AFE4300

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SBAS586B – JUNE 2012 – REVISED JUNE 2013

ELECTRICAL CHARACTERISTICS: Front-End Amplification (Weight-Scale Signal Chain)

Over operating free-air temperature range, AVDD – AVSS = 3 V, G1 = 183, and G2 = 1, unless otherwise noted.

AFE4300

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

BRIDGE SUPPLY

Output voltage (bridge supply voltage)

1.7

V

Current capability

20

mA

Output current

Short-circuit protection

100

mA

Enable/disable time

With 470 nF cap on VLDO pin

1

ms

AMPLIFICATION CHAIN

Offset error

With offset correction DAC disabled

80

µV

Offset drift vs temperature

With offset correction DAC diasbled

0.25

µV/°C

Input bias current

±70

fA

Input offset current

±140

fA

Noise voltage, equivalent input

G1 = 183, 0.01 Hz < f < 2 Hz

68

nVrms

Noise current, equivalent input

f = 10 Hz

100

fA/

√Hz

Differential input impedance

100 || 4

G

Ω || pF

Common-mode input impedance

100 || 8

G

Ω || pF

CMRR

Input common-mode rejection ratio

G1 = 183

95

dB

From input to digital output (including

Gain nonlinearity

0.01

ADC)

First-stage gain equation

V/V

Power-up time

From power up to valid reading

1

ms

R1

Internal feedback resistors

95

100

105

k

Ω

Gain2

Second-stage gain settings

1, 2, 3, 4

Total gain error

±5%

Offset DAC number of bits

6

Bits

Full-scale offset DAC output current

±6.5

µA

(1)

FS = full-scale.

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