UC3845D Fairchild Semiconductor, UC3845D Datasheet - Page 5

• Manufacturer Part Number: UC3845D
• Description: IC CTLR PWM CURR MODE 14-SOIC
• Manufacturer: Fairchild Semiconductor

Specifications of UC3845D

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 500kHz
• Duty Cycle: 50%
• Voltage - Supply: 8.2 V ~ 30 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Frequency-max: 500kHz
• Duty Cycle (max): 50 %
• Output Voltage: 4.90 V to 5.10 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: 35 ns
• Minimum Operating Temperature: 0 C
• Rise Time: 45 ns
• Synchronous Pin: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: UC3845DFS

During Under-Voltage Lock-Out, the output driver is biased to a high impedance state. Pin 6 should be shunted to ground with
a bleeder resistor to prevent activating the power switch with output leakage current.
Peak current (I
A small RC filter may be required to suppress switch transients.
I
S
MAX
=
1.0V
----------- -
R
S
S
) is determined by the formula:
Figure 3. Error Amp Configuration
Figure 2. Under Voltage Lockout
Figure 4. Current Sense Circuit
UC3842/44 UC3843/45
UC3842/UC3843/UC3844/UC3845
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