TSA1204(2006) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TSA1204
(Rev.:2006)

Dual channel 12-bit 20Msps 120mW A/D converter

STMicroelectronics 

TSA1204

8

Application information

Application information

The TSA1204 is a dual-channel, 12-bit resolution analog-to-digital converter based on a

pipeline structure and the latest deep submicron CMOS process to achieve the best

performance in terms of linearity and power consumption.

Each channel achieves 12-bit resolution through the pipeline structure which consists of 12

internal conversion stages in which the analog signal is fed and sequentially converted into

digital data. A latency time of 7 clock periods is necessary to obtain the digitized data on the

output bus.

The input signals are simultaneously sampled, for both channels, on the rising edge of the

clock. The output data is delivered on the rising edge of the clock for channel I and on the

falling edge of the clock for channel Q, as shown in Figure 2: Timing diagram on page 4. The

digital data produced at the different stages must be time delayed accordidng to the order of

conversion. Fianlly, a digital data correction completes the processing and ensures the

validity of the ending codes on the output bus.

The structure is specifically designed to accept differential signals only.

8.1

8.1.1

8.1.2

Additional functions

To simplify the application board as much as possible, the following operating modes are

provided:

● Output enable mode (OEB)

● Select mode (SELECT)

Output enable mode (OEB)

When set to low level (VIL), all digital outputs remain active and are in low impedance state.

When set to high level (VIH), all digital output buffers are in high impedance state while the

converter goes on sampling. When OEB is set to a low level again, the data arrives on the

output with a very short Ton delay. This mechanism allows the chip select of the device.

Figure 2: Timing diagram on page 4 summarizes this functionality.

If you do not want to use OEB mode, the OEB pin should be grounded through a low value

resistor.

Select mode (SELECT)

The digital data output from each of the ADC cores is multiplexed to share the same output

bus. This prevents an increase in the number of pins and allows to use the same package as

for a single-channel ADC like the TSA1201.

The information channel is selected with the "SELECT" pin. When set to high level (VIH),

channel I data is present on the D0-D11 output bus. When set to low level (VIL), channel Q

data is delivered on D0-D11.

By connecting SELECT to CLK, channel I and channel Q are simultaneously present on D0-

D11, channel I on the rising edge of the clock and channel Q on the falling edge of the clock.

(Refer to Figure 2: Timing diagram on page 4).

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