NCP1028
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5
ELECTRICAL CHARACTERISTICS (continued) (For typical values T
J
= 25°C, for min/max values T
J
= 0°C to +125°C,
Max T
J
= 150°C, V
CC
= 8.0 V, unless otherwise noted.)
Characteristic Pin Symbol Min Typ Max Unit
CURRENT COMPARATOR
Maximum Internal Current Setpoint, Pin 4 Open, T
J
= 25°C,
F
SW
= 65 kHz (Note 3)
− Ipeak_27_CS_
65 k
720 800 880 mA
Final Switch Current with a Primary Slope of 200 mA/ms,
F
SW
= 65 kHz (Note 4)
− Ipeak_27_SW_
65 k
− 820 − mA
Maximum Internal Current Setpoint, Pin 4 Open, T
J
= 25°C,
F
SW
= 100 kHz (Note 3)
− Ipeak_27_CS_
100 k
720 800 880 mA
Final Switch Current with a Primary Slope of 200 mA/ms,
F
SW
= 100 kHz (Note 4)
− Ipeak_27_SW_
100 k
− 820 − mA
Setpoint Decrease for a Pin 7 Injected Current of 40 mA, T
J
= 25°C 7 IOPP − 23 − %
Voltage Level in Pin 7 at which OPP Starts to Operate 7 IOPPtripV − 1.5 − V
Soft−Start Duration − T
SS
− 1.0 − ms
Propagation Delay from Current Detection to Drain OFF State − T
prop
− 100 − ns
Leading Edge Blanking Duration − T
LEB
− 200 − ns
INTERNAL OSCILLATOR
Oscillation Frequency (Note 5)
65 kHz Version, T
J
= 25°C
− f
OSC
58.5 65 71.5
kHz
Oscillation Frequency (Note 5)
100 kHz Version, T
J
= 25°C
− f
OSC
90 100 110
kHz
Frequency Jittering in Percentage of f
OSC
− f
Jitter
− "6.0 − %
Jittering Swing Frequency − fswing − 300 − Hz
Maximum Duty Cycle − Dmax 74 80 87 %
FEEDBACK SECTION
Internal Pullup Resistor 4 Rupp − 16 − kW
Ramp Compensation Level on Pin 1 – Rramp = 100 kW 2 Rlevel − 2.75 − V
SKIP CYCLE GENERATION
Internal Skip Mode Level, in Percentage of Maximum Peak Current − Iskip − 25 − %
PROTECTIONS
Brown−Out Level 3 VBO 510 570 620 mV
Brown−Out Hysteresis Current, T
J
= 25°C (Note 3) 3 IBOhyste 10 11.5 13 mA
Brown−Out Hysteresis Current, T
J
= 0°C to 125°C 3 IBOhyste − 10 − mA
Fault Validation further to Error Flag Assertion − TimerON 40 55 − ms
OFF Phase in Fault Mode − TimerOFF − 440 − ms
Latching Voltage on Brown−Out Pin 3 Vlatch 3.15 3.5 3.85 V
Latch Input Integrating Filter Time Constant 3 TdelBOL − 20 − ms
TEMPERATURE MANAGEMENT
Temperature Shutdown − TSD 160 − − °C
Hysteresis in Shutdown − − − 40 − °C
Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product
performance may not be indicated by the Electrical Characteristics if operated under different conditions.
3. See characterization curves for full temperature span evolution.
4. The final switch current is: Ipeak_2X_CS + Tprop x Vin / Lp, with Vin the input voltage and Lp the primary inductor in a flyback.
5. Oscillator frequency is measured with disabled jittering.
