R34DS0012EU0504 Rev.5.04

Page 25

Sep 18, 2025

ISL73141SEH Datasheet

At the input to the ADC, a simple RC filter should be sufficient for most applications. Choose the RC circuit values

appropriately for the application. A low-value resistor (RS ≤ 50) is recommended for low noise performance. Add a

high-quality shunt capacitor (CP) as close as possible to the AIN pin to shunt charge kickback from the ADC

during sampling and to limit the input bandwidth to the ADC. The recommended values for the CP range is from

220pF to 680pF. Larger values for CP can be used for slower conversion rates.

Due to the switched capacitance of the analog input, Renesas recommends limiting series inductance in the

analog input path, particularly the inductance near the analog input pins of the device. Renesas also recommends

using a high quality ceramic capacitor (CP) in shunt on the analog input that is at an appropriate value for the

required application. Choose the series resistance in the analog input circuit based on the output impedance of

the driver amplifier and the application requirements. An example topology is given in Figure 60, which converts a

0V input common-mode voltage to the ADC input common-mode voltage of VREF/2. This circuit is employed on

the ISL73141SEH evaluation board to allow the ADC to be driven from various types of signal generators.

It is important to understand the settling time associated with the analog input of the ISL73141SEH and the

impacts of RS and CP. To allow the ISL73141SEH to accurately resolve the input signal, it is important that the

input signal is settled completely before the signal is sampled by the ISL73141SEH. To meet the datasheet

Figure 59. ISL73141SEH Analog Input Amplifier Example Circuit

Figure 60. ISL73141SEH Common-Mode Conversion Amplifier Example Circuit

Analog

Input

+

-

AIN

GND

ISL73141SEH

RS

CP

AV = +2

AV = -2

+

-

-

+

AV = 1

-

+

VREF

AIN

GND

ISL73141SEH

R

R

2R

R

5R

R

0V

+VREF/4

-VREF/4

Analog

Input

VREF/2

+VREF

0V

RS

CP