Texas Instruments PGA309EVM-USB Theory of Operation for USB-DAQ-Platform, ToPCandPowerSupplies

PGA309EVM-USB Hardware Setup www.ti.com

2.5Theory of Operation for USB-DAQ-Platform

Figure 9 shows the block diagram for the USB-DAQ-Platform. This platform is a general-purpose data acquisition system that is used on several different Texas Instruments evaluation modules. The details of its operation are included in a separate document (available for download at www.ti.com). The block diagram shown in Figure 9 gives a brief overview of the platform. The primary control device on the USB-DAQ-Platform is the TUSB3210.

ToPC￿￿and￿Power￿Supplies

External

Power

(6VDC)

USB￿Bus From￿Computer

External￿Power

VLOOP =￿40VDC

Loop￿Measurement Circuitry￿= ±15V

			VCC		VDUT
	Adjustable	(2.7V￿to￿5.5V)		Power	(2.7V￿to￿5.5V)
						Switched￿Power
	Regulator			Switching
		Reference		2x￿16-Bit		2x￿16-Bit
	3.3V		Circuits	Delta-Sigma￿ADC		Delta-Sigma￿ADC
	Regulator
	VS∝C			4x￿16-Bit		2x￿16-Bit	Board￿Test￿To
V_USB				String￿DAC		Delta-Sigma￿ADC
	3.3V
5V
	TUSB3210					I2C,￿SPI
	8052 ∝C			Buffers and
	with￿USB￿Interface					Control￿Bits,￿and
				Latches
	and￿UART					Measure￿Bits
				Calibration
Reset Button				EEPROM
and	8Kx8￿Byte
Power-On￿Reset	EEPROM		USB￿DAQ￿Platform
	Loop-Switching			4mA￿to￿20mA		4mA￿to￿20mA
		Circuit		Loop￿Receiver		Receiver

Figure 9. Theory of Operation For USB-DAQ-Platform

3PGA309EVM-USB Hardware Setup

The PGA309EVM-USB Hardware setup involves connecting the two halves of the EVM together, applying power, connecting the USB cable, and setting the jumpers. This section covers the details of this procedure.

3.1Electrostatic Discharge Warning

Many of the components on the PBA309EVM-USB are susceptible to damage by electrostatic discharge (ESD). Customers are advised to observe proper ESD handling precautions when unpacking and handling the EVM, including the use of a grounded wrist strap at an approved ESD workstation.

CAUTION

Failure to observe ESD handling procedures may result in damage to EVM components.

16	PGA309EVM-USB	SBOU084 –February 2010
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