AMC1304L05-Q1 Datasheet, PDF (29/39 Pages) Texas Instruments – High-Precision, Reinforced Isolated Delta-Sigma Modulators with LDO

www.ti.com
AMC1304L05-Q1, AMC1304L25-Q1, AMC1304M05-Q1, AMC1304M25-Q1
SBAS799 – FEBRUARY 2017
Typical Applications (continued)
This additional series resistor (R3') influences the gain error of the circuit. The effect can be calculated using
Equation 5 with R5 = R5' = 50 kΩ and R4 = R4' = 2.5 kΩ (for the AMC1304x05-Q1) or 12.5 kΩ (for the
AMC1304x25-Q1).
E_G (%)
¨§ 1
©
R4 _{¸· *100%}
R4' R3' _¹
(5)
9.2.2.3 Application Curve
Figure 57 shows the dependency of the input bias current on the common-mode voltage at the input of the
AMC1304-Q1.
AMC1304x05-Q1
AMC1304x25-Q1
Figure 57. Input Current vs Input Common-Mode Voltage
9.2.3 Do's and Don'ts
Do not leave the inputs of the AMC1304-Q1 unconnected (floating) when the device is powered up. If both
modulator inputs are left floating, the input bias current drives them to the output common-mode of the analog
front end of approximately 2 V that is above the specified input common-mode range. As a result, the front gain
diminishes and the modulator outputs a bitstream resembling a zero input differential voltage.
Copyright © 2017, Texas Instruments Incorporated
Submit Documentation Feedback
29
Product Folder Links: AMC1304L05-Q1 AMC1304L25-Q1 AMC1304M05-Q1 AMC1304M25-Q1