FSEL=0

FSEL=1

TYPE

Lowpass

Bandpass

0

Butterworth

Full Octave

1

Bessel

Third Octave

2

Elliptic

Sixth Octave

The filter type is selected using the two filter select pins,

TYPE and FSEL, FSEL is a pin that selects lowpass or

bandpass (lowpass = 0, bandpass = 1). TYPE is a tertiary

control pin that selects the filter response. State 0 is

VSS, state 1 is GND and state 2 is VDD.

Selectable Low Voltage Lowpass/Bandpass Filter

Data Sheet

6/2014

Pin Description________________

1. TYPE

Filter Response Select Pin

2. GND

AC Ground, decouple

with 0.1 uF to VSS

3. VREF

Reference Voltage, internally

generated, typically VDD/2.2 for

Single Supply Operation

4. MICIN

Input to Mic Amp

5. MICOUT

Output of Mic Amp

6. FO

Clock to Corner Select Pin

7. G

Gain Select Pin

8. FSEL

Selects Filter.

0 = Low Pass, 1 = Bandpass

9. VDD

Positive Power Supply, Typically

1.2 Volts for Single Supply

10. CTVL

Activate or Disable Boost Circuit

11. PD

Power Down Pin, CMOS level,

Hi = Power Down

12. CLK

Clock Input

13. PWR

Sets Bias Current for Filter Stages,

Lo=low power, Hi=normal power

14. OUT

Filter Output

15. VSSL

Bypass Capacitor for Boost Circuit,

voltage at this pin is negative in relation

to VSS, tie positive side of

polarized cap to VSS

16. VSS

Ground Pin, 0 Volts

for Single Supply

Pin Configuration

Filter Selection________________

The Gain control pin G is a tertiary control pin where

state 0 is VSS, state 1 is GND level and state 2 is VDD.

G

Gain

0

OdB

1

6dB

2

12dB

The frequency control pin F0 is a pin where high is

clock to corner of 85.3 to 1 (170.6 to 1 for Bessel) and

low is clock to corner of 42.65 to 1 (85.3 to 1 for Bes-

sel).

16

15

14

13

12

11

10

9

TYPE

VSS

GND

VSSL

VREF

OUT

MICIN

PWR

MICOUT

CLK

FO

PD

G

CTVL

FSEL

VDD

16 Pin

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