* 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.
2
V
FB
This is the inverting input of the Error Amplifier. It is normally connected to the switching
power supply output through a resistor divider.
3
I
SENSE
A voltage proportional to inductor current is connected to this input. The PWM uses this
information to terminate the output switch conduction.
4
R
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.
7
V
CC
This pin is the positive supply of the control IC.
8
V
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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