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19-0005; Rev 2; 6/97
10A, Low-Dropout, Precision Voltage References
General Description
The MAX872/MAX874 precision 2.5V and 4.096V micropower voltage references consume a maximum of only 10A 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 500A 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. Initial accuracy of 0.2% at +25C (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. o Output Voltage 2.500V 0.2% (MAX872) 4.096V 0.2% (MAX874) o Wide Operating Voltage Range 2.7V to 20V (MAX872) 4.3V to 20V (MAX874) o 10A Max Supply Current o 40ppm/C Max Drift Over Extended Temp. Range o Line Regulation Over Temp. 20V/V (MAX872) 75V/V (MAX874) o Load Regulation Over Temp. 0.6mV/mA Max (MAX872) 1.0mV/mA Max (MAX874)
Features
MAX872/MAX874
Applications
Hand-Held Instruments Battery-Operated Equipment Power Supplies
o 500A Sink/Source Current
Ordering Information
PART MAX872CPA MAX872CSA MAX872C/D MAX872EPA MAX872ESA MAX874CPA MAX874CSA MAX874C/D MAX874EPA MAX874ESA TEMP. RANGE 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C 0C to +70C -40C to +85C -40C to +85C PIN-PACKAGE 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO 8 Plastic DIP 8 SO Dice* 8 Plastic DIP 8 SO
Typical Operating Circuit
3.0V (MAX872) 5.0V (MAX874)
* Dice are specified at +25C only.
VIN VOUT
Pin Configuration
TOP VIEW
MAX872 MAX874
TRIM I.C. 1 VIN 2 8 7 COMP I.C. VOUT TRIM
GND TEMP 3
MAX872 MAX874
6 5
GND 4
REFERENCE WITH TRIMMED OUTPUT
DIP/SO
________________________________________________________________ Maxim Integrated Products
1
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10A, Low-Dropout, Precision Voltage References MAX872/MAX874
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 = +70C) Plastic DIP (derate 9.09mW/C above +70C) .............727mW SO (derate 5.88mW/C above +70C) ..........................471mW Operating Temperature Ranges MAX87_C__ .........................................................0C to +70C MAX87_E__ ......................................................-40C to +85C Storage Temperature Range .............................-65C to +150C Junction Temperature Range (Tj) ......................-65C to +160C Lead Temperature (soldering, 10sec) .............................+300C
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 = +25C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Noise Line Regulation Load Regulation (Note 1) Quiescent Supply Current Change in Supply Current vs. VIN Short-Circuit Output Current TEMP Voltage VOUT Adjustment Range SYMBOL VOUT en VOUT/VIN VOUT/IOUT IQ IQ/VIN ISC VTEMP VADJ VOUT VOUT + 0.2V VIN = 2.7V to 20V VOUT short to GND VOUT short to VIN 0.1Hz to 10Hz VIN = 4.5V to 20V VIN = 2.7V to 5.5V Sourcing 0mA to 0.5mA Sinking 0mA to -0.5mA CONDITIONS MIN 2.495 TYP 2.500 60 4 80 0.2 4 6.5 0.35 6 3 690 +75/-20 +100/-25 12 250 0.5 12 10 0.55 15 9 MAX 2.505 UNITS V Vp-p V/V mV/mA A A/V mA mV mV
ELECTRICAL CHARACTERISTICS--MAX874
(VIN = 4.3V, IL = 0mA, TA = +25C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Noise Line Regulation Load Regulation (Note 1) Quiescent Supply Current Change in Supply Current vs. VIN Short-Circuit Output Current TEMP Voltage VOUT Adjustment Range SYMBOL VOUT en VOUT/VIN VOUT/IOUT IQ IQ/VIN ISC VTEMP VADJ VOUT VOUT + 0.2V 150 VIN = 4.3V to 20V VOUT short to GND VOUT short to VIN 0.1Hz to 10Hz VIN = 4.3V to 20V Sourcing 0mA to 0.5mA Sinking 0mA to -0.5mA CONDITIONS MIN 4.088 TYP 4.096 90 15 0.15 6 6.5 0.35 6 5 690 200 75 0.9 15 10 0.55 15 25 MAX 4.104 UNITS V Vp-p V/V mV/mA A A/V mA mV mV
2
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10A, Low-Dropout, Precision Voltage References
ELECTRICAL CHARACTERISTICS--MAX872C
(VIN = 2.7V, IL = 0mA, TA = 0C to +70C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Temperature Coefficient Line Regulation Load Regulation (Note 1) Quiescent Supply Current Change in Supply Current vs. VIN VOUT Adjustment Range TEMP Output Temperature Coefficient SYMBOL VOUT TCVOUT VOUT/VIN VOUT/IOUT IQ IQ/VIN VADJ TCVTEMP VIN = 2.7V to 20V VIN VOUT + 0.2V +75/-20 2.3 VIN = 4.5V to 20V VIN = 2.7V to 5.5V Sourcing 0mA to 0.4mA Sinking 0mA to -0.4mA CONDITIONS MIN 2.4905 20 TYP MAX 2.5095 40 20 300 0.6 15 15 0.7 UNITS V ppm/C V/V mV/mA A A/V mV mV/C
MAX872/MAX874
ELECTRICAL CHARACTERISTICS--MAX874C
(VIN = 4.3V, IL = 0mA, TA = 0C to +70C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Temperature Coefficient Line Regulation Load Regulation (Note 1) Quiescent Supply Current Change in Supply Current vs. VIN VOUT Adjustment Range TEMP Output Temperature Coefficient SYMBOL VOUT TCVOUT VOUT/VIN VOUT/IOUT IQ IQ/VIN VADJ TCVTEMP VIN = 4.3V to 20V VIN VOUT + 0.2V 150 2.3 VIN = 4.3V to 20V Sourcing 0mA to 0.4mA Sinking 0mA to -0.4mA CONDITIONS MIN 4.0805 20 TYP MAX 4.1115 40 75 1.0 25 15 0.7 UNITS V ppm/C V/V mV/mA A A/V mV mV/C
Note 1: If the load current exceeds 300A, 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.
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10A, Low-Dropout, Precision Voltage References MAX872/MAX874
ELECTRICAL CHARACTERISTICS--MAX872E
(VIN = 2.7V, IL = 0mA, TA = -40C to +85C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Temperature Coefficient Line Regulation Load Regulation Quiescent Supply Current Change in Supply Current vs. VIN VOUT Adjustment Range TEMP Output Temperature Coefficient SYMBOL VOUT TCVOUT VOUT/VIN VOUT/IOUT IQ IQ/VIN VADJ TCVTEMP VIN = 2.7V to 20V VIN VOUT + 0.2V +75/-20 2.3 VIN = 4.5V to 20V VIN = 2.7V to 5.5V Sourcing 0mA to 0.30mA Sinking 0mA to -0.30mA CONDITIONS MIN 2.488 20 TYP MAX 2.512 40 20 300 0.6 15 15 0.7 UNITS V ppm/C V/V mV/mA A A/V mV mV/C
ELECTRICAL CHARACTERISTICS--MAX874E
(VIN = 4.3V, IL = 0mA, TA = -40C to +85C, unless otherwise noted.) PARAMETER Output Voltage Output Voltage Temperature Coefficient Line Regulation Load Regulation Quiescent Supply Current Change in Supply Current vs. VIN VOUT Adjustment Range TEMP Output Temperature Coefficient SYMBOL VOUT TCVOUT VOUT/VIN VOUT/IOUT IQ IQ/VIN VADJ TCVTEMP VIN = 4.3V to 20V VIN VOUT + 0.2V 150 2.3 VIN = 4.3V to 20V Sourcing 0mA to 0.30mA Sinking 0mA to -0.30mA CONDITIONS MIN 4.077 20 TYP MAX 4.115 40 75 1.0 25 15 0.7 UNITS V ppm/C V/V mV/mA A A/V mV mV/C
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10A, Low-Dropout, Precision Voltage References
Typical Operating Characteristics
(VIN = 3V (MAX872), VIN = 5V (MAX874), no load, TA = +25C, unless otherwise noted.)
DROPOUT VOLTAGE vs. SOURCE CURRENT
MAX872/74-01
MAX872/MAX874
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX872/74-02
MAX872 SUPPLY CURRENT vs. TEMPERATURE
NO LOAD SUPPLY CURRENT (A) VIN = 20V 15 VIN = 10V VIN = 5V 10
MAX872/74-03
250
20
20
DROPOUT VOLTAGE (mV)
200 TA = +85C TA = +25C
SUPPLY CURRENT (A)
15
MAX874
150
10
100
5 50 TA = -40C
MAX872
VIN = 3V 0 100 150 200 250 SOURCE CURRENT (A) 0 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 5 -50 -25 0 25 50 75 100 TEMPERATURE (C)
MAX874 SUPPLY CURRENT vs. TEMPERATURE
MAX872/74-04
MAX872 OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX872/74-05
MAX874 OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX872/74-06
25
2.505
4.100
SUPPLY CURRENT (A)
20
VIN = 20V VOUT (V)
2.503 VOUT (V) 2 4 6 8 10 12 14 16 18 20
4.098
4.096
15
VIN = 10V VIN = 5V
2.500
4.094 10 2.498
4.092
5 -50 -25 0 25 50 75 100 TEMPERATURE (C)
2.495 INPUT VOLTAGE (V)
4.090 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V)
MAX872 LOAD REGULATION vs. TEMPERATURE
MAX872/74-07
MAX874 LOAD REGULATION vs. TEMPERATURE
MAX872/74-08
MAX872 OUTPUT VOLTAGE vs. SOURCE CURRENT
MAX872/74-09
4
5
2.502
LOAD REGULATION (mV/mA)
3
LOAD REGULATION (mV/mA)
4
2.501 VOUT (V) 75 100 3 SINKING 0A TO -500A 2 2.499 SOURCING 0A TO 500A 0 2.498 -50 -25 0 25 50 0.01 0.1 1 10 TEMPERATURE (C) SOURCE CURRENT (mA)
2
SINKING 0A TO -500A
2.500
1 SOURCING 0A TO 500A 0 -50 -25 0 25 50 75 100 TEMPERATURE (C)
1
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10A, Low-Dropout, Precision Voltage References MAX872/MAX874
Typical Operating Characteristics (continued)
(VIN = 3V (MAX872), VIN = 5V (MAX874), no load, TA = +25C, unless otherwise noted.)
MAX874 OUTPUT VOLTAGE vs. SOURCE CURRENT
MAX872/74-10
MAX872 OUTPUT VOLTAGE vs. TEMPERATURE
MAX872/74-11
MAX874 OUTPUT VOLTAGE vs. TEMPERATURE
MAX872/74-12
4.098
2.506
4.100
4.097 VOUT (V) VOUT (V)
2.504
4.098
4.096
VOUT (V)
2.502
4.096
2.500 4.095 2.498
4.094
4.092
4.094 0.01 0.1 1 10 SOURCE CURRENT (mA)
2.496 -50 -25 0 25 50 75 100 TEMPERATURE (C)
4.090 -50 -25 0 25 50 75 100 TEMPERATURE (C)
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
MAX872/74-13
TEMP OUTPUT vs. TEMPERATURE
NO LOAD 0.9 TEMP OUTPUT (V)
MAX872/74-14
NOISE vs. FREQUENCY
MAX872/74-15
-20 NO LOAD VIN = +3V TO +5V (MAX872) VIN = +5V TO +7V (MAX874) -40 PSRR (dB) NO INPUT FILTER
1.0
2.0
1.5 NOISE (mVp-p)
MAX874 MAX872
0.8
1.0
-60
INPUT FILTER CIRCUIT IN FIGURE 2
0.7
0.5 0.6 NOISE IS FROM 0.01Hz TO FREQUENCY INDICATED 0 -50 -25 0 25 50 75 100 1 10 100 FREQUENCY (Hz) 1k 10k TEMPERATURE (C)
-80 1 10 100 FREQUENCY (Hz) 1k 10k
0.5
MAX872 1Hz TO 100Hz NOISE
MAX874 1Hz TO 100Hz NOISE
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10A, Low-Dropout, Precision Voltage References
Pin Description
PIN 1, 7 2 3 4 NAME I.C. VIN TEMP GND FUNCTION Internal Connection. Make no connection to this pin Input Voltage Temperature-Proportional Output Voltage. Generates an output voltage proportional to junction temperature. Ground Output Voltage Trim. Connect to the center of a voltage divider for output trimming. Otherwise make no connection. Reference Output Compensation Input. Connect CLOAD/100 capacitor from VOUT to COMP to provide capacitive load compensation.
TRIM RANGE: -35mV/+80mV 1.5M GND 3V VIN VOUT
MAX872/MAX874
MAX872
TRIM
1M
5
TRIM
6
VOUT
8
COMP
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 +25C. 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.
5V
VIN
VOUT 2M
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].
MAX874
TRIM 1M
GND
4M
Choosing the Output and Compensation Capacitors
Connecting a capacitor between Void and GND reduces load transients. If the load exceeds 300A, 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.
TRIM RANGE: -200mV/+300mV
Figure 1b. Adjusting VOUT with the TRIM Input on the MAX874
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10A, Low-Dropout, Precision Voltage References MAX872/MAX874
REF OUT V+ VIN VIN 100F COMP VOUT 27k 0.047F 170k (MAX872) 330k (MAX874) +5V 1/2 MAX922 OVER TEMP TEMP OUT OF RANGE +5V 1/2 MAX922 GND 54k -40C TO +85C OPERATING RANGE 1/4 74HC86 UNDER TEMP
3.0V (MAX872) 5.0V (MAX874)
150
MAX872 MAX874 V OUT
MAX872 MAX874
TEMP
4.7F GND
Figure 2. Input Filter Reduces Input Ripple
Figure 3. Operating Temperature Range Window Comparator
TEMP Output
The TEMP output provides a voltage proportional to the MAX872/MAX874 junction temperature. Since the power dissipation of the MAX872/MAX874 is <100W typ, the junction temperature is within 0.5C 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.
___________________Chip Topography
MAX872/MAX874
*N.C. COMP
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 +85C or dip below -40C.
VIN TEMP
*N.C. OUT 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.
GND 0.072" (1.829mm)
*MAKE NO CONNECTIONS TO THESE PADS
TRIM
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 (c) 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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