MAX1457 Datasheet, PDF (3/12 Pages) Maxim Integrated Products – 0.1%-Accurate Signal Conditioner for Piezoresistive Sensor Compensation

0.1%-Accurate Signal Conditioner
for Piezoresistive Sensor Compensation
ELECTRICAL CHARACTERISTICS (continued)
(V_DD = +5V, V_SS = 0V, T_A = +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
ANALOG-TO-DIGITAL CONVERTER
CONDITIONS
ADC Differential Nonlinearity
V_BR = 2.5V to 3.5V, f_CLK = 100kHz
Conversion Time
ADC Resolution
OUTPUTS (LINDAC, FSOTCDAC)
Voltage Swing
Current Drive
Offset Voltage
UNCOMMITTED OP AMP
Input Common-Mode
Voltage Range
Open-Loop Gain
Offset Voltage (as unity-gain
follower)
Output Voltage Swing
V_OFS
CMR
A_V
f_CLK = 100kHz
R_BIAS = 400kΩ (no load)
R_BIAS = 400kΩ, V_IN = 2.5V,
V_OUT = 2.5V ±20mV
(V_IN - V_OUT) at V_IN = 2.5V,
R_BIAS = 400kΩ (no load)
R_BIAS = 400kΩ
R_BIAS = 400kΩ, V_IN = 2.5V (no load)
5kΩ load to V_SS or V_DD
No load
Output Current Range
V_OUT = (V_SS + 0.25V) to (V_DD - 0.25V)
MIN TYP MAX UNITS
2
LSB
160
ms
12
Bits
V_SS + 1.3
-50
VDD - 1.3
V
50
µA
-20
20
mV
V_SS + 1.3
VDD - 1.2
V
60
dB
-20
20
mV
V_SS + 0.25
V_SS + 0.02
-1.0
(sink)
VDD - 0.25
V
VDD - 0.02
1.0
(source)
mA
Note 1: Circuit of Figure 5 with current source turned off. This value is adjustable through a bias resistor and represents the IC cur-
rent consumption. This excludes the 93C66 EEPROM average current, which is approximately 13µA at a refresh rate of 3Hz
(f_CLK = 100kHz).
Note 2: Temperature errors for the entire range are compensated together with the sensor errors.
Note 3: The sensor and the MAX1457 must always be at the same temperature during calibration and use.
Note 4: This is the maximum allowable sensor offset at minimum gain (54V/V).
Note 5: This is the sensor’s sensitivity normalized to its drive voltage, assuming a desired full-span output of 4V and a bridge volt-
age of 2.5V. Lower sensitivities can be accommodated by using the auxiliary op amp. Higher sensitivities can be accommo-
dated by operating at lower bridge voltages.
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