Si838x Data Sheet
Bipolar Digital Field Inputs for PLCs and Industrial I/O Modules
The Si838x provides eight channels for 24 V digital field interface to either sinking or
sourcing inputs with integrated safety rated isolation. In combination with a few external
components, this provides compliance to IEC 61131-2 switch types 1, 2, or 3. The input
interface is based on Silicon Labs' ground-breaking CMOS based LED emulator technology which enables the bipolar capability (sinking or sourcing inputs) with no VDD required on the field side. The output interface to the controller allows for low power operation with 2.25 V operation capability. These products utilize Silicon Laboratories' proprietary silicon isolation technology, supporting up to 2.5 kVRMS withstand voltage. This
technology enables high CMTI (50 kV/μs), lower prop delays and skew, reduced variation with temperature and age, and tighter part-to-part matching.
Product options include parallel or serialized outputs. Cascading capability for a total of
128 channels (16x Si838x) is possible with serial output option. The Si838x offers longer
service life and dramatically higher reliability compared to opto-coupled input solutions.
KEY FEATURES
• Bipolar digital interface with 24 V sinking or
sourcing inputs
• Eight total inputs in one package
• High data rates of up to 2 Mbps
• Safety rated integrated isolation of 2.5
kVrms
• Low input current of 1 mA typ
• No VDD required on field side
• Status LEDs on parallel outputs
• High electromagnetic immunity
• Programmable debounce times of up to
100 ms
• Transient immunity of 50 kV/μs
Applications:
• Programmable logic controllers
• Industrial data acquisition
• Distributed control systems
• CNC machines
• I/O modules
• Motion control systems
Safety Regulatory Approvals:
• UL 1577 recognized
• Up to 2500 VRMS for one minute
• Flow-through output configuration with eight
outputs
• Option for SPI interface serialized outputs
with daisy-chain capability
• Wide 2.25 to 5.5 V VDD operation
• Wide operating temperature range
• –40 to +125 °C
• Compliant to IEC 61131-2
• Type 1, 2, 3
• RoHS-compliant packages
• QSOP-20
• CSA component notice 5A approval
• IEC 60950-1
• VDE certification conformity
• VDE 0884-10
• CQC certification approval
• GB4943.1
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5
Si838x Data Sheet
Ordering Guide
1. Ordering Guide
Table 1.1. Si838x Ordering Guide
Ordering
Serial or Parallel
Output
Number of HighSpeed Channels
Low Pass
Filter Delay
Package Type
Isolation Rating
Si8380P-IU
P
0
0 ms
20-QSOP
2.5 kVrms
Si8382P-IU
P
2
0 ms
20-QSOP
2.5 kVrms
Si8384P-IU
P
4
0 ms
20-QSOP
2.5 kVrms
Si8388P-IU
P
8
0 ms
20-QSOP
2.5 kVrms
Si8380S-IU
S
0
0 ms
20-QSOP
2.5 kVrms
Si8380PF-IU
P
0
10 ms
20-QSOP
2.5 kVrms
Si8382PF-IU
P
2
10 ms
20-QSOP
2.5 kVrms
Si8384PF-IU
P
4
10 ms
20-QSOP
2.5 kVrms
Si8380PM-IU
P
0
30 ms
20-QSOP
2.5 kVrms
Si8382PM-IU
P
2
30 ms
20-QSOP
2.5 kVrms
Si8384PM-IU
P
4
30 ms
20-QSOP
2.5 kVrms
Si8380PS-IU
P
0
100 ms
20-QSOP
2.5 kVrms
Si8382PS-IU
P
2
100 ms
20-QSOP
2.5 kVrms
Si8384PS-IU
P
4
100 ms
20-QSOP
2.5 kVrms
Part Number
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 1
Si838x Data Sheet
Functional Description
2. Functional Description
2.1 Theory of Operation
The operation of a Si838x channel is analogous to that of a bipolar opto-coupler, except an RF carrier is modulated instead of light. This
simple architecture provides a robust isolated data path and requires no special considerations or initialization at start-up. A simplified
block diagram for a single Si838x channel is shown in the figure below.
This product enables 24 V bipolar digital inputs to be connected to its input through a resistor network which acts as a voltage divider.
The inputs can be sourcing or sinking type. To enable this functionality, there is a zero drop bridge and an LED emulator at the front
end that drives an OOK (On-Off Key) modulator/demodulator across the capacitive isolation barrier.
HF
Transmitter
A
Modulator
e
COM
CMOS isolation barrier
On the output side, the debounce block controls the amount of debounce desired. There are four debounce delay time options available: no delay, or delays of 10, 30, or 100 ms. In addition, the user can use the SPI control to program user-specific debounce modes as
explained in Section 2.3.2 Debounce Filtering Modes. The user-specific debounce programming is only available on the product option
with SPI interface.
VDD
Demodulator
B
Debounce
Figure 2.1. Simplified Channel Diagram
2.2 Serial Peripheral Interface
The Si8380S includes a Serial Peripheral Interface (SPI) that provides control and monitoring capability of the isolated channels using a
commonly available microcontroller protocol. The direct-mapped registers allow an external master SPI controller to monitor the status
of the eight PLC channels, as well as to control the delay and filtering modes for the debounce of each channel. Additionally, support is
provided to easily daisy-chain up to sixteen PLC devices. Each of these daisy-chained devices may be uniquely addressed by one
master SPI controller.
2.2.1 SPI Register Map
The addressable SPI registers include one eight-bit register to reflect the status of each of the eight channels, which is read-only. Also,
four additional registers provide two bits to specify the debounce delay, and two bits to specify the debounce filtering mode for each of
the eight channels. These user accessible SPI registers are illustrated in the following table.
Table 2.1. Si838x SPI Register Map
Name
Address
Access
CHAN_STATUS
0x0
R
DBNC_MODE0
0x1
R/W
Mode control bits for the first four channel debounce filters organized as:
{md_ch3[1:0],md_ch2[1:0],md_ch1[1:0],md_ch0[1:0]}
DBNC_MODE1
0x2
R/W
Mode control bits for the second four channel debounce filters organized as:
{md_ch7[1:0],md_ch6[1:0],md_ch5[1:0],md_ch4[1:0]}
DBNC_DLY0
0x3
R/W
Delay control bits for the first four channel debounce filters organized as:
{dly_ch3[1:0],dly_ch2[1:0],dly_ch1[1:0],dly_ch0[1:0]}
DBNC_DLY1
0x4
R/W
Delay control bits for the second four channel debounce filters organized as:
{dly_ch7[1:0],dly_ch6[1:0],dly_ch5[1:0],dly_ch4[1:0]}
silabs.com | Smart. Connected. Energy-friendly.
Description
Current value of each of the eight PLC channels {PLC[7:0]}
Rev. 0.5 | 2
Si838x Data Sheet
Functional Description
2.2.2 SPI Communication Transactions
SPI communication is performed using a four wire control interface. The four Si838x device pins utilized for SPI include:
• SCLK (input) the SPI clock
• NSS (input) active low device select
• MOSI (input) master-out-slave-in
• MISO (output) master-in-slave-out
Additionally, a fifth wire SDI_THRU (output) is provided as an Si838x device pin to facilitate daisy chaining.
An Si838x SPI communication packet is composed of three serial bytes. In this sequence, byte0 is the control byte, and specifies the
operation to be performed as well as the device to be selected in a daisy chain organization. The CID[3:0] field should be set to all
zeros by the SPI master in non-daisy-chained operation. Next, byte1 specifies the address of the internal Si838x SPI register to be
accessed. The final byte in the packet consists of either the data to be written to the addressed Si838x SPI register (using MOSI), or the
data read from the addressed Si838x SPI register (using MISO). Details of the SPI communication packet are presented in the following
figure for an Si838x SPI write transaction.
NSS
SCLK
MOSI
Control[7:0]
Address[7:0]
Control Byte
7
6
BRCT R/Wb
5
4
0
0
3
2
1
BRCT
1 - broadcast (write)
0 - only addressed part (write)
Ignored on reads
R/Wb
1 - read
0 - write
CTL[5:4]
Reserved (set to 0,0)
CID[3:0]
Daisy-chained part ID (0) is closest to the master
MOSI. Accomplished by decrementing the CID as
it passes through to the next Si838x device in the
daisy chain on SDI_THRU
0
CID[0] CID[1] CID[2] CID[3]
Address Byte
7
6
5
4
3
2
1
0
A[7]
A[6]
A[5]
A[4]
A[3]
A[2]
A[1]
A[0]
Data Byte
7
6
5
4
3
2
1
0
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
Data[7:0]
Figure 2.2. SPI Communication Packet Structure, Write Operation and Control Byte Structure
The SPI master will provide the timing of the signals and framing of the communication packets for all Si838x SPI inputs: NSS, SCLK,
and MOSI. Data is communicated from the SPI master to the Si838x using the MOSI signal. The NSS and SCLK signals provide the
necessary control and timing reference allowing the Si838x to discern valid data on the MOSI signal. Data is returned to the SPI master
by the Si838x utilizing the MISO signal only during the final byte of a three byte SPI read communication packet. At all other times, the
MISO signal is tri-stated by the Si838x. Each of the eight bits for these three packets is captured by the Si838x on eight adjacent rising
edges of SCLK. Each frame of eight bits is composed within bounding periods where the device select, NSS, is deasserted. Upon the
reception of the eight bits within a byte transaction, the deassertion of NSS advances the byte counter within the internal Si838x SPI
state machine. Should the transmission of an eight bit packet be corrupted, either with the deassertion of NSS before the eighth rising
edge of SCLK, or with the absence of the deassertion of NSS after the eighth rising edge of SCLK, the internal SPI state machine may
become unsynchronized with the master SPI controller.
To re-establish SPI synchronization with the Si838x, the SPI master may, at any time, deassert the SPI device select signal NSS, and
force a clock cycle on SCLK. When unsynchronized, the rising edge of SCLK when NSS is deasserted (high) re-initializes the internal
SPI state machine. The Si838x will then treat the immediately following eight bit SPI transaction after NSS is once again asserted as
the first byte in a three byte SPI communication packet.
Any preceding communication packet will be abandoned by the Si838x at the point synchronization is lost, and the NSS signal is deasserted. This could occur at any point in the three byte sequence of a SPI communication packet. One should note that abandoning a
SPI write operation early, even during the last byte of the three byte SPI communication packet, will leave the destination register unchanged. However, if the number of SCLK cycles exceeds eight during the last byte of the three byte SPI write packet, the destination
Si838x register may be corrupted. To remedy both of these situations, it is recommended that such a corrupted write operation be repeated immediately following resynchronization of the SPI interface.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 3
Si838x Data Sheet
Functional Description
2.2.3 SPI Read Operation
Referring to Figure 2.2 SPI Communication Packet Structure, Write Operation and Control Byte Structure on page 3, in a SPI read operation the control byte will only have bit6 set to a 1 in a single Si838x device organization (no daisy-chaining). For the Si838x, bit7 (the
broadcast bit) is ignored during a read operation since only one device may be read at a time in either a single or daisy chained organization.
The second byte in the three byte read packet is provided by the SPI master to designate the address of the Si838x internal register to
be queried. If the read address provided does not correspond to a physically available Si838x internal register, all zeroes will be returned as the read value by the Si838x.
The read data is provided during the final byte of the three byte read communication packet to the querying master SPI device utilizing
the Si838x’s MISO output, which remains tristated at all other times.
The SPI read operation timing diagram is illustrated in the figure below.
NSS
SCLK
MOSI
Control[7:0]
Address[7:0]
MISO
ReadData[7:0]
Figure 2.3. SPI Read Operation
2.2.4 SPI Write Operation
Again referring to Figure 2.2 SPI Communication Packet Structure, Write Operation and Control Byte Structure on page 3, in a SPI
write operation the control byte may optionally have bit7 (the broadcast bit) set to a 1. During a SPI write operation, the broadcast bit
forces all daisy-chained Si838x devices to update the designated internal SPI register with the supplied write data, regardless of the
Si838x device being addressed using the CID[3:0] field of the control word.
The second byte in the three byte write packet is provided by the SPI master to designate the address of the Si838x internal register to
be updated. If the write address provided does not correspond to a physically available Si838x internal register, no internal Si838x SPI
register update will occur.
The write data is provided by the SPI master during the final byte of the three byte write communication packet. The Si838x MISO
output remains tri-stated during the entire SPI write operation.
The SPI write operation timing diagram is illustrated in the figure below.
NSS
SCLK
MOSI
Control[7:0]
Address[7:0]
MISO
WriteData[7:0]
hiZ
Figure 2.4. SPI Write Operation
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 4
Si838x Data Sheet
Functional Description
2.2.5 SPI Daisy Chain Organization
The Si838x provides the capability to easily interconnect multiple Si838x devices on a common SPI interface administered by a single
SPI master requiring no additional control signals. To accomplish this, the Si838x includes the additional SPI device output pin
SDI_THRU. Connecting together multiple Si838x devices in this manner utilizes the SDI_THRU pin of one Si838x device to feed the MOSI
pin of the next Si838x device in the daisy-chain. All bits composing a SPI communication packet are passed directly through by the
Si838x from the MOSI input to the SDI_THRU output unchanged, except for the CID[3:0] field of the control byte.
Si838x[15]
mosi
sclk
nss
miso
sdi_thru
Si838x[4]
mosi
sclk
nss
miso
sdi_thru
mosi
sclk
nss
miso
sdi_thru
mosi
sclk
nss
miso
sdi_thru
Si838x[3]
Si838x[2]
mosi
sclk
nss
miso
Si838x[1]
mosi
sclk
nss
miso
sdi_thru
Si838x[0]
mosi
sclk
nss
miso
sdi_thru
The least significant four bits of the control byte in a SPI communication packet, CID[3:0], are dedicated to addressing one of up to
sixteen Si838x devices thus connected, with 0000 indicating the device whose MOSI pin is fed directly by the SPI master, 0001 the
following Si838x device, etc. As this bit field is passed through the Si838x, it is decremented by one. This four bit field is placed in the
control word by the SPI master in reverse order, allowing the carry of the decrement to ripple into the next bit in the CID field as the bits
of the control word proceed: CID[0] is placed at bit 3 and CID[3] placed at bit 0 of the control word. When a given Si838x device in the
daisy chain is presented with the CID[3:0] code of 0000, it is activated as the one to be addressed. All remaining operations between
the SPI master and the Si838x activated in this manner proceed as previously discussed for the case of the single Si838x slave. The
organization of an Si838x system daisy-chained in this manner is depicted in the figure below.
SPI_master
Figure 2.5. SPI Daisy Chain Organization
From the preceding figure, and referring to Figure 2.2 SPI Communication Packet Structure, Write Operation and Control Byte Structure
on page 3, in order to read from Si838x[1], the control word would be:
Control[7:0] = 0100_1000.
Similarly, in order to write to Si838x[12], the control word would be:
Control[7:0] = 0000_0011.
Finally, if it were desired to update an internal SPI register of all daisy-chained Si838x devices, the control word would be:
Control[7:0] = 1000_0000.
If the broadcast bit is zero during a write operation, only the Si838x device being addressed using the CID[3:0] field of the control word
in a daisy-chain organization will be updated. If the broadcast bit is one during a write operation, the CID[3:0] field is ignored, and all
Si838x devices connected in a daisy-chain will be updated. For non-daisy-chain operation, the CID[3:0] field should always be all zeros.
Note that there is a finite combinational delay associated with passing the MOSI input pin of a given Si838x to the SDI_THRU output pin.
As a result, the maximum possible SCLK frequency will be reduced based on the number of Si838x devices connected in a daisy-chain
organization.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 5
Si838x Data Sheet
Functional Description
2.2.6 SPI Interface Timing Specification
The timing diagram for the Si838x SPI interface is presented in the figure below.
Tp
sclk
Tsu1
Th1
Tsu2 Th2
Tnss
nss
Rxbit
mosi
Rxbit
sdi_thru
Txbit
miso
Tdo1
Rxbit
Rxbit
Txbit
Rxbit
Rxbit
Txbit
Tdo2
Rxbit
Rxbit
Txbit
Tdz
Figure 2.6. SPI Timing Diagram
The timing specifications depicted in this figure apply to each byte of the three byte Si838x SPI communications packet. Refer to the
SPI timing specifications in Table 4.2 Electrical Characteristics on page 12.
Although this discussion of the Si838x SPI interface has focused on a preferred organization (separate MISO/MOSI wires), other options
are available with regard to the Si838x control interface. Possible Si838x organizations include:
• MISO/MOSI wired operation
• MISO/MOSI may be two separate wires, or may be connected together if the SPI master is capable of tri-stating its MOSI during
the data byte packet transfer of a read operation.
• Multiple Si838x devices interfaced in a non-daisy-chain format
• The SPI master provides multiple NSS signals, one for each of a multiple of Si838x slaves.
• Every Si838x shares a single trace from its MOSI input back to the SPI master (the Si838x SDI_THRU signal is not utilized).
2.3 Debounce Filter
The Si838x includes a user programmable debounce filter, providing the user a mechanism to individually control the debounce behavior for each of the eight Si838x isolation channels. User control of the debounce filter is accomplished via the included Si838x SPI interface. Consequently, user control of this feature is available only on the serial interface accessible Si838x device versions. The debounce filter is incorporated into the path of the input data stream allowing signal conditioning of the PLC inputs.
There are product options available with the parallel output interface with discrete debounce time constants of 0, 10, 30 or 100 ms—
these are only available on the low speed channels. The high speed channels have no debounce filtering (See 1. Ordering Guide for
more details on part numbers).
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 6
Si838x Data Sheet
Functional Description
2.3.1 Debounce Control Registers
The operation of the Si838x debounce filters is controlled using r/w control registers mapped into the Si838x SPI address space. The
details of these registers are covered in the Si838x SPI register map section of this document. The options available using these registers are outlined in the following tables. For each of the eight PLC channels, two data bits are allocated to control the debounce delay,
and two bits are used to stipulate the debounce filtering mode. This consumes a total of 32 bits, which are allocated across four individual Si838x SPI control registers of one byte each.
Table 2.2. Debounce Filter Delay Control
dbnc_dly[1:0]
Delay (ms)
Comment
00
0
Bypass debounce
01
10
10
30
11
100
Table 2.3. Debounce Filter Mode Control
dbnc_mode[1:0]
Filter Mode
Comment
00
no filter
Simple trailing edge delay
01
low pass
1X
leading edge
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 7
Si838x Data Sheet
Functional Description
2.3.2 Debounce Filtering Modes
In addition to the user specifiable delays, three filtering modes are provided by the debounce function. Like the debounce delay setting,
these filtering modes may be unique for each of the eight Si838x PLC channels.
The first of these three modes, corresponding to dbnc_mode[1:0] == 00, employs only a simple trailing edge delay. In this mode, once
the debounce filter input has been stable for the amount of time specified in the corresponding channel’s debounce delay setting, D, the
output of the debounce filter assumes the value of the new debounce input. Consequently, any glitches on the debounce input having a
duration less than the channel’s debounce delay setting, D, will be suppressed.
The second mode, corresponding to dbnc_mode[1:0] == 01, performs a low pass filtering function on the input to the debounce filter.
When the input to the debounce filter has assumed a new value, a counter begins counting toward the current delay setting, D. If before
the count D is reached the debounce input returns to its previous state, this counter is decremented. Assuming that the debounce filter
input again assumes the new value before the counter is decremented back to 0 (i.e. glitch width is less than time the input had previously assumed a new value), the counter incrementing resumes from a non-zero value. Once this count has reached the designated
delay, D, the debounce filter output assumes the value of the new debounce input. Using this mechanism, any input glitches on the
debounce input having a duration less than the channel’s debounce delay setting, D, will be suppressed. However unlike mode 0, when
the debounce input returns to the new value after this glitch, credit is given for the time this new value was active before the glitch.
The final mode, corresponding to dbnc_mode[1:0] == 1X, realizes a leading edge filtering function on the input to the debounce filter.
Internally, a counter is initialized to zero. When the input to the debounce filter changes, the output of the debounce filter immediately
assumes the new value, and the counter is reset to the current delay setting, D. Independent of what occurs on the input of the debounce filter, the counter begins decrementing after this change. When the counter again reaches zero, the current input of the debounce filter is compared to the current output of the filter. If they are they are different, again the debounce filter immediately assumes
the new value. If they are the same, the output of the debounce filter will immediately change on the next new value of the debounce
input. In either case, a change on the debounce output filter resets the counter to the current delay setting, D.
A graphical depiction of the operation and characteristics for each these debounce filter modes is provided in the following figure.
din
A
B
D– t1
dout Imode = 00
A
t2
(old)
A
D
dout Imode = 01
(old)
A
t 1 + t2
dout I mode = 1x
A
B
D
D
A
Figure 2.7. Debounce Filter Modes Timing Diagram
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 8
Si838x Data Sheet
Functional Description
2.4 Typical Operating Characteristics
Si838x I F Vs. V F
12.00
-40C
10.00
0C
Over Temperature
25C
125C
IF (mA)
8.00
6.00
4.00
2.00
0.00
0.00
0.50
1.00
1.50
2.00
2.50
3.00
V F (V)
Figure 2.8. Input Current vs. Input Voltage Over Temperature
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 9
Si838x Data Sheet
Device Operation
3. Device Operation
Table 3.1. Truth Table Summary
VDD
Input, Ax/AHx
Output, Bx/BHx
P1
ON
High
P
OFF
Low
UP2
X
Low
1. P = powered (> UVLO).
2. UP = Unpowered (< UVLO).
3.1 Device Start-up
During start-up, Output Bx/BHx are held low until the VDD is above the UVLO threshold for a time period of at least tSTART. Following
this, the output is high when the current flowing from anode to cathode is > IF(ON). Device startup, normal operation, and shutdown
behavior is shown in the figure below.
+
UVLO
VDDHYS
-
UVLO
VDD
IF(ON)
IHYS
IF
tPLH
tPHL
t START
tPHL
t START
Output:
Bx, BHx
Figure 3.1. Device Start-up
3.2 Undervoltage Lockout
Undervoltage Lockout (UVLO) is provided to prevent erroneous operation during device startup and shutdown or when VDD is below its
specified operating circuits range. For example, the output side unconditionally enters UVLO when VDD falls below VDDUV– and exits
UVLO when VDD rises above VDDUV+.
3.3 Layout Recommendations
To ensure safety in the end user application, high voltage circuits (i.e., circuits with >30 VAC) must be physically separated from the
safety extra-low voltage circuits (SELV is a circuit with 109
Ω
Note:
1. This isolator is suitable for basic electrical isolation only within the safety limit data. Maintenance of the safety data is ensured by
protective circuits. The Si838x provides a climate classification of 40/125/21.
Table 4.7. IEC Safety Limiting Values1
Parameter
Symbol
Test Condition
Max
Unit
QSOP-20
Case Temperature
TS
Safety Current
IS
θJA = 105 °C/W
150
°C
370
mA
1.2
W
VF = 2.8 V, TJ = 150 °C,
TA = 25 °C
Power Dissipation
PS
Note:
1. Maximum value allowed in the event of a failure; also see the thermal derating curve in Figure 4.2 (QSOP-20) Thermal Derating
Curve, Dependence of Safety Limiting Values with Case Temperature per VDE 0884 on page 17.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 16
Si838x Data Sheet
Electrical Specifications
Table 4.8. Thermal Characteristics
Parameter
IC Junction-to-Air Thermal Resistance
VDD = 2.5 V
450
QSOP-20
Unit
θJA
105
°C/W
VDD = 3.3 V
VDD = 5.0 V
398
400
Safety Limit Current (mA)
Symbol
389
350
370
300
250
200
150
100
50
0
0
20
40
60
80
Temperature
100
120
140
160
(oC)
Figure 4.2. (QSOP-20) Thermal Derating Curve, Dependence of Safety Limiting Values with Case Temperature per VDE 0884
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 17
Si838x Data Sheet
Electrical Specifications
Table 4.9. Absolute Maximum Ratings1
Parameter
Symbol
Min
Max
Unit
Storage Temperature
TSTG
–65
+150
°C
Ambient Temperature
TA
–40
+125
°C
Junction Temperature
TJ
—
+150
°C
IF(AVG)
—
30
mA
IFTR
—
1
A
Ax, AHx
± –0.5
±7
V
Supply Voltage
VDD
–0.5
7
V
Output Voltage
VOUT
–0.5
VDD+0.5
V
Average Output Current
IO(AVG)
—
10
mA
Input Power Dissipation
PI
—
480
mW
Output Power Dissipation (includes 3 mA per channel for
status LED)
PO
—
484
mW
Total Power Dissipation
PT
—
964
mW
Lead Solder Temperature (10 s)
—
260
°C
HBM Rating ESD
4
—
kV
Machine Model ESD
200
—
V
CDM
500
—
V
—
3000
VRMS
Average Forward Input Current
Peak Transient Input Current
(< 1 µs pulse width, 300 ps)
Input voltage, referred to COM
Maximum Isolation Voltage (1 s)
Note:
1. Permanent device damage may occur if the absolute maximum ratings are exceeded. Functional operation should be restricted to
the conditions specified in the operational sections of this data sheet.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 18
Si838x Data Sheet
Applications
5. Applications
5.1 System Level Transitions with the Si838x
PLC Digital Input Module
Field
PLC
Si838xP
IIN
Sensor
Or Switch
R2
24V DC
Field
Potential
VD
High-side
Resistor
C1
R1
2.2nF
High Speed
Channels Only
Isolation Barrier
VIN
uController
VDD
VDD
AHx
Input
Input
BHx
Output
ID
Current
Limit
Resistor
Status Lamp
LED
Low-side
Resistor
R3
D2
GND
COM
GND
Figure 5.1. System Level Drawing of a High-speed Channel on the Si838xP with the Supporting Bill of Materials
The Si838x combined with an appropriate input resistor network and indication LED will produce a PLC Digital Input Module which adheres to the IEC 61131-2 specification.
Resistors R1 and R2 set the transition voltages and currents for the system, as visualized in the figure below, while capacitor C1, is
required only for high-speed channels and serves to improve CMTI performance. Further, resistor R3 is selected based on desired
LED, D2, brightness during a system ON condition.
VIN
Device On
System I-V Curve
VTR1
VTR2
TR1
Hysteresis Region
Device Off
Hysteresis Region
TR2
Device Off
Device On
ITR2
ITR1
IIN
Figure 5.2. Visualization of System Level Transitions when Utilizing a Si838x According to the Recommended Design Process
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 19
Si838x Data Sheet
Applications
5.2 IEC 61131-2 Compliance Options
IEC 61131-2 articulates three types of digital inputs for PLC sensing. Each type category dictates boundary conditions on the system
level input space, (VIN, IIN), defining the range of values for which the module must output a logic LOW, a logic HIGH, or transition
between the two.
More details on the specification can be found on the IEC website: https://webstore.iec.ch/publication/4551.
The table below provides per-input type bill of materials recommendations for plug-n-play designs adhering to the specification or as a
starting point for custom designs. These recommendations assume a resistor tolerance of 5%.
Table 5.1. Si838x Recommended Input Bill of Materials and System Level Transition Values1
Input Resistor Values
PLC Digital Input Type
Nominal TR1 Values
Nominal TR2 Values
R1 (Ω)
R2 (Ω)
IIN (mA)
VIN (V)
IIN (mA)
VIN (V)
Type-1
2400
6200
1.18
8.70
1.07
7.97
Type-2
390
1500
4.14
7.60
3.88
7.13
Type-3
750
2700
2.45
7.98
2.27
7.44
Note:
1. Based on 24 V DC PLC digital input types.
5.3 Custom Bill of Materials
A PLC digital input module based on the Si838x can have its transition values customized on a per-channel basis in accordance with
the system level equations and tolerances. An extended discussion of this process and an example design are available in "AN970:
Design Guide for PLC Digital Input Modules Using the Si838x".
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 20
Si838x Data Sheet
Pin and Package Definitions
6. Pin and Package Definitions
The Si838x consists of multiple dies in one package. Each package and bond-out serves a customer need and may reflect multiple
bond options. The following packages are defined: QSOP-20. 1. Ordering Guide describes the part number and OPN configuration
quantities envisioned for these products. Subsequent sections define the pins for each package type.
6.1 Pin Descriptions
e
20
B1/BH1
A1
1
e
20
MISO
A2/AH2
2
e
19
B2/BH2
A2
2
e
19
MOSI
A3/AH3
3
e
18
B3/BH3
A3
3
e
18
NSS
A4/AH4
4
e
17
B4/BH4
A4
4
e
17
SCLK
COM
5
16
VDD
COM
5
16
VDD
COM
6
15
GND
COM
6
15
GND
A5/AH5
7
e
14
B5/BH5
A5
7
e
14
SDITHRU
A6/AH6
8
e
13
B6/BH6
A6
8
e
13
NC
A7/AH7
9
e
12
B7/BH7
A7
9
e
12
NC
A8/AH8
10
e
11
B8/BH8
A8
10
e
11
NC
Isolation Barrier
1
Isolation Barrier
AI/AH1
SPI
Si8380S
Si8380P/Si8388P
e
20
BH1
AH1
1
e
20
BH1
AH2
2
e
19
BH2
AH2
2
e
19
BH2
A1
3
e
18
B1
AH3
3
e
18
BH3
A2
4
e
17
B2
AH4
4
e
17
BH4
COM
5
16
VDD
COM
5
16
VDD
COM
6
15
GND
COM
6
15
GND
A3
7
e
14
B3
A1
7
e
14
B1
A4
8
e
13
B4
A2
8
e
13
B2
A5
9
e
12
B5
A3
9
e
12
B3
A6
10
e
11
B6
A4
10
e
11
B4
Si8382P
Isolation Barrier
1
Isolation Barrier
AH1
Si8384P
Figure 6.1. Si838x Pin Assignments
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 21
Si838x Data Sheet
Pin and Package Definitions
Table 6.1. Si838x Pin Descriptions
Pin Name
Description
A1 – A8
Low-speed input channels
AH1-AH8
High-speed input channels
COM
Common. Can be connected to ground or 24 V
B1-B8
Low-speed output channels
BH1-BH8
High-speed output channels
VDD
Controller side power supply
GND
Controller side ground
MOSI
SPI, input
SCLK
SPI Clock
NSS
SPI Chip select
SDITHRU
MISO
SPI Serial data out for cascading multiple Si838x (up to 16)
SPI, output
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 22
Si838x Data Sheet
Package Outline
7. Package Outline
The figure below illustrates the package details for the 20-pin QSOP package. The table below lists the values for the dimensions
shown in the illustration.
Figure 7.1. 20-Pin QSOP Package Outline
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 23
Si838x Data Sheet
Package Outline
Table 7.1. Package Dimensions
Dimension
Min
Max
A
—
1.75
A1
0.10
0.25
A2
1.25
—
b
0.20
0.30
c
0.17
0.25
D
8.66 BSC
E
6.00 BSC
E1
3.91 BSC
e
0.635 BSC
L
0.40
L2
1.27
0.25 BSC
h
0.25
0.50
θ
0°
8°
aaa
0.10
bbb
0.20
ccc
0.10
ddd
0.20
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to the JEDEC Solid State Outline M0-137, Variation AD.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body Components.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 24
Si838x Data Sheet
Land Pattern
8. Land Pattern
The figure below illustrates the PCB land pattern details for the 20-pin QSOP package. The table below lists the values for the dimensions shown in the illustration.
Figure 8.1. 20-Pin QSOP PCB Land Pattern
Table 8.1. 20-Pin QSOP PCB Land Pattern Dimensions
Dimension
Feature
mm
C1
Pad Column Spacing
5.40
E
Pad Row Pitch
0.635
X1
Pad Width
0.40
Y1
Pad Length
1.55
1. This Land Pattern Design is based on IPC-7351 design rules for Density Level B (Median Land Protrusion).
2. All feature sizes shown are at Maximum Material Condition (MMC), and a card fabrication tolerance of 0.05 mm is assumed.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 25
Si838x Data Sheet
Top Marking
9. Top Marking
Figure 9.1. Si838x Top Marking (20-Pin QSOP)
Table 9.1. Top Marking Explanation (20-Pin QSOP)
Line 1 Marking:
Base Part Number
Si838 = 8-ch PLC input isolator
Ordering Options
X = # of high speed channels
See 1. Ordering Guide for
more information.
Y = S, P
S = serial outputs
P = parallel outputs
U = Debounce option
F = fast debounce, 10 ms
M = slower debounce, 30 ms
S = slow debounce, 100 ms
Line 2 Marking:
YY = Year
WW = Workweek
Assigned by the Assembly House. Corresponds to the year and workweek
of the mold date and manufacturing code from Assembly Purchase Order
form.
TTTTTT = Mfg Code
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 26
Si838x Data Sheet
Document Change List
10. Document Change List
10.1 Revision 0.5
April 4, 2016
• Initial release.
silabs.com | Smart. Connected. Energy-friendly.
Rev. 0.5 | 27
Table of Contents
1. Ordering Guide
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Functional Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1 Theory of Operation .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. 2
2.2 Serial Peripheral Interface . . . .
2.2.1 SPI Register Map . . . . . .
2.2.2 SPI Communication Transactions
2.2.3 SPI Read Operation . . . . .
2.2.4 SPI Write Operation . . . . .
2.2.5 SPI Daisy Chain Organization . .
2.2.6 SPI Interface Timing Specification
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
2.3 Debounce Filter . . . . . .
2.3.1 Debounce Control Registers .
2.3.2 Debounce Filtering Modes . .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. 6
. 7
. 8
2.4 Typical Operating Characteristics .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
. 9
3. Device Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10
3.1 Device Start-up .
.
.
.
.
.
2
2
3
4
4
5
6
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.10
3.2 Undervoltage Lockout .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.10
3.3 Layout Recommendations.
3.3.1 Supply Bypass . . . .
3.3.2 Output Pin Termination .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.10
.11
.11
4. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . .
12
5. Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19
5.1 System Level Transitions with the Si838x
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.19
5.2 IEC 61131-2 Compliance Options .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.20
5.3 Custom Bill of Materials
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.20
6. Pin and Package Definitions. . . . . . . . . . . . . . . . . . . . . . . . .
21
6.1 Pin Descriptions .
23
8. Land Pattern
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25
9. Top Marking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26
10. Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . .
27
.
.
.
.
.
.
7. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.
.
.
.21
.
.
.
.
10.1 Revision 0.5 .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.27
Table of Contents
28
Smart.
Connected.
Energy-Friendly.
Products
Quality
www.silabs.com/products
www.silabs.com/quality
Support and Community
community.silabs.com
Disclaimer
Silicon Laboratories intends to provide customers with the latest, accurate, and in-depth documentation of all peripherals and modules available for system and software implementers using
or intending to use the Silicon Laboratories products. Characterization data, available modules and peripherals, memory sizes and memory addresses refer to each specific device, and
"Typical" parameters provided can and do vary in different applications. Application examples described herein are for illustrative purposes only. Silicon Laboratories reserves the right to
make changes without further notice and limitation to product information, specifications, and descriptions herein, and does not give warranties as to the accuracy or completeness of the
included information. Silicon Laboratories shall have no liability for the consequences of use of the information supplied herein. This document does not imply or express copyright licenses
granted hereunder to design or fabricate any integrated circuits. The products are not designed or authorized to be used within any Life Support System without the specific written consent
of Silicon Laboratories. A "Life Support System" is any product or system intended to support or sustain life and/or health, which, if it fails, can be reasonably expected to result in significant
personal injury or death. Silicon Laboratories products are not designed or authorized for military applications. Silicon Laboratories products shall under no circumstances be used in
weapons of mass destruction including (but not limited to) nuclear, biological or chemical weapons, or missiles capable of delivering such weapons.
Trademark Information
Silicon Laboratories Inc.® , Silicon Laboratories®, Silicon Labs®, SiLabs® and the Silicon Labs logo®, Bluegiga®, Bluegiga Logo®, Clockbuilder®, CMEMS®, DSPLL®, EFM®, EFM32®,
EFR, Ember®, Energy Micro, Energy Micro logo and combinations thereof, "the world’s most energy friendly microcontrollers", Ember®, EZLink®, EZRadio®, EZRadioPRO®, Gecko®,
ISOmodem®, Precision32®, ProSLIC®, Simplicity Studio®, SiPHY®, Telegesis, the Telegesis Logo®, USBXpress® and others are trademarks or registered trademarks of Silicon Laboratories Inc. ARM, CORTEX, Cortex-M3 and THUMB are trademarks or registered trademarks of ARM Holdings. Keil is a registered trademark of ARM Limited. All other products or brand
names mentioned herein are trademarks of their respective holders.
Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
USA
http://www.silabs.com
工商网监
湘ICP备2023018690号
