UC2845BD1G ON Semiconductor, UC2845BD1G Datasheet - Page 12
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UC2845BD1G
Manufacturer Part Number
UC2845BD1G
Description
IC CTRLR CURRENT MODE HP 8-SOIC
Manufacturer
ON Semiconductor
Datasheet
1.UC3844BDR2G.pdf
(19 pages)
Specifications of UC2845BD1G
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
-25°C ~ 85°C
Package / Case
8-SOIC (3.9mm Width)
Frequency-max
275kHz
Duty Cycle (max)
48 % (Typ)
Output Voltage
4.95 V to 5.05 V
Output Current
1000 mA (Max)
Mounting Style
SMD/SMT
Switching Frequency
500 KHz
Operating Supply Voltage
30 V
Maximum Operating Temperature
85 C
Fall Time
50 ns
Minimum Operating Temperature
- 25 C
Rise Time
50 ns
Synchronous Pin
No
Topology
Boost or Flyback
Rohs Compliant
YES
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Error Amp compensation circuit for stabilizing any current mode topology except
for boost and flyback converters operating with continuous inductor current.
From V
R
R
d
i
R
f
O
C
≥ 8.8k
f
R
1(1)
2(3)
f
2.5V
+
-
EA
5.0V Ref
+
The MCR101 SCR must be selected for a holding of < 0.5 mA @ T
simple two transistor circuit can be used in place of the SCR as shown. All
resistors are 10 k.
MCR
Comp/Latch
1.0mA
101
S
R
T
Q
Figure 29. Error Amplifier Compensation
2R
R
Figure 27. Isolated MOSFET Drive
+
-
Figure 28. Latched Shutdown
3905
5(9)
2N
7(12)
V
CC
http://onsemi.com
7(11)
6(10)
5(8)
3(5)
3903
8(14)
2N
4(7)
2(3)
1(1)
C
Boundary
Isolation
R
R
12
S
EA
R
R
N
S
Q1
+
Osc
1.0 mA
Bias
V
N
in
+
0
-
P
Error Amp compensation circuit for stabilizing current mode boost
and flyback topologies operating with continuous inductor current.
C
From V
R
p
2R
I
pk
p
R
50% DC
=
V
O
GS
R
5(9)
i
V
Waveforms
R
(Pin 1)
d
A(min)
3 R
+
0
-
C
f
- 1.4
S
. The
25% DC
R
1(1)
2(3)
f
N S
N p
2.5V
EA
+
1.0mA
2R
R
5(9)