LM350_09

www.fairchildsemi.com LM350 3-Terminal 3A Positive Adjustable Voltage Regulator Features • • • • • • • Output Adjustable Between 1.2V and 33V Guaranteed 3A Output Current Internal Thermal Overload Protection Load Regulation (Typ: 0.1%) Line Regulation (Typ: 0.015%/V) Internal Short Circuit Current Limit Output Transistor Safe-Area Compensation Description The LM350 is an adjustable 3-terminal positive voltage regulator capable of supplying in excess of 3.0A over an output voltage range of 1.2V to 33V TO-220 1 1. Adj 2. Output 3. Input Internal Block Diagram 3 INPUT + VREF VOLTAGE REFERENCE PROTECTION CIRCUITRY RSC Q1 _ Q0 ADJUSTABLE OUTPUT 2 1 Rev. 1.0.1 ©2009 Fairchild Semiconductor Corporation LM350 Absolute Maximum Ratings Parameter Input Output Voltage Differential Lead Temperature (Soldering, 10sec) Power Dissipation Operating Temperature Range Storage Temperature Range Symbol VI - VO TLEAD PD TOPR TSTG Value 35 300 Internally limited 0 ~ +125 -65 ~ +150 Unit VDC °C °C °C Electrical Characteristics (VI-VO = 5V, IO = 1.5A, TJ = 0°C to +125°C; PD ≤ PDMAX, unless otherwise specified) Parameter Line Regulation (Note1) Load Regulation (Note1) Adjustment Pin Current Adjustment Pin Current Change Thermal Regulation Reference Voltage Line Regulation Load Regulation Temperature Stability Maximum Output Current Minimum Load Current RMS Noise, %of VOUT Ripple Rejection Long-Term Stability Symbol Rline Rload IADJ ΔIADJ REGT VREF Rline Rload STT Io(MAX) IL(MIN) VN RR ST Conditions TA = +25°C, 3V ≤ VI -VO ≤ 35V TA = +25°C, 3V ≤ VI -VO ≤ 35V V O ≤ 5V V O ≥ 5V 3V ≤ VI -VO ≤ 35V, 10mA ≤ Io ≤ 3A, PD ≤ PMAX Pulse = 20ms, TA =+25°C 3V ≤ VI -VO ≤ 35V, 10mA ≤I O≤ 3A,PD ≤ 30W 3.0V ≤ VI -VO ≤ 35V 10mA ≤ I O ≤ 3.0A VO ≤ 5.0V VO ≥ 5.0V TJ = 0°C to +125°C VI -VO ≤ 10V, PD ≤ PMAX VI -VO = 30V, PD ≤ PMAX,TA = +25°C VI -VO = 35V 10Hz ≤ f ≤ 10kHz, TA= +25°C VO = 10V, f = 120Hz, CADJ = 0 CADJ = 10μF TJ = +125°C Min. 1.2 3.0 0.25 Typ. Max. Unit %/V mV % μA μA %/W V %/W mV % % A A mA %/Vo dB dB %/ 1000HR 0.015 0.03 5 0.1 50 0.2 0.002 1.25 0.02 20 0.3 1.0 4.5 1.0 3.5 0.003 65 80 0.3 25 0.5 100 5.0 1.30 0.07 70 1.5 10 1 66 - Note: 1. Regulation is measured at constant junction temperature. Changes in output voltage due to heating effects must be taken into account separately. Pulse testing with low duty cycle is used. 2 LM350 Typical Performance Characteristics Figure 1. Load Regulation Figure 2. Current Limit Figure 3. Adjustment Pin Current Figure 4. Dropout Voltage Figure 5. Temperature Stability Figure 6. Minimum Load Current 3 LM350 Typical Performance Characteristics (Continued) Figure 7. Ripple Rejection vs Vo Figure 8. Ripple Rejection vs Io Figure 9. Ripple Rejection vs Frequency Figure 10. Output Impedance Figure 11. Line Transient Response Figure 12. Load Transient Response 4 LM350 Typical Application LM350 IN Input ADJ OUT I1 R1 120 CO 1uF Output IADJ CI 0.1uF R2 Figure 13. CI : CI is required if the regulator is located an appreciable distance from power supply filter. CO: Output capacitors in the range of 1μF to 100μF of aluminum or tantalum electronic are commonly used to provide improved output impedance and rejection of transients. In operation, the LM350 develops a nominal 1.25V reference voltage, VREF, between the output and adjustment terminal. The reference voltage is impressed across program resistor R1 and, since the voltage is constant, a constant current I1 then flows through the output set resistor R2, giving an output voltage of VO = 1.25V(1+R2/R1) + IADJ R2 Since IADJ current (less than 100μA) from the adjustment terminal represents an error term, the LM350 was designed to minimize IADJ and make it very constant with line and load changes. To do this, all quiescent operating current is returned to the output establishing a minimum load current requirement. If there is insufficient load on the output, the output voltage will rise. Since the LM350 is a floating regulator, it is only the voltage differential across the circuit which is important to performance, and operation at high voltage with respect to ground is possible. Since IADJ is controlled to less than 100μA, the error associated with this term is negligible in most applications. 5 LM350 Mechanical Dimensions Package Dimensions in millimeters TO-220 [SINGLE GAUGE] 6 LM350 Ordering Information Product Number LM350T Package TO-220 Operating Temperature 0°C to +125°C 7 LM350 DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. www.fairchildsemi.com 7/7/09 0.0m 001 Stock#DS400307 © 2009 Fairchild Semiconductor Corporation 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.