Datasheet

LM87
SNAS034J –APRIL 2000–REVISED MARCH 2013 www.ti.com
DC Electrical Characteristics (continued)
The following specifications apply for +2.8 V
DC
≤ V
+
≤ +3.8 V
DC
, Analog voltage inputs R
S
= 510 Ω, unless otherwise specified.
Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
= 25 °C.
(1)
Typical Limits Units
Symbol Parameter Conditions
(2) (3)
(Limits)
FAN RPM-TO-DIGITAL CONVERTER
+25 °C ≤ T
A
≤ +75 °C ±10 % (max)
Fan RPM Error −10 °C ≤ T
A
≤ +100 °C ±15 % (max)
−40 °C ≤ T
A
≤ +125 °C ±20 % (max)
Full-scale Count 255 (max)
Divisor = 1, Fan Count = 153 8800 RPM
(9)
Divisor = 2, Fan Count = 153 4400 RPM
(9)
FAN1 and FAN2 Nominal Input
RPM (See FAN INPUTS)
Divisor = 3, Fan Count = 153 2200 RPM
(9)
Divisor = 4, Fan Count = 153 1100 RPM
(9)
DIGITAL OUTPUTS (NTEST_OUT)
I
OUT
= ±3.0 mA at 2.4 V (min)
V
OUT(1)
Logical “1” Output Voltage
V
+
= +2.8 V
I
OUT
= ±3.0 mA at 0.4 V (max)
V
OUT(0)
Logical “0” Output Voltage
V
+
= +3.8 V
OPEN- DRAIN DIGITAL OUTPUTS (SMBData, RESET#, CI, INT#, THERM#)
V
OUT(0)
Logical “0” Output Voltage (SMBData) I
OUT
= −755 μA 0.4 V (min)
V
OUT(0)
Logical “0” Output Voltage (Others) I
OUT
= −3 mA 0.4 V (min)
I
OH
High Level Output Current V
OUT
= V
+
5 12 μA (max)
RESET# and Chassis Intrusion 45 20 ms (min)
Pulse Width
DIGITAL INPUTS: VID0–VID4, NTEST_IN, ADD/NTEST_OUT, Chassis Intrusion (CI)
V
IN(1)
Logical “1” Input Voltage 2.0 V (min)
V
IN(0)
Logical “0” Input Voltage 0.8 V (max)
SMBus DIGITAL INPUTS (SMBCLK, SMBData)
V
IN(1)
Logical “1” Input Voltage 2.1 V (min)
V
IN(0)
Logical “0” Input Voltage 0.8 V (max)
V
HYST
Input Hysteresis Voltage 243 mV
Tach Pulse Logic Inputs (FAN1, FAN2)
V
IN(1)
Logical “1” Input Voltage 0.7 × V
+
V (min)
V
IN(0)
Logical “0” Input Voltage 0.3 × V
+
V (max)
ALL DIGITAL INPUTS
I
IN(1)
Logical “1” Input Current V
IN
= V
+
−12 μA (min)
I
IN(0)
Logical “0” Input Current V
IN
= 0 V
DC
12 μA (max)
C
IN
Digital Input Capacitance 20 pF
(9) The total fan count is based on 2 pulses per revolution of the fan tachometer output.
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