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