Variable Reluctance Sensor Interfaces with

Differential Input and Adaptive Peak Threshold

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3

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

INPUT DIFFERENTIAL AMPLIFIER (MAX9924/MAX9926)

Input Voltage Range

IN+, IN-

Guaranteed by CMRR

-0.3

0.3

V

MAX9924 (Note 5)

60

87

Differential Amplifier

Common-Mode Rejection Ratio

CMRR

MAX9926 (Note 5)

55

78

dB

Input Resistance

(Note 5)

65

100

135

k

Ω

ADAPTIVE PEAK DETECTION

MAX9924/MAX9925

-6.5

0

+6.5

Zero-Crossing Threshold

Mode B

operation

(Notes 5, 6)

MAX9926/MAX9927

-6.5

0

+10

mV

Adaptive peak threshold

33

%PK

Minimum threshold of hysteresis

comparator MAX9924/MAX9926

(Notes 5, 6)

415

30

Minimum threshold of hysteresis

comparator MAX9925/MAX9927

(Notes 5, 6)

20

30

50

MAX9924 (Notes 5, 6)

715

26

MAX9926 (Notes 5, 6)

215

30

Fixed and Adaptive Peak

Threshold

MAX9925/MAX9927 (Notes 5, 6)

19

30

50

mV

Watchdog Timeout for Adaptive

Peak Threshold

Timing window to reset the adaptive

peak threshold if not triggered (input

level below threshold)

45

85

140

ms

ENTIRE SYSTEM

Comparator Output Low Voltage

0.2

V

Overdrive = 2V to 3V, zero-crossing

50

Propagation Delay

Overdrive = 2V to 3V, adaptive peak

150

ns

COUT Transition Time

2ns

Propagation Delay Jitter

Includes noise of differential amplifier

and comparator, f = 10kHz,

20

ns

ELECTRICAL CHARACTERISTICS (continued)