SA56004X Datasheet, PDF (20/36 Pages) NXP Semiconductors – 1 Degrees Celcious accurate, SMBus-compatible, 8-pin, remote/local digital temperature sensor with over temperature alarms

NXP Semiconductors
SA56004X
Digital temperature sensor with overtemperature alarms
7.10.1 Serial interface reset
If the SMBus master attempts to reset the SA56004X while the SA56004X is controlling
the data line and transmitting on the data line, the SA56004X must be returned to a known
state in the communication protocol. This may be accomplished in two ways:
1. When the SDATA is LOW, the SA56004X SMBus state machine resets to the SMBus
idle state if SCLK is held LOW for more than 35 ms (maximum TIMEOUT period).
According to SMBus specification 2.0, all devices are required to time-out when the
SCLK line is held LOW for 25 ms to 35 ms. Therefore, to insure a time-out of all
devices on the bus, the SCLK line must be held LOW for at least 35 ms.
2. When the SDATA is HIGH, the master initiates an SMBus START. The SA56004X will
respond properly to a SMBus START condition only during the data retrieving cycle.
After the START, the SA56004X will expect an SMBus Address byte.
8. Simplified system diagram
shielded twisted pair
remote sensor
2N3904 (NPN), 2N3906 (PNP),
or similar standalone, ASIC or
microprocessor thermal diode
+5 V
V_DD
100 nF
2.2 nF(1)
V_DD
R
10 kΩ
1 _VDD
R
10 kΩ
SCLK ⁸
SA56004X
2 _D+
SDATA ⁷
3 _D−
ALERT ⁶
4 _{T_CRIT}
GND ⁵
R
10 kΩ
R
10 kΩ
CLOCK ^VDD
SMBus
CONTROLLER
DATA
INT
FAN CONTROL
CIRCUIT
(1) Typical value; placed close to temperature sensor.
Fig 10. Simplified system diagram
002aad201
SA56004X_5
Product data sheet
Rev. 05 — 22 May 2008
© NXP B.V. 2008. All rights reserved.
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