NCP1308DR2G ON Semiconductor, NCP1308DR2G Datasheet - Page 13

• Manufacturer Part Number: NCP1308DR2G
• Description: IC CTRLR PWM CM UVLO HV 8SOIC
• Manufacturer: ON Semiconductor

Specifications of NCP1308DR2G

• Pwm Type: Current Mode
• Number Of Outputs: 1
• Frequency - Max: 75kHz
• Voltage - Supply: 11 V ~ 20 V
• Buck: No
• Boost: No
• Flyback: Yes
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: 0°C ~ 125°C
• Package / Case: 8-SOIC (3.9mm Width)
• Frequency-max: 75kHz
• Output Current: 500 mA
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 20 V
• Fall Time: 20 ns
• Rise Time: 40 ns
• Synchronous Pin: No
• Topology: Flyback
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Duty Cycle: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: NCP1308DR2G; NCP1308DR2GOSTR

Protecting Pin 8 Against Negative Spikes
negative voltages that could appear on its pins (Figure 23).
To avoid any adverse latchup of the IC, we strongly
recommend to insert a resistor in series with pin 8. This
series for safety) from the V
Figure 12 details this other option:
As any CMOS controller, NCP1308 is sensitive to
Another option consists in adding a diode (or two in
+
Figure 24. A diode will force the V
the same pace the bulk capacitor does, avoiding a
Cbulk
negative ringing on the HV pin.
1
2
3
4
8
7
6
5
Figure 23. A negative spike can occur at mains switch-off if the
CC
+
to the bulk capacitor.
CVCC
Vcc
quality coefficient of Cbulk-Lp is high enough.
1N4007
CC
to decrease at
or
Vbulk
1N4007
1N4007
http://onsemi.com
NCP1308
13
resistor prevents from adversely latching the controller in
case of negative spikes appearing on the bulk capacitor
during the power-off sequence. Please refer to the power
dissipation section of this data sheet to see how to calculate
this element.
Vbulk
< 0
Latch!