sx8744emstrt Semtech Corporation, sx8744emstrt Datasheet - Page 7
sx8744emstrt
Manufacturer Part Number
sx8744emstrt
Description
Precision Diode Digital Temperature For Up To 3 External Sensors
Manufacturer
Semtech Corporation
Datasheet
1.SX8744EMSTRT.pdf
(24 pages)
3. Configuration
3.1. General Presentation
Figure 2. Functional Diagram
3.2. Modes
The mode set in RegConfig allows numerous circuit configurations described in Figure 3 and Figure 4.
Up to 3 external sensors can be connected. Theses are configured with differential or single-ended connections.
Some modes provide a track resistance cancellation feature to decrease temperature inaccuracy linked to long PCB traces
connecting the external sensor to the chip. This is set in RegControl (bits Point3 or Algo). Table 4 presents the mode for the
SX8743.
Mode
External sensor
Differential
Single-ended
Algorithmic track resistance cancellation
3-point track resistance cancellation
Kelvin (4-wire) track resistance cancellation
Alarm #
Due to their limited number of ports, SX8733 and SX8744 do not offer all theses features. SX8733 does not provide ports
P3 and P4 so modes 8 to 20 should not be used. Also port P3 is not available on SX8744 and this typically reduces the
number of alarm or the number of external sensors.
ACS Revision 2.91/February 2010
©2010 Semtech Corp.
ADVANCED COMMUNICATIONS & SENSING
4
3
2
6
SX8743
2
3
6
SX8744
1
6
P3
P4
P1
P2
SX8733
D2-
D1+
D1-
D2+
D3+
D3-
AL2
AL1
+
+
-
+
-
-
Table 4 Features Available With SX8743
0
1
x
0
1
1
x
x
0
SMBUS
2
1
0
x
x
+
-
3
0
2
Page 7
ALARM
ADC
4
2
x
0
5
2
x
x
0
SMBCLK
SMBDAT
SX8733/SX8743/SX8744
VDD
VSS
Precision Diode Digital Temperature
6
1
1
x
4
3
5
2
7
1
1
x
x
8
7
1
5
8
1
2
x
For Up To 3 External Sensors
SX8733 / SX8743 / SX8744 include an on-
chip PN junction to measure local tempera-
ture T
The device has a 2-level current source
and an ADC to measure each diode’s
forward
temperature. The input multiplexer allows 3
external and 1 internal sensors to be
connected to the ADC.
Two alarms can provide to the system the
information that a sensor temperature has
reached the programmable threshold.
The chip is configured with a 2-wire
SMBUS serial line.
The functional diagram is shown in
Figure 2.
9
1
2
x
x
10 11 12 13 14 15 16 17 18 20
1
2
x
x
J
.
2
0
x
voltage
2
x
x
0
2
x
2
2
x
x
2
to
www.semtech.com
DATASHEET
2
x
x
1
compute
3
x
1
3
x
x
1
3
x
x
0
the
1
x
x
0