UC3845BN STMicroelectronics, UC3845BN Datasheet - Page 10

• Manufacturer Part Number: UC3845BN
• Description: IC CTLR PWM HP CURR MODE 8-DIP
• Manufacturer: STMicroelectronics

Specifications of UC3845BN

• 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
• Duty Cycle (max): 50 %
• Output Voltage: 4.90 V to 5.10 V
• Output Current: 1000 mA (Max)
• Mounting Style: Through Hole
• Switching Frequency: 500 KHz
• Operating Supply Voltage: 30 V
• Maximum Operating Temperature: 150 C
• Fall Time: 50 ns
• Minimum Operating Temperature: - 40 C
• Rise Time: 50 ns
• Synchronous Pin: No
• Topology: Boost or Flyback
• Input Voltage: 15V
• Frequency: 250kHz
• Power Dissipation Pd: 1.25W
• Supply Voltage Range: 12V To 25V
• Digital Ic Case Style: DIP
• No. Of Pins: 8
• Rohs Compliant: Yes
• For Use With: 497-5863 - EVAL BOARD 2W 3PH SMPS BRKR ESBT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: STUC3845BN

Figure 20 : Latched Shutdown.
UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
Figure 21: Error Amplifier Compensation
10/15
SCR must be selected for a holding current of less than 0.5mA at T
The simple two transistor circuit can be used in place of the SCR as shown. All resistors are 10K.
C
Error Amp compensation circuit for stabilizing any current-mode topology except
for boost and flyback converters operating with continuous inductor current.
Error Amp compensation circuit for stabilizing current-mode boost and flyback
topologies operating with continuous inductor current.
R
P
From V
P
From V
O
R
R
i
R
R
O
d
d
i
C
3905
2N
f
C
f
3903
R
R
2N
f
f
4
8
2
1
2
1
2
1
2.5V
2.5V
+
-
+
+
-
-
R
R
EA
EA
EA
+
+
+
1mA
1mA
1mA
OSC
BIAS
2R
2R
2R
D95IN350
R
R
R
A(min)
5
5
5
.
D95IN351