UC3845AN STMicroelectronics, UC3845AN Datasheet - Page 2

• Manufacturer Part Number: UC3845AN
• Description: IC CURR-MODE PWM CTRLR 8-MINIDIP
• Manufacturer: STMicroelectronics

Specifications of UC3845AN

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 500kHz
• Duty Cycle: 50%
• Voltage - Supply: 8.2 V ~ 25 V
• Buck: No
• Boost: Yes
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 8-DIP (0.300", 7.62mm)
• Frequency-max: 500kHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 497-3083-5

PIN CONNECTION (top view)
UC2842A/3A/4A/5A - UC3842A/3A/4A/5A
ABSOLUTE MAXIMUM RATINGS
* All voltages are with respect to pin 5, all currents are positive into the specified terminal.
PIN FUNCTIONS
ORDERING NUMBERS
2/15
Symbol
No
1
2
3
4
5
6
7
8
T
P
P
E
T
T
V
V
I
O
stg
tot
tot
O
J
L
i
i
GROUND
Function
OUTPUT
COMP
I
R
SENSE
V
V
V
T
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
Power Dissipation at T
Power Dissipation at Tamb
Storage Temperature Range
Junction Operating Temperature
Lead Temperature (soldering 10s)
CC
/C
FB
ref
UC2842AD1; UC3842AD1
UC2843AD1; UC3843AD1
UC2844AD1; UC3844AD1
UC2845AD1; UC3845AD1
T
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
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
SO8
COMP
I
R
T
SENSE
to Vref and cpacitor C
T
V
/C
amb
FB
T
Parameter
25 C (Minidip)
25 C (SO8)
1
2
3
4
Minidip/SO8
D95IN332
T
to ground. Operation to 500kHz is possible.
8
7
6
5
Description
V
Vi
OUTPUT
GROUND
REF
UC2842AN; UC3842AN
UC2843AN; UC3843AN
UC2844AN; UC3844AN
UC2845AN; UC3845AN
Minidip
Self Limiting
– 0.3 to 5.5
– 65 to 150
– 40 to 150
Value
1.25
800
300
30
10
5
1
T
through resistor R
Unit
mW
mA
°C
W
V
A
V
C
C
J
T
.