Introduction
1-2
1.1
Introduction
Many data converter evaluation fixtures contain a computer interface or a mi-
crocontroller, but the ADS1244/45EVM contains only the ADS1244 or
ADS1245 device and a few support components. All ADS1244/45 pins are ac-
cessible through various pins on the ADS1244/45EVM’s analog and digital
connectors.
The ADS1244/45EVM is designed using a simple card format developed by
TI. This simple, consistent design makes it very easy to connect the
ADS1244/45EVM to your own prototype system. You can even think of the
ADS1244/45EVM as an alternate package for the ADS1244/45 – one much
larger than the device itself, but also much easier to wire up by hand on your
test bench.
The ADS1244/45EVM can be plugged directly into suitable motherboards
such as the HPA449 MSP430 microcontroller development system from Soft-
Baugh, Inc. (
http://www.softbaugh.com/
). See TI’s web site for sample code
using the ADS1244/45EVM with the HPA449.
The ADS1244/45EVM, together with the HPA449 and the appropriate soft-
ware, also forms a complete evaluation system for verifying the performance
of the ADS1244/45. See TI’s web site for more information and software.
1.2
Built−in Accessories
The ADS1244/45EVM includes a system clock generator and a low−noise
voltage reference. Both features are optional; you can select an external sys-
tem clock and an external reference using the slide switches.
The +2.5V reference circuit is based on a REF1004−2.5. Its noise perfor-
mance is sufficient to allow the ADS1244/45 to perform at its lowest noise lev-
el.
The system clock is based on a 4.9152MHz CMOS crystal clock generator
module. A flip−flop divides the clock generator by two in order to provide an
additional 2.4576MHz clock source. The two clocks can be selected using the
clock source select switch.
1.3
Connectors
The ADS1244/45 device on the ADS1244/45EVM is connected through three
headers: the analog connector, the serial connector, and the power connector.
Pinouts and locations for the connectors are given in the following chapter.
The analog connector (J1) carries analog I/O. The ADS1244/45 has a single
differential input channel connected to pins 1 and 2. An optional external differ-
ential reference can be connected to pins 18 and 20.
The serial connector (J5) carries the ADS1244/45 serial digital interface, an
optional external system clock signal, and an I
2
C connection to the on−board
serial EEPROM.
