Texas Instruments DAC7716EVM manual Digital Interface, J1 Analog Interface Pinout

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2Analog Interface

For maximum flexibility, the DAC7716EVM can interface to multiple analog sources. Samtec part numbers SSW-110-22-F-D-VS-K and TSM-110-01-T-DV-P provide a 10-pin, dual-row, header at J1. This header provides access to the analog input and output pins of the DAC. Consult Samtec at http://www.samtec.com or call 1-800-SAMTEC-9 for a variety of mating connector options.

Table 1 summarizes the pinouts for analog interface J1.

Table 1. J1: Analog Interface Pinout

Pin Number	Signal	Description
J1.1	SGND-0	Signal GND DAC output 0
J1.2	VOUT-0	Analog output 0
J1.3	SGND-1	Signal GND DAC output 1
J1.4	VOUT-1	Analog output 1
J1.5	SGND-2	Signal GND DAC output 2
J1.6	VOUT-2	Analog output 2
J1.7	SGND-3	Signal GND DAC output 3
J1.8	VOUT-3	Analog output 3
J1.9-13 (odd)	AGND	Analog ground connections
J1.10	AIN	Auxiliary analog input
J1.14	VMON_BUF	Monitor output after buffer
J1.15	Unused	—
J1.17-19 (odd)	AGND	Analog ground connections
J1.18	RefGND	Reference ground pins on the
		DAC7716 (see below)
J1.20	EXTREF+	External reference source input (+
		side of reference input)
J1.12	Unused	—
J1.16	Unused	—

The analog interface is populated on the top of the evaluation model. This configuration makes it possible to stack multiple EVMs to run them in daisy-chain mode. J4 can be installed with a 90-degree connector to allow access to the analog outputs if multiple EVMs are stacked. The J1B connector can be installed if the part is used as a standalone board.

The DAC7716 can be configured with an output gain of 2 or 4. By default, the analog outputs of the DAC7716EVM are configured with a gain of 4. If a gain of 2 is desired, the proper jumper must be installed (JP2-JP5, depending on the output channel), and the command register must be set accordingly.

The SGND pins of the DAC7716 are connected to the ground of the evaluation board.

The Auxiliary Analog Input pin can be further protected from over-voltage and over-driving conditions. A Schottky diode (D1) can be installed to protect the DAC7716 from an input over-voltage condition. An op amp buffer is placed on the VMON output to limit the current that passes through the pin.

The DAC7716EVM has an external reference voltage option. If an external reference voltage is used, switches S2 and S3 must be properly configured. Use the EXTREF+ (J1.20) to apply an external reference voltage.

The DAC7716 is designed to have the REFGND-A and REFGND-B pins within 0.3V of the AGND. Therefore, we recommend not using the RefGND pin when connecting an external reference. Connect the ground source of the reference voltage to the ground of the board (J1.19). See the Reference Voltage section for more information.

3Digital Interface

The DAC7716EVM is a serial input data converter. The evaluation module is designed for interfacing to multiple control platforms.

SBAU159 –October 2009	DAC7716EVM 3
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