Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsTLV320AIC3100IRHBR

1 2

0 1 2

15 1 2

1 2

N 2 N z N z

H(z)

2 2 D z D z

- -

+ ´ +

- ´ -

0 1

15 1

N N z

H(z)

2 D z

LargestPositiveNumber:

=0.111 1111 1111 111

=0.999969482421875=1.0 – 1LSB

LargestNegativeNumber:

=1.0000 0000 0000 000

=0x8000= –1.0(bydefinition)

1 1 1

S.xxxx xxxx xxxx xxx.. x x x

SignBit

2 Bit

–1

2 Bit

–4

2 Bit

–15

Fraction

Point

TLV320AIC3100

www.ti.com

SLAS667A –NOVEMBER 2009–REVISED MAY 2012

The coefficients of these filters are each 16 bits wide, in 2s-complement format, and occupy two

consecutive 8-bit registers in the register space. Specifically, the filter coefficients are in 1.15 (one dot 15)

format with a range from –1.0 (0x8000) to 0.999969482421875 (0x7FFF), as shown in Figure 5-12.

Figure 5-12. 1.15 2s-Complement Coefficient Format

5.4.4.3.1 First-Order IIR Section

The transfer function for the first-order IIR filter is given by

(1)

The frequency response for the first-order IIR section with default coefficients is flat at a gain of 0 dB.

Table 5-18. ADC First-Order IIR Filter Coefficients

Filter Filter Coefficient ADC Coefficient Default (Reset) Values

N0 Page 4 / register 8 and page 4 / register 9 0x7FFF (decimal 1.0 – LSB value)

First-order IIR N1 Page 4 / register 10 and page 4 / register 11 0x0000

D1 Page 4 / register 12 and page 4 / register 13 0x0000

5.4.4.3.2 Biquad Section

The transfer function of each of the biquad filters is given by

(2)

The default values for each biquad section yield an all-pass (flat) frequency response at a gain of 0 dB.

Table 5-19. ADC Biquad Filter Coefficients

Filter Filter Coefficient Filter Coefficient RAM Location Default (Reset) Values

Biquad A N0 Page 4 / register 14 and page 4 / register 15 0x7FFF (decimal 1.0 – LSB value)

N1 Page 4 / register 16 and page 4 / register 17 0x0000

N2 Page 4 / register 18 and page 4 / register 19 0x0000

D1 Page 4 / register 20 and page 4 / register 21 0x0000

D2 Page 4 / register 22 and page 4 / register 23 0x0000

Biquad B N0 Page 4 / register 24 and page 4 / register 25 0x7FFF (decimal 1.0 – LSB value)