Datasheet

LM63
www.ti.com SNAS190E –SEPTEMBER 2002–REVISED MAY 2013
Table 7. Tachometer Count And Limit Registers
ADDRESS READ/ POR
BITS NAME DESCRIPTION
HEX WRITE VALUE
47
HEX
TACHOMETER COUNT (MSB) and 46
HEX
TACHOMETER COUNT (LSB) REGISTERS (16 bits: Read LSB first to lock MSB and
ensure MSB and LSB are from the same reading)
Tachometer
These registers contain the current 16-bit Tachometer
47 Read Only 7:0 N/A
Count (MSB)
Count, representing the period of time between tach pulses.
Note that the 16-bit tachometer MSB and LSB are reversed
Tachometer
Read Only 7:2 N/A
from the 16-bit temperature readings.
Count (LSB)
Bits Edges Used Tach_Count_Multiple
00: Reserved - do not use
01: 2 4
Tachometer
10: 3 2
46 Read Only 1:0 00
Edge Count
11: 5 1
Note: If PWM_Clock_Select = 360 kHz, then
Tach_Count_Multiple = 1 regardless of the setting of these
bits.
49
HEX
TACHOMETER LIMIT (MSB) and 48
HEX
TACHOMETER LIMIT (LSB) REGISTERS
Tachometer These registers contain the current 16-bit Tachometer
49 R/W 7:0 0xFF
Limit MSB) Count, representing the period of time between tach pulses.
Fan RPM = (f * 5,400,000) / (Tachometer Count), where f =
1 for 2 pulses/rev fan; f = 2 for 1 pulse/rev fan; and f = 2/3
for 3 pulses/rev fan. See the APPLICATION NOTES section
Tachometer
R/W 7:2 0xFF
at the end of this datasheet for more tachometer
Limit (LSB)
48
information. Note that the 16-bit tachometer MSB and LSB
are reversed from the 16 bit temperature readings.
R/W 1:0 [Reserved] Not Used.
Table 8. Local Temperature And Local High Setpoint Registers
ADDRESS READ/ POR
BITS NAME DESCRIPTION
HEX WRITE VALUE
00
HEX
LOCAL TEMPERATURE REGISTER (8-bits)
Local Temperature
00 Read Only 7:0 N/A 8-bit integer representing the temperature of the LM63 die.
Reading (8-bit)
05 (0B)
HEX
LOCAL HIGH SETPOINT REGISTER (8-bits)
05 R/W 7:0 0x46 (70°) Local HIGH Setpoint High Setpoint for the internal diode.
Copyright © 2002–2013, Texas Instruments Incorporated Submit Documentation Feedback 25
Product Folder Links: LM63