AMC3843B

Manufacturer Part NumberAMC3843B
Description(AMC3842B / AMC3843B) CURRENT MODE PWM CONTROLLER
ManufacturerETC
AMC3843B datasheet
 
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AMC DOC. #: AMC3842B_C (LF)
March 2004
®
A
DD MICROTECH CORP.
DESCRIPTION
The AMC3842B/43B are fixed frequency current-mode
PWM controllers specially designed for OFF-Line switching
power supply and DC-to-DC converters with a minimum
number of external components. These devices feature a
trimmed oscillator for precise duty cycle control, a
temperature compensated reference, high gain error
amplifier, current sensing comparator, and high current
totem pole output which is suitable for driving MOSFETs.
The under voltage lock-out (U.V.L.O.) is designed to
operated with 200µA typ. start-up current, allowing an
efficient bootstrap supply voltage design. The U.V.L.O.
thresholds for the AMC3842B are 16V (on) and 10V (off)
which are ideal for off-line applications. The corresponding
typical threshold for the AMC3843B are 8.4V (on) and 7.6V
(off). The AMC3842B/43B can operated within 100% duty
cycle.
APPLICATIONS
Off-line flyback or forward
converters.
DC-to-DC buck or boost
converter.
Monitor Power Supply
AVAILABLE OPTIONS
Start-UP
Max. Duty
Device
Hysteresis
Voltage
Cycle
AMC3842B
16V
6V
< 100%
AMC3843B
8.4V
0.8V
< 100%
Plastic DIP-8
M
O
T
(
C)
A
8-pin
0 to 70
AMC384XBM
0 to 70
AMC384XBMF(Lead Free)
Note: 1.All surface-mount packages are available in Tape & Reel. Append the letter “T” to part number (i.e.
AMC384XBDT, or AMC384XBDMT).
2.The letter ”F” is marked for Lead Free process.
Copyright © 2002, ADD Microtech Corp.
C
M
URRENT
ODE
Low Start-Up current ( typ. 200 µA)
Optimized for Off-Line and
DC-to-DC Converters
Maximum Duty Cycle
U.V.L.O. with Hysteresis
Operating Frequency Up to 500KHz
Internal Trimmed Bandgap Reference
High Current Totem Pole Output
Error Amplifier With Low Output
Resistance
Available in 8-Pin Plastic DIP and
Surface Mount 14-Pin S.O.I.C.
Identical pin assignment to earlier
UC384X series.
PACKAGE PIN OUT
COMP
V
FB
I
SENSE
R
/C
T
T
8-Pin Plastic DIP
(Top View)
V
COMP
REF
NC
NC
V
V
CC
FB
V
NC
C
I
OUTPUT
SENSE
NC
GND
R
/C
PWR
T
T
14-Pin Plastic S.O.I.C.
Surface Mount
(Top View)
ORDER INFORMATION
Plastic SO-14
D
14-pin
AMC384XBD
AMC384XBDF(Lead Free)
1
AMC3842B/43B
PWM C
ONTROLLER
FEATURES
V
REF
V
CC
OUTPUT
GND
V
COMP
REF
V
V
FB
CC
I
SENSE
OUTPUT
R
/C
GND
T
T
8-Pin Plastic S.O.I.C.
Surface Mount
(Top View)
Plastic SO-8
DM
8-pin
AMC384XBDM
AMC384XBDMF(Lead Free)
www.addmtek.com

AMC3843B Summary of contents

  • Page 1

    ... The U.V.L.O. thresholds for the AMC3842B are 16V (on) and 10V (off) which are ideal for off-line applications. The corresponding typical threshold for the AMC3843B are 8.4V (on) and 7.6V (off). The AMC3842B/43B can operated within 100% duty cycle. APPLICATIONS Off-line flyback or forward converters ...

  • Page 2

    AMC DOC. #: AMC3842B_C (LF) March 2004 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply voltage Output current Analog inputs Error amp output sink current, I SINK(EA) O Power dissipation ( C ...

  • Page 3

    AMC DOC. #: AMC3842B_C (LF) March 2004 Internal Bias V REF (14) REF Error Amp (1) COMP CURRENT 3 (5) SENSE 4 ( Oscillator ( ) are 14 ...

  • Page 4

    AMC DOC. #: AMC3842B_C (LF) March 2004 RECOMMENDED OPERATING CONDITIONS Parameter Supply Voltage Input Voltage Output Voltage Supply Current Average Output Current Reference Output Current Timing Capacitor Oscillator Frequency Operating Free-air Temperature Unless otherwise specified, these specifications apply over the ...

  • Page 5

    ... SOURCE 1nF 1nF AMC3842B V TH(ST) AMC3843B AMC3842B AMC3843B AMC3842B/43B AMC3842B AMC3843B SENSE 25mA and COMP with the input changing from 0V to 0.8V SENSE 5 AMC3842B/43B M PWM C ODE ONTROLLER µA -0.1 -2 2.42 2.50 2 ...

  • Page 6

    AMC DOC. #: AMC3842B_C (LF) March 2004 R S Fig. 1. Current Sense Circuit 2. COMP Z f Fig. 2. Error Amplifier Configuration amplifier can source or sink up to 0.5mA 2N2222 4.7K 100K 1K Error ...

  • Page 7

    AMC DOC. #: AMC3842B_C (LF) March 2004 1K 330Ω Shutdown 500Ω To Current Sense Resistor Fig. 5. Shutdown Techniques - there are two ways to shutdown the PWM controller: 1) raise the voltage at I above 1V or, 2) pull ...

  • Page 8

    AMC DOC. #: AMC3842B_C (LF) March 2004 8-Pin Plastic DIP 8-Pin Plastic S.O.I. SEATING PLAN Copyright © 2002, ADD Microtech ...

  • Page 9

    AMC DOC. #: AMC3842B_C (LF) March 2004 14-Pin Plastic S.O.I. SEATING PLAN Copyright © 2002, ADD Microtech Corp. C URRENT AMC3842B/43B M PWM C ODE ONTROLLER INCHES MILLIMETERS ...

  • Page 10

    AMC DOC. #: AMC3842B_C (LF) March 2004 ADD Microtech (ADDM) reserves the right to make changes to its products or to discontinue any integrated circuit product or service without notice, and advises its customers to obtain the latest version of ...