Texas Instruments SN65HVS880, SLAU245 User Manual
1 Introduction
The SN65HVS880 evaluation module (EVM) supports the parametric evaluation of the SN65HVS880
digital input serializer. It is intended to be used in conjunction with the SN65HVS880 data sheet,
(SLAS252 ).
Note: this EVM is not intended for electromagnetic compatibility (EMC) tests.
2 EVM Schematic and Layout
Figure 1 shows the board circuit schematic, and Figure 2 shows the board layout top view. The board
includes a terminal block, TB1, and four connectors, JMP1 to 4.
TB1 receives the board supply of 24V nominal. V24 supplies the SN65HVS880 device, and VFIELD
provides the supply for sensor switches.
Upon the application of V24, the blue Chip-Okay LED (CHOK) indicates proper board function. At the
same time, the red LED indicates 5V availability at the regulator output 5VOP.
JMP1 provides the field inputs IN0:IN7 for field voltages of 24V nominal. They can be applied via:
a. an external supply in series to a sensor switch connected to a field input,
b. or a sensor switch connected between and input and VFIELD,
c. or a direct connection between an input and VFIELD.
In all three cases, a 24V level represents the ON-status of a sensor switch, which is indicated by the
corresponding LEDs D0:D7.
JMP2 provides access to the control and data lines of the internal serializer. To operate the serializer, CE
must be connected either to ground or to CLK.
Upon an active-low load pulse, (a high-to-low-to-high transition) at LD, the status information of the field
inputs is latched into the serializer. Applying eight consecutive clock cycles at CLK, shifts out the serializer
data at SOP with each rising edge of the clock.
Cascading of multiple boards is also possible by connecting the SOP output of a leading device with the
SIP input of a following device.
JMP3 allows the selection of three different debounce times and 3 different current limits.
Debounce default is 3ms, and does not require any connection between the DB inputs to ground.
Otherwise, for zero debounce time connect DB1 to ground, and for 1ms debounce time connect DB0 to
ground.
Note: the open DB inputs are internally pulled high and will not float.
Setting a specific current limit requires a connection between the R
1:3. For a current limit of 3.6mA connect R
JMP4 allows to connect VFIELD to V24, thus driving the board with only one supply.
For detailed information on device functionality and system design recommendations, see the
SN65HVS880 data sheet.
User's Guide
SLAU245 – March 2008
SN65HVS880 EVM User's Guide
output and one of the resistors, R
to 24.9k Ω , for 3mA to 30.1k Ω , and for 2.5mA to 36.1k Ω .
LIM
LIM
LIM
SLAU245 – March 2008 SN65HVS880 EVM User's Guide 1
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SN65HVS880
IP0
IP1
IP3
IP2
IP4
IP5
IP6
IP7
FGND
PAD
V24
DB0
DB1
RLIM
RE0
RE1
RE2
RE3
RE4
RE5
RE6
RE7
SIP
LD
CLK
CE
SOP
CHOK
3
5
7
9
11
18
20
22
28
14
1
2
13
4
6
8
10
12
17
19
21
27
26
25
24
23
16
JMP2
SIP
LD
CLK
CE
SOP
CHOK
5VOP
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
5VOP
15
VFIELD
GND
V24
R
LIM
1:3
R 0:7
1.2k
D 0:7
(3mA)
JMP1
JMP3
TB1
24.9k
29.1k
34.8k
1.3k
2.2 Fm
2.2 Fm
22nF
2.2 Fm
1.3k
JMP4
CHOK5VOP
GND
SN65HVS880
RIN0:7
LED 0:7
CHOK
RLIM 1:3
JMP1
TB1
JMP3
JMP2
VFIELD
V24
GND
5VOP
GND
GND
24.9k
30.1k
36.1k
RLIM 1:3
DB0
DB1
IN0
IN1
IN2
IN3
IN4
IN5
IN6
IN7
SN65HVS880
V24SEN
LD
EVM
6498378
JMP4
CE
CLK
5VOP
CHOK
SIP
SOP
EVM Schematic and Layout
Figure 1. SN65HVS880 EVM Schematic
2 SN65HVS880 EVM User's Guide SLAU245 – March 2008
Figure 2. SN65HVS880 EVM layout
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