ADuC844 SPECIFICATIONS

1

-2-

REV. PrB

PRELIMINARY TECHNICAL DATA

(AVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V, DVDD = 2.7 V to 3.6 V or 4.75 V to 5.25 V,

REFIN(+) = 2.5 V, REFIN(–) = AGND; AGND = DGND = 0 V; XTAL1/XTAL2 = 32.768 kHz

PARAMETER

MIN

TYP

MAX

UNITS

CONDITION

PRIMARY ADC

Conversion Rate

5.35

19.79

105

Hz

On Both Channels

No Missing Codes

2

24

Bits

19.79Hz Update Rate

Resolution

13.5

Bits Pk-Pk

Range = ± 20mV, 20Hz Update Rate

18.5

Bits Pk-Pk

Range = ± 2.56V, 20Hz Update Rate

Output Noise

See Tables X and XI in ADC

Description

Output Noise varies with selected Update Rates

and Gain Range

Integral Non Linearity

± 15

ppm of FSR

Offset Error

3

± 3

µV

Offset Error Drift (vs. Temp)

± 10

nV/°C

Full-Scale Error

4

± 10

µV

Gain Error Drift

± 0.5

ppm/°C

ADC Range Matching

± 2

µV

AIN=18mV

Power Supply Rejection

80

dBs

AIN=1V, Range=± 2.56V

113

dBs

AIN=7.8mV, Range=± 20mV

Common Mode DC Rejection

On AIN

95

dBs

@DC, AIN=7.8mV, Range=± 20mV

On AIN

113

dBs

@DC, AIN=1V, Range=± 2.56V

Common Mode 50/60Hz Rejection

20 Hz Update Rate

On AIN

95

dBs

50/60Hz ± 1Hz, AIN=7.8mV, Range=± 20mV

On AIN

90

dBs

50/60Hz ± 1Hz, AIN=1V, Range=± 2.56V

Normal Mode 50/60 Hz Rejection

On AIN

60

dBs

50/60Hz ± 1Hz, 20 Hz Update Rate

PRIMARY ADC ANALOG INPUTS

Differential Input Voltage Ranges

9,10

Bipolar Mode (ADC0CON.5 = 0)

V

GAIN = 1 to 128

Unipolar Mode (ADC0CON.5 = 1)

0 à 1.024 x REFIN/GAIN

V

GAIN=1 to 128

Analog Input Current

2

± 1

nA

± 5

nA

Analog Input Current Drift

± 5

pA/°C

± 15

pA/°C

Absolute AIN Voltage Limits

2

V

EXTERNAL REFERENCE INPUTS

REFIN(+) to REFIN(–) Range

2

1

2.5

V

Average Reference Input Current

+/- 1

µA/V

Both ADCs Enabled

Average Reference Input Current Drift

+/- 0.01

nA/V/°C

‘NO Ext. REF’ Trigger Voltage

0.3

0.65

V

NOXREF bit active if VREF<0.3V

NOXREF bit Inactive if VREF>0.65

Common Mode DC Rejection

125

dBs

@DC, AIN=1V, Range=± 2.56V

Common Mode 50/60Hz Rejection

90

dBs

50/60Hz ± 1Hz, AIN=1V, Range=± 2.56V

Normal Mode 50/60 Hz Rejection

60

dBs

50/60Hz ± 1Hz, 59.4 Hz Update Rate