UCD9240

Digital Point of Load System Controller

SLUS766 – APRIL 2007

8

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the external NPN connected to a pull up resistor and the VD33FB pin. The NPN emitter becomes the 3.3 V

supply for the chip and should be bypassed to ground with 4 to 5 uF.

Analog Inputs/Outputs

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Vsense Differential

Voltage Range

0.0

0.8

1.6

V

EAPn, EANn

Maximum Vsense

excursion

-0.3

2.0

V

Small Signal Error voltage

resolution

during start/stop ramp

during run mode

4.0

1.0

mV

mV

EAP-EAN

Error Voltage Accuracy

“DAC commanded to be 1V”

.99

1

1.01

V

Input impedance

ground reference

TBD

ohm

Input capacitance

differential

TBD

pF

Bias current

PMBus Addr pins

9

11

uA

PMBus Address

programming bins

See Table 2

0.141

2.50

uA

voltage range for current

sense input

0

2.5

V

Vtemp

input voltage range

0

2.5

V

CS1-A, CS2-A,

CS3-A, CS4-A

Analog Overcurrent

Threshold

2.0

V

2

Current Sense Input

capacitance

5

10

pF

ADCRefIn

External Reference

(80-pin package)

(Not currently supported in the Firmware!)

1.8

V33A

V

Timing

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Retention of configuration

parameters

100

Years

Pulse length needed at

Reset

2

µS

Fault Detection Latency

time to disable PWM

output

High level on FAULT pin

20

nS

t(CLF)

time to disable PWM

output

Step change in CS voltage from 1.0V to

2.5V

20

nS

t(OC)

time to disable PWM

output due to overcurrrent

detection on average KKK

Step change in CS voltage from 50% of

PMBus programmed over-current threshold

to 150% of threshold

800

uS

2

Not production tested. Limits verified by design.