TLC3574, TLC3578, TLC2574, TLC2578

5V ANALOG, 3/5V DIGITAL, 14/12BIT, 200KSPS, 4/8CHANNEL

SERIAL ANALOGTODIGITAL CONVERTERS WITH ±10V INPUTS

SLAS262C − OCTOBER 2000 − REVISED MAY 2003

32

POST OFFICE BOX 655303

FIFO operation

76543210

ADC

×8

FIFO

SOD

Serial

FIFO Full

FIFO 3/4 Full

FIFO 1/2 Full

FIFO 1/4 Full

FIFO Threshold Pointer

Figure 20. FIFO Structure

FIFO operation (continued)

The device has an 8-level FIFO that can be programmed for different thresholds. An interrupt is sent to the host

after the preprogrammed threshold is reached. The FIFO is used to store conversion results in mode 01, 10,

and 11, from either a fixed channel or a series of channels according to the preprogrammed sweep sequence.

For example, an application may require eight measurements from channel 3. In this case, if the threshold is

set to full, the FIFO is filled with 8 data conversions sequentially taken from channel 3. Another application may

require data from channel 0, 2, 4, and 6 in that order. The threshold is set to 1/2 full and sweep sequence is

selected as 0−2−4−6−0−2−4−6. An interrupt is sent to the host as soon as all four data conversions are in the

FIFO. FIFO is reset after power on and WRITE CFR operation. The contents of the FIFO are retained during

autopower down.

Autopower-Down Mode: The device enters the autopower-down state at the end of conversion. The power

current is about 20

µA if SCLK stops, and 120 µA maximum if SCLK is running. Active CS , FS, or CSTART

resumes the device from power-down state. The bipolar input current is not turned off when device is in

power-down mode.

The configuration register is not affected by the power-down mode but the SWEEP operation sequence must

be started over again. All FIFO contents are retained in power-down mode.