WM8948ECSSLASHR datasheet(91/189 Pages) WOLFSON

91 / 189 page

Production Data

WM8948

PD, May 2011, Rev 4.1

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

AUX_AUX2_SEL

AUXADC AUX2 input select

0 = Disable AUX2 measurement

1 = Enable AUX2 measurement

AUX_AUX1_SEL

AUXADC AUX1 input select

0 = Disable AUX1 measurement

1 = Enable AUX1 measurement

Table 57 AUXADC Control

AUXADC INPUT CONFIGURATION

For inputs AUX1 and AUX2, the AUXADC uses either LDOVDD/2 or the 1.5V (nominal) bandgap as

a reference. This is selected independently for each AUX input, as described in Table 58. Selecting

the bandgap as a reference provides additional immunity to any noise on the supply rails.

The internal bandgap reference is nominally 1.5V. Note that this value is not trimmed and may vary

significantly (+/-10%) between different devices. When using this reference, the internal bandgap

reference must be enabled by setting the BG_ENA register, as described in Table 58.

For SPKVDD measurement, the SPKVDD voltage is connected to a potential divider in order to

reduce it to a suitable level. Two different scaling factors are available, controlled by the

AUX_BATT_SCALE register bit. The scaling factor should be selected such that the scaled output is

less than the maximum measurable level (LDOVDD).

For optimum measurement of the SPKVDD voltage, the SPKVDD potential divider can be connected

to the AUX1 pin, allowing an external capacitor to be used to filter noise from the SPKVDD supply.

This is enabled by setting the AUX_AUX1_FILTB register bit. This option can only be used when

AUX1 is not also used as an input to the AUXADC.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R54 (36h)

Bandgap

BG_ENA

Bandgap Reference Control

0 = Disabled

1 = Enabled

R63 (3Fh)

AuxADC

Config

AUX_AUX1_

FILTB

AUXADC Battery (SPKVDD)

measurement filter control

0 = Disabled

1 = Enabled

When AUX_AUX1_FILTB is set, the

Battery (SPKVDD) measurement

point is connected to the AUX1 pin,

allowing an external capacitor to be

used to filter noise.

AUX_BATT_

SCALE

AUXADC Battery (SPKVDD)

measurement divider control

0 = 0.45 x SPKVDD

(Note that 0.45 x 3.3V = 1.485V)

1 = 0.41 x SPKVDD

(Note that 0.41 x 3.6V = 1.476V)

AUX_AUX2_

REF

AUXADC AUX2 reference select

0 = LDOVDD/2

1 = 1.5V (nominal) Bandgap

AUX_AUX1_

REF

AUXADC AUX1 reference select

0 = LDOVDD/2

1 = 1.5V (nominal) Bandgap

Table 58 AUXADC Input Configuration

WM8948ECS/R Datenblatt(PDF) 91 Page - Wolfson Microelectronics plc

WM8948ECS/R Datenblatt(HTML) 91 Page - Wolfson Microelectronics plc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datenblatt Download

Link URL