UC3843BVD1G ON Semiconductor, UC3843BVD1G Datasheet - Page 12
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UC3843BVD1G
Manufacturer Part Number
UC3843BVD1G
Description
IC CTRLR CURRENT MODE HP 8-SOIC
Manufacturer
ON Semiconductor
Datasheet
1.UC3842BDR2G.pdf
(21 pages)
Specifications of UC3843BVD1G
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
-40°C ~ 105°C
Package / Case
8-SOIC (3.9mm Width)
Frequency-max
275kHz
Duty Cycle (max)
96 % (Typ)
Output Voltage
4.9 V to 5.1 V
Output Current
1000 mA (Max)
Mounting Style
SMD/SMT
Switching Frequency
500 KHz
Operating Supply Voltage
30 V
Maximum Operating Temperature
105 C
Fall Time
50 ns
Minimum Operating Temperature
- 40 C
Rise Time
50 ns
Synchronous Pin
No
Topology
Boost or Flyback or Forward
Number Of Pwm Outputs
1
On/off Pin
No
Adjustable Output
No
Switching Freq
500KHz
Operating Supply Voltage (max)
30V
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
8
Package Type
SOIC N
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
C
-
+
Virtually lossless current sensing can be achieved with the implementation of a
SENSEFET power switch. For proper operation during over-current conditions, a
reduction of the I
1.0M
Figure 26. Current Sensing Power MOSFET
5.0V Ref
8(14)
4(7)
2(3)
1(1)
Comp/Latch
pk(max)
S
R
t
Soft-Start
Q
Figure 24. Soft−Start Circuit
Control Circuitry Ground:
clamp level must be implemented. Refer to Figures 23 and 25.
≈ 3600C in mF
To Pin (9)
EA
+
R
R
-
+
(12)
Osc
1.0mA
Bias
V
(11)
(10)
(8)
(5)
CC
2R
G
R
1/4 W
S
R
-
+
D
M
5(9)
1.0V
SENSEFET
V
in
Then : V Pin 5 [ 0.075 I pk
V Pin 5 [
If: SENSEFET = MTP10N10M
R
5.0V Ref
K
To Input Source
S
S
Power Ground:
= 200
Return
S
R
r DM(on) ) R S
R S I pk r DS(on)
Q
http://onsemi.com
C
12
R
R
2
1
8(14)
t SoftStart + * In 1 *
4(7)
2(3)
1(1)
MPSA63
V Clamp [
Figure 25. Adjustable Buffered Reduction of
Figure 27. Current Waveform Spike Suppression
EA
R
R
-
+
+
R 2
R 1
The addition of the RC filter will eliminate instability caused by the leading
edge spike on the current waveform.
Clamp Level with Soft−Start
Osc
1.67
Bias
1.0 mA
) 1
5.0V Ref
Comp/Latch
3 V Clamp
2R
V C
R
S
R
Where: 0 ≤ V
V
C
Clamp
Q
1.0V
5(9)
R 1 ) R 2
-
+
R 1 R 2
5.0V Ref
Clamp
Comp/Latch
7(12)
≤ 1.0 V
+
-
S
R
V
CC
I pk(max) [
Q
7(11)
6(10)
5(8)
3(5)
+
-
C
R
V Clamp
7(12)
R S
V
CC
V
Q1
R
7(11)
6(10)
5(8)
3(5)
in
S
Q1
V
R
in
S