Datasheet

*
All voltages are with respect to pin 5, all currents are positive into the specified terminal.
PIN CONNECTION (top view)
COMP
V
FB
I
SENSE
R
T
/C
T
GROUND
OUTPUT
Vi
V
REF
1
3
2
4
6
5
7
8
D95IN332
Minidip/SO8
ORDERING NUMBERS
SO8 Minidip
UC2842BD1; UC3842BD1
UC2843BD1; UC3843BD1
UC2844BD1; UC3844BD1
UC2845BD1; UC3845BD1
UC2842BN; UC3842BN
UC2843BN; UC3843BN
UC2844BN; UC3844BN
UC2845BN; UC3845BN
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
i
Supply Voltage (low impedance source) 30 V
V
i
Supply Voltage (Ii < 30mA) Self Limiting
I
O
Output Current
±
1
A
E
O
Output Energy (capacitive load) 5
µ
J
Analog Inputs (pins 2, 3) – 0.3 to 5.5 V
Error Amplifier Output Sink Current 10 mA
P
tot
Power Dissipation at T
amb
≤
25
°
C (Minidip)
1.25 W
P
tot
Power Dissipation at Tamb
≤
25
°
C (SO8)
800 mW
T
stg
Storage Temperature Range – 65 to 150
°
C
T
J
Junction Operating Temperature – 40 to 150 °C
T
L
Lead Temperature (soldering 10s) 300
°
C
PIN FUNCTIONS
No Function Description
1 COMP This pin is the Error Amplifier output and is made available for loop compensation.
2V
FB
This is the inverting input of the Error Amplifier. It is normally connected to the switching
power supply output through a resistor divider.
3I
SENSE
A voltage proportional to inductor current is connected to this input. The PWM uses this
information to terminate the output switch conduction.
4R
T
/C
T
The oscillator frequency and maximum Output duty cycle are programmed by connecting
resistor R
T
to Vref and cpacitor C
T
to ground. Operation to 500kHz is possible.
5 GROUND This pin is the combined control circuitry and power ground.
6 OUTPUT This output directly drives the gate of a power MOSFET. Peak currents up to 1A are sourced
and sunk by this pin.
7V
CC
This pin is the positive supply of the control IC.
8V
ref
This is the reference output. It provides charging current for capacitor C
T
through resistor R
T
.
UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
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