UC3845AD Microsemi Analog Mixed Signal Group, UC3845AD Datasheet - Page 5

• Manufacturer Part Number: UC3845AD
• Description: IC CTRLR PWM CURRENT MODE 14SOIC
• Manufacturer: Microsemi Analog Mixed Signal Group

Specifications of UC3845AD

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 500kHz
• Duty Cycle: 50%
• Voltage - Supply: 8.2 V ~ 25 V
• Buck: Yes
• Boost: Yes
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Frequency-max: 500kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Copyright © 1995
Rev. 1.2a 10/25
FIGURE 1. — OSCILLATOR FREQUENCY vs. TIMING
100k
10k
1M
0
RESISTOR
300
1.0k
C
T
R
= 4.7nF
T
P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7
- (ohms)
3.0k
FIGURE 2. — MAXIMUM DUTY CYCLE vs. TIMING RESISTOR
100.0
C
80.0
60.0
40.0
20.0
U R R E N T
P
0
10.0k
C
R O D U C T I O N
T
C H A R A C T E R I S T I C C U R V E S
= 1nF
C
T
= 2.2nF
30.0k
300
M
O D E
100k
1.0k
R
T
P W M C
- (ohms)
3.0k
D
Note: Output drive frequency is half the oscillator frequency for
A T A
10.0k
O N T R O L L E R
the UCx844A/5A devices.
UC184xA/284xA/384xA
S
30.0k
H E E T
GROUND
For R
100k
R
T
T
V
/C
> 5k, f
REF
T
8
4
5
1.72
R
T
C
T
R
T
C
T
5