Datasheet

ADS8528

ADS8548

ADS8568

www.ti.com

SBAS543A –AUGUST 2011– REVISED OCTOBER 2011

Output Data Format

The data output format of the ADS8528/48/68 is binary twos complement, as shown in Table 7. For the

ADS8528/48 (which deliver 12-bit or 14-bit conversion results, respectively), the leading bits of either the 16-bit

frame (serial interface) or the output pins (DB[15:12] for the ADS8528 or DB[15:14] for the ADS8548 in parallel

mode) deliver a sign extension.

Table 7. Output Data Format

BINARY CODE HEXADECIMAL CODE

DESCRIPTION INPUT VOLTAGE VALUE ADS8528 ADSS8548 ADS8568

0000 0111 1111 1111 0001 1111 1111 1111 0111 1111 1111 1111

Positive full-scale +4VREF or +2VREF

07FFh 1FFFh 7FFFh

0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000

Midscale +0.5LSB VREF/(2 × resolution)

0000h 0000h 0000h

1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111

Midscale –0.5LSB –VREF/(2 × resolution)

FFFFh FFFFh FFFFh

1111 1000 0000 0000 1110 0000 0000 0000 1000 0000 0000 0000

Negative full-scale –4VREF or –2VREF

F800h E000h 8000h

Reset and Power-Down Modes

The device supports two reset mechanisms: a power-on reset (POR) and a pin-controlled reset (RESET) that

can be issued using pin 10. Both, the POR and RESET act as a master reset that causes any ongoing

conversion to be interrupted, the Configuration Register content to be set to the default value, and all channels to

be switched into the sample mode.

When the device is powered up, the POR sets the device in default mode when AVDD reaches 1.2V. In normal

operation, glitches on the AVDD supply below this threshold trigger a device reset.

The entire device, except for the digital interface, can be powered down by pulling the STBY pin low (pin 9). As

the digital interface section remains active, data can be retrieved while in stand-by mode. To power the part on

again, the STBY pin must be brought high. The device is ready to start a new conversion after the 10ms required

to activate and settle the internal circuitry. This user-controlled approach can be used in applications that require

lower data throughput rates at lowest power dissipation. The content of CONFIG is not changed during stand-by

mode and it is not required to perform a reset after returning to normal operation.

Product Folder Link(s): ADS8528 ADS8548 ADS8568