User Guide

EVAL-AD74115H

EVALUATION BOARD HARDWARE

analog.com

Rev. 0 | 4 of 24

BOARD LAYOUT

The EVAL-AD74115H-ARDZ is laid out with the following three

isolated zones:

►

The input power supply is applied to the power side of the

EVAL-AD74115H-ARDZ.

►

Communications to the EVAL-AD74115H-ARDZ are received on

the microside via the SDP Arduino

® header connection.

►

The AD74115H and all related circuitry are on the AD74115H (or

field) side of the EVAL-AD74115H-ARDZ.

Each zone is separated by a 2.2 mm isolation barrier. Figure 2

shows the three isolation zones as these zones are laid out on the

EVAL-AD74115H-ARDZ.

Figure 2. Isolation Zones on the EVAL-AD74115H-ARDZ

POWER SUPPLIES

The EVAL-AD74115H-ARDZ comes with a power supply connector

(P18) that provides power directly to the VINP pin of the ADP1034.

Set this supply between 4.5 V and 60 V, as described in the

ADP1034 data sheet.

The ADP1034 generates the following isolated, resistor program-

mable supply voltages to the AD74115H:

►

VOUT1 provides the AD74115H AVDD voltage supply, VAVDD, of

24.0 V.

►

VOUT2 provides the AD74115H AVCC and DVCC voltage sup-

plies, VAVCC and VDVCC, of 5 V.

►

VOUT3 provides the AD74115H AVSS voltage supply, VAVSS, of

−15 V.

The ADP1034 VOUT2 also provides power to a 2.5 V external

reference (ADR4525). The ADR4525 can be used as an alternative

to the AD74115H on-chip reference.

The ADP1034 provides all the necessary power to the AD74115H

to perform the analog output, analog input, digital input, and digital

output functions.

However, if the digital output function is required to provide more

than 100 mA of continuous current, an additional external power

supply is required. The DO_SUPPLY connector can provide this

power supply directly to the digital output circuitry on the AD74115H

isolated side of the EVAL-AD74115H-ARDZ. See the Digital Output

section for details on how to configure for digital output functionality.

The digital output schematic entry is shown in Figure 23.

SPI COMMUNICATION

The SDP-K1 board handles the communication to the EVAL-

AD74115H-ARDZ via the PC. The SDP-K1 is connected to the

EVAL-AD74115H-ARDZ using the Arduino header connections. The

SDP-K1 board controls the SPI communication and the RESET pin

(driven high) and monitors the ALERT pin and ADC_RDY pin of the

AD74115H. ALERT, ADC_RDY, RESET, and all four SPI pins, are

isolated using the ADP1034.

A reset button (S1) is also available on the EVAL-AD74115H-ARDZ

to manually reset the AD74115H.

REFERENCE OPTIONS

By default, the EVAL-AD74115H-ARDZ is configured to use an

external reference, the ADR4525. Alternatively, the AD74115H on-

chip reference can be used by shorting the REFOUT pin to the

REFIN pin. The appropriate jumpers must be connected if using the

external reference. See Table 1 for the specific jumper connections.

OUTPUT CHANNEL

The AD74115H channel is configured as described in the

AD74115H data sheet. Figure 22 shows the schematic details for

the channel.

There are two screw terminal blocks on the EVAL-AD74115H-

ARDZ. Use the I/OP and I/ON connector (P21) to connect the

desired load to the AD74115H channel. To apply stimulus to

the two auxiliary high voltage sense pins, SENSE_EXT1 and

SENSE_EXT2, use the I/O_EXT1 and I/O_EXT2 connector (P8).

TEST POINTS

Multiple test points are available on the EVAL-AD74115H-ARDZ

for all critical pins and on the connector screw terminals. The test

points are located next to the relevant pins on the AD74115H.

LINK CONFIGURATION OPTIONS

The JPx and Px jumpers must be set properly for operation of the

EVAL-AD74115H-ARDZ. The functions and default states of these

options are listed in Table 1. Before applying power and signals

to the EVAL-AD74115H-ARDZ, ensure that all links are set to the

default positions, as defined in Table 1.