IMP38C42EPA Datasheet, PDF (1/10 Pages) A1 PROs co., Ltd. – BiiCMOS Currentt--Mode BiiCMOS Currentt--Mode

IMP38C/HC/42/3/4/5
POWER MANAGEMENT
BiCMOS Current-Mode
PWM Controllers
– 1MHz Operation
– No Cross-Conduction Current
– 50ns Current-Sense Delay
The IMP38C4x and IMP38HC4x are fixed frequency, high performance,
current-mode PWM controllers that are pin compatible with bipolar 384x
devices but feature improvements resulting from IMP’s BiCMOS
processing and circuit design. Notable among the improvements are zero
cross-conduction/shoot-through current, reduced start-up and operating
current, lower current-sense delay, higher frequency operation, full
supply voltage swing at the output and a 1% trimmed voltage reference.
IMP38C4x and IMP38HC4x output driver stage has zero cross-conduction
current. A proprietary output state-machine monitors each output
MOSFET and guarantees by design zero cross-conduction current. This is
an industry first for 384x PWM devices.
Under-voltage lockout (UVL) performance has been improved. When
the power supply voltage is below the startup voltage, internal circuitry
puts the output into a low impedance state. The output will sink 20mA
and remain below 1.3V, well below the turn-on threshold voltage of the
external MOSFET. Even when V_DD drops to zero volts, the out pin will
not rise above approximately 1.3V because the output UVLO circuit is
Key Features
N 384x Series Pinout with BiCMOS Technology
N Zero Cross-Conduction Current by Design
N 1MHz Operation
N 65ns Maximum Current-Sense Delay
N 120µA Maximum Start-Up Current
N 1.5mA Maximum Operating Current
N High Output Current Drive
– 1.0A, IMP38HC4x
– 0.5A, IMP38C4x
N 20V Maximum Supply Voltage
N 2.5V, 1%, Trimmed Error Amplifier Reference
N Trimmed Oscillator Discharge Current
N Pin-for-Pin Enhanced Replacements for Micrel
MIC38C/HC4x and GMT38C4x/HC4x
Block Diagrams
7 (12)
V_DD
8 (14)
V_REF
RTCT
COMP
FB
4 (7)
1 (1)
2 (3)
–
EA
+
+
–
2.5V
Ref
5V
Reference
Oscillator
+
UVLO
–
+
–
2R
–
1V _COMP
R
+
T
Q
S
Q
R
(11)
V_D
6 (10)
OUT
(8)
PGND
( ) Pins Are 14-Pin Devices Only
3 (5)
GND 5 ISNS
AGND (9)
Connection Notes
IMP38C4X, IMP38HC4X (8-Pin Devices)
50% Maximum Duty Cycle:
IMP38C44, IMP38HC44, IMP38C45, IMP38HC45
96% Maximum Duty Cycle:
IMP38C42, IMP38HC42, IMP38C43, IMP38HC43
38C/HC_01.eps
© 2000 IMP, Inc.
408-432-9100/www.impweb.com
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