F1978 Datasheet

© 2017 Integrated Device Technology, Inc.

21

Rev O August 28, 2017

Evaluation Kit Operation

Power Supply Setup

Set up a power supply in the voltage range of 3.0V to 5.25V with the power supply output disabled. The voltage can be applied via one of the

following connections (see Figure 24):



J8 connector



J5 header connection (note the polarity of the GND pin on this connector)



Figure 24. Power Supply and Logic Voltage Connections

J8 Connector

GND

– J4, Pin 9

VDD

– J4, Pin 8

J5

J1 Connector

J2

J3

Parallel Logic Control Setup

The Evaluation Board has the ability to control the F1978 in the Parallel Mode. For external control, apply logic voltages to the J4 header pins 1

through 6 (see Figure 21). For manual control, switches 1 through 6 on U2 can be set. The switch is a three-position switch. The bottom position,

“–” will ground the pin. The center position “O” will leave the pin open circuited. Setting the switch to the top position “+” will apply a voltage that

is supplied to the switch.

The logic voltage can be applied in one of two ways (see Figure 24):



Connect directly to connector J1.



Leave J1 open circuit, and add jumpers to headers J2 and J3. This will apply a logic voltage that is 0.24

V

The F1978 has internal pull-up resistors for the D0

proper operation. To use the Parallel Mode, either apply a ground to the VMOD pin 7 on J4 or set U2 switch 7 (VMOD)

to the “–” position (see

Figure 21). The attenuation setting can be set via the U2 switches 1 through 6 (D0 through D5) according to Table 12.