Description:
The NTE1721 and NTE1723 are pulse width modulator control–circuits designed to offer improved
performance and lowered external parts count when implemented for controlling all types of switching
power supplies. The no–chip +5.1V reference is trimmed to 1% and the input common–mode range
of the errror amplifier includes the reference voltage, thus eliminating the need for external divider
resistors. A sync input to the oscillator enables multiple units to be slaved or a single unit to be syn-
chronized to an external system clock. A wide range of dead time can be programmed by a single
resistor connected between the C
soft–start circuitry, requiring only an external timing capacitor. A shutdown pin controls both the soft–
start circuitry and the output stages, provided instantaneous turn–off through the PWM latch with
pulsed shutdown, as well as soft–start recycle with longer shutdown commands. The under voltage
lockout inhibits the outputs and the changing of the soft–start capacitor when V
The output stages are totem–pole design capable of sinking and sourcing in excess of 200mA. The
output stages of the NTE1721 features NOR logic resulting in a low output for an off state while the
NTE1723 utilizes OR logic which gives a high output when off.
Features:
D 8V to 35V Operation
D +5.1V 1% Trimmed Reference
D 100Hz to 400kHz Oscillator Range
D Separate Oscillator Sync Pin
D Adjustable Dead Time Control
Absolute Maximum Ratings: (Note 1)
Supply Voltage, V
Collector Supply Voltage, V
Logic Inputs
Analog Inputs
Output Current, Source or Sink, I
Reference Output Current, I
Oscillator Charging Current
Power Dissipation (T
Power Dissipation (T
Operating Junction Temperature, T
Storage Temperature Range, T
Thermal Resistance, Junction–to–Ambient, R
Thermal Resistance, Junction–to–Case, R
Lead Temperature (During Soldering, 10sec), T
Note 1 Values beyond which damage may occur
Derate Above 50 C
Derate Above 25 C
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CC
Pulse Width Modulator (PWM) Regulator
A
C
= +25 C), P
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= +25 C), P
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C
ref
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stg
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O
T
D
NTE1721 & NTE1723
D
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J
and the Discharge pins. These devices also feature a built–in
Integrated Circuit
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thJC
thJA
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L
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D Input Undervoltage Lockout
D Latching PWM to Prevent Multiple Pulses
D Pulse–by–Pulse Shutdown
D Dual Source/Sink Outputs:
CC
is below nominal.
–55 to +125 C
–0.3V to +5.5V
400mA Peak
–0.3V to V
10mW/ C
16mW/ C
1000mW
2000mW
100 C/W
60 C/W
+150 C
+300 C
500mA
50mA
+40V
+40V
5mA
CC