UC2845BNG ON Semiconductor, UC2845BNG Datasheet - Page 14

• Manufacturer Part Number: UC2845BNG
• Description: IC CTLR CURRENT MODE HP 8-DIP
• Manufacturer: ON Semiconductor

Specifications of UC2845BNG

• 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-DIP (0.300", 7.62mm)
• Frequency-max: 275kHz
• Duty Cycle (max): 48 %
• Output Current: 1000 mA
• Mounting Style: Through Hole
• Switching Frequency: 500 KHz
• Maximum Operating Temperature: + 85 C
• Fall Time: 50 ns
• Minimum Operating Temperature: - 25 C
• Rise Time: 50 ns
• Synchronous Pin: No
• Topology: Boost, Flyback
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1.0nF
1.0nF
10k
10k
The capacitor's equivalent series resistance must limit the Drive Output current to 1.0 A. An additional series resistor
may be required when using tantalum or other low ESR capacitors. The converter's output can provide excellent line
and load regulation by connecting the R2/R1 resistor divider as shown.
The capacitor's equivalent series resistance must limit the Drive Output current to 1.0 A.
An additional series resistor may be required when using tantalum or other low ESR capacitors.
8(14)
8(14)
4(7)
2(3)
1(1)
4(7)
2(3)
1(1)
2.5V
2.5V
Amplifier
Amplifier
Error
Error
R
R
R
R
+
+
Osc
Osc
Internal
0.5mA
Internal
0.5mA
Bias
Bias
Figure 32. Voltage−Inverting Charge Pump Converter
2R
2R
R
R
3.6V
Figure 31. Step−Up Charge Pump Converter
3.6V
UC3845B
UC3845B
5(9)
5(9)
1.0V
1.0V
-
+
-
+
Current Sense
Current Sense
Reference
Comparator
Regulator
Reference
Comparator
Regulator
UVLO
UVLO
V
V
ref
ref
S
R
S
R
http://onsemi.com
T
T
Q
Q
UVLO
V
UVLO
V
CC
CC
PWM
Latch
PWM
Latch
+
-
+
-
14
7(12)
7(12)
34V
34V
V
7(11)
6(10)
7(11)
6(10)
5(8)
3(5)
in
V
5(8)
3(5)
in
= 15V
V
= 15V
O
= 2.5
15
15
+
+
Connect to
Pin 2 for
closed loop
operation.
R2
R1
1N5819
10
10
47
47
) 1
+
1N5819
1N5819
Output Load Regulation
I
O
(Open Loop Configuration)
Output Load Regulation
(mA)
18
32
1N5819
R2
R1
0
2
9
I
O
(mA)
18
36
0
2
9
+
+
47
47
V
−14.4
−13.2
−12.5
−10.6
−11.7
V
V
O
O
O
≈
V
(V)
≈
29.9
28.8
28.3
27.4
24.4
2 (V
O
-V
(V)
in
in
)