NTE1721 Datasheet, PDF (1/4 Pages) NTE Electronics – Integrated Circuit Pulse Width Modulator (PWM) Regulator

NTE1721 & NTE1723
Integrated Circuit
Pulse Width Modulator (PWM) Regulator
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_T and the Discharge pins. These devices also feature a built–in
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_CC is below nominal.
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
D Input Undervoltage Lockout
D Latching PWM to Prevent Multiple Pulses
D Pulse–by–Pulse Shutdown
D Dual Source/Sink Outputs: ±400mA Peak
Absolute Maximum Ratings: (Note 1)
Supply Voltage, V_CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V
Collector Supply Voltage, V_C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +40V
Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to +5.5V
Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to V_CC
Output Current, Source or Sink, I_O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±500mA
Reference Output Current, I_ref . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Oscillator Charging Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5mA
Power Dissipation (T_A = +25°C), P_D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000mW
Derate Above 50°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mW/°C
Power Dissipation (T_C = +25°C), P_D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2000mW
Derate Above 25°C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16mW/°C
Operating Junction Temperature, T_J . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +150°C
Storage Temperature Range, T_stg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55° to +125°C
Thermal Resistance, Junction–to–Ambient, R_thJA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100°C/W
Thermal Resistance, Junction–to–Case, R_thJC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60°C/W
Lead Temperature (During Soldering, 10sec), T_L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300°C
Note 1 Values beyond which damage may occur