Texas Instruments DAC7741EVM - Manual (Page 10)

Features
1-2
1.1 Features
This EVM features the DAC7741 digital-to-analog converter. The DAC7741
EVM is a simple evaluation module designed for a quick and easy way to
evaluate the functionality of the high resolution, single-channel, and parallel
input DAC. This EVM features a parallel interface to communicate to any host
processor base system.
1.2 Power Requirements
The following sections describe the power requirements of this EVM.
1.2.1 Supply Voltage
The dc power supply requirement for the digital section of this EVM is typically
5 V connected to the J11-2 or via J6-2 terminal (when plugged in with another
EVM board or interface card) and is referenced to ground through the J11-1
and J6-1 terminal. The dc power supply requirement for the analog section
(V
CC
and V
SS
) of this EVM range from 15.75 V to -15.75 V maximum and
connects through J10-4 and J12-1 or through J7-6 and J7-8 terminals and
is referenced to analog ground through J10-2, J12-2 and J7-1 terminals.
A dc source of ± 15 V supply is required to provide the rails for the external
output op-amp provided for output signal conditioning or boost capacitive load
drive and for other output modes of application. The 15 V supply connects
through J10-1 or J7-2 terminal, and the –15 V supply connects through J10-3
or J7-4 terminals. The
±
15 V supply is referenced to ground through J10-2
or J7-3 terminals. The supply source for V
CC
and V
SS
can also be used as the
supply source for 15 V and -15 V respectively.
To avoid potential damage to the EVM board, make sure that the
correct cables are connected to their respective terminals as
labeled on the EVM board.
Stresses above the maximum listed voltage ratings may cause
permanent damage to the device.
1.2.2 Reference Voltage
Although the DAC7741 has a built-in 10-V voltage reference, an external
reference circuit is provided in the EVM board. The external reference circuit
can be isolated if the internal reference voltage is selected.
The 10-V precision voltage reference is provided to supply the external voltage
reference for the DAC through REF102, U3, via jumper W4 by shorting pins
1 and 2. An adjustable 100-k
Ω
potentiometer, R11, is installed in series with
20 k
Ω
, R10, to allow the user to adjust the reference voltage to its desired
settings. TP1 and TP2 are also provided, as well as J4-20, to allow the user
to connect other external reference source if the onboard reference circuit is
not desired. The external voltage reference should not exceed 10-V dc.