MAX6620_14 Datasheet, PDF (16/30 Pages) Maxim Integrated Products – Quad Linear Fan-Speed Controller

MAX6620
Quad Linear Fan-Speed Controller
BIT
R/W
Run:
7
R/W
0 = run
1 = standby
Register Descriptions
Global Configuration Register (00h)—POR = 0000 0XXX
FUNCTION
POR:
6
R/W
0 = normal operation
1 = reset all registers to POR values
This bit automatically resets itself and will always return a 0 when read.
I²C Bus Timeout:
5
R/W
0 = enabled
1 = disabled
The I²C interface will reset if SDA is low for more than 35ms.
Fans to 100% on failure:
4
R/W
0 = if a fan failure is detected, all other fan channels immediately go to full-scale drive voltage to
ensure adequate cooling
1 = disabled
Oscillator Selection:
Selects on-chip oscillator or 32.768kHz crystal/ceramic resonator. Use crystal if 1% RPM accuracy is
required.
3
R/W
0 = internal oscillator (default at power-on)
1 = external 32.768kHz crystal
When switching from the internal oscillator to an external crystal, the MAX6620 operates from the internal
oscillator until the crystal oscillator has started up. If the crystal is damaged or the oscillator fails to start,
the MAX6620 will continue to operate from the internal oscillator.
16
Maxim Integrated