Datasheet

ADC128D818

SNAS483E –FEBRUARY 2010–REVISED MARCH 2013

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The second option is the Continuous Conversion Mode, where the device continuously converts the enabled

channels, thus never entering shutdown mode. A voltage conversion takes 12.2 ms, and a temperature

conversion takes 3.6 ms. For example, if operating in mode 2 and three voltage channels were enabled, then

each round-robin monitor would take 40.2 ms (3 x 12.2ms + 3.6ms) to complete. Use the "Channel Disable

The third option is called the On-Shot mode, which will be discussed in the next subsection.

One-Shot Register (address 09h)

The One-Shot register is used to initiate a single conversion and comparison cycle when the device is in

shutdown mode or deep shutdown mode, after which the device returns to the respective mode it was in. The

obvious advantage of using this mode is lower power consumption because the device is operating in shutdown

or deep shutdown mode.

This register is not a data register, and it is the write operation that causes the one-shot conversion. The data

written to this address is irrelevant and is not stored. A zero will always be read from this register.

Deep Shutdown Register (address 0Ah)

The ADC128D818 can be placed in deep shutdown mode, thus reducing more power consumption. The

procedures for deep shutdown entrance are:

1. Enter shutdown by setting the ‘START’ bit of the “Configuration Register’ (address 00h, bit 0) to 0.

2. Enter deep shutdown by setting the ‘DEEP SHUTDOWN’ bit (address 0Ah, bit 0) to 1.

3. A one-shot conversion can be triggered by writing any values to register address 09h.

Deep Shutdown Exit Procedure:

1. Set the ‘DEEP SHUTDOWN’ bit to 0.

Channel Readings Registers (addresses 20h - 27h)

The channel conversion readings are available in registers 20h to 27h. Each register is 16-bit wide to

accommodate the 12-bit voltage reading or 9-bit temperature reading. Conversions can be read at any time and

will provide the result of the last conversion. If a conversion is in progress while a communication is started, that

conversion will be completed, and the Channel Reading Registers will not be updated until the communication is

complete.

TEMPERATURE MEASUREMENT SYSTEM

The ADC128D818 delta-V

type temperature sensor and delta-sigma ADC perform 9-bit two's-complement

conversions of the temperature. This temperature reading can be obtained at the Temperature Reading Register

(address 27h). This register is 16-bit wide, and thus, all 9 bits of the temperature reading can be read using a

double byte read (Figure 30 or Figure 32). The following Figure 33 and the table below it show the theoretical

output code (D

OUT

) vs. temperature and some typical temperature-to-code conversions.

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