MAX6651EEE Maxim Integrated Products, MAX6651EEE Datasheet - Page 9

• Manufacturer Part Number: MAX6651EEE
• Description: IC REG/MONITOR FAN-SPEED 16-QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6651EEE

• Applications: Fan Controller, Brushless (BLDC)
• Number Of Outputs: 1
• Voltage - Load: 0.3 V ~ 5.2 V
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Operating Supply Voltage: 3 V to 5.5 V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: Q1113225

tor that overrides the internal oscillator (see General-
Purpose Input/Output ). When using an external oscillator
(f
equal to f
allowed, but will not significantly decrease the frequency.
The Configuration-Byte Register (Table 4) adjusts the
prescaler, changes the tachometer threshold voltage,
and sets the mode of operation. The three least-signifi-
cant bits configure the prescaler division used to scale
the tachometer period. Select the prescaler value so the
Table 2. Command-Byte Assignments
* The minimum allowed tachometer period is 1ms.
Table 3. Fan Speed
OSC
ALARM ENABLE
REGISTER
GPIO STAT
), calculate the Fan-Speed Register value with f
GPIO DEF
CONFIG
COUNT
ALARM
TACH0
TACH1
TACH2
TACH3
SPEED
DAC
0000 0000
0000 0001
0000 0010
0001 1110
0001 1111
0010 0000
0100 0000
1111 1000
K
OSC
TACH
—
—
—
. Codes above F8h (1111 1000) are
_______________________________________________________________________________________
Configuration-Byte Register
COMMAND
0000 0000
0000 0010
0000 0100
0000 0110
0000 1000
0000 1010
0000 1100
0000 1110
0001 0000
0001 0010
0001 0100
0001 0110
with SMBus/I
Fan-Speed Regulators and Monitors
125
1.0
1.0
1.5
—
—
—
16
16
17
33
1
K
SCALE
t
TACH
—
3.9
4.0
4.2
—
8.2
—
31
4
*
*
*
(ms)
READ
x
x
x
x
x
x
x
x
x
x
x
x
16
—
1.0
1.0
—
2.1
—
7.8
*
*
*
*
CLK
WRITE
—
—
—
—
—
—
2
x
x
x
x
x
x
15.3
500
500
330
C-Compatible Interface
32
31
30
—
—
—
fan’s full speed is achieved with a register value of
approximately 64 (0100 0000) to optimize speed range
and resolution (see the Fan Speed Register section). The
fourth bit selects the fan operating voltage.
The fifth and sixth bits configure the operating mode.
The MAX6650/MAX6651 have four modes of operation:
full-on, full-off (shutdown), closed-loop, and open-loop.
In closed-loop operation, the external microcontroller
(µC) sets the desired speed by writing an 8-bit word to
the Fan-Speed Register (see the Fan-Speed Register
section). The MAX6650/MAX6651 monitor the fan’s
tachometer output and automatically adjust the voltage
1
4
FAN SPEED (RPS)
POR (DEFAULT)
K
SCALE
128
124
120
61.1
15.9
—
—
—
4
*
*
*
STATE
0Ah
00h
FFh
00h
00h
00h
00h
00h
00h
00h
1Fh
02h
500
480
240
16
—
—
—
64
*
*
*
*
Fan speed
Configuration
GPIO definition
DAC
Alarm enable
Alarm status
Tachometer 0 count
Tachometer 1 count
Tachometer 2 count
Tachometer 3 count
GPIO status
Tachometer count time
30,000
30,000
20,000
1900
1900
1800
910
240
—
—
—
1
FAN SPEED (RPM)
FUNCTION
K
7700
7400
7200
3700
SCALE
960
—
—
—
4
*
*
*
30,000
29,000
15,000
3830
16
—
—
—
*
*
*
*
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