ADS1242, 1243

4

SBAS235H

www.ti.com

ELECTRICAL CHARACTERISTICS: VDD = 3V

All specifications TMIN to TMAX, VDD = +3V, fMOD = 19.2kHz, PGA = 1, Buffer ON, fDATA = 15Hz, VREF ≡ (REF IN+) – (REF IN–) = +1.25V, unless otherwise specified.

ADS1242

ADS1243

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

ANALOG INPUT (AIN0 – AIN7)

Analog Input Range

Buffer OFF

GND – 0.1

VDD + 0.1

V

Buffer ON

GND + 0.05

VDD – 1.5

V

Full-Scale Input Voltage Range

(In+) – (In–) See Block Diagram, RANGE = 0

±V

REF /PGA

V

RANGE = 1

±V

REF /(2 • PGA)

V

Input Impedance

Buffer OFF

5/PGA

M

Ω

Buffer ON

5

G

Ω

Bandwidth

fDATA = 3.75Hz

–3dB

1.65

Hz

fDATA = 7.50Hz

–3dB

3.44

Hz

fDATA = 15.00Hz

–3dB

14.6

Hz

Programmable Gain Amplifier

User-Selectable Gain Ranges

1

128

Input Capacitance

9pF

Input Leakage Current

Modulator OFF, T = 25

°C5

pA

Burnout Current Sources

2

µA

OFFSET DAC

Offset DAC Range

RANGE = 0

±V

REF /(2 • PGA)

V

RANGE = 1

±V

REF /(4 • PGA)

V

Offset DAC Monotonicity

8

Bits

Offset DAC Gain Error

±10

%

Offset DAC Gain Error Drift

2

ppm/

°C

SYSTEM PERFORMANCE

Resolution

No Missing Codes

24

Bits

Integral Nonlinearity

End Point Fit

±0.0015

% of FS

Offset Error(1)

15

ppm of FS

Offset Drift(1)

0.04

ppm of FS/

°C

Gain Error(1)

0.01

%

Gain Error Drift(1)

1.0

ppm/

°C

Common-Mode Rejection

at DC

100

dB

fCM = 60Hz, fDATA = 15Hz

130

dB

fCM = 50Hz, fDATA = 15Hz

120

dB

Normal-Mode Rejection

fSIG = 50Hz, fDATA = 15Hz

100

dB

fSIG = 60Hz, fDATA = 15Hz

100

dB

Output Noise

See Typical Characteristics

Power-Supply Rejection

at DC, dB = –20 log(

∆V

OUT /VDD)

(2)

75

90

dB

VOLTAGE REFERENCE INPUT

Reference Input Range

REF IN+, REF IN–

0VDD

V

VREF

VREF ≡ (REF IN+) – (REF IN–), RANGE = 0

0.1

1.25

1.30

V

RANGE = 1

0.1

2.5

2.6

V

Common-Mode Rejection

at DC

120

dB

Common-Mode Rejection

fVREFCM = 60Hz, fDATA = 15Hz

120

dB

Bias Current(3)

VREF = 1.25

0.65

µA

POWER-SUPPLY REQUIREMENTS

Power-Supply Voltage

VDD

2.7

3.3

V

Current

PGA = 1, Buffer OFF

190

375

µA

PGA = 128, Buffer OFF

460

700

µA

PGA = 1, Buffer ON

240

375

µA

PGA = 128, Buffer ON

870

1325

µA

SLEEP Mode

75

µA

Read Data Continuous Mode

113

µA

PDWN = 0

0.5

nA

Power Dissipation

PGA = 1, Buffer OFF

0.6

1.2

mW

TEMPERATURE RANGE

Operating

–40

+85

°C

Storage

–60

+100

°C

NOTES: (1) Calibration can minimize these errors.

(2)

∆V

OUT is a change in digital result. (3) 12pF switched capacitor at fSAMP clock frequency.