UC3845AN STMicroelectronics, UC3845AN Datasheet - Page 12

• 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

Figure 23: Soft-Start Circuit
UC2842A/3A/4A/5A - UC3842A/3A/4A/5A
Figure 24: Soft-Start and Error Amplifier Output Duty Cycle Clamp.
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C
R2
R1
BC109
C
8
4
2
1
1M
+
-
EA
V
8
4
2
1
CLAMP
+
R
R
=
1mA
·
+
-
R
1
EA
R
+ R
1
2
BIAS
OSC
2R
+
where 0 <V
R
R
R
1mA
5
V
Clamp
BIAS
OSC
CLAMP
1V
2R
<1V
R
+
+
-
-
5V
5
I
pk(max)
ref
Comp/Latch
=
5V
1V
S
R
ref
Q
V
CLAMP
R
S
+
+
-
-
+
D95IN354
-
7
S
R
Q
D95IN355
7
6
5
V
CC
R
S
V
in
Q1