MAX872C Ver la hoja de datos (PDF) - Maxim Integrated
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componentes Descripción
Fabricante
MAX872C Datasheet PDF : 8 Pages
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10µA, Low-Dropout,
Precision Voltage References
Pin Description
PIN NAME
FUNCTION
1, 7
I.C.
Internal Connection. Make no connection
to this pin
2
VIN
Input Voltage
Temperature-Proportional Output
3
TEMP Voltage. Generates an output voltage
proportional to junction temperature.
4
GND Ground
Output Voltage Trim. Connect to the
5
TRIM
center of a voltage divider for output
trimming. Otherwise make no
connection.
6
VOUT Reference Output
Compensation Input. Connect
8
COMP
CLOAD/100 capacitor from VOUT to
COMP to provide capacitive load
compensation.
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 facto-
ry-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, fur-
ther 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 capaci-
tance from VOUT to GND (CLOAD = output capacitor +
other capacitive load) is larger than 1000pF, connect a
compensation capacitor with a value of CLOAD/100
between COMP and VOUT.
3V
VIN
VOUT
MAX872 TRIM
1M
1.5M
GND
TRIM RANGE: -35mV/+80mV
Figure 1a. Adjusting VOUT with the TRIM Input on the MAX872
5V
VIN
VOUT
2M
MAX874
TRIM
1M
GND
4M
TRIM RANGE: -200mV/+300mV
Figure 1b. Adjusting VOUT with the TRIM Input on the MAX874
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