UC3845BVN ON Semiconductor, UC3845BVN Datasheet - Page 11
UC3845BVN
Manufacturer Part Number
UC3845BVN
Description
IC CTRLR CURRENT MODE HP 8DIP
Manufacturer
ON Semiconductor
Datasheet
1.UC3844BDR2G.pdf
(19 pages)
Specifications of UC3845BVN
Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
275kHz
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
-40°C ~ 105°C
Package / Case
8-DIP (0.300", 7.62mm)
Frequency-max
275kHz
Duty Cycle (max)
48 %
Output Voltage
4.9 V to 5.1 V
Output Current
1000 mA
Mounting Style
Through Hole
Switching Frequency
500 KHz
Operating Supply Voltage
30 V
Maximum Operating Temperature
+ 70 C
Fall Time
50 ns
Minimum Operating Temperature
0 C
Rise Time
50 ns
Synchronous Pin
No
Topology
Boost, Flyback
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
UC3845BVNOS
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
UC3845BVN
Manufacturer:
MOTOROLA/摩托罗拉
Quantity:
20 000
Figure 25. MOSFET Parasitic Oscillations
Series gate resistor R
parasitic oscillations caused by the MOSFET input
capacitance and any series wiring inductance in the
gate-source circuit.
+
-
5.0V Ref
Comp/Latch
S
R
T
Q
-
+
g
will damp any high frequency
5.0V Ref
+
-
7(12)
Comp/Latch
Figure 24. Current Waveform Spike Suppression
V
CC
R
S
7(11)
6(10)
5(8)
3(5)
T
Q
R
g
+
-
7(12)
Q1
R
V
V
in
S
CC
7(11)
6(10)
5(8)
3(5)
http://onsemi.com
C
R
11
Q1
R
V
S
in
The addition of the RC filter will eliminate
instability caused by the leading edge spike
on the current waveform.
+
0
-
The totem pole output can furnish negative base current
for enhanced transistor turn-off, with the addition of
capacitor C
Figure 26. Bipolar Transistor Drive
I
B
1
.
Base Charge
Removal
6(10)
5(8)
3(5)
C1
Q1
V
R
in
S