Detailed Description

The MAX6602 is a precision multichannel temperature

monitor that features one local and four remote temper-

ature-sensing channels with a programmable alert

threshold for each temperature channel and a program-

mable overtemperature threshold for channels 1 and 4

(see Figure 1). Communication with the MAX6602 is

achieved through the SMBus serial interface and a

dedicated alert output. The alarm outputs, OVERT and

ALERT, assert if the software-programmed temperature

thresholds are exceeded. ALERT typically serves as an

interrupt, while OVERT can be connected to a fan, sys-

tem shutdown, or other thermal-management circuitry.

ADC Conversion Sequence

In the default conversion mode, the MAX6602 starts the

conversion sequence by measuring the temperature on

channel 1, followed by 2, 3, local channel, and 4. The

conversion result for each active channel is stored in

the corresponding temperature data register.

In some systems, one of the remote thermal diodes may

be monitoring a location that experiences temperature

changes that occur much more rapidly than in the other

channels. If faster temperature changes must be moni-

tored in one of the temperature channels, the MAX6602

allows channel 1 to be monitored at a faster rate than

the other channels. In this mode (set by writing a 1 to

bit 4 of the configuration 1 register), measurements of

channel 1 alternate with measurements of the other

channels. The sequence becomes channel 1, channel

2, channel 1, channel 3, channel 1, etc. Note that the

time required to measure all five channels is consider-

ably greater in this mode than in the default mode.

Low-Power Standby Mode

Enter software standby mode by setting the STOP bit to

1 in the configuration 1 register. Enter hardware stand-

by by pulling STBY low. Software standby mode dis-

ables the ADC and reduces the supply current to

approximately 30µA. Hardware standby mode halts the

ADC clock, but the supply current is approximately

350µA. During either software or hardware standby,

data is retained in memory. During hardware standby,

the SMBus interface is inactive. During software stand-

by, the SMBus interface is active and listening for

SMBus commands. The timeout is enabled if a start

condition is recognized on SMBus. Activity on the

SMBus causes the supply current to increase. If a

standby command is received while a conversion is in

progress, the conversion cycle is interrupted, and the

temperature registers are not updated. The previous

data is not changed and remains available.

Five-Channel Precision Temperature Monitor

6

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PIN

NAME

FUNCTION

7

DXP4

Combined Current Source and A/D Positive Input for Channel 4 Remote Diode. Connect to the anode

remote diode is used. Place a 2200pF capacitor between DXP4 and DXN4 for noise filtering.

8

DXN4

Cathode Input for Channel 4 Remote Diode. Connect the cathode of the channel 4 remote-diode-

connected transistor to DXN4.

9

STBY

Standby Input. Drive STBY logic-low to place the MAX6602 in hardware standby mode, or logic-high

for normal operation. Temperature and threshold data are retained in standby mode.

10

N.C.

No Connection. Must be connected to ground.

11

OVERT

Overtemperature Active-Low, Open-Drain Output. OVERT asserts low when the temperature of

channels 1 and 4 exceed the programmed threshold limit.

12

Supply Voltage Input. Bypass to GND with a 0.1µF capacitor.

13

ALERT

SMBus Alert (Interrupt), Active-Low, Open-Drain Output. ALERT asserts low when the temperature of

any channel exceeds the programmed ALERT threshold.

14

SMBDATA

SMBus Serial-Data Input/Output. Connect to a pullup resistor.

15

SMBCLK

SMBus Serial-Clock Input. Connect to a pullup resistor.

16

GND

Ground

Pin Description (continued)