KA3511DS Fairchild Semiconductor, KA3511DS Datasheet - Page 10

• Manufacturer Part Number: KA3511DS
• Description: IC PWM/SECONDARY COMBO 22-DIP
• Manufacturer: Fairchild Semiconductor

Specifications of KA3511DS

• Pwm Type: Current Mode
• Number Of Outputs: 3
• Frequency - Max: 10kHz
• Duty Cycle: 50%
• Voltage - Supply: 14 V ~ 30 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -25°C ~ 85°C
• Package / Case: 22-DIP (0.400", 10.16mm)
• Frequency-max: 10kHz
• Topology: Push-Pull
• Output Voltage: 40 V
• Output Current: 200 mA
• Switching Frequency: 10 KHz
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 25 C
• Fall Time: 50 ns
• Mounting Style: Through Hole
• Rise Time: 100 ns
• Synchronous Pin: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.3 DEADTIME CONTROL for SOFT-START
Deadtime control for soft-start makes a power supply output rising time (Typ. 15ms) to reduce out-
put ringing voltage for 3.3V, 5V, and 12V. If output rising time is too fast, output ringing voltage
reaches OVP level.
You can make a soft start function by add external components R1, R2 and C1 (refer to figure 5).
At first the main power is turned-on, the deadtime control voltage keeps high state ( · = · 3V), and
then go to the low voltage( · = · 105mV) that devided by R1, R2.
V
DTC LOW
Figure 4. Operating Waveform
=
Figure 5. Soft-Start Circuit
--------------------- -
R1
R2
+
R2
10
Vref(5V) = 104.9mV
Rev C, November 1999