UC3845BVD ON Semiconductor, UC3845BVD Datasheet - Page 4

• Manufacturer Part Number: UC3845BVD
• Description: IC CTRLR CURRENT MODE HP 14SOIC
• Manufacturer: ON Semiconductor

Specifications of UC3845BVD

• 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: 14-SOIC (3.9mm Width), 14-SOL
• Frequency-max: 275kHz
• Duty Cycle (max): 48 %
• 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
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: UC3845BVDOS

11. Adjust V
12. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
2.55 V
2.45 V
ELECTRICAL CHARACTERISTICS
values T
PWM SECTION
TOTAL DEVICE
2.5 V
Duty Cycle
Power Supply Current
Power Supply Zener Voltage (I
T
Maximum (UC284XB, UC384XB)
Maximum
Minimum
Startup (V
Startup (V
Operating (Note 11)
8.0
5.0
2.0
0.8
low
80
50
20
10 k
= 0°C for UC3844B, UC3845B
= − 25°C for UC2844B, UC2845B
= − 40°C for UC3844BV, UC3845BV
NOTE: Output switches at
1/2 the oscillator frequency
A
is the operating ambient temperature range that applies [Note 12], unless otherwise noted.)
CC
20 k
above the Startup threshold before setting to 15 V.
CC
CC
(UC384XBV)
Figure 4. Error Amp Small Signal
= 6.5 V for UCX845B,
=
versus Oscillator Frequency
14 V for UCX844B, BV)
f
For R
OSC
Figure 2. Timing Resistor
Characteristic
, OSCILLATOR FREQUENCY (kHz)
Transient Response
50 k
T
u 5 Kf X 1.72
0.5 ms/DIV
CC
100 k
= 25 mA)
R
200 k
T
(V
C
CC
T
= 15 V [Note 11], R
T
V
A
T
high
A
CC
V
= 25°C
500 k
= -1.0
V
T
A
= 15 V
CC
= + 70°C for UC3844B, UC3845B
= + 85°C for UC2844B, UC2845B
= +105°C for UC3844BV, UC3845BV
= 25°C
http://onsemi.com
= 15 V
1.0 M
Symbol
DC
DC
I
V
CC
(max)
T
(min)
4
Z
= 10 k, C
3.0 V
2.5 V
2.0 V
75
70
65
60
55
50
10 k
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
Ä Ä Ä Ä Ä
T
Min
47
30
1. C
2. C
3. C
4. C
5. C
6. C
7. C
= 3.3 nF. For typical values T
−
−
−
−
T
T
T
T
T
T
T
UC284XB
= 10 nF
= 5.0 nF
= 2.0 nF
= 1.0 nF
= 500 pF
= 200 pF
= 100 pF
20 k
Figure 5. Error Amp Large Signal
Typ
0.3
48
12
36
−
−
versus Oscillator Frequency
f
Figure 3. Output Deadtime
OSC
Transient Response
, OSCILLATOR FREQUENCY (kHz)
Max
0.5
50
17
−
0
−
50 k
1.0 ms/DIV
100 k
Min
47
46
30
−
−
−
UC384XB, XBV
A
= 25°C, for min/max
200 k
Typ
0.3
48
48
12
36
−
1
Max
V
A
T
0.5
50
50
17
A
CC
V
0
−
500 k
= 25°C
= -1.0
= 15 V
2
6
5
3
4
Unit
mA
7
1.0 M
%
V