Diodes AP3968/69/70 - Manual (Page 9)

AP3968/69/70
Document number: DS36759 Rev. 2 - 2
9 of 15
www.diodes.com
December 2013
© Diodes Incorporated
AP3968/69/70
A Product Line of
Diodes Incorporated
Operation Description
(Cont.)
At the instant of D1 turn-on, the primary current transfers to the secondary at an amplitude of:
Ipk
N
N
Ipks
S
P
  …………(8)
Thus the output constant current is given by:
Ipk
N
N
7
2
Iout
S
P    …………(9)
Leading Edge Blanking (LEB)
When the power switch is turned on, a turn-on spike on the output pulse rising edge will occur on the sense-resistor. To avoid false termination of
the switching pulse, a typical 500ns leading edge blanking is built in. During this blanking period, the current sense comparator is disabled and the
gate driver cannot be switched off.
The built-in LEB in AP3968/69/70 has shorter delay time from current sense terminal to output pulse than those IC solutions adopting external RC
filter as LEB.
Built-in Cable Compensation
The AP3968/69/70 has built-in fixed voltage of 0.35V typical to compensate the drop of output cable when the load is changed from zero to full
load. A typical 0.01

F external capacitor connected to the CPC pin is used to smooth voltage signal for cable compensation.
Over Temperature Protection
The AP3968/69/70 has internal thermal sensing circuit to shut down the PFM driver output when the die temperature reaches +160ºC typical.
When the die temperature drops about 40ºC, the IC will recover automatically to normal operation.
Ordering Information
AP39XX XX XX - XX
Packing Package
TR : Tape & Reel M : SO-7 G1 : Green
Product Name RoHS/Green Product Version
68 : AP3968
69 : AP3969
70 : AP3970
P7 : PDIP-7 Blank : Tube
P: PDIP-8
Diodes IC’s Pb-free products with "G1" suffix in the part number, are RoHS compliant and green.
Package Temperature Range Part Number Marking ID Packing
SO-7
-40°C to +85°C
AP3968MTR-G1 AP3968M-G1 4000/Tape & Reel
PDIP-7
AP3969P7-G1 AP3969P7-G1 50/Tube
AP3970P7-G1 AP3970P7-G1 50/Tube
PDIP-8 AP3970P-G1 AP3970P-G1 50/Tube