8th-Order, Lowpass, Bessel,

Switched-Capacitor Filters

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5

-70

-50

-60

-40

-10

0

-20

-30

10

012345

FREQUENCY RESPONSE

INPUT FREQUENCY (kHz)

fC = 1kHz

-3.5

-2.5

-3.0

-2.0

-0.5

0

-1.0

-1.5

0.5

0

202

404

606

808

1010

PASSBAND FREQUENCY RESPONSE

INPUT FREQUENCY (Hz)

fC = 1kHz

1.97

1.99

1.98

2.01

2.00

2.02

2.03

-40

20

40

-20

0

60

80

100

SUPPLY CURRENT

vs. TEMPERATURE

TEMPERATURE (°C)

NO LOAD

MAX7401

MAX7405

10,000

0.1

0.01

0.1

1

10

100

1000

INTERNAL OSCILLATOR FREQUENCY

vs. COSC CAPACITANCE

1

COSC CAPACITANCE (nF)

10

100

1000

-20

-15

-10

-5

0

5

10

15

20

2.5

3.5

3.0

4.0

4.5

5.0

5.5

OFFSET VOLTAGE

vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

MAX7401

VIN = VCOM = VDD / 2

MAX7405

0.80

0.85

0.90

0.95

1.00

1.05

1.10

1.15

1.20

2.5

3.5

3.0

4.0

4.5

5.0

5.5

NORMALIZED OSCILLATOR FREQUENCY

vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

COSC = 390pF

MAX7401

MAX7405

-400

-300

-350

-250

-100

-50

-150

-200

0

0

400

800

1200

1600

2000

PHASE RESPONSE

INPUT FREQUENCY (Hz)

fC = 1kHz

1.5

1.8

1.7

1.6

1.9

2.0

2.1

2.2

2.3

2.4

2.5

2.5

3.5

3.0

4.0

4.5

5.0

5.5

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

NO LOAD

MAX7405

MAX7401

-1.5

-1.0

0

-0.5

0.5

1.0

-40

0

-20

20

40

60

80

100

OFFSET VOLTAGE vs. TEMPERATURE

TEMPERATURE (°C)

VIN = VCOM = VDD / 2

Typical Operating Characteristics

(VDD = +5V for MAX7401, VDD = +3V for MAX7405; fCLK = 100kHz; SHDN = VDD; VCOM = VOS = VDD / 2; TA = +25°C; unless otherwise

noted.)