Fan Control Device with High Frequency PWM and Temperature Monitors
Datasheet
Table 6.1 AVG[2:0] Bit Decoder
MEASUREMENTS PER READING
SFTR[7:5]
AVG1
REMOTE
DIODE 1
REMOTE
DIODE 2
INTERNAL
DIODE
ALL VOLTAGE READINGS
AVG2
AVG0
(VCCP, AND VCC)
0
0
0
1
0
0
1
X
0
1
128
16
128
16
8
1
8
1
X
X
16
16
16
32
16
32
32
32
Note: The default for the AVG[2:0] bits is ‘010’b.
To calculate conversion cycle timing for a given averaging mode:
Compute total number of temperature conversions (TEMP_CONV)
Compute total number of voltage conversions (VOLT_CONV)
Calculate Time to complete all conversions is:
Total Conversion Time = (TEMP_CONV)*96/(45kHz +/-10%)+ (VOLT_CONV)*68/(45kHz +/-10%)
Example: To calculate the nominal conversion time FOR AVG[2:0] = 001b.
Total Conversion Time = (TEMP_CONV)*96/(45kHz)+ (VOLT_CONV)*68/(45kHz)
Total Conversion Time = (16+16+1)*96/(45kHz)+ (2*1)*68/(45kHz)
Total Conversion Time = (33)*2.133ms+ (2)*1.511ms = ~73ms
Table 6.2 illustrates the min., nom., and max. conversion cycle timing for each of the four averaging
modes.
Table 6.2 Conversion Cycle Timing
CONVERSION CYCLE TIME (MSEC)
TOTAL
TEMPERATURE
CONVERSIONS
TOTAL
VOLTAGE
CONVERSIONS
AVG[2:0]
MIN.
NOM.
MAX.
000
001
(2x128)+(1x8)=264
(2x16)+(1x1)=33
3x16=48
2x8=16
2x1=2
536
67
587
73
652
82
01X (default)
1XX
2x16=32
2x32=64
191
382
210
420
233
466
3x32=96
Note 6.1 The hardware monitor conversion clock is 45KHz ± 10%.
Note 6.2 Temperature conversions take 96 clocks, each (2.133ms nom.); Voltage conversions take
68 clocks, each (1.511ms nom).
SMSC EMC2300
Revision 0.2 (06-14-06)
DATA2S1HEET
SMSC [ SMSC CORPORATION ]
