UC3843BD1 ON Semiconductor, UC3843BD1 Datasheet - Page 5
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UC3843BD1
Manufacturer Part Number
UC3843BD1
Description
IC CTRLR CURRENT MODE HP 8SOIC
Manufacturer
ON Semiconductor
Datasheet
1.UC3842BDR2G.pdf
(21 pages)
Specifications of UC3843BD1
Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
275kHz
Duty Cycle
96%
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-SOIC (3.9mm Width)
Frequency-max
275kHz
Duty Cycle (max)
96 %
Output Voltage
4.9 V to 5.1 V
Output Current
1000 mA
Mounting Style
SMD/SMT
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, Forward
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
UC3843BD1OS
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2.55 V
2.50 V
2.45 V
9.0
8.5
8.0
7.5
7.0
8.0
5.0
2.0
0.8
80
50
20
10 k
- 55
Freq +
V
T
A
CC
= 25°C
= 15 V
20 k
Figure 4. Oscillator Discharge Current
- 25
Figure 6. Error Amp Small Signal
Ct
versus Oscillator Frequency
f
Vosc
OSC
I Rt
Figure 2. Timing Resistor
T
A
, OSCILLATOR FREQUENCY (kHz)
, AMBIENT TEMPERATURE (°C)
0
Transient Response
) Ct
versus Temperature
50 k
1
25
Idis*I Rt
0.5 ms/DIV
Vosc
100 k
50
200 k
Where: Vosc = 1.7 V
75
V
V
Idis = 8.3 mA
V
A
T
CC
OSC
I
V
A
CC
Rt
500 k
= 25°C
= -1.0
= 15 V
100
= 2.0 V
= 15 V
= Vref/Rt
http://onsemi.com
1.0 M
125
5
3.0 V
2.5 V
2.0 V
100
100
5.0
2.0
1.0
50
20
10
90
80
70
60
50
40
10 k
0.8
1. C
2. C
3. C
4. C
5. C
6. C
7. C
T
T
T
T
T
T
T
1.0
= 10 nF
= 5.0 nF
= 2.0 nF
= 1.0 nF
= 500 pF
= 200 pF
= 100 pF
Figure 5. Maximum Output Duty Cycle
I
20 k
dischg
Figure 7. Error Amp Large Signal
versus Oscillator Frequency
= 7.5 mA
f
OSC
Figure 3. Output Deadtime
I
dischg
versus Timing Resistor
Transient Response
, OSCILLATOR FREQUENCY (kHz)
R
T
50 k
, TIMING RESISTOR (kW)
= 8.8 mA
2.0
1.0 ms/DIV
100 k
3.0
1
200 k
4.0
V
C
T
A
CC
T
V
A
T
2
= 25°C
V
T
= 3.3 nF
5.0 6.0 7.0 8.0
A
V
CC
A
CC
= 15 V
500 k
= -1.0
= 25°C
= 25°C
5
= 15 V
= 15 V
3
6
4
1.0 M
7