©2009 CADEKA Microcircuits LLC

www.cadeka.com

24

PRELIMINARY Data Sheet

Table 19. Performance Control

Name

Description

Default

D

1

5

D

1

4

D

1

3

D

1

2

D

1

1

D

1

0

D

9

D

8

D

7

D

6

D

5

D

4

D

3

D

2

D

1

D

0

Address

In Hex

perfm_

cntrl<2:0>

ADC performance control

Nominal

X X X

50

ext_vcm_

bc<1:0>

VCM buffer driving strength

control

Nominal

X X

There are two registers that impact performance and power dissipation.

The

perfm_cntrl register adjusts the performance level of the ADC core. If full performance is required, the nominal

setting must be used. The lowest code can be used in situations where power dissipation is critical and performance is

less important. For most conditions the performance at the minimum setting will be similar to nominal setting. However,

only 10-bit performance can be expected at worst case conditions. The power dissipation savings shown in Table 20 are

only approximate numbers for the ADC current alone.

Table 20. Performance Control Settings

performance_control <2:0>

Power Dissipation

100

-40% (lower performance)

101

-30%

110

-20%

111

-10%

000 (default)

Nominal

001

Do not use

010

Do not use

011

Do not use

The

ext_vcm_bc register controls the driving strength in the buffer supplying the voltage on the VCM pin. If this pin is

not in use, the buffer can be switched off. If current is drawn from the VCM pin, the driving strength can be increased

to keep the voltage on this pin at the correct level.

Table 21. External Common Mode Voltage Buffer Driving Strength

ext_vcm_bc <1:0>

VCM Buffer Driving Strength

00

Off (VCM floating)

01 (default)

Low

10

High

11

Max