UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
ABSOLUTE MAXIMUM RATINGS
Symbol
V
i
V
i
I
O
E
O
Parameter
Supply Voltage (low impedance source)
Supply Voltage (Ii < 30mA)
Output Current
Output Energy (capacitive load)
Analog Inputs (pins 2, 3)
Error Amplifier Output Sink Current
P
tot
P
tot
T
stg
T
J
T
L
Power Dissipation at T
amb
≤
25
°
C (Minidip)
Power Dissipation at Tamb
≤
25
°
C (SO8)
Storage Temperature Range
Junction Operating Temperature
Lead Temperature (soldering 10s)
Valu e
30
Self Limiting
±
1
5
– 0.3 to 5.5
10
1.25
800
– 65 to 150
– 40 to 150
300
A
µ
J
V
mA
W
mW
°
C
°C
°
C
Un it
V
* All voltages are with respect to pin 5, all currents are positive into the specified terminal.
PIN CONNECTION
(top view)
Minidip/SO8
COMP
V
FB
I
SENSE
R
T
/C
T
1
2
3
4
D95IN332
8
7
6
5
V
REF
Vi
OUTPUT
GROUND
PIN FUNCTIONS
No
1
2
3
4
5
6
7
8
Function
COMP
V
FB
I
SENSE
R
T
/C
T
GROUND
OUTPUT
V
CC
V
ref
Description
This pin is the Error Amplifier output and is made available for loop compensation.
This is the inverting input of the Error Amplifier. It is normally connected to the switching
power supply output through a resistor divider.
A voltage proportional to inductor current is connected to this input. The PWM uses this
information to terminate the output switch conduction.
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.
This pin is the combined control circuitry and power ground.
This output directly drives the gate of a power MOSFET. Peak currents up to 1A are sourced
and sunk by this pin.
This pin is the positive supply of the control IC.
This is the reference output. It provides charging current for capacitor C
T
through resistor R
T
.
ORDERING NUMBERS
SO8
UC2842BD1;
UC2843BD1;
UC2844BD1;
UC2845BD1;
UC3842BD1
UC3843BD1
UC3844BD1
UC3845BD1
Minidip
UC2842BN;
UC2843BN;
UC2844BN;
UC2845BN;
UC3842BN
UC3843BN
UC3844BN
UC3845BN
2/15
STMICROELECTRONICS [ STMICROELECTRONICS ]
