±18-Bit ADC with Serial Interface

4

_______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

-0.30

-0.25

-0.20

-0.15

-0.10

-0.05

0.05

0

ERROR vs. COMMON-MODE

COMMON-MODE VOLTAGE (V)

-3

-2

-1

0

1

2

3

4

-4

IN HI = IN LO

0

0

0.5

1.5

50Hz/60Hz READ-ZERO OFFSET

vs. VREF

1.5

3.5

VREF (V)

1.0

2.0

2.5

4.0

1.0

0.5

3.0

2.0

4.5

60Hz MODE

50Hz MODE

0

-40

-20

20

50Hz/60Hz READ-ZERO OFFSET

vs. TEMPERATURE

0.6

1.4

TEMPERATURE (°C)

0

40

60

80

100

1.0

1.6

0.4

0.2

1.2

0.8

60Hz MODE, VREF = 545mV

50Hz MODE, VREF = 655mV

-40

0

50

150

SUPPLY CURRENT

vs. CRYSTAL FREQUENCY

20

100

CRYSTAL FREQUENCY (kHz)

100

200

250

300

350

60

120

0

-20

80

40

140

V-

V+

0.10

0.08

0.06

0.04

0.02

0

FULL-SCALE ROLLOVER ERROR

vs. VREF

VREF (V)

0

0.5

1.0

1.5

2.5

2.0

0

5

10

15

20

NOISE vs. NUMBER

OF SAMPLES AVERAGED

NUMBER OF SAMPLES AVERAGED

010

20

30

50

40

______________________________________________________________Pin Description

Oscillator Output 2 is normally connected to a 32,768Hz crystal. Do not connect with external clock source.

OSC2

5

Serial Clock Input. On SCLK’s rising edge, data is shifted into the internal shift register through DIN. On

SCLK’s falling edge, data is clocked out of DOUT.

SCLK

4

Serial Data Out, D7 first bit out. Data is clocked out at the falling edge of SCLK. High impedance when CSis high.

DOUT

3

User-programmable output bit 1—programmed through the serial port.

P1

8

User-programmable output bit 0—programmed through the serial port.

P0

7

Oscillator Input 1 is normally connected to a 32,768Hz crystal, or may be connected to an external clock.

OSC1

6

Serial Data In, D7 first bit in. Data is clocked into the register on the rising edge of SCLK.

DIN

2

PIN

CHIP SELECT Input has 3 functions: 1) When low, selects IC for communication; 2) on rising edge, loads

input shift register data into one of the command registers; 3) on falling edge, loads data from one of the

output registers into the output shift register. When CS is high, DOUT is high impedance.

CS

1

FUNCTION

NAME