Datasheet

AMC7812

SBAS513E –JANUARY 2011–REVISED SEPTEMBER 2013

www.ti.com

ADC Data Format

For a single ended input, the conversion result is stored in straight binary format. For a differential input, the

results are stored in twos complement format.

SCLK Clock Noise Reduction

To avoid noise caused by the bus clock, it is recommended that no bus clock activity occurs for at least the

conversion process time immediately after the ADC conversion starts.

Programmable Conversion Rate

The maximum conversion rate is 500kSPS for a single channel in auto mode, as shown in Table 1. The

conversion rate is programmable through the CONV-RATE-[1:0] bits of AMC Configuration Register 1. When

more than one channel is selected, the conversion rate is divided by the number of channels selected in ADC

Channel Register 0 and ADC Channel Register 1. In auto mode, the CONV-RATE-[1:0] bits determine the actual

conversion rate. In direct mode, the CONV-RATE-[1:0] bits limit the maximum possible conversion rate. The

actual conversion rate in direct mode is determined by the rate of the conversion trigger. Note that when a trigger

is issued, there may be a delay of up to 4µs to internally synchronize and initiate the start of the sequential

channel conversion process. In both direct and auto modes, when the CONV-RATE-[1:0] bits are set to a value

other than the maximum rate ('00'), nap mode is activated between conversions. By activating nap mode, the

supply current is reduced; see Figure 67.

Table 1. ADC Conversion Rate

ACQ

CONV

NAP THROUGHPUT

CONV-RATE-1 CONV-RATE-0 (µs) (µs) ENABLED (Single-Channel Auto Mode)

0 0 0.375 1.625 No 500kSPS (default)

0 1 2.375 1.625 Yes 250kSPS

1 0 6.375 1.625 Yes 125kSPS

1 1 14.375 1.625 Yes 62.5kSPS

Product Folder Links: AMC7812