MAX872 View Datasheet(PDF) - Maxim Integrated
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MAX872 Datasheet PDF : 8 Pages
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10µA, Low-Dropout,
Precision Voltage References
3.0V (MAX872)
5.0V (MAX874)
150Ω
100µF
VIN
COMP
MAX872
MAX874 VOUT
GND
Figure 2. Input Filter Reduces Input Ripple
0.047µF
4.7µF
V+
VIN
VOUT
MAX872
MAX874
TEMP
GND
REF OUT
170k (MAX872)
330k (MAX874)
+5V
1/2 OVER TEMP
27k
MAX922
TEMP OUT OF RANGE
+5V
1/2
1/4 74HC86
MAX922
UNDER TEMP
54k
-40°C TO +85°C OPERATING RANGE
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 <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 ther-
mal 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.
Start-Up
When the input voltage is below the factory-selected
output voltage, the MAX872/MAX874 can draw exces-
sive 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 low-
dropout applications, ensure that the power supply has
a low source resistance.
___________________Chip Topography
MAX872/MAX874
*N.C. COMP
VIN
TEMP
*N.C.
OUT
0.110"
(2.794mm)
GND
TRIM
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.
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