UC3845N ON Semiconductor, UC3845N Datasheet - Page 4

• 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

2.55 V
2.45 V
2.5 V
− 20
100
5.0
2.0
1.0
80
60
40
20
10
50
20
10
0
0
10
10 k
NOTE: Output switches
at one−half the oscillator
frequency.
Figure 6. Error Amp Open Loop Gain and
20 k
100
Figure 4. Error Amp Small Signal
Figure 2. Timing Resistor versus
f
Phase versus Frequency
osc
, OSCILLATOR FREQUENCY (Hz)
Oscillator Frequency
Transient Response
1.0 k
Gain
50 k
f, FREQUENCY (Hz)
0.5 ms/DIV
10 k
100 k
200 k
100 k
V
V
R
T
A
CC
O
L
= 25°C
= 100 K
= 2.0 V to 4.0 V
= 15 V
V
A
T
V
A
CC
V
T
1.0 M
Phase
A
500 k
CC
= −1.0
= 25°C
= 25°C
= 15 V
= 15 V
http://onsemi.com
1.0 M
10 M
0
30
60
90
120
150
180
4
3.0 V
2.5 V
2.0 V
70
65
60
55
50
75
1.2
1.0
0.8
0.6
0.4
0.2
10 k
0
0
V
CC
Figure 7. Current Sense Input Threshold
20 k
Figure 5. Error Amp Large Signal
Figure 3. Output Deadtime versus
= 15 V
versus Error Amp Output Voltage
T
A
f
V
osc
= 125°C
T
O
2.0
A
, ERROR AMP OUTPUT VOLTAGE (V)
, OSCILLATOR FREQUENCY (Hz)
Oscillator Frequency
Transient Response
= 25°C
C
T
50 k
= 10 nF
1.0 ms/DIV
T
100 k
A
= −55°C
4.0
5.0 nF
200 k
500
pF
6.0
2.0 nF
V
A
T
V
A
CC
500 k
= −1.0
= 25°C
200
pF
= 15 V
1.0 nF
100
pF
1.0 M
8.0