LM78 National Semiconductor, LM78 Datasheet - Page 6

• Manufacturer Part Number: LM78
• Description: Microprocessor System Hardware Monitor
• Manufacturer: National Semiconductor

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Symbol
FAN RPM-TO-DIGITAL CONVERTER
DIGITAL OUTPUTS (Power Switch Bypass, NTEST, NMI/IRQ)
V
V
ISA D0–D7 DIGITAL OUTPUTS
V
V
I
OPEN DRAIN DIGITAL OUTPUTS (SDA, RESET, SMI, Chassis Intrusion)
V
I
DIGITAL INPUTS: SMI__IN, VID0–VID3, BTI, CS, A0, A1, A2, Mode Control and Interface Inputs (IORD, IOWR, SYSCLK),
Data Lines (D0–D7), Chassis Intrusion, and Tach Pulse Logic Inputs (FAN1, FAN2, FAN3)
V
V
SERIAL BUS DIGITAL INPUTS (SCL, SDA)
V
V
ALL DIGITAL INPUTS EXCEPT FOR BTI
I
I
C
BIT DIGITAL INPUT
I
I
C
OUT
OH
IN(1)
IN(0)
IN(1)
IN(0)
The following specifications apply for +4.25 V
fied. Boldface limits apply for T
OUT(1)
OUT(0)
OUT(1)
OUT(0)
OUT(0)
IN(1)
IN(0)
IN(1)
IN(0)
DC Electrical Characteristics
IN
IN
FAN1 and FAN2 Nominal Input
RPM (See Section 6.0)
FAN3 Design Nominal Input RPM
Internal Clock Frequency
Logical “1” Output Voltage
Logical “0” Output Voltage
Logical “1” Output Voltage
Logical “0” Output Voltage
TRI-STATE
Logical “0” Output Voltage
High Level Output Current
RESET and Chassis Intrusion
Pulse Width
Logical “1” Input Voltage
Logical “0” Input Voltage
Logical “1” Input Voltage
Logical “0” Input Voltage
Logical “1” Input Current
Logical “0” Input Current
Digital Input Capacitance
Logical “1” Input Current
Logical “0” Input Current
Digital Input Capacitance
®
Output Current
Parameter
A
= T
J
= T
MIN
DC
(Note 7) (Continued)
to T
V
CC
MAX
; all other limits T
+5.75 V
Divisor = 1, Fan Count = 153
(Note 12)
Divisor = 2, Fan Count = 153
(Note 12)
Divisor = 3, Fan Count = 153
(Note 12)
Divisor = 4, Fan Count = 153
(Note 12)
Fan Count = 153 (Note 12)
+25˚C
−10˚C
I
I
I
I
V
V
I
V
V
V
V
V
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
IN
IN
IN
IN
= V
= 0 V
= V
= 0 V
=
=
=
=
= −5.0 mA
6
= 0 V
= V
= V
DC
±
±
±
±
CC
CC
T
T
5.0 mA
5.0 mA
12.0 mA
12.0 mA
Conditions
CC
CC
DC
DC
, f
A
A
DC
SYSCLK
+75˚C
+100˚C
A
= T
= 8.33 MHz, R
J
= 25˚C.
S
(Note 8)
Typical
−0.005
−0.005
0.005
0.005
= 25 , unless otherwise speci-
8800
4400
2200
1100
4400
−500
22.5
22.5
0.1
45
20
20
1
0.7 x V
0.3 x V
(Note 9)
Limits
−2000
20.2
24.8
19.1
25.9
100
2.4
0.4
2.4
0.4
0.4
2.0
0.8
−1
20
−1
10
1
1
CC
CC
kHz (max)
kHz (max)
kHz (min)
kHz (min)
µA (max)
µA (max)
µA (max)
µA (max)
µA (max)
µA (min)
ms (min)
µA (min)
(Limits)
V (max)
V (max)
V (max)
V (max)
V (min)
V (min)
V (min)
V (min)
V (min)
Units
RPM
RPM
RPM
RPM
RPM
pF
pF