UC3845BD ON Semiconductor, UC3845BD Datasheet - Page 13
![IC CTRLR CURRENT MODE HP 14SOIC](/photos/6/57/65767/14-soic_751a_sml.jpg)
UC3845BD
Manufacturer Part Number
UC3845BD
Description
IC CTRLR CURRENT MODE HP 14SOIC
Manufacturer
ON Semiconductor
Datasheet
1.UC3844BDR2G.pdf
(19 pages)
Specifications of UC3845BD
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
0°C ~ 70°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
UC3845BDOS
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
UC3845BD1
Manufacturer:
ST
Quantity:
18 420
Company:
Part Number:
UC3845BD1013TR
Manufacturer:
STM
Quantity:
12 500
Part Number:
UC3845BD1013TR
Manufacturer:
ST
Quantity:
20 000
Company:
Part Number:
UC3845BD1G
Manufacturer:
ON Semiconductor
Quantity:
2 000
Part Number:
UC3845BD1R2G
Manufacturer:
ON/安森美
Quantity:
20 000
18k
4.7k
100
pF
0.01
T1 -
1.0nF
Primary: 45 Turns #26 AWG
Secondary ±12 V: 9 Turns #30 AWG (2 Strands) Bifiliar Wound
Secondary 5.0 V: 4 Turns (six strands) #26 Hexfiliar Wound
Secondary Feedback: 10 Turns #30 AWG (2 strands) Bifiliar Wound
Core: Ferroxcube EC35-3C8
Bobbin: Ferroxcube EC35PCB1
Gap: ≈ 0.10" for a primary inductance of 1.0 mH
150k
33k
8(14)
4(7)
2(3)
1(1)
All outputs are at nominal load currents unless otherwise noted.
115 Vac
Line Regulation: 5.0 V
Load Regulation: 5.0 V
Output Ripple:
Efficiency
4.7W
EA
Test
R
R
+
Osc
Bias
MDA
202
±12 V
±12 V
5.0 V
±12 V
Figure 30. 7 W Off−Line Flyback Regulator
-
+
5(9)
V
V
V
V
V
in
in
in
in
in
= 115 Vac, I
= 115 Vac, I
= 115 Vac
= 115 Vac
= 95 Vac to 130 Vac
5.0V Ref
+
http://onsemi.com
Comp/Latch
250
S
R
T
Conditions
Q
out
out
13
= 1.0 A to 4.0 A
= 100 mA to 300 mA
+
-
7(12)
56k
7(11)
6(10)
5(8)
3(5)
100
L2, L3
4.7k
+
1N4937
1N4935 1N4935
1N5819
L1
68
22
470pF
- 15 mH at 5.0 A, Coilcraft Z7156
- 25 mH at 5.0 A, Coilcraft Z7157
D = 50 mV or ±0.5%
D = 24 mV or ±0.1%
D = 300 mV or ±3.0%
D = 60 mV or ±0.25%
1.0k
+
3300
pF
47
4N50
Results
MTP
40 mV
80 mV
70%
T1
680pF 2.7k
0.5
pp
pp
MUR110
MBR1635
MUR110
2200
1000
1000
+
+
+
1N4937
1000
L2
L1
L3
10
10
+
+
+
5.0V/4.0A
5.0V RTN
12V/0.3A
±
-12V/0.3A
12V RTN