|
|
PDF ADT7461A Data sheet ( Hoja de datos )
| Número de pieza | ADT7461A | |
| Descripción | Temperature Monitor | |
| Fabricantes | ON Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de ADT7461A (archivo pdf) en la parte inferior de esta página. Total 19 Páginas | ||
|
No Preview Available !
ADT7461A
+15C Temperature Monitor
with Series Resistance
Cancellation
The ADT7461A is a dual-channel digital thermometer and
undertemperature/overtemperature alarm, intended for use in PCs and
thermal management systems. It is pin- and register-compatible with the
ADM1032 and ADT7461. A feature of the ADT7461A is series
resistance cancellation, where up to 1.5 kW (typical) of resistance in
series with the temperature monitoring diode can be automatically
cancelled from the temperature result, allowing noise filtering. The
ADT7461A has a configurable ALERT output and an extended,
switchable temperature measurement range.
The ADT7461A can measure the temperature of a remote thermal
diode accurate to ±1°C and the ambient temperature accurate to ±3°C.
The temperature measurement range defaults to 0°C to +127°C,
compatible with the ADM1032, but it can be switched to a wider
measurement range of −64°C to +191°C.
The ADT7461A communicates over a 2-wire serial interface,
compatible with system management bus (SMBus) standards. The
default SMBus address of the ADT7461A is 0x4C. An ADT7461A−2 is
available with an SMBus address of 0x4D. This is useful if more than one
ADT7461A is used on the same SMBus.
An ALERT output signals when the on-chip or remote temperature is
out of range. The THERM output is a comparator output that allows
on/off control of a cooling fan. The ALERT output can be reconfigured
as a second THERM output, if required.
Features
• On-Chip and Remote Temperature Sensor
• 0.25°C Resolution/1°C Accuracy on Remote Channel
• 1°C Resolution/1°C Accuracy on Local Channel
• Automatically Cancels Up to 1.5 kW (Typ) of Resistance in Series
with Remote Diode to Allow Noise Filtering
• Extended, Switchable Temperature Measurement Range
0°C to +127°C (Default) or –64°C to +191°C
• Pin- and Register-Compatible with ADM1032 and ADT7461
• 2-wire SMBus Serial Interface with SMBus Alert Support
• Programmable Over/Undertemperature Limits
• Offset Registers for System Calibration
• Up to Two Overtemperature Fail-Safe THERM Outputs
• Small 8-lead MSOP
• 240 mA Operating Current, 5 mA Standby Current
• These are Pb-Free Devices*
http://onsemi.com
MSOP−8
CASE 846AB
PIN ASSIGNMENT
VDD 1
D+ 2
D− 3
THERM 4
8 SCLK
7 SDATA
6 ALERT/THERM2
5 GND
(Top View)
MARKING DIAGRAM
8
T1x
AYWG
G
1
T1x = Refer to Ordering Information Table
A = Assembly Location
Y = Year
W = Work Week
G = Pb-Free Package
(Note: Microdot may be in either location)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 18 of this data sheet.
Applications
• Desktop and Notebook Computers
• Industrial Controllers
• Smart Batteries
• Automotive
• Embedded Systems
• Burn-In Applications
• Instrumentation
* For additional information on our Pb-Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting
Techniques Reference Manual, SOLDERRM/D.
© Semiconductor Components Industries, LLC, 2013
April, 2013 − Rev. 8
1
Publication Order Number:
ADT7461A/D
1 page  
ADT7461A
TYPICAL PERFORMANCE CHARACTERISTICS
3.5
DEV 1
DEV 8
DEV 15
3.0
DEV 2
DEV 9
DEV 16
DEV 3
DEV 10
MEAN
2.5
DEV 4
DEV 11
HIGH 4S
DEV 5
DEV 12
LOW 4S
2.0
DEV 6
DEV 7
DEV 13
DEV 14
1.5
1.0
0.5
0
−0.5
−1.0
−50 0 50 100 150
TEMPERATURE (°C)
Figure 3. Local Temperature Error vs. Temperature
10
5
D+ To GND
0
−5
−10 D+ To VCC
−15
−20
−25
1
10 100
LEAKAGE RESISTANCE (MW)
Figure 5. Temperature Error vs. D+/D− Leakage
Resistance
3.5
DEV 1
DEV 8
DEV 15
3.0
DEV 2
DEV 9
DEV 16
DEV 3
DEV 10
HIGH 4S
2.5
DEV 4
DEV 11
LOW 4S
DEV 5
DEV 12
2.0
DEV 6
DEV 7
DEV 13
DEV 14
1.5
1.0
0.5
0
−0.5
−1.0
−50 0 50 100 150
TEMPERATURE (°C)
Figure 4. Remote Temperature Error vs. Actual
Temperature
0
−2
−4
−6
−8
−10
DEV 3
−12
DEV 2
−14
−16 DEV 4
−18
0
5 10 15
CAPACITANCE (nF)
20
25
Figure 6. Temperature Error vs. D+/D− Capacitance
1000
900
DEV 2BC
800
700
600
500 DEV 4BC
400
300 DEV 3BC
200
100
0
0.01
0.1
1
10
CONVERSION RATE (Hz)
Figure 7. Operating Supply Current vs.
Conversion Rate
100
422
420
DEV 2BC
418
416
414 DEV 3BC
DEV 4BC
412
410
408
3.0 3.1 3.2 3.3 3.4 3.5 3.6
VDD (V)
Figure 8. Operating Supply Current vs. Voltage
http://onsemi.com
5
5 Page 
ADT7461A
The ALERT interrupt latch is not reset by reading the
status register. It resets when the ALERT output has been
serviced by the master reading the device address, provided
the error condition has gone away and the status register flag
bits are reset.
When Flag 1 and/or Flag 0 are set, the THERM output
goes low to indicate that the temperature measurements are
outside the programmed limits. The THERM output does
not need to be reset, unlike the ALERT output. Once the
measurements are within the limits, the corresponding status
register bits are automatically reset and the THERM output
goes high. The user may add hysteresis by programming
Register 0x21. The THERM output is reset only when the
temperature falls to limit value minus the hysteresis value.
When Pin 6 is configured as THERM2, only the high
temperature limits are relevant. If Flag 6 and/or Flag 4 are
set, the THERM2 output goes low to indicate that the
temperature measurements are outside the programmed
limits. Flag 5 and Flag 3 have no effect on THERM2. The
behavior of THERM2 is otherwise the same as THERM.
Table 11. STATUS REGISTER BIT ASSIGNMENTS
Bit Name
Function
7
BUSY
1 when ADC is converting
6 LHIGH 1 when local high temperature limit is
(Note 1) tripped
5
LLOW
1 when local low temperature limit is
(Note 1) tripped
4 RHIGH 1 when remote high temperature limit is
(Note 1) tripped
3 RLOW 1 when remote low temperature limit is
(Note 1) tripped
2
OPEN
1 when remote sensor is an open circuit
(Note 1)
1 RTHRM 1 when remote THERM limit is tripped
0 LTHRM 1 when local THERM limit is tripped
1. These flags stay high until the status register is read or they are
reset by POR unless Pin 6 is configured as THERM2. Then, only
Bit 2 remains high until the status register is read or is reset by
POR.
Offset Register
Offset errors can be introduced into the remote
temperature measurement by clock noise or when the
thermal diode is located away from the hot spot. To achieve
the specified accuracy on this channel, these offsets must be
removed.
The offset value is stored as a 10-bit, twos complement
value in Register 0x11 (high byte) and Register 0x12 (low
byte, left justified). Only the upper two bits of Register 0x12
are used. The MSB of Register 0x11 is the sign bit. The
minimum, programmable offset is −128°C, and the
maximum is +127.75°C. The value in the offset register is
added to, or subtracted from, the measured value of the
remote temperature.
The offset register powers up with a default value of 0°C
and has no effect unless the user writes a different value to it.
Table 12. SAMPLE OFFSET REGISTER CODES
Offset Value
0x11
0x12
−128°C
−4°C
−1°C
−0.25°C
0°C
+0.25°C
+1°C
+4°C
+127.75°C
1000 0000
1111 1100
1111 1111
1111 1111
0000 0000
0000 0000
0000 0001
0000 0100
0111 1111
00 00 0000
00 00 0000
00 000000
10 00 0000
00 00 0000
01 00 0000
00 00 0000
00 00 0000
11 00 0000
One-Shot Register
The one-shot register is used to initiate a conversion and
comparison cycle when the ADT7461A is in standby mode,
after which the device returns to standby. Writing to the
one-shot register address (0x0F) causes the ADT7461A to
perform a conversion and comparison on both the internal
and the external temperature channels. This is not a data
register as such, and it is the write operation to Address 0x0F
that causes the one-shot conversion. The data written to this
address is irrelevant and is not stored.
Consecutive ALERT Register
The value written to this register determines how many
out-of-limit measurements must occur before an ALERT is
generated. The default value is that one out-of-limit
measurement generates an ALERT. The maximum value
that can be chosen is 4. The purpose of this register is to
allow the user to perform some filtering of the output. This
is particularly useful at the fastest three conversion rates,
where no averaging takes place. This register is at
Address 0x22.
Table 13. CONSECUTIVE ALERT REGISTER CODES
Register Value
Number of Out-of-Limit
Measurements Required
NOTE:
yxxx 000x
1
yxxx 001x
2
yxxx 011x
3
yxxx 111x
4
x = don’t care bits, and y = SMBus timeout bit.
Default = 0. See SMBus section for more information.
http://onsemi.com
11
11 Page | ||
| Páginas | Total 19 Páginas | |
| PDF Descargar | [ Datasheet ADT7461A.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| ADT7461 | Temperature Monitor |  Analog Devices |
| ADT7461 | Temperature Monitor | ON Semiconductor |
| ADT7461A | Temperature Monitor | ON Semiconductor |
| ADT7461A | Temperature Monitor | Analog Devices |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |