UC3843BD1 STMicroelectronics, UC3843BD1 Datasheet - Page 5
![IC CTLR PWM HP CURR MODE SO-8](/photos/1/38/13851/497-8-soic_sml.jpg)
UC3843BD1
Manufacturer Part Number
UC3843BD1
Description
IC CTLR PWM HP CURR MODE SO-8
Manufacturer
STMicroelectronics
Datasheet
1.UC3845BD1013TR.pdf
(15 pages)
Specifications of UC3843BD1
Pwm Type
Current Mode
Number Of Outputs
1
Frequency - Max
500kHz
Duty Cycle
100%
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
0°C ~ 70°C
Package / Case
8-SOIC (3.9mm Width)
Frequency-max
500kHz
Number Of Pwm Outputs
1
On/off Pin
No
Adjustable Output
No
Switching Freq
500KHz
Operating Supply Voltage (max)
30V
Output Current
1000A
Synchronous Pin
No
Rise Time
50ns
Fall Time
50ns
Operating Temperature Classification
Automotive
Mounting
Surface Mount
Pin Count
8
Package Type
SO
Duty Cycle (max)
100 %
Output Voltage
5.1 V
Mounting Style
SMD/SMT
Switching Frequency
500 KHz
Operating Supply Voltage
30 V
Maximum Operating Temperature
+ 150 C
Minimum Operating Temperature
- 40 C
Topology
Boost or Flyback or Forward
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
STUC3843BD1
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High peak currents associated with capacitive loads
necessitate careful grounding techniques. Timing
and bypass capacitors should be connected close
Figure 2: Timing Resistor vs. Oscillator Fre-
Figure 1: Open Loop Test Circuit.
(K )
RT
0.8
50
20
10
5
2
1
10K
ERROR AMP.
V
T
A
i
=15V
ADJUST
=25˚C
20K
4.7K
4.7K
quency
C
T
30K
=5nF
C
T
=10nF
1K
50K
ADJUST
2N2222
D95IN343
I
100K
SENSE
100K
C
T
5K
=2nF
200K 300K
COMP
I
R
SENSE
R
500K
T
T
V
/C
FB
T
D95IN333
f
OSC
1
2
3
4
V
(KHz)
UC2842B
REF
8
C
T
to pin 5 in a single point ground. The transistor and
5 K potentiometer are used to sample the oscillator
waveform and apply an adjustable ramp to pin 3.
Figure 3: Output Dead-Time vs. Oscillator Fre-
50
30
20
10
%
UC2842B/3B/4B/5B - UC3842B/3B/4B/5B
7
6
5
5
3
2
1
10K
V
OUTPUT
GROUND
i
0.1 F
C
20K
T
quency
=200pF
C
T
30K
=500pF
0.1 F
C
T
50K
=1nF
100K
A
C
T
=10nF
1K
1W
C
200K 300K
T
=100pF
C
T
=5nF
C
T
V
V
OUTPUT
GROUND
V
T
=2nF
A
500K fOSC(KHz)
i
=15V
REF
i
=25˚C
D95IN334
5/15