Resetting Alarm

Reset alarms by writing to monitor-setup data. See the

Configuring Monitor Mode section and Table 10.

SMBus Alert

The SMBus-alert feature provides a quick method to

identify alarming devices on a shared interrupt. Upon

receiving an interrupt signal, the host µC can broadcast

a receive byte request to the alert-response slave

address (0001100). Any slave device that generated an

interrupt attempts to identify itself by putting its own

address on the bus. The alert response can activate

several different slave devices simultaneously. If more

than one slave attempts to respond, bus arbitration

rules apply, and the device with the lower address wins

as a consequence of the open-collector bus. The losing

device does not generate an acknowledgement and

continues to hold the alert line low until serviced.

Successful reading of the alert response address de-

asserts INT.

The MAX1361/MAX1362 resume monitoring after clean-

ing an alarm-status register. INT may immediately re-

assert if a fault is still present, or if the alarm register

has not been thoroughly cleared.

Transfer Functions

Output data coding for the MAX1361/MAX1362 is bina-

ry in unipolar mode and two’s complement in bipolar

bits. Code transitions occur halfway between succes-

sive-integer LSB values. Figures 14 and 15 show the

transfer functions for unipolar and bipolar operations,

respectively.

Layout, Grounding, and Bypassing

Only use PC boards. Wire-wrap configurations are not

recommended since the layout should ensure proper

separation of analog and digital traces. Do not run ana-

log and digital lines parallel to each other, and do not

layout digital signal paths underneath the ADC pack-

age. Use separate analog and digital PC board ground

sections with only one star point (Figure 16).

influence the proper operation of the ADC’s fast com-

of two parallel capacitors, 0.1µF and 4.7µF, located as

close as possible to the MAX1361/MAX1362 power sup-

ply. Minimize capacitor lead length for best supply noise

rejection. For extremely noisy supplies, add an attenua-

tion resistor (5

Ω) in series with the power supply.

Definitions

Integral Nonlinearity

Integral nonlinearity (INL) is the deviation of the values

on an actual transfer function from a straight line. This

straight line can be either a best straight-line fit or a line

drawn between the endpoints of the transfer function,

once offset and gain errors have been nullified. The

4-Channel, 10-Bit, System Monitor with Programmable

Trip Window and SMBus Alert Response

______________________________________________________________________________________

21

111...111

OUTPUT CODE

FS = REF + GND

ZS = GND

FULL-SCALE

TRANSITION

111...110

100...010

100...001

100...000

011...111

011...110

011...101

000...001

000...000

0

1

512

INPUT VOLTAGE (LSB)

(GND)

1 LSB =

1024

FS - 0.5 LSB

Figure 14. Unipolar Transfer Function

011...111

OUTPUT CODE

ZS = AIN-

011...110

000...010

000...001

000...000

111...111

111...110

111...101

100...001

100...000

AIN-

INPUT VOLTAGE (LSB)

+FS - 1 LSB

1 LSB =

1024

AIN-

≥

2

FS =

+ AIN-

2

-FS =

+ AIN-

2

-FS + 0.5 LSB

Figure 15. Bipolar Transfer Function