UC3845N ON Semiconductor, UC3845N Datasheet - Page 12

• Manufacturer Part Number: UC3845N
• Description: IC CTRLR CURRENT MODE HP 8DIP
• Manufacturer: ON Semiconductor
• Type: High Performance Current Mode Controllersr

Specifications of UC3845N

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 60kHz
• 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: 8-DIP (0.300", 7.62mm)
• Frequency-max: 60kHz
• Output Voltage Range: 4.9 V to 5.1 V
• Input Voltage Range: 30 V
• Operating Temperature Range: 0 C to + 70 C
• Mounting Style: Through Hole
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: UC3845NOS

L2, L3 − 25 mH at 1.0 A, Coilcraft Z7157.
T1 − Primary: 45 Turns # 26 AWG
T1 −
T1 −
T1 −
T1 −
T1 −
T1 −
4.7k
18k
L1 − 15 mH at 5.0 A, Coilcraft Z7156.
T1 −
T1 −
T1 −
Secondary ± 12 V: 9 Turns # 30 AWG
Secondary 5.0 V: 4 Turns (six strands)
Secondary Feedback: 10 Turns #30 AWG
Core: Ferroxcube EC35−3C8
Bobbin: Ferroxcube EC35PCB1
Gap ≈ 0.01" for a primary inductance of 1.0 mH
0.01
(2 strands) Bifiliar Wound
#26 Hexfiliar Wound
(2 strands) Bifiliar Wound
1.0nF
33k
8(14)
4(7)
2(3)
1(1)
115VA
C
4.7W
+
−
EA
+
OSC
Bias
MDA
202
5(9)
Figure 30. 27 Watt Off−Line Flyback Regulator
All outputs are at nominal load currents, unless otherwise noted.
Line Regulation:
Load Regulation:
Output Ripple:
Efficiency
+
5.0V
−
+
+
−
ref
+
Comp/Latch
250
Test
S
R
T
Q
http://onsemi.com
+
−
± 12 V
± 12 V
± 12 V
5.0 V
5.0 V
5.0 V
+
56k
7(12)
12
V
V
V
mA
V
V
in
in
in
in
in
7(11)
6(10)
5(8)
3(5)
= 95 VAC to 130 VAC
= 115 VAC, I
= 115 VAC, I
= 115 VAC
= 115 VAC
100
+
1N4935
1N4937
4.7k
1N5819
22W
470pF
68
1.0k
Conditions
out
out
1N4935
+
3300pF
= 1.0 A to 4.0 A
= 100 mA to 300
4N50
MTP
0.5W
47
T1
680pF
2.7k
MBR1635
MUR110
MUR110
1000
2200
1000
1N4937
+
+
+
1000
L1
L2
L3
10
10
D = 50 mV or ± 0.5%
D = 24 mV or ± 0.1%
D = 300 mV or ± 3.0%
D = 60 mV or ± 0.25%
40 mV
80 mV
70%
+
+
+
pp
pp
5.0V/4.0A
5.0V RTN
12V/0.3A
±12V RTN
−12V/0.3A
Results