Renesas ISL73100SEHEV1Z User Manual

User’s Manual

ISL73100SEHEV1Z

High Reliability

User’s Manual: Evaluation Board

All information contained in these materials, including products and product specifications,
represents information on the product at the time of publication and is subject to change by
Renesas Electronics Corp. without notice. Please review the latest information published by
Renesas Electronics Corp. through various means, including the Renesas Electronics Corp.
website (http://www.renesas.com).

Renesas Electronics Corporation

www.renesas.com

Rev.1.00

May.28.20

User’s Manual

OUT

V+

RS+

RS-

V-

1.7V

V-

V-V-

ISL73100SEHEV1Z

Evaluation Board

The ISL73100SEHEV1Z evaluation board is designed to evaluate the performance of the ISL70100SEH and
ISL73100SEH. The ISL70100SEH and ISL73100SEH are radiation hardened 40V current-sense amplifiers built
using the Renesas proprietary PR40 SOI process.

Key Features

• Large current-sense resistor footprint (2512)

• Easy gain configuration using a single resistor

• Kelvin sensing for improved measurement accuracy

Specifications

• Power supply voltage range: 2.7V to 40V

• Current-sense input common-mode range: -0.3V to 40V (regardless of power supply voltage)

• Board dimension: 4.25cm x 5.25cm

• Board layers: Two

• Board revision: A

Ordering Information

Part Number Description

ISL73100SEHEV1Z ISL73100SEHEV1Z evaluation board

Related Literature

For a full list of related documents, visit our website:

• ISL73100SEH

, ISL70100SEH device pages

R34UZ0001EU0100 Rev.1.00 Page 2 of 12
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Figure 1. ISL73100SEHEV1Z Block Diagram

ISL73100SEHEV1Z 1. Functional Description

(EQ. 1)

ROUT

A

CSA

gm

---------------

=

1. Functional Description

The evaluation board includes a 2512 sized SMD pad for populating a current-sense resistor and an output
termination resistor to set the current-sense to output voltage scaling.

1.1 Operating Range

The ISL70100SEH and ISL73100SEH have a wide power supply range from 2.7V up to 40V. The input
common-mode range extends from -0.3V to 40V, making them ideal to use in both high-side and low-side
current-sense applications. The current-sense amplifiers are voltage-to-current converters that monitor current
using an external sense resistor and output a scaled current of the sensed input voltage.

1.2 Quick Start Guide

1. R2 is a 15mΩ 2512 sized to provide 150mV for 10A. The analog differential input voltage for RS+ to RS- is 0V
to 150mV. If R2 needs to be changed, the product of the current-sense resistance and maximum load current
must fall within 150mV.

2. With the load unbiased: Connect the current-sense terminals to the circuit load either in a high-side sense (RS+
goes to load positive supply rail, RS- goes to load positive terminal) or low-side sense (RS+ goes to load
negative terminal, RS- goes to load negative supply rail) configuration.

3. Provide a power supply voltage to V+ (BA1) and GND (BA2) terminals of the ISL73100SEHEV1Z board. The
power supply voltage range is 2.7V to 40V.

4. Power-up load.

5. The voltage on OUT (BNC1) with the 25kΩ output resistor is 50mV for every 1mV input sense voltage. The
full-scale 150mV input produces 7.5V output.
Note: To use the full-scale output voltage at 150mV full-scale input sense voltage with the 25kΩ output resistor,
the minimum supply range must be increased to 9.5V to account for the 2.0V output head-room to the V+
supply voltage.

1.3 Current-Sense Resistor

To pick the current-sense resistor value, a decision has to be made between power dissipation and measurement
accuracy. As a general rule for all applications, the sense resistor should be as small as possible while still
providing adequate input dynamic range across the operating range. The minimum accurately sensed input
voltage is primarily limited by the offset voltage of the ISL70100SEH and ISL73100SEH.

The sense resistor value can be calculated when the maximum load current is determined. The maximum
recommended sense voltage for the amplifier is 150mV, so dividing that by the maximum load current provides
the sense resistor value.

The current-sense error is the amplifier offset voltage divided by the current-sense resistor.

On the ISL73100SEHEV1Z, the current-sense signal is connected to the R2 current-sense resistor in a Kelvin
configuration for sense accuracy.

1.4 Current-Sense Amplifier Output Voltage (Gain Setting)

The ISL73100SEHEV1Z is populated with a 25kΩ resistor at the current-sense amplifier output to GND (BNC
terminal OUT).

The overall gain (A
ISL70100SEH outputs 2µA for every 1mV of differential across the inputs. Equation 1
output load resistance to get a specific gain:

R34UZ0001EU0100 Rev.1.00 Page 3 of 12
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) on the ISL70100SEH can be adjusted using a single resistor on the output. The

CSA

can be used to calculate the

ISL73100SEHEV1Z 1. Functional Description

For the 25kΩ resistor, the current-sense amplifier gain ACSA is (25mV/µA) * (2µA/mV) = 50V/V. Therefore, at
full-scale of the 150mV input, 300µA output current, the 25kΩ output resistor produces a full-scale output voltage
of 7.5V. Therefore, the output produces 50mV for every 1mV input sense voltage.

1.5 Power Supply Bias Range

The ISL73100SEHEV1Z can be biased anywhere from 2.7V to 40V. The current-sense input common-mode
voltage range is from -0.3V to 40V, regardless of the V+ to V- power supply bias. The current-sense amplifier
output voltage range is V- to 2.0V below V+.

The ISL73100SEHEV1Z is populated with a 25kΩ output resistor that produces 7.5V output voltage at 150mV
full-scale input voltage. To achieve full-scale output voltage, the minimum power supply bias voltage is 9.5V.

If the minimum power supply of 2.7V is used with the 25kΩ output resistor, the maximum accurately sensed
current would be 0.93A.

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