UC3845D Fairchild Semiconductor, UC3845D Datasheet - Page 4

• Manufacturer Part Number: UC3845D
• Description: IC CTLR PWM CURR MODE 14-SOIC
• Manufacturer: Fairchild Semiconductor

Specifications of UC3845D

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 500kHz
• Duty Cycle: 50%
• Voltage - Supply: 8.2 V ~ 30 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Frequency-max: 500kHz
• Duty Cycle (max): 50 %
• Output Voltage: 4.90 V to 5.10 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: 35 ns
• Minimum Operating Temperature: 0 C
• Rise Time: 45 ns
• Synchronous Pin: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: UC3845DFS

UC3842/UC3843/UC3844/UC3845
Electrical Characteristics
(V
Adjust V
Note:
1. Parameter measured at trip point of latch
2. Gain defined as:
3. These parameters, although guaranteed, are not 100 tested in production.
High peak currents associated with capacitive loads necessitate careful grounding techniques Timing and bypass capacitors
should be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the
oscillator waveform and apply an adjustable ramp to pin 3.
4
A
Parameter
PWM SECTION
Max. Duty Cycle
Min. Duty Cycle
TOTAL STANDBY CURRENT
Start-Up Current
Operating Supply Current
Zener Voltage
CC
=
=15V, R
----------------- -
V
V
CC
pin1
pin3
above the start threshould before setting at 15V
T
,0
=10k , C
V
pin3
T
=3.3nF, T
0.8V
A
= 0 C to +70 C, unless otherwise specified)
I
Symbol
CC(OPR)
D
D
D
(Continued)
(Max)
(Max)
(MIN)
I
V
ST
Figure 1. Open Loop Test Circuit
Z
UC3842/UC3843
UC3844/UC3845
V
I
CC
pin3
= 25mA
=V
UC3842
pin2
Conditions
=ON
-
-
Min.
95
47
30
-
-
-
Typ.
0.45
97
48
14
38
-
Max.
100
50
17
0
1
-
Unit
mA
mA
%
%
%
V