ADM1034ARQZ-REEL(2012) Ver la hoja de datos (PDF) - ON Semiconductor
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ADM1034ARQZ-REEL Datasheet PDF : 38 Pages
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ADM1034
TYPICAL PERFORMANCE CHARACTERISTICS (Cont’d)
1200
1000
800
600
DEV 31
400
DEV 33
200
DEV 32
0
0.01
0.1
1
10
100
CONVERSION RATE (Hz)
Figure 13. Supply Current vs. Conversion Rate
Functional Description
The ADM1034 is a local- and remote-temperature
monitor and fan controller for use in a variety of
applications, including microprocessor-based systems. The
device accurately monitors remote and ambient temperature
and uses that information to quietly control the speed of a
cooling fan. Whenever one of the fans stalls, the device
asserts a FAN_FAULT output.
The ADM1034 features a THERM I/O. As an input, this
measures assertions on the THERM pin. As an output, it
asserts a low signal to indicate when the measured
temperature exceeds the programmed THERM
temperature. The ADM1034 communicates over an SMBus
2.0 interface. Its LOCATION input determines which
version of SMBus to use, as well as the SMBus address (in
fixed and discoverable mode) and the LOCATION bits in
the UDID (in ARP-capable mode).
Internal Registers
Table 5 gives a brief description of the ADM1034’s
principal internal registers. For more detailed information
on the function of each register, refer to Table 35.
Serial Bus Interface
The ADM1034 communicates with the master via the
2-wire SMBus 2.0 interface. It supports two versions of
SMBus 2.0, determined by the value of the LOCATION
input’s resistors.
The first version is fully ARP-capable. This means that it
supports address resolution protocol (ARP), allowing the
master to dynamically address the device on powerup. It
responds to ARP commands such as “Prepare to ARP.”
The second SMBus version, fixed and discoverable, is
backwards compatible with SMBus 1.0 and 1.1. In this mode,
the ADM1034 powers up with a fixed address, which is
determined by the state of the LOCATION pin on powerup.
1.55
1.50
1.45
1.40
1.35
1.30
1.25
−60 −40 −20 0 20 40 60
TEMPERATURE (C)
80 100
Figure 14. Supply Current vs.
ADM1034 Temperature
NOTE: When using the ADM1034, Addresses 0xC2 and 0xCA
should not be used by any other device on the bus.
Location Input
The LOCATION input is a resistor divider input. It has
multiple functions and can specify the SMBus version (in
fixed and discoverable or ARP-capable modes); the SMBus
address (in fixed and discoverable mode); and the LLL bits
(in UDID in ARP-capable mode).
The voltage of this 8-level input is set by a potential
divider. The voltage on LOCATION is sampled on powerup
and digitized by the on-chip ADC to determine the
LOCATION input value. Because the LOCATION input is
sampled only at powerup, changes made while power is
applied have no effect.
VCC
R1
ADM1034
PIN 13
LOCATION
R2
GND
Figure 15. Bootstrapping the LOCATION Input
SMBus 2.0 ARP-capable Mode
In ARP-capable mode, the ADM1034 supports features
such as address resolution protocol (ARP) and unique
device identifier (UDID). The UDID is a 128-bit message
that describes the ADM1034’s capabilities to the master.
The UDID also includes a vendor specific ID for
functionally equivalent devices.
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