ADM1031

http://onsemi.com

4

Parameter

Unit

Max

Typ

Min

Test Conditions/Comments

OPEN−DRAIN SERIAL DATA BUS OUTPUT (SDA)

0.4

V

0.1

1.0

mA

SERIAL BUS DIGITAL INPUTS (SCL, SDA)

2.1

V

0.8

V

Hysteresis

500

mV

DIGITAL INPUT LOGIC LEVELS (Note 2) (ADD, THERM, TACH1/2)

2.1

V

0.8

V

DIGITAL INPUT LEAKAGE CURRENT

–1.0

mA

1.0

mA

5.0

pF

FAN RPM−TO−DIGITAL CONVERTER

Accuracy

±6.0

%

Full−Scale Count

255

TACH Nominal Input RPM

Divisor N = 1, Fan Count = 153

Divisor N = 2, Fan Count = 153

Divisor N = 4, Fan Count = 153

Divisor N = 8, Fan Count = 153

4400

2200

1100

550

RPM

Conversion Cycle Time

637

ms

SERIAL BUS TIMING (Note 3)

See Figure 2

10

100

kHz

See Figure 2

50

ns

See Figure 2

4.7

ms

See Figure 2

4.7

ms

See Figure 2

4.0

ms

See Figure 2

4.0

ms

See Figure 2

1.3

ms

See Figure 2

4.0

50

ms

See Figure 2

1000

ns

See Figure 2

300

ns

See Figure 2

250

ns

See Figure 2

300

ns

2. ADD is a three−state input that can be pulled high, low, or left open−circuit.

Figure 2. Diagram for Serial Bus Timing

P

S

SCL

PS

SDA