KA3842
KA3842 is CurrentMode PWM Controller manufactured by Unknown Manufacturer.
KA3842/43/44/45
Inv № 59
Current Mode PWM Controller
July 1995
- revised July 2002
DESCRIPTION
KA3842/43/44/45 are fixed frequency current mode PWM controller. They are specially designed for OFF- Line and DC to DC converter applications with a minimal external ponents. Internally implemented circuits include a trimmed oscillator for precise duty cycle control, a temperature pensated reference, high gain error amplifier, current sensing parator, and a high current totempole output ideally suited for driving a power MOSFET. Protection circuitry includes built undervoltage lockout and current limiting.
The UC3842A(AM) and UC3844A(AM) have UVLO thresholds of 16 V (on) and 10 V (off).
The corresponding thresholds for the UC3843A(AM)/45A(AM) are 8.4V (on) and
7.6V
(off). The UC3842A(AM) and UC3843A(AM) can operate within 100% duty cycle. The
UC3844A(AM) and UC3845A(AM) can operate within 50% duty cycle.
The UC384XA(AM) has Start-Up Current 0.17m A (typ).
Features
- Low Start-Up and Operating Current
- High Current Totem Pole Output
- Undervoltage Lockout With Hysteresis
- Operating Frequency Up To 300KHz (384XA)
500KHz (384XAM)
BLOCK DIAGRAM (toggle flip flop used only in UC3844, UC3845)
PIN CONNECTION
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