MAX6650 Maxim, MAX6650 Datasheet - Page 6

• Manufacturer Part Number: MAX6650
• Description: Fan-Speed Regulators and Monitors with SMBus/I2C-Compatible Interface
• Manufacturer: Maxim

Fan-Speed Regulators and Monitors
with SMBus/I
Figure 1. Block Diagram
The MAX6650/MAX6651 employ three standard SMBus
protocols: write byte, read byte, and receive byte
(Figure
transfers, provided that the correct data register was
previously selected by a write or read byte instruction.
Use caution with the shorter protocol in multimaster
systems, since a second master could overwrite the
command byte without informing the first master.
The device address can be set to one of four different
values. Accomplish this by pin-strapping ADD so that
more than one MAX6650/MAX6651 can reside on the
same bus without address conflicts (Table 1).
6
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INTERFACE
SMBus/I
3V TO 5.5V
2). The shorter protocol (receive) allows quicker
10kΩ
V
2
CC
C
V
SCL
SDA
ADD
GND
CC
ALARM ENABLE
ALARM STATUS
ADDRESS
DECODE
TACH COUNT
GPIO STATUS
COUNT TIME
CONFIGURE
SMBus/I
INTERFACE
FAN SPEED
GPIO DEF
DAC
2
2
C
C-Compatible Interface
Slave Addresses
MAX6650
MAX6651
TACHOMETER
CONTROL
COUNT
LOGIC
8-BIT
DAC
V
REF
10kΩ
Table 1. Slave Address Decoding (ADD)
V
OFFSET
90kΩ
10kΩ
No connection (high-Z)
10kΩ resistor to GND
90kΩ
GND
ADD
V
CC
(FIGURE 5)
BLOCKS
GPIO
TACH0
GPIO0
GPIO1
OUT
FB
V
FAN
FULL ON
ALERT
= 5V OR 12V
ADDRESS
1001 000
1001 011
0011 011
0011 111
BINARY
FAN