3.5- and 4.5-Digit, Single-Chip ADCs

with LED Drivers

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9

Pin Description

PIN

MAX1496

MAX1447/

MAX1498

NAME

FUNCTION

1

31

VNEG

-2.5V Charge-Pump Voltage Output. Connect a 0.1µF capacitor to GND.

232

REF-

Negative Reference Voltage Input. For internal-reference operation, connect REF- to GND.

31

REF+

Positive Reference Voltage Input. For internal-reference operation, connect a 4.7µF

capacitor from REF+ to GND. For external-reference operation, bypass REF+ to GND with a

42

AIN+

Positive Analog Input. Positive side of fully differential analog input. Bypass AIN+ to GND

with a 0.1µF or greater capacitor.

53

AIN-

Negative Analog Input. Negative side of fully differential analog input. Bypass AIN- to GND

with a 0.1µF or greater capacitor.

64

ISET

Segment Current Controller. Connect to ground through a resistor to set the segment

current. See Table 5 for current selection.

75

GND

Ground

8—

98

INTREF

Internal-Reference Logic Input. Connect to GND to select external-reference mode. Connect

reference mode.

10

9

RANGE

Range Logic Input. RANGE controls the fully differential analog input range. Connect to

the ±200mV input range.

11

10

DPSET1

Decimal-Point Logic-Input 1. Controls the decimal point of the LED. See the Decimal-Point

Control section.

12

11

DPSET2

Decimal-Point Logic-Input 2. Controls the decimal point of the LED. See the Decimal-Point

Control section.

13

12

PEAK

highest ADC value on the LED. Connect to GND to disable the peak function.

14

13

HOLD

current ADC value on the LED. Connect to GND to update the LED at a rate of 2.5Hz and

disable the hold function. For the MAX1447, only placing the device into hold mode initiates

an offset mismatch calibration. Assert HOLD high for a minimum of 2s to ensure the

completion of offset mismatch calibration.

15

14

DIG0

Digit 0 Driver

16

15

DIG1

Digit 1 Driver

17

16

GLED

Ground for LED Display Digit Driver

18

17

DIG2

Digit 2 Driver