R34DS0012EU0504 Rev.5.04

Page 24

Sep 18, 2025

ISL73141SEH Datasheet

5.7

ISL73141 Transfer Function

Figure 58 gives the transfer function of the device. Code transitions in the digital outputs bits of the device occur at

midway points between successive integer LSB values that range from 0.5 LSB, 1.5 LSB, 2.5 LSB, 3.5 LSB... and

FS - 3.5 LSB, FS - 2.5 LSB, FS - 1.5 LSB, FS - 0.5 LSB. The device is a 14-bit ADC with an output code range in

decimal from 0 to 2N-1 where N = 14, making the total code range 0 to 16383 inclusive.

5.8

Power Supply Sequencing

The ISL73141SEH does not have any specific power sequencing requirements when increasing the supply

voltages. IMPORTANT: You must follow the guidelines in the recommended operating conditions and take care in

observing the maximum supply voltage conditions outlined in the Absolute Maximum Ratings section.

5.9

Analog Input (AIN) Pin

The ISL73141SEH supports single-ended input drive only. IMPORTANT: Ensure that proper grounding techniques

and supply decoupling are used in circuit board layout to achieve optimum performance. The ISL73141SEH

evaluation board can be used as a guide for proper circuit optimization. The analog input is a high-impedance

input that exhibits a capacitive load of approximately 15pF during sample mode and 3pF during hold mode. Due to

the high bandwidth (50MHz) of the analog input, Renesas recommends using an Anti-Alias Filter (AAF)

appropriate for the desired application. It is not required to operate the ISL73141SEH with an input amplifier, but it

can improve performance and/or provide gain in certain applications. An example topology is given in Figure 59,

which uses a driver amplifier and an RC input filter. Care must be taken to choose an amplifier with low noise and

distortion because the ADC performance is directly impacted. It is also important to choose feedback resistance

values that are less than 1kΩ (typically, 100Ω to 200Ω) to minimize the impact of resistor thermal noise. The noise

of the resistor is directly related to its value by Equation 2.

where

▪ k = Boltzmans constant (1.38 x 10-23)

▪ T = Temperature in Kelvin (room temperature = 27°C = 300K)

▪ R = Resistance value

Figure 58. ISL73141SEH Transfer Function

(EQ. 2)

00 0000 0000 0000

00 0000 0000 0001

11 1111 1111 1110

11 1111 1111 1111

ADC Input Voltage

Power Spectral Density (PSD)

4kTR V2 Hz

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