CDB5464U

4

DS847DB1

1.3

Analog Section

The CDB5464U evaluation board provides screw-type terminals (J23, J27, & J28) to connect input signals

to the voltage and current channels. The screw terminals are labels as VIN1-, VIN1+, IIN1+, IIN1-, and

IIN2+, IIN2-. An R-C network at each channel input provides a simple anti-alias filter.

The evaluation board provides three voltage reference options for VREFIN to the CS5464. The three volt-

age reference options include: VREFOUT from CS5464, the on-board +2.5V reference, and external

REF+ (screw terminal J14). Table 1 and Table 2 illustrate the options available for VREFIN. With a jumper

on J25 in the position labeled VREFOUT, the reference is supplied by the on-chip voltage reference. With

a jumper on J25 in the position labeled VREF, the reference is supplied by an off-chip voltage reference.

Table 2

illustrates the options available for VREF. With a jumper on J12 in position LT1019, the LT1019

provides a +2.5V reference (the LT1019 was chosen for its low drift - typically 5 ppm/°C). By setting the

jumper on J12 to position REF+, an external voltage reference is supplied via screw terminal J14's REF+

input.

The three input signal options for the voltage (VIN1±) and current (IIN1±, IIN2±) channels input include:

an external signal (screw terminals J23, J27, and J28), GND, or VREF. Table3 illustrates the options avail-

able. By installing jumpers on J17 to position VIN1-, J22 to position VIN1+, J24 to position IIN1+, J26 to

position IIN1-, J20 to position IIN2+, and J19 to position IIN2-, the input voltage signal is supplied from the

screw terminals J23, J27, and J28. With a jumper on J17, J22, J24, J26, J20, and J19 in the GND position,

Reference

Description

J25

VREFOUT

Selects On-chip

Reference (25 ppm/

VREF

Selects External or

LT1019 Reference(J12)

Table 1. Internal Voltage Reference Selection for VREF

Reference

Description

J12

LT1019

Selects On-board

LT1019 Reference

(5 ppm/

REF+

Selects External

Reference Source

(J14)

Table 2. External Voltage Reference Selection for VREF

O

O

VREF

VREFIN

VREFOUT

(Default)

O

O

VREF

VREFIN

VREFOUT

O

LT1019

REF+

O

LT1019

REF+

(Default)