a +5 V Fixed, Adjustable Micropower Linear Voltage Regulators ADM663/ADM666 FEATURES 5 V Fixed or +1.3 V to +16 V Adjustable Low Power CMOS: 12 µA max Quiescent Current 40 mA Output Current Current Limiting Pin Compatible with MAX663/666 +2 V to +16.5 V Operating Range Low Battery Detector ADM666 No Overshoot on Power-Up FUNCTIONAL BLOCK DIAGRAMS ADM663 VOUT2 VIN VOUT1 0.5V C1 SENSE APPLICATIONS Handheld Instruments LCD Display Systems Pagers Remote Data Acquisition A1 50mV C2 VSET SHDN GENERAL DESCRIPTION The ADM663/ADM666 are precision voltage regulators featuring a maximum quiescent current of 12 µA. They can be used to give a fixed +5 V output with no additional external components or can be adjusted from 1.3 V to 16 V using two external resistors. Fixed or adjustable operation is automatically selected via the VSET input. The low quiescent current makes these devices especially suitable for battery powered systems. The input voltage range is 2 V to 16.5 V and an output current up to 40 mA is provided. The ADM663 can directly drive an external pass transistor for currents in excess of 40 mA. Additional features include current limiting and low power shutdown. Thermal shutdown circuitry is also included for additional safety. 1.3V REF VOUT ADM666 0.5V C1 SENSE A1 50mV C2 VSET SHDN LBI C3 Temperature Range Package Option ADM663AN ADM663AR ADM666AN ADM666AR –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C N-8 R-8 N-8 R-8 VTC VIN ORDERING GUIDE Model A2 GND The ADM666 features additional low battery monitoring circuitry to detect for low battery voltages. The ADM663/ADM666 are pin-compatible replacements for the MAX663/666. Both are available in 8-pin DIP and in narrow surface mount (SOIC) packages. 0.9V LBO 1.3V REF GND REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel: 617/329-4700 Fax: 617/326-8703 ADM663/ADM666–SPECIFICATIONS (V IN Parameter Min Input Voltage, VIN Quiescent Current, IQ 2.0 Typ 6 Output Voltage, VOUT Line Regulation, ∆VOUT/∆VIN Load Regulation, ∆VOUT/∆IOUT 4.75 Reference Voltage, VSET Reference Tempco, ∆VSET/∆T VSET Internal Threshold, VF/A 1.27 VSET Input Current, ISET Shutdown Input Voltage, VSHDN 5.0 0.03 3.0 1.0 3.0 ± 100 50 ± 0.01 Max Units Test Conditions/Comments 16.5 V 12 15 5.25 0.35 7.0 5.0 7.0 1.33 µA µA V %/V Ω Ω Ω V ppm/°C mV ± 10 nA V V nA V MΩ TA = TMIN to TMAX No Load, VIN = +16.5 V TA = +25°C TA = TMIN to TMAX TA = TMIN to TMAX, VSET = GND +2 V ≤ VIN ≤ +15 V, VOUT = VREF ADM663, 1 mA ≤ IOUT2 ≤ 20 mA ADM663, 50 µA ≤ IOUT1 ≤ 5 mA ADM666, 1 mA ≤ IOUT ≤ 20 mA VOUT = VSET TA = TMIN to TMAX VSET < VF/A for +5 V Out; VSET > VF/A for Adj. Out TA = TMIN to TMAX VSHDN High = Output Off VSHDN Low = Output On 1.4 0.3 ± 10 ± 0.01 0.5 3 Shutdown Input Current, ISHDN SENSE Input Threshold, VOUT–VSENSE SENSE Input Resistance, RSENSE Input-Output Saturation Resistance, RSAT ADM663 VOUT1 200 70 50 Output Current from VOUT(2), IOUT Minimum Load Current, IL (MIN) 40 LBI Input Threshold, VLBI LBI Input Current, ILBI LBO Output Saturation Resistance, RSAT LBO Output Leakage Current VTC Open Circuit Voltage, VTC VTC Sink Current, ITC VTC Temperature Coefficient 1.21 2.0 500 150 150 1.0 5.0 1.37 ± 10 100 1.28 ± 0.01 35 10 0.9 8.0 +2.5 = +9 V, VOUT = + 5 V, TA = + 25°C unless otherwise noted) Ω Ω Ω mA µA µA V nA Ω nA V mA mV/°C Current Limit Threshold VIN = +2 V, IOUT = 1 mA VIN = +9 V, IOUT = 2 mA VIN = +15 V, IOUT = 5 mA +3 V ≤ VIN ≤ +16.5 V, VIN–VOUT = +1.5 V TA = +25°C TA = TMIN to TMAX ADM666 ADM666 ADM666, ISAT = 2 mA ADM666, LBI = 1.4 V ADM663 ADM663 ADM663 Specifications subject to change without notice. ABSOLUTE MAXIMUM RATINGS* (TA= +25°C unless otherwise noted) Input Voltage, VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +18 V Terminal Voltage (ADM663) Pins 1, 3, 5, 6, 7 . . . . . . . . . . . . . . . . . . . . (GND – 0.3 V) to (VIN + 0.3 V) (ADM666) Pins 1, 2, 3, 5, 6 . . . . . . . . . . . . . . . . . . . . . (GND – 0.3 V) to (VIN + 0.3 V) (ADM663) Pin 2 . . . . . . . (GND – 0.3 V) to (VOUT1 + 0.3 V) (ADM666) Pin 7 . . . . . . . . . . . . (GND – 0.3 V) to +16.5 V Output Source Current (ADM663, ADM666) Pin 2 . . . . . . . . . . . . . . . . . . . . 50 mA (ADM663) Pin 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 mA Output Sink Current, (ADM663, ADM666) Pin 7 . . . . . . . . . . . . . . . . . . . . –20 mA –2– Power Dissipation, N-8 . . . . . . . . . . . . . . . . . . . . . . . . 625 mW (Derate 8.3 mW/°C above +50°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 120°C/W Power Dissipation R-8 . . . . . . . . . . . . . . . . . . . . . . . . . 450 mW (Derate 6 mW/°C above +50°C) θJA, Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 170°C/W Operating Temperature Range Industrial (A Version) . . . . . . . . . . . . . . . . . . –40°C to +85°C Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . +300°C Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . +215°C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . . +220°C ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .>5000 V *This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. REV. 0 ADM663/ADM666 PIN FUNCTION DESCRIPTION DIP & SOIC PIN CONFIGURATIONS Mnemonic Function SENSE 1 VOUT2 2 ADM663 VOUT1 3 TOP VIEW (Not to Scale) GND 4 SENSE 1 VOUT 2 ADM666 LBI 3 TOP VIEW (Not to Scale) GND 4 8 VIN 7 VTC 6 VSET 5 SHDN 8 VIN 7 LBO 6 VSET 5 SHDN VOUT(1) (2) VIN SENSE GND LBI LBO SHDN VSET VTC an open drain FET connected to the Low Battery Output pin, LBO. The Low Battery Threshold may be set using a suitable voltage divider connected to LBI. When the voltage on LBI falls below 1.3 V, the open drain output LBO is pulled low. GENERAL INFORMATION The ADM663/ADM666 contains a micropower bandgap reference voltage source, an error amplifier A1, two comparators C1, C2 and a series pass output transistor. A P-channel FET and an NPN transistor are used on the ADM663 while the ADM666 uses an NPN output transistor. Both the ADM663 and the ADM666 contain a shutdown (SHDN) input which can be used to disable the error amplifier and hence the voltage output. The quiescent current in shutdown is less than 12 µA. CIRCUIT DESCRIPTION The internal bandgap reference is trimmed to 1.3 V ± 30 mV. This is used as a reference input to the error amplifier A1. The feedback signal from the regulator output is supplied to the other input by an on-chip voltage divider or by two external resistors. When VSET is at ground, the internal divider provides the error amplifier’s feedback signal giving a +5 V output. When VSET is at more than 50 mV above ground, the error amplifier's input is switched directly to the VSET pin, and external resistors are used to set the output voltage. The external resistors are selected so that the desired output voltage gives 1.3 V at VSET. ADM663 VOUT2 VIN VOUT1 0.5V C1 SENSE Comparator C1 monitors the output current via the SENSE input. This input, referenced to VOUT(2), monitors the voltage drop across a load sense resistor. If the voltage drop exceeds 0.5 V, then the error amplifier A1 is disabled and the output current is limited. A1 50mV C2 VSET SHDN The ADM663 has an additional amplifier, A2, which provides a temperature-proportional output, VTC. If this is summed into the inverting input of the error amplifier, a negative temperature coefficient results at the output. This is useful when powering liquid crystal displays over wide temperature ranges. 1.3V REF 0.9V A2 VTC GND Figure 1. ADM663 Functional Block Diagram The ADM666 has an additional comparator, C3 which compares the voltage on the Low Battery Input, LBI, pin to the internal +1.3 V reference. The output from the comparator drives REV. 0 Voltage Regulator Output(s) Voltage Regulator Input Current Limit Sense Input. (Referenced to VOUT(2).) If not used it should be connected to VOUT(2) Ground Pin. Must be connected to 0 V Low Battery Detect Input. Compared with 1.3 V Low Battery Detect Output. Open Drain Output Digital Input. May be used to disable the device so that the power consumption is minimized Voltage Setting Input. Connect to GND for +5 V output or connect to resistive divider for adjust able output Temperature-Proportional Voltage for negative TC Output –3– ADM663/ADM666 SENSE VIN VOUT VIN +2V TO +16V INPUT ADM666 0.5V RCL ADM663 ADM666 +1.3V TO +15V OUTPUT VOUT(2) R2 SHDN C1 SENSE GND VSET R1 A1 50mV C2 VSET SHDN Figure 4. ADM663/ADM666 Adjustable Output LBI Current Limiting LBO C3 Current limiting may be achieved by using an external current sense resistor in series with VOUT(2). When the voltage across the sense resistor exceeds the internal 0.5 V threshold, current limiting is activated. The sense resistor is therefore chosen such that the voltage across it will be 0.5 V when the desired current limit is reached. 1.3V REF GND Figure 2. ADM666 Functional Block Diagram RCL = Circuit Configurations For a fixed +5 V output the VSET input is grounded and no external resistors are necessary. This basic configuration is shown in Figure 3. Current limiting is not being utilized so the SENSE input is connected to VOUT(2). The input voltage can range from +6 V to +16 V and output currents up to 40 mA are available provided that the maximum package power dissipation is not exceeded. VIN +6V TO +16V INPUT where RCL is the current sense resistor, ICL is the maximum current limit. The value chosen for RCL should also ensure that the current is limited to less than the 50 mA absolute maximum rating and also that the power dissipation will also be within the package maximum ratings. If current limiting is employed, there will be an additional voltage drop across the sense resistor which must be considered when determining the regulators dropout voltage. SENSE ADM663 ADM666 VOUT(2) GND SHDN VSET If current limiting is not used, the SENSE input should be connected to VOUT(2). +5V OUTPUT Shutdown Input (SHDN) The SHDN input allows the regulator to be switched off with a logic level signal. This will disable the output and reduce the current drain to a low quiescent (12 µA maximum) current. This is very useful for low power applications. The SHDN input should be driven with a CMOS logic level signal since the input threshold is 0.3 V. In TTL systems, an open collector driver with a pull-up resistor may be used. Figure 3. ADM663/ADM666 Fixed +5 V Output Output Voltage Setting If VSET is not connected to GND, the output voltage is set according to the following equation. V OUT =V SET 0.5 ICL If the shutdown function is not being used, then SHDN should be connected to GND. R1 + R2 × where V SET = 1. 30V R1 Low Supply or Low Battery Detection The ADM666 contains on-chip circuitry for low power supply or battery detection. If the voltage on the LBI pin falls below the internal 1.3 V reference, then the open drain output LBO will go low. The low threshold voltage may be set to any voltage above 1.3 V by appropriate resistor divider selection. The resistor values may be selected by firstly choosing a value for R1 and then selecting R2 according to the following equation. V R2 = R1 × OUT – 1 1. 30 V R3 = R4 × BATT – 1 1. 30 The input leakage current on VSET is 10 nA maximum. This allows large resistor values to be chosen for R1 and R2 with little degradation in accuracy. For example, a 1 MΩ resistor may be selected for R1 and then R2 may be calculated accordingly. The tolerance on VSET is guaranteed at less than ± 30 mV so in most applications, fixed resistors will be suitable. where R3 and R4 are the resistive divider resistors and VBATT is the desired low voltage threshold. –4– REV. 0 ADM663/ADM666 Since the LBI input leakage current is less than 10 nA, large values may be selected for R3 and R4 in order to minimize loading. For example, a 6 V low threshold, may be set using 10 MΩ for R3 and 2.7 MΩ for R4. SENSE VOUT2 VOUT ADM663 R2 VSET +2V TO +16V INPUT R3 VIN R3 SENSE RCL ADM666 +1.3V TO +15V OUTPUT R1 VTC VOUT R2 LBI Figure 7. ADM663 Temperature Proportional Output VSET R4 SHDN LBO GND R2 R2 V OUT =V SET × 1 + × (V SET –V TC ) + R1 R3 R1 LOW BATTERY OUTPUT – R2 × TVCTC R3 = +0.9V , TCV TC = +2.5 mV /°C TCV OUT = where V SET = +1. 3V , V TC Figure 5. ADM666 Adjustable Output with Low Battery Detection High Current Operation APPLICATION HINTS Input-Output (Dropout Voltage) The ADM663 contains an additional output, VOUT1, suitable for directly driving the base of an external NPN transistor. Figure 6 shows a configuration which can be used to provide +5 V with boosted current drive. A 1 Ω current sensing resistor limits the current at 0.5 A. A regulator’s minimum input-output differential or dropout voltage determines the lowest input voltage for a particular output voltage. The ADM663/ADM666 dropout voltage is 0.8 V at its rated output current. For example when used as a fixed +5 V regulator the minimum input voltage is +5.8 V. At lower output currents, (IOUT < 5 mA), on the ADM663, VOUT1 may be used as the output driver in order to achieve lower dropout voltages. Please refer to Figure 9. In this case the dropout voltage depends on the voltage drop across the internal FET transistor. This may be calculated by multiplying the FET’s saturation resistance by the output current. As the current limit circuitry is referenced to VOUT2, VOUT2 should be connected to VOUT1. For high current operation VOUT2 should be used alone and VOUT1 left unconnected. VIN VIN + 2N4237 VOUT1 10µ F ADM663 VOUT2 100Ω SHDN 1.0Ω SHUTDOWN VSET GND SENSE + 10µF Bypass Capacitors +5V, 0.5A OUTPUT The high frequency performance of the ADM663/ADM666 may be improved by decoupling the output using a filter capacitor. A capacitor value of 10 µF is suitable. Figure 6. ADM663 Boosted Output Current (0.5 A) An input capacitor helps reduce noise and improves dynamic performance. A suitable input capacitor of 0.1 µF or greater may be used. Temperature Proportional Output The ADM663 contains a VTC output with a positive temperature coefficient of +2.5 mV/°C. This may be connected to the summing junction of the error amplifier (VSET) through a resistor resulting in a negative temperature coefficient at the output of the regulator. This is especially useful in multiplexed LCD displays to compensate for the inherent negative temperature coefficient of the LCD threshold. At 25°C the voltage at the VTC output is typically 0.9 V. The equations for setting both the output voltage and the tempco are given below. If this function is not being used, then VTC should be left unconnected. REV. 0 –5– ADM663/ADM666–Typical Performance Characteristics 80 12 VINDC = +9V TA = +25°C VIN p-p = +2V VOUT DC = +5V 10 TA = +25°C 60 40 C1907–18–4/94 VOUT = +5V IIN – µA PSRR – dB 8 6 VOUT = +3.3V 4 20 2 0 0.01 0.1 1 10 100 1000 0 10000 2 4 6 8 10 VIN – Volts FREQUENCY – Hz Figure 8. Power Supply Rejection Ratio vs. Frequency 14 16 Figure 10. Quiescent Current vs. Input Voltage 2.0 1.0 TA = +25°C 1.8 VIN = +2V 0.9 TA = +25°C 1.6 0.8 1.4 0.7 |VIN – VOUT| – Volts 1.2 1.0 0.8 0.6 VIN = +9V 0.4 0.6 VIN = +15V 0.5 VIN = +9V 0.4 0.3 0.2 VIN = +15V 0.2 VIN = +2V 0.1 0 0 2 4 6 8 10 12 14 16 18 0 20 10 0 20 30 IOUT2 – mA IOUT1 – mA Figure 9. VOUT1 Input-Output Differential vs. Output Current 40 50 Figure 11. VOUT(2) Input-Output Differential vs. Output Current OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 8-Lead Plastic DIP (N-8) 8 8-Lead Narrow-Body (R-8) 5 0.280 (7.11) 0.240 (6.10) PIN 1 1 5 8 4 0.1574 (4.00) 0.1497 (3.80) PIN 1 0.060 (1.52) 0.015 (0.38) 0.210 (5.33) MAX 0.130 (3.30) MIN 0.160 (4.06) 0.115 (2.93) 0.022 (0.558) 0.014 (0.356) 0.100 (2.54) BSC 0.2440 (6.20) 0.2284 (5.80) 4 1 0.325 (8.25) 0.300 (7.62) 0.430 (10.92) 0.348 (8.84) 0.070 (1.77) 0.045 (1.15) 0.1968 (5.00) 0.1890 (4.80) 0.195 (4.95) 0.115 (2.93) 0.0500 (1.27) BSC SEATING PLANE –6– 0.0196 (0.50) x 45 ° 0.0099 (0.25) 0.102 (2.59) 0.094 (2.39) 0.0098 (0.25) 0.0040 (0.10) 0.015 (0.381) 0.008 (0.204) PRINTED IN U.S.A. (VIN – VOUT ) – Volts 12 0.0192 (0.49) 0.0138 (0.35) 0.0098 (0.25) 0.0075 (0.19) 8° 0° 0.0500 (1.27) 0.0160 (0.41) REV. 0