UC3845BDG ON Semiconductor, UC3845BDG Datasheet - Page 8

• Manufacturer Part Number: UC3845BDG
• Description: IC CTRLR CURRENT MODE HP 14SOIC
• Manufacturer: ON Semiconductor

Specifications of UC3845BDG

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 275kHz
• Duty Cycle: 50%
• Voltage - Supply: 8.2 V ~ 25 V
• Buck: No
• Boost: Yes
• Flyback: Yes
• Inverting: Yes
• 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: 275kHz
• Duty Cycle (max): 48 %
• Output Voltage: 4.9 V to 5.1 V
• Output Current: 1000 mA
• Mounting Style: SMD/SMT
• Switching Frequency: 500 KHz
• Operating Supply Voltage: 30 V
• Maximum Operating Temperature: + 70 C
• Fall Time: 50 ns
• Minimum Operating Temperature: 0 C
• Rise Time: 50 ns
• Synchronous Pin: No
• Topology: Boost, Flyback
• Number Of Pwm Outputs: 1
• On/off Pin: No
• Adjustable Output: No
• Switching Freq: 500KHz
• Operating Supply Voltage (max): 30V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 14
• Package Type: SOIC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: UC3845BDGOS

Capacitor C
Latch “Set"
Input
Output/
Compensation
Current Sense
Input
Latch “Reset"
Input
Output
Compensation
Feedback
T
R
C
Voltage
Output/
Pin numbers adjacent to terminals are for the 8-pin dual-in-line package.
Pin numbers in parenthesis are for the D suffix SOIC-14 package.
T
T
Input
8(14)
V
4(7)
2(3)
1(1)
ref
2.5V
Amplifier
Error
Large R
R
R
Oscillator
+ 1.0mA
T
Internal
/Small C
Bias
Figure 16. Representative Block Diagram
T
2R
GND
R
Figure 17. Timing Diagram
5(9)
3.6V
http://onsemi.com
1.0V
Current Sense
Reference
Comparator
Regulator
-
+
8
UVLO
V
ref
R
S
T
UVLO
V
Q
CC
PWM
Latch
V
CC
+
-
7(12)
(See
Text)
36V
= Sink Only Positive True Logic
V
7(11)
Output
6(10)
Power Ground
5(8)
Current Sense Input
3(5)
Small R
C
V
CC
T
/Large C
T
V
in
Q1
R
S