Advanced Monolithic Systems AMS2911 1A LOW DROPOUT VOLTAGE REGULATOR RoHS compliant FEATURES APPLICATIONS • Three Terminal Adjustable or Fixed Voltages* 1.5V, 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. • Available in TO-220, TO-263, TO-252 and SOT-223 packages • 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 AMS2911 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 1.5V 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 AMS2911 devices are pin compatible with other three-terminal regulators and are offered in the 3 lead TO-220 package, in the 3Lead TO-263 (Plastic DD), in the TO-252 (DPAK) and in the low profile surface mount SOT-223 package. ORDERING INFORMATION: PACKAGE TYPE 3 LEAD TO-220 3 LEAD TO-263 TO-252 AMS2911CT AMS2911CM AMS2911CD AMS2911CT-1.5 AMS2911CM-1.5 AMS2911CD-1.5 AMS2911CT-1.8 AMS2911CM-1.8 AMS2911CD-1.8 AMS2911CT-2.5 AMS2911CM-2.5 AMS2911CD-2.5 AMS2911CT-2.85 AMS2911CM-2.85 AMS2911CD-2.85 AMS2911CT-3.3 AMS2911CM-3.3 AMS2911CD-3.3 AMS2911CT-5.0 AMS2911CM-5.0 AMS2911CD-5.0 *For additional available fixed voltages contact factory. OPERATING JUNCTION SOT-223 AMS2911 AMS2911-1.5 AMS2911-1.8 AMS2911-2.5 AMS2911-2.85 AMS2911-3.3 AMS2911-5.0 SOT-223 Top View TEMPERATURE RANGE -40 to 125° C -40 to 125° C -40 to 125° C -40 to 125° C -40 to 125° C -40 to 125° C -40 to 125° C TO-220 FRONT VIEW PIN CONNECTIONS 3 2 1 FIXED VERSION ADJUSTABLE VERSION 1- VIN 2- Ground 3- VOUT 1- VIN 2- Adjust 3- VOUT Advanced Monolithic Systems, Inc. 1 2 3 TO-263 FRONT VIEW TO-252 FRONT VIEW 3 3 2 1 www.advanced-monolithic.com Phone (925) 443-0722 2 1 Fax (925) 443-0723 AMS2911 ABSOLUTE MAXIMUM RATINGS (Note 1) Power Dissipation Input Voltage Operating Junction Temperature Control Section Power Transistor Storage temperature Soldering information Lead Temperature (25 sec) Internally limited 15V -40°C to 125°C -40°C to 150°C - 65°C to +150°C 265°C Thermal Resistance TO-220 package TO-263 package TO-252 package SOT-223 package ϕ JA= 50°C/W ϕ JA= 30°C/W ϕ JA= 80°C/W ϕ JA= 90°C/W* * With package soldering to copper area over backside ground plane or internal power plane ϕ JA can vary from 46°C/W to >90°C/W depending on mounting technique and the size of the copper area. ELECTRICAL CHARACTERISTICS Electrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified. Parameter Device Conditions Reference Voltage (Note 2) AMS2911 IOUT = 10 mA 10mA ≤ IOUT ≤ 1A, 1.5V≤ (VIN - VOUT) ≤ 12V 1.238 1.225 Output Voltage (Note 2) AMS2911-1.5 0 ≤ IOUT ≤ 1A , 4.35V≤ VIN ≤ 12V AMS2911-1.8 Line Regulation Load Regulation Max Units 1.250 1.250 1.262 1.270 V V 1.485 1.476 1.500 1.500 1.515 1.524 V V 0 ≤ IOUT ≤ 1A , 4.35V≤ VIN ≤ 12V 1.782 1.773 1.800 1.800 1.818 1.827 V V AMS2911-2.5 0 ≤ IOUT ≤ 1A , 4.35V≤ VIN ≤ 12V 2.475 2.460 2.500 2.500 2.525 2.540 V V AMS2911-2.85 0 ≤ IOUT ≤ 1A , 4.35V≤ VIN ≤ 12V 2.82 2.79 2.850 2.850 2.88 2.91 V V AMS2911-3.3 0 ≤ IOUT ≤ 1A , 4.75V ≤ VIN ≤ 12V 3.267 3.235 3.300 3.300 3.333 3.365 V V AMS2911-5.0 0 ≤ IOUT ≤ 1A , 6.5V ≤ VIN ≤ 12V 4.950 4.900 5.000 5.000 5.050 5.100 V V AMS2911 ILOAD = 10 mA , 1.5V≤ (VIN - VOUT) ≤ 12V 0.015 0.035 .02 .02 % % AMS2911-1.5 4.35V≤ VIN ≤ 12V 0.3 0.6 5 6 mV mV AMS2911-1.8 4.35V≤ VIN ≤ 12V 0.3 0.6 5 6 mV mV AMS2911-2.5 4.35V≤ VIN ≤ 12V 0.3 0.6 6 6 mV mV AMS2911-2.85 4.35V≤ VIN ≤ 12V 0.3 0.6 6 6 mV mV AMS2911-3.3 4.75V≤ VIN ≤ 12V 0.5 1.0 10 10 mV mV AMS2911-5.0 6.5V≤ VIN ≤ 12V 0.5 1.0 10 10 mV mV AMS2911 (VIN - VOUT) =3V, 10mA ≤ IOUT ≤ 1A 0.1 0.2 0.3 0.4 % % AMS2911-1.5 VIN = 5V, 0 ≤ IOUT ≤ 1A 3 6 10 20 mV mV AMS2911-1.8 VIN = 5V, 0 ≤ IOUT ≤ 1A 3 6 10 20 mV mV AMS2911-2.5 VIN = 5V, 0 ≤ IOUT ≤ 1A 3 6 12 20 mV mV (Notes 2, 3) Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Min Typ Phone (925) 443-0722 Fax (925) 443-0723 AMS2911 ELECTRICAL CHARACTERISTICS Electrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified. Parameter Device Conditions Min Typ Load Regulation AMS2911-2.85 VIN = 5V, 0 ≤ IOUT ≤ 1A 3 6 12 20 mV mV AMS2911-3.3 VIN = 5V, 0 ≤ IOUT ≤ 1A 3 7 15 25 mV mV AMS2911-5.0 VIN = 8V, 0 ≤ IOUT ≤ 1A 5 10 20 35 mV mV Dropout Voltage (VIN - VOUT) AMS2911-1.5/-1.8/-2.5/2.85/ -3.3/-5.0 ∆VOUT , ∆VREF = 1%, IOUT = 1A (Note 4) 1.3 1.5 V Current Limit AMS2911-1.5/-1.8/-2.5/2.85/ -3.3/-5.0 (VIN - VOUT) = 5V 1.1 1.5 A Minimum Load Current AMS2911 (VIN - VOUT) = 12V (Note 5) 5 10 mA Quiescent Current AMS2911-1.5/-1.8/-2.5/2.85/ -3.3/-5.0 VIN ≤ 12V 5 10 mA Ripple Rejection AMS2911 f =120Hz , COUT = 25µF Tantalum, IOUT = 1A, (VIN-VOUT ) = 3V, CADJ =25µF 60 75 dB AMS2911-1.5/-1.8/-2.5/2.85 f =120Hz , COUT = 25µF Tantalum, IOUT = 1A, VIN = 6V 60 72 dB AMS2911-3.3 f =120Hz , COUT = 25µF Tantalum, IOUT = 1A VIN = 6.3V 60 72 dB AMS2911-5 f =120Hz , COUT = 25µF Tantalum, IOUT = 1A VIN = 8V 60 68 dB Thermal Regulation AMS2911 TA = 25°C, 30ms pulse Adjust Pin Current AMS2911 10mA ≤ IOUT ≤ 1A , 1.5V≤ (VIN - VOUT) ≤ 12V (Notes 2, 3) Adjust Pin Current Change AMS2911 .9 0.008 10mA ≤ IOUT ≤ 1A , 1.5V≤ (VIN - VOUT) ≤ 12V Temperature Stability Max 0.04 %W 120 µA µA 5 µA 55 0.2 % 0.5 Long Term Stability TA =125°C, 1000Hrs RMS Output Noise TA = 25°C , 10Hz ≤ f ≤ 10kHz Units 0.3 1 0.003 % % (% of VOUT ) Thermal Resistance Junction-to-Case M Package: Control Circuitry/ Power Transistor T Package: Control Circuitry/ Power Transistor 1.5/4.0 1.5/4.0 °C/W °C/W Parameters identified with boldface type apply over the full operating temperature range. 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. Note 2: Line and Load regulation are guaranteed up to the maximum power dissipation of 1.2W. 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: Dropout voltage is specified over the full output current range of the device. Note 5: Minimum load current is defined as the minimum output current required to maintain regulation. When 1.5 ≤ (VIN - VOUT) ≤12V the device is guaranteed to regulate if the output current is greater than 10mA. Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS2911 APPLICATION HINTS The AMS2911 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 165°C 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. D1 AMS2911 IN OUT ADJ VIN VOUT R1 + COUT 150µF Stability The circuit design used in the AMS2911 series requires the use of an output capacitor as part of the device frequency compensation. The addition of 150µF aluminum electrolytic or a 22µF 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 22µF tantalum or 150µF aluminum covers all cases of bypassing the adjustment terminal. Without bypassing the adjustment terminal smaller capacitors can be used with equally good results. To further improve stability and transient response of these devices larger values of output capacitor can be used. Protection Diodes Unlike older regulators, the AMS2911 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 AMS2911 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 output capacitors are used, such as 1000µF to 5000µF 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 AMS2911 is used (Figure 1). CADJ 10µF Figure 1. Output Voltage The AMS2911 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. AMS2911 IN OUT ADJ VIN VOUT VREF R1 IADJ 50µA R2 VOUT = VREF (1+ R2/R1)+IADJR2 Figure 2. Basic Adjustable Regulator Load Regulation True remote load sensing it is not possible to provide, because the AMS2911 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 Advanced Monolithic Systems, Inc. R2 www.advanced-monolithic.com RP = Parasitic Line Resistance Phone (925) 443-0722 Fax (925) 443-0723 AMS2911 APPLICATION HINTS Connected as shown , RP is not multiplied by the divider ratio VIN AMS2911 IN OUT ADJ RP PARASITIC LINE RESISTANCE RL R1* R2* *CONNECT R1 TO CASE The total thermal resistance from junction to ambient can be as low as 45°C/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 resistor 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 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 AMS2911 is equal to: PD = ( VIN - VOUT )( IOUT ) CONNECT R2 TO LOAD Maximum junction temperature will be equal to: Figure 3. Connections for Best Load Regulation TJ = TA(MAX) + PD( Thermal Resistance(junction-to-ambient)) 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 AMS2911 series have internal power and thermal limiting circuitry designed to protect the device under overload conditions. However maximum junction temperature ratings of 125°C 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. The thermal resistance from the junction to the tab for the AMS2911 is 15°C/W. Thermal resistance from tab to ambient can be as low as 30°C/W. Maximum junction temperature must not exceed 125°C. Ripple Rejection 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 100Ω to 200Ω) 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=100Ω at 120Hz the adjust pin capacitor should be >13µF. At 10kHz only 0.16µF 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 ). 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. Advanced Monolithic Systems, Inc. THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 45°C/W 45°C/W 53°C/W 59°C/W 52°C/W 55°C/W www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723 AMS2911 TYPICAL PERFORMANCE CHARACTERISTICS Minimum Operating Current (Adjustable Device) Short-Circuit Current 1.25 9 SHORT CIRCUIT CURRENT (A) MINIMUM OPERATING CURRENT (mA) 12 TJ = 125°C TJ = 25°C 6 3 TJ = 125°C 1.00 TJ = 25°C 0.75 0.50 0.25 0 0 0 5 10 15 20 0 5 INPUT/OUTPUT DIFFERENTIAL (V) Load Regulation 15 Ripple Rejection vs. Current 0.10 100 ∆ ILOAD = 1A 90 fRIPPLE = 120Hz 0.05 80 RIPPLE REJECTION (dB) OUTPUT VOLTAGE DEVIATION (%) 10 INPUT/OUTPUT DIFFERENTIAL 0 -0.05 -0.10 VRIPPLE≤3Vp-p 70 60 fRIPPLE = 20Hz 50 40 VRIPPLE≤0.5Vp-p 30 20 -0.15 VOUT = 5V CADJ = 25µF COUT = 25µF 10 -0.20 0 -50 -25 0 25 50 75 100 125 0 0.25 TEMPERATURE (°C) 0.5 0.75 1.0 OUTPUT CURRENT (A) Temperature Stability Adjust Pin Current 100 2.0 80 1.0 ADJUST PIN CURRENT (µA) OUTPUT VOLTAGE CHANGE (%) 90 0 -1.0 70 60 50 40 30 20 10 0 -2.0 -50 -25 0 25 50 75 100 125 150 TEMPERATURE (°C) Advanced Monolithic Systems, Inc. www.advanced-monolithic.com -50 -25 0 25 50 75 100 125 150 TEMPERATURE (°C) Phone (925) 443-0722 Fax (925) 443-0723 AMS2911 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) 0.050 (1.270) TYP 0.028-0.038 (0.711-0.965) 0.013-0.023 (0.330-0.584) 0.095-0.115 (2.413-2.921) T (TO-220) AMS DRW# 042193 3 LEAD TO-263 PLASTIC DD (M) 0.060 (1.524) TYP 0.390-0.415 (9.906-10.541) 0.335-0.380 (8.50-9.65) 0.165-0.180 (4.191-4.572) 0.045-0.055 (1.143-1.397) 0.004 +0.008 -0.004 (0.102 +0.203 ) -0.102 0.595-0.615 (15.113-15.621) 0.095-0.115 (2.413-2.921) 0.059 (1.499) TYP 0.050±0.012 (1.270±0.305) 0.090-0.110 (2.286-2.794) Advanced Monolithic Systems, Inc. 0.050 (1.270) TYP 0.013-0.023 (0.330-0.584) www.advanced-monolithic.com M (DD3) AMS DRW# 042191 Phone (925) 443-0722 Fax (925) 443-0723 AMS2911 PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted (Continued). TO-252 PLASTIC PACKAGE (D) 0.255-0.265 (6.48-6.73) 0.206-0.214 (5.23-5.44) 0.087-0.094 (2.21-2.39) 0.018-0.023 (0.46-0.58) 0.035-0.050 (0.89-1.27) 7.0° 0.235-0.245 (5.969-6.223) 0.380-0.410 (9.65-10.41) 0.035-0.045 (0.89-1.14) 0.045-0.060 (1.14-1.52) 0.025 (0.635) TYP 0.020±0.002 (0.510±0.0508) 0.030 (0.762) TYP 0.156-0.204 (3.96-5.18) 0.018-0.023 (0.46-0.58) D (D3) AMS DRW# 011601 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) 0.012 (0.31) MIN 0.181 (4.60) NOM Advanced Monolithic Systems, Inc. www.advanced-monolithic.com 0.025-0.033 (0.64-0.84) (SOT-223 ) AMS DRW# 042292 Phone (925) 443-0722 Fax (925) 443-0723