4

Maxim Integrated

Digitally-Programmed, Dual

2nd-Order Continuous Lowpass Filter

MAX270/MAX271

TIMING CHARACTERISTICS (Figure 2)

(V+ = +5V, V- = -5V; TA = +25NC, unless otherwise noted.)

Note 11: All input control signals specified with tr = tf = 5ns (10% to 90% of +5V) and timed from a +1.6V voltage level.

Typical Operating Characteristics

FILTER GAIN vs. FREQUENCY

fIN (Hz)

100k

10k

-60

-40

-20

0

-80

1k

1M

V+ = +5V

V- = -5V

fC CODE = 127 (25kHz TYP)

TA = +25˚C

FILTER GAIN vs. FREQUENCY

(NORMALIZED TO CUTOFF FREQUENCY)

fIN/fC

10

1.0

-60

-40

-20

0

-80

0.1

100

V+ = +5V

V- = -5V

fC CODE = 0-127 (1-25kHz TYP)

TA = +25˚C

fIN/fC

100

10

-2

-1

0

0.5

-3

11k

V+ = +5V

V- = -5V

fC CODE = 0 (1kHz TYP)

TA = +125˚C

TA = +25˚C

TA = -55˚C

PASSBAND FILTER GAIN

vs. FREQUENCY

PASSBAND FILTER GAIN

vs. FREQUENCY

fIN (Hz)

1k

10k

100

-2

-1

0

0.5

-3

25

25k

V+ = +5V

V- = -5V

fC CODE = 127 (25kHz TYP)

TA = +125˚C

TA = +25˚C

TA = -55˚C

fIN/fC

0.1

0.01

-2

-1

0

+0.5

-3

0.001

1.0

PASSBAND FILTER GAIN vs. FREQUENCY

(NORMALIZED TO CUTOFF FREQUENCY)

V+ = +5V

V- = -5V

fC CODE = 0-127 (1-25kHz TYP)

TA = +25˚C

fIN/fC

1.0

0.1

-45

-90

-135

-180

0

0.01

10

FILTER PHASE SHIFT vs. FREQUENCY

(NORMALIZED TO CUTOFF FREQUENCY)

V+ = +5V

V- = -5V

fC CODE = 0-127

(1-25kHz TYP)

TA = +25˚C

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

CS to WR Setup

tWS

0

ns

CS to WR Hold

tWH

0

ns

WR Pulse Width

tSV

100

ns

Address-Setup Time

tAS

30

ns

Address-Hold Time

tAH

10

ns

Data-Setup Time

tDS

30

ns

Data-Hold time

tDH

10

ns