UC3845BN STMicroelectronics, UC3845BN Datasheet - Page 11

• 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 22: External Clock Synchronization.
Figure 23: External Duty Cycle Clamp and Multi Unit Synchronization.
f =
R
R
C
(R
A
B
A
V
1.44
+ 2R
REF
SYNC INPUT
EXTERNAL
The diode clamp is required if the Sync amplitude is large enough to cause
the bottom side of C
B
)C
6
5
2
5K
5K
5K
D
max
8
1
=
0.01 F
+
+
-
-
R
A
R
+ 2R
B
T
to go more than 300mV below ground
NE555
B
R
S
Q
4
47
R
C
T
T
V
REF
8
4
2
1
3
7
+
-
UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
EA
+
R
R
8
4
2
1
+
-
BIAS
OSC
EA
TO ADDITIONAL
2R
UCX84XAs
R
+
R
R
5
BIAS
OSC
D95IN352
D95IN353
2R
R
5
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