NTE NTE953

NTE953
Linear Integrated Circuit
4–Terminal Positive Adjustable Voltage Regulator
Description:
The NTE953 4–Terminal adjustable voltage regulator is designed to deliver continuous load currents
of up to 1.0A with a maximum input voltage of +40V. Output current capability can be increased to
greater than 1.0A through the use of one or more external transistors. The output voltage range is
5V to 30V. For systems requiring both a positive and negative, the NTE953 and NTE954 are excellent
for use as a dual tracking regulator with appropriate external circuitry.
Features:
D Output Current in Excess of 1A
D Positive Output 5V to 30V
D Internal Thermal Overload Protection
D Internal Short Circuit Protection
D Output Transistor Safe–Area Protection
D Power Watt Package
Absolute Maximum Ratings:
Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Control Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 ≤ V ≤ VOUT
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Internally Limited
Operating Junction Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 150°C
Storage Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +150°C
Lead Temperature (During soldering, 10s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +230°C
Electrical Characteristics:
Parameter
(–0°C ≤ TJ ≤ 125°C, VIN = 10V, IOUT = 500mA, CIN = 0.33µF,
COUT = 0.1µF, unless otherwise specified.)
Test Conditions (Note 1, Note 3)
Min
Typ
Max
Unit
Input Voltage Range
TJ = 25°C
7.5
–
40
V
Output Voltage Range
VIN = VOUT +5V
5.0
–
30
V
Output Voltage Tolerance
VOUT +3V ≤ VIN ≤ VOUT +15V, TJ = 25°C
5mA ≤ IOUT ≤ 1.0A,
PD ≤ 15W, VIN (max) = 38V
–
–
4.0
%(VOUT)
–
–
5.0
%(VOUT)
TJ = 25°C, VOUT ≤ 10V,
(VOUT 2.5V) ≤ VIN ≤ (VOUT +20V)
–
–
1.0
TJ = 25°C, VOUT ≥ 10V,
(VOUT +3V) ≤ VIN ≤ (VOUT +15V)
(VOUT +3V) ≤ VIN ≤ (VOUT +7V)
–
–
–
–
0.75
0.67
250mA ≤ IOUT ≤ 750mA
TJ = 25
25°C,
C,
VIN = VOUT +5V 5mA ≤ IOUT ≤ 1.5A
–
–
1.0
%(VOUT)
–
–
2.0
%(VOUT)
TJ = 25°C
–
1.0
5.0
µA
–
–
8.0
µA
–
3.2
5.0
µA
–
–
6.0
µA
Line Regulation
Load Regulation
Control Pin Current
Quiescent Current
TJ = 25°C
%(VOUT)
%(VOUT)
Ripple Rejection
8V ≤ VIN ≤ 18V, VOUT = 5V, f = 120Hz
62
78
–
dB
Output Noise Voltage
TJ = 25°C, 10Hz ≤ f ≤ 100kHz,
VOUT = 5V, IOUT = 5mA
–
8
40
µV/VOUT
Dropout Voltage
Note 2
–
–
2.5
V
Short Circuit Current
TJ = 25°C, VIN = 30V
–
0.75
1.2
A
Peak Output Current
TJ = 25°C
1.3
2.2
3.3
A
Average Temperature
Coefficient of
Output Voltage
VOUT = 5V,
IOUT = 5mA
TJ = –55°C to +25°C
–
–
0.4
TJ = +25°C to +150°C
–
–
0.3
mV/°C/
VOUT
Control Pin Voltage
(Reference)
TJ = 25°C
4.8
5.0
5.2
V
4.75
–
5.25
V
Note 1. VOUT is defined as: V
OUT =
R1 + R2
R2
(5.0)
Note 2. Dropout Voltage is defined as that input–output voltage differential which causes the output
voltage to decrease by 5% of its initial value.
Note 3. All characteristics except noise voltage and ripple rejection ratio are measured using pulse
techniques (tW ≤ 10ms, duty cycle ≤ 5%). Output voltage changes due to changes in internal
temperature must be taken into account separately.
Design Considerations:
The NTE953 adjustable voltage regulator has an output voltage which varies from VCONTROL to typically
(R1 + R2)
VIN –2V by VOUT = VCONTROL
R2
The nominal reference in the NTE953 is 5.0V. If we allow 1.0mA to flow in the control string to eliminate bias current effects, we can make R2 = 2.2kΩ. The output voltage is then:
VOUT = (R1 + R2)V, where R1 and R2 are in kΩs.
Example:
If R2 = 5kΩ and R1 = 10kΩ then
VOUT = 15V nominal
By proper wiring of the feedback resistors, load regulation of the device can be improved significantly.
The NTE953 voltage regulator contains thermal–overload protection from excessive power, internal
short–circuit protection which limits each circuit’s maximum current, and output transistor safe–area
protection for reducing the output current as the voltage across each pass transistor is increased.
Although the internal power dissipation is limited, the junction temperature must be kept below the
maximum specified temperature in order to meet data sheet specifications. To calculate the maximum junction temperature or heat sink required, the following thermal resistance values should be
used:
Typ
°C/W
Max
°C/W
Typ
°C/W
Max
°C/W
ΘJC
ΘJC
ΘJA
ΘJA
7.5
11
75
80
PD(max) =
TJ(max) – TA
or
TJ(max) – TA
ΘJC + ΘCA
ΘJA
(Without a heat sink)
ΘCA = ΘCS + ΘSA
TJ = TA + PD (ΘJC + ΘCA) or
TA + PD ΘJA (Without heat sink)
Solving for TJ:
Where:
TJ
TA
PD
ΘJA
ΘJC
ΘCA
ΘCS
ΘSA
=
=
=
=
=
=
=
=
Junction Temperature
Ambient Temperature
Power Dissipation
Junction to Ambient Thermal Resistance
Junction to Case Thermal Resistance
Case to Ambient Thermal Resistance
Case to Heat Sink Resistance
Heat Sink to Ambient Thermal Resistance
.375
(9.52)
.360
(9.14)
.125
(3.17)
Dia
.135 (3.45)
.110
(2.79)
Tab
.310
(7.87)
Indicating
Mark #1 Pin
1
2
3
.955
(24.27)
4
.250
(6.35)
.395
(10.05)
.270
(6.85)
.100 (2.54)
Pin 1.
2.
3.
4.
Tab
GND
VIN
VOUT
Adjust
GND