ADC12H034 datasheet(34/53 Pages) TI1

34 / 53 page

ADC12030, ADC12032, ADC12034

ADC12038, ADC12H030, ADC12H032

ADC12H034, ADC12H038

SNAS080K – JULY 1999 – REVISED MARCH 2013

www.ti.com

1.8 Brown Out Conditions

When the supply voltage dips below about 2.7V, the internal registers, including the calibration coefficients and

all of the other registers, may lose their contents. When this happens the ADC will not perform as expected or

not at all after power is fully restored. While writing the desired information to all registers and performing a

calibration might sometimes cause recovery to full operation, the only sure recovery method is to reduce the

supply voltage to below 0.5V, then reprogram the ADC and perform a calibration after power is fully restored.

2.0 THE ANALOG MULTIPLEXER

For the ADC12038, the analog input multiplexer can be configured with 4 differential channels or 8 single ended

channels with the COM input as the zero reference or any combination thereof (see Figure 63). The difference

between the voltages at the VREF

+ and V

REF

− pins determines the input voltage span (V

REF). The analog input

voltage range is 0 to VA

+. Negative digital output codes result when V

− > V

+. The actual voltage at V

− or V

cannot go below AGND.

8 Single-Ended Channels

4 Differential

with COM

Channels

as Zero Reference

Figure 63. Input Multiplexer Options

Differential

Single-Ended

Configuration

A/DIN1 and A/DIN2 can be assigned as the + or

− input

A/DIN1 is + input

A/DIN2 is

− input

Figure 64. MUXOUT connections for multiplexer option

CH0, CH2, CH4, and CH6 can be assigned to the MUXOUT1 pin in the differential configuration, while CH1,

CH3, CH5, and CH7 can be assigned to the MUXOUT2 pin. In the differential configuration, the analog inputs

are paired as follows: CH0 with CH1, CH2 with CH3, CH4 with CH5 and CH6 with CH7. The A/DIN1 and A/DIN2

pins can be assigned positive or negative polarity.

With the single-ended multiplexer configuration, CH0 through CH7 can be assigned to the MUXOUT1 pin. The

COM pin is always assigned to the MUXOUT2 pin. A/DIN1 is assigned as the positive input; A/DIN2 is assigned

as the negative input. (See Figure 64).

The Multiplexer assignment tables for these ADCs (Table 2,Table 3, andTable 4) summarize the aforementioned

functions for the different versions of ADCs.

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Product Folder Links: ADC12030 ADC12032 ADC12034 ADC12038 ADC12H030 ADC12H032 ADC12H034

ADC12H038

ADC12H034 Datasheet(PDF) 34 Page - Texas Instruments

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