MAX6639(2005) View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX6639
(Rev.:2005)

2-Channel Temperature Monitor with Dual, Automatic, PWM Fan-Speed Controller

Maxim Integrated 

2-Channel Temperature Monitor with Dual,

Automatic, PWM Fan-Speed Controller

A

B

C

D

EF

G

tLOW tHIGH

SCL

H

IJK

LM

SDA

tSU:STA tHD:STA

tSU:DAT

A = START CONDITION

B = MSB OF ADDRESS CLOCKED INTO SLAVE

C = LSB OF ADDRESS CLOCKED INTO SLAVE

D = R/W BIT CLOCKED INTO SLAVE

E = SLAVE PULLS SMBDATA LINE LOW

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO SLAVE

H = LSB OF DATA CLOCKED INTO SLAVE

Figure 2. SMBus Write Timing Diagram

tSU:STO tBUF

I = MASTER PULLS DATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO SLAVE

K = ACKNOWLEDGE CLOCK PULSE

L = STOP CONDITION

M = NEW START CONDITION

A

B

C

D

EF

G

tLOW tHIGH

SCL

H

I JK

LM

SDA

tSU:STA tHD:STA

A = START CONDITION

B = MSB OF ADDRESS CLOCKED INTO SLAVE

C = LSB OF ADDRESS CLOCKED INTO SLAVE

D = R/W BIT CLOCKED INTO SLAVE

E = SLAVE PULLS SMBDATA LINE LOW

tSU:DAT

tHD:DAT

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO MASTER

H = LSB OF DATA CLOCKED INTO MASTER

I = MASTER PULLS DATA LINE LOW

tSU:STO tBUF

J = ACKNOWLEDGE CLOCKED INTO SLAVE

K = ACKNOWLEDGE CLOCK PULSE

L = STOP CONDITION

M = NEW START CONDITION

Figure 3. SMBus Read Timing Diagram

SMBus Digital Interface

From a software perspective, the MAX6639 appears as

a set of byte-wide registers. This device uses a stan-

dard SMBus 2-wire/I2C*-compatible serial interface to

access the internal registers.

The MAX6639 features an address select input (ADD)

that allows the MAX6639 to have three unique addresses

(see Table 1).

The MAX6639 employs four standard SMBus protocols:

write byte, read byte, send byte, and receive byte

(Figures 1, 2, and 3). The shorter receive byte protocol

allows quicker transfers, provided that the correct data

register was previously selected by a read byte instruc-

tion. Use caution with the shorter protocols in multimas-

*Purchase of I2C components from Maxim Integrated Products,

Inc., or one of its sublicensed Associated Companies, conveys

a license under the Philips I2C Patent Rights to use these com-

ponents in an I2C system, provided that the system conforms to

the I2C Standard Specification as defined by Philips.

Table 1. I2C Slave Address

ADD INPUT STATE I2C SLAVE ADDRESS

BINARY

EQUIVALENT

VCC

Floating

5Eh

0101 111

5Ch

0101 110

GND

58h

0101 100

ter systems, since a second master could overwrite the

command byte without informing the first master.

Table 4 details the register addresses and functions,

whether they can be read or written to, and the power-

on reset (POR) state. See Tables 5–9 for all other regis-

ter functions and the Register Descriptions section.

Temperature Reading

Temperature data can be read from registers 00h and

01h. The temperature data format for these registers is

8 bits, with the LSB representing 1°C (Table 2) and the

MSB representing +128°C. The MSB is transmitted first.

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