NTE1721 NTE Electronics, Inc., NTE1721 Datasheet - Page 3

• Manufacturer Part Number: NTE1721
• Description: Regulator; Pulse Width Modulator; DIP; 50 mA; 5.1 V (Typ.); 35 V (Max.)
• Manufacturer: NTE Electronics, Inc.
• Type: Pulse Width Modulator Regulator, Voltage Referencer

Specifications of NTE1721

• Common Mode Rejection Ratio: 75
• Current, Input Bias: 1 μA
• Current, Output: 50 μA
• Current, Supply: 14 mA
• Frequency, Oscillator: 400 kHz
• Load Regulation: 20 mV (Typ.)
• Package Type: DIP-16
• Power Dissipation: 1000 mW
• Regulation, Line: 10 mV
• Regulation, Load: 20 mV
• Regulator Type: Switching
• Resistance, Thermal, Junction To Case: 60 °C/W
• Temperature, Operating: 0 to 70 °C
• Temperature, Operating, Range: 0 to +70 °C
• Time, Fall: 50 ns
• Time, Rise: 100 ns
• Type, Voltage Regulator: Pulse Width Modulator
• Voltage Noise, Output: 40 μV (RMS) (Typ.)
• Voltage, Noise: 40 μV
• Voltage, Offset: 2 mV
• Voltage, Output: 5.1 V
• Voltage, Output, High: 5.6 V
• Voltage, Output, Low: 0.2 V
• Voltage, Rating: 35 V (Max.)
• Voltage, Supply: 35 V
• Voltage, Supply, Rejection Ratio: 60 dB
• Lead Free Status / Rohs Status: RoHS Compliant part

Electrical Characteristics (Cont’d): (V
Note 3.Applies to NTE1721 Only, due to polarity of output pulses.
Application Information (Shutdown Options):
Since both the compensation and soft–start terminals (Pin9 and Pin8) have current source pull–ups,
either can readily accept a pull–down signal which only has to sink a maximum of 100 A to turn off
the outputs. This is subject to the added requirement of discharging whatever external capacitance
may be attached to these pins.
An alternate approach is the use of the shutdown circuitry of Pin10 which has been improved to en-
hance the available shutdown options. Activating this circuit by applying a positive signal on Pin10
performs two functions: the PWM latch is immediately set providing the fastest turn–off signal to the
outputs; and a 150 A current sink begins to discharge the external soft–start capacitor. If the shut-
down command is short, the PWM signal is terminated without significant discharge of the soft–start
capacitor, thus, allowing, for example, a convenient implementation of pulse–by–pulse current limit-
ing. Holding Pin10 high for a longer duration, however, will ultimately discharge this external capaci-
tor, recycling slow turn–on upon release.
Pin10 should not be left floating as noise pickup could conceivably interrupt normal operation.
Error Amplifier Section (Cont’d) (V
DC Open Loop Gain
Low Level Output Voltage
High Level Output Voltage
Common Mode Rejection Ratio
Power Supply Rejection Ratio
PWM Comparator Section
Minimum Duty Cycle
Maximum Duty Cycle
Input Threshold, Zero Duty Cycle
Input Threshold, Maximum Duty Cycle
Input Bias Current
Soft–Start Section
Soft–Start Current
Soft–Start Voltage
Shutdown Input Current
Output Drivers (Each Output, V
Output Low Level
Output High Level
Under Voltage Lockout
Collector Leakage
Rise Time
Fall Time
Shutdown Delay
Supply Current
Parameter
CC
= +20V)
CM
= +5.1V)
Symbol
CMRR
DC
PSRR
DC
I
A
C(leak)
V
V
V
V
V
V
I
t
VOL
I
CC
OH
OH
t
ds
OL
TH
IB
OL
t
UL
max
r
f
min
CC
R
+1.5V V
+8V
f
C
V
V
V
I
I
I
I
V8 and V9 = High
V
C
C
V
V
= +20V, T
osc
sink
sink
sink
sink
shutdown
shutdown
shutdown
C
DS
CC
L
T
L
L
= 1.0nF, T
= 1.0nF, T
= 0.01 F, R
= +35V, Note 3
= 40kHz, R
= 20mA
= 100mA
= 20mA
= 100mA
= +3V, C
= +35V
10M
V
CC
Test Conditions
CM
= 0V
= 2.0V
= 2.5V
A
+35V
J
J
S
= 0 to +70 C unless otherwise specified)
+5.2V
= +25 C
= +25 C
D
= 0, T
T
= 0
= 3.6k ,
J
= +25 C
Min
3.8
0.6
6.0
60
60
50
45
25
18
17
–
–
–
–
–
–
–
–
–
–
–
–
–
0.05
Typ
100
0.2
5.6
0.9
3.3
0.4
0.4
0.2
1.0
7.0
0.2
75
75
60
49
50
19
18
50
14
–
–
Max
200
600
300
0.5
3.6
1.0
0.6
1.0
0.4
2.0
8.0
0.5
80
20
–
–
–
–
0
–
–
–
–
Unit
mA
mA
dB
dB
dB
ns
ns
%
%
V
V
V
V
V
V
V
V
V
V
A
A
A
s