AP3842 Datasheet, PDF (1/8 Pages) Anachip Corp – High Performance Current Mode PWM Controller

High Performance Current Mode PWM Controller
AP3842/3/4/5
„ Features
• Optimized for Off-Line and DC to DC Converters
• Low Start-Up Current (≦0.5mA)
• Automatic Feed Forward Compensation
• Pulse-by-Pulse Current Limiting
• Enhanced Load Response Characteristics
• Under-Voltage Lockout (UVLO) with Hysteresis
• Double Pulse Suppression
• High Current Totem Pole Output
• Internally Trimmed Bandgap Reference
• Current Mode Operation to 500KHZ
• Low Ro Error Amplifier
„ Pin Connections
PDIP-8L, SOP-8L
Top View
COMP. 1
V_FB 2
I_SENSE ³
R_T/C_T 4
8 V_REF
7 V_I
6 _OUTPUT
5 GROUND
„ General Description
The AP3842/3/4/5 family of control ICs provides the
necessary features to implement off-line or DC to
DC fixed frequency current mode control schemes
with a minimal external parts count. Internally
implemented circuits include under voltage lockout
featuring start-up current less than 0.5 mA, a
precision reference trimmed for accuracy at the
error amp input, logic to insure latched operation, a
PWM comparator which also provides current limit
control, 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.
Differences between members of this family are the
under-voltage lockout thresholds and maximum
duty cycle ranges. The AP3842 and AP3844 have
UVLO thresholds of 16V(on) and 10V(off), ideally
suited for off-line applications. The corresponding
thresholds for the AP3843 and AP3845 are 8.5V
and 7.6V. The AP3842 and AP3843 can operate to
duty cycles approaching 100%. A range of the zero
to < 50% is obtained by the AP3844 and AP3845
by the addition of an internal toggle flip flop which
blanks the output off every other clock cycle.
„ Ordering Information
AP 384X X X X
Part No.
2:3842
3:3843
4:3844
5:3845
Package
Lead Free
Packing
S8:SOP-8L _{Blank : Normal}
Blank: Tube
N8:PDIP-8L L : Lead Free Package A : Taping
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev.1.0 Oct.11, 2004
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