19-0005; Rev 2; 6/97 10µA, Low-Dropout, Precision Voltage References Features The MAX872/MAX874 precision 2.5V and 4.096V micropower voltage references consume a maximum of only 10µA and operate from supply voltages up to 20V. The combination of ultra-low quiescent current and low 200mV dropout makes them ideal for battery-powered equipment. They source and sink up to 500µA with only 200mV input voltage headroom, which makes the 2.5V MAX872 ideal for use with a 3V supply and the 4.096V MAX874 ideal for use with a 5V supply. ♦ Output Voltage 2.500V ±0.2% (MAX872) 4.096V ±0.2% (MAX874) Initial accuracy of 0.2% at +25°C (±5mV for the MAX872, ±8mV for the MAX874) and low 40ppm/°C max drift make these references suitable for a wide range of precision applications. ♦ Line Regulation Over Temp. 20µV/V (MAX872) 75µV/V (MAX874) ♦ Wide Operating Voltage Range 2.7V to 20V (MAX872) 4.3V to 20V (MAX874) ♦ 10µA Max Supply Current ♦ 40ppm/°C Max Drift Over Extended Temp. Range ♦ Load Regulation Over Temp. 0.6mV/mA Max (MAX872) 1.0mV/mA Max (MAX874) Applications ♦ ±500µA Sink/Source Current Ordering Information Hand-Held Instruments Battery-Operated Equipment Power Supplies Typical Operating Circuit 3.0V (MAX872) 5.0V (MAX874) PART TEMP. RANGE PIN-PACKAGE MAX872CPA 0°C to +70°C 8 Plastic DIP MAX872CSA MAX872C/D MAX872EPA MAX872ESA MAX874CPA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 0°C to +70°C 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP MAX874CSA MAX874C/D MAX874EPA MAX874ESA 0°C to +70°C 0°C to +70°C -40°C to +85°C -40°C to +85°C 8 SO Dice* 8 Plastic DIP 8 SO * Dice are specified at +25°C only. VIN Pin Configuration VOUT TOP VIEW MAX872 MAX874 TRIM I.C. 1 VIN 2 GND TEMP 3 MAX872 MAX874 GND 4 REFERENCE WITH TRIMMED OUTPUT 8 COMP 7 I.C. 6 VOUT 5 TRIM DIP/SO ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX872/MAX874 General Description MAX872/MAX874 10µA, Low-Dropout, Precision Voltage References ABSOLUTE MAXIMUM RATINGS Supply Voltage .......................................................................24V Output Short-Circuit Duration ..........Continuous to Either Supply CCOMP Input...........................................................-0.3V to VOUT TRIM Input ...................................................-0.3V to (VIN + 0.3V) TEMP Output ...............................................-0.3V to (VIN + 0.3V) Continuous Power Dissipation (TA = +70°C) Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW SO (derate 5.88mW/°C above +70°C) ..........................471mW Operating Temperature Ranges MAX87_C__ .........................................................0°C to +70°C MAX87_E__ ......................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Junction Temperature Range (Tj) ......................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS—MAX872 (VIN = 2.7V, IL = 0mA, TA = +25°C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Noise SYMBOL VOUT en Line Regulation VOUT/VIN Load Regulation (Note 1) VOUT/IOUT Quiescent Supply Current Change in Supply Current vs. VIN Short-Circuit Output Current TEMP Voltage VOUT Adjustment Range CONDITIONS MIN TYP MAX 2.495 2.500 2.505 0.1Hz to 10Hz 60 VIN = 4.5V to 20V 4 12 VIN = 2.7V to 5.5V 80 250 Sourcing 0mA to 0.5mA 0.2 0.5 Sinking 0mA to -0.5mA 4 12 IQ IQ/VIN ISC V µVp-p µV/V mV/mA 6.5 10 µA 0.35 0.55 µA/V VOUT short to GND 6 15 VOUT short to VIN 3 9 VIN = 2.7V to 20V VTEMP VADJ UNITS 690 VOUT ≥ VOUT + 0.2V mA mV +75/-20 +100/-25 mV ELECTRICAL CHARACTERISTICS—MAX874 (VIN = 4.3V, IL = 0mA, TA = +25°C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Noise SYMBOL VOUT en Line Regulation VOUT/VIN Load Regulation (Note 1) VOUT/IOUT Quiescent Supply Current Change in Supply Current vs. VIN Short-Circuit Output Current TEMP Voltage VOUT Adjustment Range 2 CONDITIONS MIN TYP MAX 4.088 4.096 4.104 0.1Hz to 10Hz 90 VIN = 4.3V to 20V 15 75 Sourcing 0mA to 0.5mA 0.15 0.9 Sinking 0mA to -0.5mA 6 15 IQ IQ/VIN ISC V µVp-p µV/V mV/mA 6.5 10 µA 0.35 0.55 µA/V VOUT short to GND 6 15 VOUT short to VIN 5 25 VIN = 4.3V to 20V VTEMP VADJ UNITS VOUT ≥ VOUT + 0.2V ±150 mA 690 mV ±200 mV _______________________________________________________________________________________ 10µA, Low-Dropout, Precision Voltage References (VIN = 2.7V, IL = 0mA, TA = 0°C to +70°C, unless otherwise noted.) PARAMETER Output Voltage SYMBOL CONDITIONS VOUT Output Voltage Temperature Coefficient TCVOUT Line Regulation VOUT/VIN Load Regulation (Note 1) VOUT/IOUT Quiescent Supply Current TYP 2.4905 20 MAX UNITS 2.5095 V 40 ppm/°C VIN = 4.5V to 20V 20 VIN = 2.7V to 5.5V 300 Sourcing 0mA to 0.4mA 0.6 Sinking 0mA to -0.4mA 15 15 µA 0.7 µA/V IQ Change in Supply Current vs. VIN IQ/VIN VIN = 2.7V to 20V VOUT Adjustment Range VADJ VIN ≥ VOUT + 0.2V TEMP Output Temperature Coefficient MIN +75/-20 TCVTEMP µV/V mV/mA mV 2.3 mV/°C ELECTRICAL CHARACTERISTICS—MAX874C (VIN = 4.3V, IL = 0mA, TA = 0°C to +70°C, unless otherwise noted.) PARAMETER Output Voltage SYMBOL CONDITIONS MAX UNITS 4.1115 V 40 ppm/°C VIN = 4.3V to 20V 75 µV/V Sourcing 0mA to 0.4mA 1.0 Sinking 0mA to -0.4mA 25 VOUT Output Voltage Temperature Coefficient TCVOUT Line Regulation VOUT/VIN Load Regulation (Note 1) VOUT/IOUT Quiescent Supply Current IQ 20 IQ/VIN VIN = 4.3V to 20V VOUT Adjustment Range VADJ VIN ≥ VOUT + 0.2V TCVTEMP TYP 4.0805 Change in Supply Current vs. VIN TEMP Output Temperature Coefficient MIN ±150 mV/mA 15 µA 0.7 µA/V mV 2.3 mV/°C Note 1: If the load current exceeds 300µA, connect a minimum of 1000pF from VOUT to GND. Note that if a capacitor larger than 1000pF is used, a compensation capacitor of COUT/100 must be connected from VOUT to COMP. _______________________________________________________________________________________ 3 MAX872/MAX874 ELECTRICAL CHARACTERISTICS—MAX872C MAX872/MAX874 10µA, Low-Dropout, Precision Voltage References ELECTRICAL CHARACTERISTICS—MAX872E (VIN = 2.7V, IL = 0mA, TA = -40°C to +85°C, unless otherwise noted.) PARAMETER Output Voltage SYMBOL Output Voltage Temperature Coefficient TCVOUT Line Regulation VOUT/VIN Load Regulation VOUT/IOUT Quiescent Supply Current CONDITIONS VOUT TYP 20 MAX UNITS 2.512 V 40 ppm/°C VIN = 4.5V to 20V 20 VIN = 2.7V to 5.5V 300 Sourcing 0mA to 0.30mA 0.6 Sinking 0mA to -0.30mA 15 15 µA 0.7 µA/V IQ Change in Supply Current vs. VIN IQ/VIN VIN = 2.7V to 20V VOUT Adjustment Range VADJ VIN ≥ VOUT + 0.2V TEMP Output Temperature Coefficient MIN 2.488 +75/-20 TCVTEMP µV/V mV/mA mV 2.3 mV/°C ELECTRICAL CHARACTERISTICS—MAX874E (VIN = 4.3V, IL = 0mA, TA = -40°C to +85°C, unless otherwise noted.) PARAMETER Output Voltage SYMBOL Output Voltage Temperature Coefficient TCVOUT Line Regulation VOUT/VIN Load Regulation Quiescent Supply Current CONDITIONS MAX UNITS 4.115 V 40 ppm/°C VIN = 4.3V to 20V 75 µV/V Sourcing 0mA to 0.30mA 1.0 Sinking 0mA to -0.30mA 25 15 µA 0.7 µA/V VOUT VOUT/IOUT IQ IQ/VIN VIN = 4.3V to 20V VOUT Adjustment Range VADJ VIN ≥ VOUT + 0.2V 4 TYP 20 Change in Supply Current vs. VIN TEMP Output Temperature Coefficient MIN 4.077 TCVTEMP ±150 mV/mA mV 2.3 _______________________________________________________________________________________ mV/°C 10µA, Low-Dropout, Precision Voltage References SUPPLY CURRENT vs. INPUT VOLTAGE TA = +85°C 150 TA = +25°C 100 15 MAX874 10 MAX872 5 50 NO LOAD SUPPLY CURRENT (µA) 200 20 MAX872/74-02 MAX872/74-01 20 SUPPLY CURRENT (µA) DROPOUT VOLTAGE (mV) 250 MAX872 SUPPLY CURRENT vs. TEMPERATURE MAX872/74-03 DROPOUT VOLTAGE vs. SOURCE CURRENT VIN = 20V 15 VIN = 10V VIN = 5V 10 TA = -40°C VIN = 3V 0 0 100 150 200 250 4 6 8 -50 10 12 14 16 18 20 -25 0 25 50 75 100 INPUT VOLTAGE (V) TEMPERATURE (°C) MAX874 SUPPLY CURRENT vs. TEMPERATURE MAX872 OUTPUT VOLTAGE vs. INPUT VOLTAGE MAX874 OUTPUT VOLTAGE vs. INPUT VOLTAGE VIN = 20V 15 VIN = 10V 2.500 MAX872/74-06 4.098 2.503 VOUT (V) 20 4.100 MAX872/74-05 MAX872/74-04 2.505 VOUT (V) 4.096 4.094 VIN = 5V 2.498 10 4.092 2.495 5 -50 -25 0 25 50 75 4.090 2 100 4 6 8 10 12 14 16 18 20 4 6 8 10 12 14 16 TEMPERATURE (°C) INPUT VOLTAGE (V) INPUT VOLTAGE (V) MAX872 LOAD REGULATION vs. TEMPERATURE MAX874 LOAD REGULATION vs. TEMPERATURE MAX872 OUTPUT VOLTAGE vs. SOURCE CURRENT 2 SINKING 0µA TO -500µA 1 2.501 3 SINKING 0µA TO -500µA 2.499 SOURCING 0µA TO 500µA SOURCING 0µA TO 500µA 0 0 -25 0 25 50 TEMPERATURE (°C) 2.500 2 1 -50 20 MAX872/74-09 4 18 2.502 VOUT (V) 3 5 MAX872/74-08 MAX872/74-07 4 LOAD REGULATION (mV/mA) SUPPLY CURRENT (µA) 2 SOURCE CURRENT (µA) 25 LOAD REGULATION (mV/mA) 5 0 75 100 2.498 -50 -25 0 25 50 TEMPERATURE (°C) 75 100 0.01 0.1 1 10 SOURCE CURRENT (mA) _______________________________________________________________________________________ 5 MAX872/MAX874 Typical Operating Characteristics (VIN = 3V (MAX872), VIN = 5V (MAX874), no load, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VIN = 3V (MAX872), VIN = 5V (MAX874), no load, TA = +25°C, unless otherwise noted.) 2.502 4.098 VOUT (V) VOUT (V) VOUT (V) 4.096 4.094 2.498 4.092 4.090 2.496 0.1 1 10 -25 0 25 50 75 TEMPERATURE (°C) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY TEMP OUTPUT vs. TEMPERATURE 0 25 1.5 0.8 0.7 MAX872 1.0 1k FREQUENCY (Hz) MAX872 1Hz TO 100Hz NOISE 6 NOISE IS FROM 0.01Hz TO FREQUENCY INDICATED 0 0.5 100 100 0.5 -80 10 75 MAX874 0.6 1 50 2.0 NOISE (mVp-p) INPUT FILTER CIRCUIT IN FIGURE 2 -60 NO LOAD 0.9 TEMP OUTPUT (V) NO INPUT FILTER -25 NOISE vs. FREQUENCY 1.0 MAX872/74-13 NO LOAD VIN = +3V TO +5V (MAX872) VIN = +5V TO +7V (MAX874) -50 100 TEMPERATURE (°C) SOURCE CURRENT (mA) -20 -40 -50 MAX872/74-14 0.01 4.096 2.500 4.095 4.094 MAX872/74-12 2.504 4.097 4.100 MAX872/74-11 2.506 MAX872/74-10 4.098 MAX874 OUTPUT VOLTAGE vs. TEMPERATURE MAX872 OUTPUT VOLTAGE vs. TEMPERATURE MAX872/74-15 MAX874 OUTPUT VOLTAGE vs. SOURCE CURRENT PSRR (dB) MAX872/MAX874 10µA, Low-Dropout, Precision Voltage References 10k -50 -25 0 25 50 TEMPERATURE (°C) 75 100 1 10 100 FREQUENCY (Hz) MAX874 1Hz TO 100Hz NOISE _______________________________________________________________________________________ 1k 10k 10µA, Low-Dropout, Precision Voltage References PIN NAME FUNCTION 1, 7 I.C. Internal Connection. Make no connection to this pin 2 VIN Input Voltage 3 TEMP Temperature-Proportional Output Voltage. Generates an output voltage proportional to junction temperature. 4 GND Ground 5 TRIM Output Voltage Trim. Connect to the center of a voltage divider for output trimming. Otherwise make no connection. 6 VOUT Reference Output COMP Compensation Input. Connect CLOAD/100 capacitor from VOUT to COMP to provide capacitive load compensation. 8 3V VIN MAX872/MAX874 Pin Description VOUT MAX872 TRIM 1M 1.5M GND TRIM RANGE: -35mV/+80mV Figure 1a. Adjusting VOUT with the TRIM Input on the MAX872 Applications Information Trimming the Output Voltage The MAX872/MAX874’s output voltage is trimmed for 0.2% tolerance at +25°C. If additional VOUT trimming is desired, connect a potentiometer to TRIM, as shown in Figures 1a and 1b. Adjusting VOUT away from its factory-trimmed voltage typically changes the output voltage tempco by 7ppm/°C per 100mV. Reducing Input Ripple with an Input Filter The Power-Supply Rejection Ratio vs. Frequency graph in the Typical Operating Characteristics shows ripple rejection between 10Hz and 2kHz. As input RC filter with a pole less than 10Hz, as shown in Figure 2, further attenuates input ripple with this band. The voltage drop across the input resistor (due to supply and load current) slightly increases the dropout voltage. The increase is given by [(ILOAD + ISUPPLY) • R]. Choosing the Output and Compensation Capacitors Connecting a capacitor between Void and GND reduces load transients. If the load exceeds 300µA, connect a minimum of 1000pF from VOUT to GND. The type of capacitor is not critical. If the total load capacitance from VOUT to GND (CLOAD = output capacitor + other capacitive load) is larger than 1000pF, connect a compensation capacitor with a value of C LOAD/100 between COMP and VOUT. 5V VIN VOUT 2M MAX874 TRIM GND 1M 4M TRIM RANGE: -200mV/+300mV Figure 1b. Adjusting VOUT with the TRIM Input on the MAX874 _______________________________________________________________________________________ 7 MAX872/MAX874 10µA, Low-Dropout, Precision Voltage References REF OUT V+ 3.0V (MAX872) 5.0V (MAX874) 170k (MAX872) 330k (MAX874) +5V VIN 150Ω VIN COMP 1/2 MAX922 VOUT 27k 100µF MAX872 MAX874 V OUT 0.047µF MAX872 MAX874 TEMP OUT OF RANGE TEMP +5V 4.7µF GND OVER TEMP 1/2 MAX922 GND 1/4 74HC86 UNDER TEMP 54k -40°C TO +85°C OPERATING RANGE Figure 3. Operating Temperature Range Window Comparator Figure 2. Input Filter Reduces Input Ripple TEMP Output ___________________Chip Topography The TEMP output provides a voltage proportional to the MAX872/MAX874 junction temperature. Since the power dissipation of the MAX872/MAX874 is <100µW typ, the junction temperature is within 0.5°C of the ambient temperature. Although it goes unused in most applications, the ambient temperature information given by the TEMP output may be used to control LCD contrast, or to provide ADC gain compensation or thermal out-of-range indication. TEMP must be buffered or connected to a high-impedance input. Operating Temperature Window Comparator In Figure 3, a window comparator monitors the TEMP output and indicates if the temperature is out of the nominal operating range. For the resistor values shown, the circuit will indicate an out-of-range condition if the ambient temperature should rise above +85°C or dip below -40°C. MAX872/MAX874 *N.C. COMP *N.C. VIN TEMP OUT GND TRIM 0.110" (2.794mm) Start-Up When the input voltage is below the factory-selected output voltage, the MAX872/MAX874 can draw excessive supply current (hundreds of microamps). If the source resistance is too high, the voltage drop across the source resistance can prevent the input voltage to the device from reaching the minimum dropout voltage. Therefore, when using the MAX872/MAX874 in lowdropout applications, ensure that the power supply has a low source resistance. 0.072" (1.829mm) *MAKE NO CONNECTIONS TO THESE PADS TRANSISTOR COUNT: 89 SUBSTRATE CONNECTED TO GND. Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.