Advanced Monolithic Systems AMS317 1A LOW DROPOUT VOLTAGE REGULATOR FEATURES APPLICATIONS * Three Terminal Adjustable or Fixed Voltages* 1.8V, 2.5V, 2.85V, 3.3V and 5.0V * Output Current of 1A * Operates Down to 1V Dropout * Line Regulation: 0.2% Max. * Load Regulation: 0.4% Max. * TO-220, TO-263, TO-252 and SOT-223 package available * High Efficiency Linear Regulators * Post Regulators for Switching Supplies * 5V to 3.3V Linear Regulator * Battery Chargers * Active SCSI Terminators * Power Management for Notebook * Battery Powered Instrumentation GENERAL DESCRIPTION The The AMS317 series of adjustable and fixed voltage regulators are designed to provide 1A output current and to operate down to 1V input-to-output differential. The dropout voltage of the device is guaranteed maximum 1.3V at maximum output current, decreasing at lower load currents. On-chip trimming adjusts the reference voltage to 1%. Current limit is also trimmed, minimizing the stress under overload conditions on both the regulator and power source circuitry. The AMS317 devices are pin compatible with other three-terminal regulators and are offered in 3 lead TO-220 package, in the 2 & 3 Lead TO-263 (Plastic DD), in the TO-252 (D PAK) and in the low profile surface mount SOT-223 package. ORDERING INFORMATION: OUTPUT PACKAGE TYPE 3 Lead TO-220 2 &3 Lead TO-263 VOLTAGE ADJUSTABLE AMS317ACT AMS317ACM AMS317CT AMS317CM FIXED* AMS317ACT-X AMS317ACM-X AMS317CT-X AMS317CM-X X= 1.8V, 2.5V, 2.85V, 3.3V and 5.0V. *For additional available fixed voltages contact factory. OPERATING JUNCTION TO-252 AMS317ACD AMS317CD AMS317ACD-X AMS317CD-X SOT-223 AMS317A AMS317 AMS317A-X AMS317-X TEMPERATURE RANGE -40 to +125 C 0 to 125 C -40 to +125 C 0 to 125 C SOT-223 Top View PIN CONNECTIONS TO-263 FRONT VIEW FIXED VERSION 1- Ground 2- VOUT 3- VIN ADJUSTABLE VERSION TAB IS OUTPUT 1- Adjust 2- VOUT 3- VIN 1 3 Advanced Monolithic Systems, Inc. 2 1 TAB IS OUTPUT 2 1 3 TO-252 FRONT VIEW TO-220 FRONT VIEW TAB IS OUTPUT 2 3 3 2 1 2L TO-263 FRONT VIEW TAB IS OUTPUT 3 2 1 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 ABSOLUTE MAXIMUM RATINGS (Note 1) Power Dissipation Internally limited Input Voltage 25V Operating Junction Temperature Range AMS317A -40C to +125C AMS317 0C to +125C Storage temperature - 65C to +150C Soldering information Lead Temperature (10 sec) 300C Thermal Resistance TO-220 package TO-263 package TO-252 package SOT-223 package JA= 50C/W JA= 30C/W JA= 80C/W JA= 90C/W* * With package soldering to copper area over backside ground plane or internal power plane JA can vary from 46C/W to >90C/W (for SOT-223) (20C/W to >40C/W for TO-263) depending on mounting technique and the size of the copper area. ELECTRICAL CHARACTERISTICS Electrical Characteristics at IOUT = 10 mA, (VIN - VOUT) = 5V, and TJ = +25C unless otherwise specified. Parameter Device Conditions Min Reference Voltage (Note 2) AMS317 Output Voltage (Note 2) AMS317-1.8 AMS317A Typ Max Min AMS317 Typ Max Units IOUT = 10 mA 10mA IOUT IMAX, 3V (VIN - VOUT) 25V 1.238 1.225 1.250 1.250 1.262 1.270 1.225 1.20 1.250 1.250 1.270 1.30 V V 0 IOUT IMAX, 3.3V VIN 25V 1.782 1.764 1.800 1.800 1.818 1.836 1.764 1.746 1.800 1.800 1.836 1.854 V V 0 IOUT IMAX , 4.0V VIN 25V 2.475 2.460 2.500 2.500 2.525 2.560 2.450 2.425 2.500 2.500 2.550 2.575 V V 0 IOUT IMAX , 4.35V VIN 25V 2.82 2.793 2.850 2.850 2.88 2.907 2.793 2.765 2.850 2.850 2.907 2.935 V V 0 IOUT IMAX, 4.75V VIN 25V 3.267 3.235 3.300 3.300 3.333 3.365 3.235 3.201 3.300 3.300 3.365 3.399 V V 0 IOUT IMAX , 6.5V VIN 25V 4.950 4.900 5.000 5.000 5.050 5.100 4.900 4.850 5.000 5.000 5.100 5.150 V V 0.015 0.035 0.2 0.2 0.015 0.035 0.2 0.2 % % AMS317-2.5 AMS317-2.85 AMS317-3.3 AMS317-5.0 Line Regulation AMS317 ILOAD = 10 mA , 3V (VIN - VOUT) 25V Load Regulation AMS317 10mA IOUT IMAX 0.1 0.3 0.5 1.0 0.1 0.3 0.5 1.0 % % Current Limit AMS317/-1.8/2.5/-2.85/-3.3/-5.0 (VIN - VOUT) = 5V 1.5 2.0 1.5 2.0 A Minimum Load Current AMS317 (VIN - VOUT) = 25V 5 10 5 10 mA Thermal Regulation AMS317 TA = 25C, 20ms pulse 0.04 0.07 0.04 0.07 %W Adjust Pin Current AMS317 100 A A 5 A (Notes 2, 3) 40 40 100 10mA IOUT IMAX , 3V (VIN - VOUT) 25V 0.2 Temperature Stability TMIN TJ TMAX 1.0 Long Term Stability TA =125C, 1000Hrs 0.3 Adjust Pin Current Change Ripple Rejection AMS317 AMS317 f =120Hz , COUT = 25F Tantalum, (VIN-VOUT ) = 3V, CADJ =10F 66 80 5 0.2 % 1.0 1 0.3 66 1 % 80 dB 0.003 % RMS Output Noise (% of VOUT ) TA = 25C , 10Hz f 10kHz Thermal Resistance Junction-to-Case TO-252 Package 5 5 C/W SOT-223 Package 23.5 23.5 C/W 5 5 C/W TO-220 / TO-263 Package Advanced Monolithic Systems, Inc. 0.003 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Parameters identified with boldface type apply over the full operating temperature range. Note 2: Line and Load regulation are guaranteed up to the maximum power dissipation of 1.2 W. Power dissipation is determined by the input/output differential and the output current. Guaranteed maximum power dissipation will not be available over the full input/output range. Note 3: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured at a constant junction temperature by low duty cycle pulse testing. Load regulation is measured at the output lead ~1/8" from the package. Note 4: Minimum load current is defined as the minimum output current required to maintain regulation. When 3V (VIN - VOUT) 25V the device is guaranteed to regulate if the output current is greater than 10mA. APPLICATION HINTS The AMS317 series of adjustable and fixed regulators are easy to use and are protected against short circuit and thermal overloads. Thermal protection circuitry will shut-down the regulator should the junction temperature exceed 165C at the sense point. Pin compatible with older three terminal adjustable regulators, these devices offer the advantage of a lower dropout voltage, more precise reference tolerance and improved reference stability with temperature. output capacitors are used, such as 1000F to 5000F and the input pin is instantaneously shorted to ground, damage can occur. A diode from output to input is recommended, when a crowbar circuit at the input of the AMS317 is used (Figure 1). D1 Stability The circuit design used in the AMS317 series requires the use of an output capacitor as part of the device frequency compensation. The addition of 150F aluminum electrolytic or a 22F solid tantalum on the output will ensure stability for all operating conditions. When the adjustment terminal is bypassed with a capacitor to improve the ripple rejection, the requirement for an output capacitor increases. The value of 22F tantalum or 150F aluminum covers all cases of bypassing the adjustment terminal. Without bypassing the adjustment terminal smaller capacitors can be used with equally good results. To ensure good transient response with heavy load current changes capacitor values on the order of 100F are used in the output of many regulators. To further improve stability and transient response of these devices larger values of output capacitor can be used. Protection Diodes Unlike older regulators, the AMS317 family does not need any protection diodes between the adjustment pin and the output and from the output to the input to prevent over-stressing the die. Internal resistors are limiting the internal current paths on the AMS317 adjustment pin, therefore even with capacitors on the adjustment pin no protection diode is needed to ensure device safety under short-circuit conditions. Diodes between the input and output are not usually needed. Microsecond surge currents of 50A to 100A can be handled by the internal diode between the input and output pins of the device. In normal operations it is difficult to get those values of surge currents even with the use of large output capacitances. If high value Advanced Monolithic Systems, Inc. AMS317 IN OUT ADJ VIN CADJ 10F VOUT R1 + COUT 150F R2 Figure 1. Output Voltage The AMS317 series develops a 1.25V reference voltage between the output and the adjust terminal. Placing a resistor between these two terminals causes a constant current to flow through R1 and down through R2 to set the overall output voltage. This current is normally the specified minimum load current of 10mA. Because IADJ is very small and constant it represents a small error and it can usually be ignored. VIN AMS317 IN OUT ADJ VOUT VREF R1 IADJ 50A R2 VOUT = VREF (1+ R2/R1)+IADJR2 Figure 2. Basic Adjustable Regulator 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 APPLICATION HINTS Load Regulation True remote load sensing it is not possible to provide, because the AMS317 is a three terminal device. The resistance of the wire connecting the regulator to the load will limit the load regulation. The data sheet specification for load regulation is measured at the bottom of the package. Negative side sensing is a true Kelvin connection, with the bottom of the output divider returned to the negative side of the load. The best load regulation is obtained when the top of the resistor divider R1 is connected directly to the case not to the load. If R1 were connected to the load, the effective resistance between the regulator and the load would be: RP x ( R2+R1 ) , R1 RP = Parasitic Line Resistance Connected as shown , RP is not multiplied by the divider ratio VIN AMS317 IN OUT ADJ RP PARASITIC LINE RESISTANCE R1* RL The thermal resistance from the junction to the tab for the AMS317 is 15C/W; thermal resistance from tab to ambient can be as low as 30C/W. The total thermal resistance from junction to ambient can be as low as 45C/W. This requires a reasonable sized PC board with at least on layer of copper to spread the heat across the board and couple it into the surrounding air. Experiments have shown that the heat spreading copper layer does not need to be electrically connected to the tab of the device. The PC material can be very effective at transmitting heat between the pad area, attached to the pad of the device, and a ground plane layer either inside or on the opposite side of the board. Although the actual thermal resistance of the PC material is high, the Length/Area ratio of the thermal resistance between layers is small. The data in Table 1, was taken using 1/16" FR-4 board with 1 oz. copper foil, and it can be used as a rough guideline for estimating thermal resistance. For the TO-252 package, if the maximum allowable value is found to be 92C/W, no heat sink is needed since the package alone will dissipate enough heat to satisfy these requirements. If the calculated value for JA falls bellow these limits, a heat sink is required. For each application the thermal resistance will be affected by thermal interactions with other components on the board. To determine the actual value some experimentation will be necessary. The power dissipation of the AMS317 is equal to: PD = ( VIN - VOUT )( IOUT ) Maximum junction temperature will be equal to: R2* TJ = TA(MAX) + PD(Thermal Resistance (junction-to-ambient)) Maximum junction temperature must not exceed 125C. Ripple Rejection *CONNECT R1 TO CASE CONNECT R2 TO LOAD Figure 3. Connections for Best Load Regulation In the case of fixed voltage devices the top of R1 is connected Kelvin internally, and the ground pin can be used for negative side sensing. Thermal Considerations The AMS317 series have internal power and thermal limiting circuitry designed to protect the device under overload conditions. However maximum junction temperature ratings of 125C should not be exceeded under continuous normal load conditions. Careful consideration must be given to all sources of thermal resistance from junction to ambient. For the surface mount package SOT-223 additional heat sources mounted near the device must be considered. The heat dissipation capability of the PC board and its copper traces is used as a heat sink for the device. Advanced Monolithic Systems, Inc. The ripple rejection values are measured with the adjustment pin bypassed. The impedance of the adjust pin capacitor at the ripple frequency should be less than the value of R1 (normally 100 to 200) for a proper bypassing and ripple rejection approaching the values shown. The size of the required adjust pin capacitor is a function of the input ripple frequency. If R1=100 at 120Hz the adjust pin capacitor should be >13F. At 10kHz only 0.16F is needed. The ripple rejection will be a function of output voltage, in circuits without an adjust pin bypass capacitor. The output ripple will increase directly as a ratio of the output voltage to the reference voltage (VOUT / VREF ). 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 Table 1. COPPER AREA TOP SIDE* BACK SIDE BOARD AREA 2500 Sq. mm 2500 Sq. mm 2500 Sq. mm 1000 Sq. mm 2500 Sq. mm 2500 Sq. mm 225 Sq. mm 2500 Sq. mm 2500 Sq. mm 100 Sq. mm 2500 Sq. mm 2500 Sq. mm 1000 Sq. mm 1000 Sq. mm 1000 Sq. mm 1000 Sq. mm 0 1000 Sq. mm * Tab of device attached to topside copper. THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 45C/W 45C/W 53C/W 59C/W 52C/W 55C/W TYPICAL PERFORMANCE CHARACTERISTICS Minimum Operating Current (Adjustable Device) Short-Circuit Current 1.25 TJ = 125C 9 SHORT CIRCUIT CURRENT (A) MINIMUM OPERATING CURRENT (mA) 12 TJ = 125C TJ = 25C 6 3 1.00 TJ = 25C 0.75 0.50 0.25 0 0 0 5 10 15 20 0 Load Regulation 10 15 Ripple Rejection vs. Current 0.10 100 ILOAD = 1A 90 fRIPPLE = 120Hz 0.05 80 RIPPLE REJECTION (dB) OUTPUT VOLTAGE DEVIATION (%) 5 INPUT/OUTPUT DIFFERENTIAL INPUT/OUTPUT DIFFERENTIAL (V) 0 -0.05 -0.10 VRIPPLE3Vp-p 70 60 fRIPPLE = 20Hz 50 40 VRIPPLE0.5Vp-p 30 20 -0.15 VOUT = 5V CADJ = 25 F COUT = 25F 10 -0.20 0 -50 -25 0 25 50 75 TEMPERATURE (C) Advanced Monolithic Systems, Inc. 100 125 0 0.2 0.4 0.6 0.8 OUTPUT CURRENT (A) 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 TYPICAL PERFORMANCE CHARACTERISTICS (Continued). Adjust Pin Current Temperature Stability 2.0 100 80 ADJUST PIN CURRENT (A) OUTPUT VOLTAGE CHANGE (%) 90 1.0 0 -1.0 70 60 50 40 30 20 10 -2.0 0 -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) TEMPERATURE (C) PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted. 3 LEAD TO-220 PLASTIC PACKAGE (T) 0.147-0.155 (3.734-3.937) DIA 0.390-0.415 (9.906-10.541) 0.165-0.180 (4.191-4.572) 0.045-0.055 (1.143-1.397) 0.230-0.270 (5.842-6.858) 0.570-0.620 (14.478-15.748) 0.460-0.500 (11.684-12.700) 0.330-0.370 (8.382-9.398) 0.980-1.070 (24.892-27.178) 0.218-0.252 (5.537-6.401) 0.520-0.570 (13.208-14.478) 0.090-0.110 (2.286-2.794) 0.028-0.038 (0.711-0.965) 0.050 (1.270) TYP 0.013-0.023 (0.330-0.584) 0.095-0.115 (2.413-2.921) T (TO-220) AMS DRW# 042193 Advanced Monolithic Systems, Inc. 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued). 3 LEAD TO-263 PLASTIC DD (M) 0.060 (1.524) TYP 0.390-0.415 (9.906-10.541) 0.165-0.180 (4.191-4.572) 0.004 +0.008 -0.004 (0.102 +0.203 ) -0.102 0.330-0.370 (8.382-9.398) 0.199-0.218 (5.05-5.54 ) 0.090-0.110 (2.286-2.794) 0.032 (0.81) TYP 0.045-0.055 (1.143-1.397) 0.108 (2.74) TYP 0.095-0.115 (2.413-2.921) 0.90-0.110 (2.29-2.79) 0.013-0.023 (0.330-0.584) M (DD3) AMS DRW# 042191R1 2 LEAD TO-263 PLASTIC DD (M) 0.060 (1.524) TYP 0.390-0.415 (9.906-10.541) 0.165-0.180 (4.191-4.572) 0.004 +0.008 -0.004 (0.102 +0.203 ) -0.102 0.330-0.370 (8.382-9.398) 0.0295 (0.7495) TYP 0.090-0.110 (2.286-2.794) Advanced Monolithic Systems, Inc. 0.199-0.218 (5.05-5.54 ) 0.032 (0.81) TYP 0.045-0.055 (1.143-1.397) 0.108 (2.74) TYP 0.095-0.115 (2.413-2.921) 0.90-0.110 (2.29-2.79) 0.013-0.023 (0.330-0.584) M (DD2) AMS DRW# 072191 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140 AMS317 PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued). TO-252 PLASTIC PACKAGE (D) 0.020-0.030 (0.508-0.762) 0.258-0.262 (6.553-6.654) 0.208-0.212 (5.283-5.384) 0.020-0.030 (0.508-0.762) 0.033-0.037 (0.838-0.939) 0.085-0.095 (2.159-2.413) 0.030-0.034 (0.762-0.863) 0.038-0.042 (0.965-1.066) 7.0 0.023-0.027 (0.584-0.685) 45.0 0.175-0.180 (4.191-4.445) 0.235-0.245 (5.969-6.223) 0.057-0.067 (0.144-0.170) DIA 0.025 (0.635) TYP 0.038 (0.965) TYP 0.099-0.103 (2.514-2.615) 0.088-0.092 (2.235-2.336) 0.038-0.042 (0.965-1.066) 0.0240.002 (0.6100.0508) 0.030 (0.762) TYP 0.018-0.022 (0.451-0.558) D (D3) AMS DRW# 042891 3 LEAD SOT-223 PLASTIC PACKAGE 0.248-0.264 (6.30-6.71) 0.116-0.124 (2.95-3.15) 0.264-0.287 (6.71-7.29) 0.130-0.146 (3.30-3.71) 0.033-0.041 (0.84-1.04) 0.090 (2.29) NOM 10-16 10 MAX 0.071 (1.80) MAX 0.010-0.014 (0.25-0.36) 10-16 0.025-0.033 (0.64-0.84) 0.181 (4.60) NOM Advanced Monolithic Systems, Inc. 0.012 (0.31) MIN 0.025-0.033 (0.64-0.84) (SOT-223 ) AMS DRW# 042292 6680B Sierra Lane, Dublin, CA 94568 Phone (925) 556-9090 Fax (925) 556-9140