Up Current (300µA Typical)
l Internal Precision Reference.
l 500KHz Current-Mode Operation.
l Pulse-by-Pulse Current Limiting.
l Automatic Feed-Forward Compensation.
l Optimized for Off-Line and DC/DC Converters.
l Undervoltage Lockout with Hysteresis.
l Double Pulse Suppression.
l High Current Totem-Pole Output.
n APPLICATIONS
l Off-Line Converter.
l DC/DC Converter.
n DESCRIPTION
The AIC3842 control IC provides the features
that are necessary to implement off-line or
DC/DC Converter fixed-frequency current-mode
schemes with a minimum number of external
components. This integrated circuits features
an undervoltage lockout (UVLO) with
approximately 300µA start-up current, a
precision reference trimmed for accuracy at the
error amplifier input, high gain error amplifier,
current sensing comparator, logic to insure
latched operation, and a totem-pole output
stage designed to source or sink high peak
current. The output stage, suitable for driving N
channel MOSFETs, is low in the off state.
n TYPICAL APPLICATION CIRCUIT
2 _VFB
7
VCC
C2
+
R3 ^{300pF C3}
51K
1000P
FEEDBACK
SIGNAL
C5
0.1µF
R4
7.5K
C4
2.2nF
1 _COMP
6
OUTPUT
R1
10
8 _VREF
GND ⁵
4 _RT/CT
3
ISENSE
AIC3842
C6
300P
C1
47µF
VCC
INDUCTOR
M1
R2
20K
R5
390
C7
RS
1nF
0.33
Current Mode PWM Control Circuit
n ORDERING INFORMATION
AIC3842CX
PACKAGE TYPE
N: PLASTIC DIP
S: SMALL OUTLINE
ORDER NUMBER
PIN CONFIGURATION
AIC3842CN
(PLASTIC DIP)
AIC3842CS
(PLASTIC SO)
COMP 1
VFB 2
ISENSE 3
RT/CT 4
8 VREF
7 VCC
6 OUTPUT
5 GND
Analog Integrations Corporation 4F, 9, Industry E. 9th Rd, Science Based Industrial Park, Hsinchu Taiwan, ROC
DS-3842-P1 May 5, 00
TEL: [phone] FAX: [phone]
www.analog.com.tw
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