NCP1397ADR2G ON Semiconductor, NCP1397ADR2G Datasheet - Page 14

• Manufacturer Part Number: NCP1397ADR2G
• Description: IC CTLR RESONANT HI PERF 16-SOIC
• Manufacturer: ON Semiconductor

Specifications of NCP1397ADR2G

• Pwm Type: Controller
• Number Of Outputs: 1
• Frequency - Max: 560kHz
• Duty Cycle: 52%
• Voltage - Supply: 10.3 V ~ 20 V
• Buck: No
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: Yes
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width, 15 Leads)
• Frequency-max: 560kHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

in case the FB pin cannot rise above 0.3 V (to actually close
the loop) in less than a duration imposed by the
programmable timer. Please refer to the fault section for
detailed operation of this mode.
control voltage will be constrained between 0.5 V and 2.3 V,
whereas the feedback loop will drive Pin 6 (FB) between
1.1 V and 5.3 V. If we take the default FB pin excursion
numbers, 1.1 V = 50 kHz, 5.3 V = 500 kHz, then the VCO
maximum slope will be:
depending on the feedback pin voltage level in a different
frequency clamp combination.
This techniques allows us to detect a fault on the converter
As shown on Figure 26, the internal dynamics of the VCO
Figures 27 and 28 portray the frequency evolution
Rt = 41 kW on Pin 4 and R
Figure 27. Maximal Default Excursion,
500k * 50k
4.2
+ 107 kHz/V
F(max)
= 1.9 kW on Pin 2
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now been reduced to 300k / 4.1 = 71 kHz / V on M
M
excursion on systems where the load range does not generate
a wide switching frequency excursion. Due to this option,
we will see how it becomes possible to observe the feedback
level and implement skip cycle at light loads. It is important
to note that the frequency evolution does not have a real
linear relationship with the feedback voltage. This is due to
the deadtime presence which stays constant as the switching
period changes.
deadtime) requires the usage of the selection charts
displayed below:
Figure 28. Here a different minimum frequency was
Figure 29. Maximum Switching Frequency Resistor
Please note that the previous small−signal VCO slope has
lower
The selection of the three setting resistors (F
550
450
350
250
150
50
Selection Depending on the Adopted Minimum
programmed as well as a maximum frequency
1.9
outputs. This offers a mean to magnify the feedback
11.9
Switching Frequency
excursion
21.9
R
Fmax
(kW)
F
F
min
min
31.9
= 200 kHz
= 50 kHz
DT = 300 ns
V
V
FB
CC
max
= 6.5 V
= 15 V
41.9
, F
upper
min
and
and