ADS1294CZXGR datasheet(28/114 Pages) TI2

28 / 114 page

Temperature ( C) =

Temperature Reading ( V)

145,300 V

490 V/ C

+ 25 C

AVDD

AVSS

TemperatureSensorMonitor

ToMUXTempP

ToMUXTempN

ADS1294, ADS1294R, ADS1296, ADS1296R, ADS1298, ADS1298R

SBAS459K – JANUARY 2010 – REVISED AUGUST 2015

www.ti.com

Feature Description (continued)

9.3.1.3.1

Device Noise Measurements

Setting CHnSET[2:0] = 001 sets the common-mode voltage of (AVDD – AVSS) / 2 to both inputs of the channel.

Use this setting to test the inherent noise of the device.

9.3.1.3.2

Test Signals (TestP and TestN)

Setting CHnSET[2:0] = 101 provides internally-generated test signals for use in subsystem verification at power

up. This functionality allows the entire signal chain to be tested. Although the test signals are similar to the CAL

signals described in the IEC60601-2-51 specification, this feature is not intended for use in compliance testing.

Use register settings to control the test signals (see the CONFIG2: Configuration Register 2 (address = 02h)

(reset = 40h) section for details). The TEST_AMP bit controls the signal amplitude, and the TEST_FREQ bits

control switching at the required frequency.

The test signals are multiplexed and transmitted out of the device at the TESTP_PACE_OUT1 and

TESTN_PACE_OUT2 pins. A bit register (CONFIG2.INT_TEST = 0) deactivates the internal test signals so that

the test signal can be driven externally. This feature allows the calibration of multiple devices with the same

signal. The test signal feature cannot be used in conjunction with the external hardware pace feature (see the

External Hardware Approach section for details).

9.3.1.3.3

Auxiliary Differential Input (TESTP_PACE_OUT1, TESTN_PACE_OUT2)

When hardware pace detection is not used, the TESTP_PACE_OUT1 and TESPN_PACE_OUT2 signals can be

used as a multiplexed differential input channel. These inputs can be multiplexed to any of the eight channels.

The performance of the differential input signal fed through these pins is identical to the normal channel

performance.

9.3.1.3.4

Temperature Sensor (TempP, TempN)

The ADS129x contain an on-chip temperature sensor. This sensor uses two internal diodes with one diode

having a current density 16x that of the other, as shown in Figure 26. The difference in current densities of the

diodes yields a difference in voltage that is proportional to absolute temperature.

Figure 26. Measurement of the Temperature Sensor in the Input

As a result of the low thermal resistance of the package to the printed circuit board (PCB), the internal sensor

tracks the PCB temperature closely. Self-heating of the ADS129x causes a higher reading than the temperature

of the surrounding PCB.

The scale factor of Equation 1 converts the temperature reading to °C. Before using this equation, scale the the

temperature reading code to

μV.

(1)

Submit Documentation Feedback

Product Folder Links: ADS1294 ADS1294R ADS1296 ADS1296R ADS1298 ADS1298R

ADS1294CZXGR Datasheet(PDF) 28 Page - Texas Instruments

ADS1294CZXGR Datasheet(HTML) 28 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL