UCD9240

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

TEST CONDITIONS

MIN

NOM

MAX

UNIT

DIGITAL INPUTS/OUTPUTS

Dgnd

Low-level output voltage

V

+0.25

High-level output voltage

V

-0.6V

High-level input voltage

2.1

V

Low-level input voltage

1.1

V

FAN CONTROL INPUTS/OUTPUTS

FAN-PWM period

156

kHz

FAN-PWM duty cycle range

0%

100%

Duty cycle resolution

1%

For 1 Tach pulse per revolution. At 2,

FAN-TACH range

30

300k

RPM

3, or 4 pulse/rev, divide by that value

FAN-TACH resolution

For 1 Tach pulse per revolution

30

RPM

FAN-TACH minimum pulse width

Either positive or negative polarity

150

µs

SYSTEM PERFORMANCE

Setpoint Reference Accuracy

-10

10

mV

AFEgain = 4, 1V input to EAP/N

Setpoint Reference Accuracy over

-40 °C to 125 °C

-20

20

mV

temeprature

AFEgain = 4 compared to

Differential offset between gain

-4

4

mV

setetings

AFEgain = 1, 2, or 8

ns

Switching Frequency

15.260

2000

kHz

Duty

Max and Min Duty Cycle

Configured via PMBus

0%

100%

0.25

V/ms

Retention of configuration parameters

100

Years

Number of nonvolatile erase/write

Write_Cycles

20

K cycles

cycles

(2)

specified.

(3)

voltage drop specified.

(4)

With default device caliibration. PMBus calibration can be used to improve the regulation tolerance.

(5)

Time from close of error ADC sample window to time when digitally calculated control effort (duty cycle) is available. This delay must be

accounted for when calculating the system dynamic response.

(6)

The PMBus command: EADC_SAMPLE_TRIGGER defines the start of the 32ns ADC sample window. So the minimum

EAD_SAMPLE_TRIGGER time is 208 + 32 = 240 ns.

4

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