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

31

POST OFFICE BOX 655303

conversion operation (continued)

CS

FS

SDI

INT

SDO

***

Command = Configure Write for Mode 11, FIFO

Threshold = 1/2 Full, Sweep Sequence: 0−0−2−2

**

COMMAND = Select Any Channel

*

COMMAND = Read FIFO

*

Configure

Conversion

From CH0

Conversion

From CH2

Conversion

From CH2

Conversion

From CH0

1st SWEEP

1st FIFO Read

REPEAT

2nd FIFO Read

CH0

CH0

CH2

CH2

CH0

READ FIFO after 1st SWEEP Completed

CSTART

*** **

**

*

***

*

Possible Signal

Don’t Care

Figure 19. Mode 11, CSTART Triggers Samplings/Conversions, FS Initiates SELECT Operation

conversion clock and conversion speed

The conversion clock source can be the internal OSC, or the external clock, SCLK. The conversion clock is equal

to the internal OSC if the internal clock is used, or equal to SCLK/4 when the external clock is selected. It takes

18 conversion clocks plus 15 ns to finish the conversion for TLC3574 and TLC3578, and 13 conversion clocks

plus 15 ns for the TLC2574 and TLC2578. If the external clock is selected, the conversion time (not including

TLC2578. Table 4 shows the maximum conversion rate (including sampling time) when the analog input source

resistor is 25

Ω.

Table 4. Maximum Conversion Rate

DEVICE

SAMPLING MODE

CONVERSION CLK

MAX SCLK

(MHz)

CONVERSION

TIME (

µs)

RATE

(KSPS)

SHORT (16 SCLK)

External

SCLK/4

10

8.815

113.4

TLC3574/78

LONG (48 SCLK)

External

SCLK/4

25

4.815

207.7

TLC3574/78

(Rs = 25

Ω)

SHORT (16 SCLK)

Internal

6.5 MHz

10

4.384

228.0

(Rs = 25

)

LONG (48 SCLK)

Internal

6.5 MHz

25

4.705

212.5

SHORT (16 SCLK)

Exernal

SCLK/4

10

6.815

146.7

TLC2574/78

LONG (48 SCLK)

External

SCLK/4

25

4.015

249.1

TLC2574/78

(Rs = 25

Ω)

SHORT (16 SCLK)

Internal

6.5 MHz

10

3.615

276.6

(Rs = 25

)

LONG (48 SCLK)

Internal

6.5 MHz

25

3.935

254.1