Si834x Data Sheet
Isolated Smart Switch
KEY FEATURES
The Si834x provides four isolated high-side or low-side switches with low R
ON
. These switches
are ideal for driving resistive and inductive loads like solenoids, relays, and lamps commonly
found in industrial control systems like Programmable Logic Controllers (PLC). Each switch is
galvanically isolated for safety using Silicon Labs’ groundbreaking CMOS-based isolation tech-
nology, offering better reliability and performance than the traditional optocoupler-based isola-
tion, including high Common-Mode Transient Immunity (CMTI) over 100 kV/µs.
The logic interface supports low-power 2.25 V MCUs, while the switches offer a wide supply
range of 9 V – 32 V ideal for industrial voltage levels. The switches are capable of providing 0.7
A depending on load conditions. Each switch offers complete fault protection. An innovative
multi-voltage clamp efficiently handles an unlimited amount of demagnetization energy (E
AS
).
The over-current protection includes an Inrush Current Mode to drive loads like lamps. Addi-
tionally, the device power supplies are monitored, and the switches are safely constrained or
shutdown on faults.
Eight diagnostics are reported through the logic interface, offering an unprecedented level of
details and control. Diagnostics are configured, monitored, and cleared via the Serial Peripheral
Interface (SPI) or exposed on active-low, open-drain indicator pins for easy access and
combination. Diagnostic communication is independent of switch control signals, with separate
isolation channels and constant error checking, ensuring long-term reliability.
Applications
• Programmable logic controllers
• Industrial data acquisition
• Motion controllers
• Smart solid-state relays
NC
A1
4x Input Interface
A2
A3
A4
OE
• High-side or low-side switch
• Logic Supply: 2.25 V – 5.5 V
• Switch Supply: 9 V – 32 V
• Fast (10 µs) update rate
• High continuous current (700 mA)
and low R
ON
(145 mΩ)
• Unique multi-voltage output clamp
• Unlimited demagnetization (E
AS
)
• Efficient and fast turn-OFF
• Inrush Current Mode: 8 A for 20 ms
• Current-limited overload protection
• Over-temperature protection
• Undervoltage protected supplies
• Up to 8 different diagnostics
• Multiple power supply reports
• Over-current, over-temperature
• Open-circuit warning
• Communication error
• Channel status indicators
• Dedicated fault indicator
• Disable outputs asynchronously
• Control 128 channels via SPI
• 1.5 kV
RMS
safety rated isolation
• Transient immunity > 100 kV/μs
• Compliant to IEC 61131-2
• Compact 9x9 DFN-32 package
• 5 kV ESD Protection
• -40 – 125 ˚C operating temperature
Safety Approvals (Pending)
• UL 1577 recognized: Up to 1500 Vrms for 1 minute
• CSA certified under: IEC 60950-1, 62368-1
• VDE certification conformity: VDE 0884-10
• CQC certification approval: GB4943.1
GND2
DNC
GND2
VDD2
B1
4x High-Side Switches
VDD2
B2
VDD2
B3
VDD2
B4
VDD2
NC
A1
A2
A3
A4
OE
4x Input Interface
GND2
DNC
VDD2
GND2
B1
Isolation Barrier
Isolation Barrier
GND1
FLT
VDD1
Status & Diagnostics
GND1
MOSI_THRU
NSS
SCLK
MOSI
MISO
NC
GND1
FLT
VDD1
GND1
VDD2_WRN
LED1
LED2
LED3
LED4
NC
Status & Diagnostics
4x Low-Side Switches
GND2
B2
GND2
B3
GND2
B4
GND2
6x Transmitters/
1x Receiver
6x Transmitters/
1x Receiver
6x Receivers/
1x Transmitter
6x Receivers/
1x Transmitter
Sensors &
Protection
GND2
VDD2
DNC
GND2
Sensors &
Protection
VDD2
VDD2
DNC
GND2
Si83408AFA-IF
Si83414AAA-IF
silabs.com
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Rev. 0.5
Si834x Data Sheet
Ordering Guide
1. Ordering Guide
Table 1.1. Si834x Ordering Guide
Output
1
Switch
Type
Continuous
Output
Current
Channel
Status
Indicators
Low
Voltage
Indicator
Open
Channel
Indicator
Clear
Fault
Input
Ordering Part
Number
Input
2
Interface
Output
Channels
Iso.
Rating
Products Available Now
Si83404AAA-IF
Si83408ADA-IF
Si83408AFA-IF
Si83414AAA-IF
Si83418ADA-IF
Si83418AFA-IF
Sinking
Sourcing
Parallel
SPI
Parallel/
SPI
Parallel
SPI
Parallel/
SPI
4
0.7 A
No
4
0.7 A
No
Yes
Yes
No
No
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
1.5
kVrms
Yes
Contact Silicon Labs Sales for These Options
Si83404ABA-IF
Si83404ACA-IF
Si83414ABA-IF
Si83414ACA-IF
Sourcing
Parallel
4
0.7 A
Yes
No
No
No
No
Yes
No
Yes
No
No
Yes
No
Yes
1.5
kVrms
Sinking
Parallel
4
0.7 A
Yes
Note:
1. Output switch can source current in a high-side, open-source configuration or sink current in a low-side, open-drain configuration.
2. SPI provides access to all diagnostic, configuration, and channel status information. Devices without a parallel interface allow out-
put channel control through the SPI as well.
3. "Si" and "SI" are used interchangeably.
4. An "R" at the end of the Ordering Part Number indicates tape and reel option.
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Rev. 0.5 | 2
Table of Contents
1. Ordering Guide
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Device Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Truth Tables .
3.3 Switch Types
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. 7
.12
.13
.13
.14
.15
.18
.20
.23
.24
.25
.26
.27
.27
.28
.28
.29
.32
.33
.33
.34
.35
3.2 Switch Timing Behavior .
3.4 Switch Protection . . . . . . . . . . . . .
3.4.1 Demagnetization Energy Protection . . . . .
3.4.2 Over-Current Protection with Inrush Current Mode
3.4.3 Over-Temperature Protection . . . . . . .
3.4.4 Power Supply Protection . . . . . . . . .
3.5 Diagnostics and Monitoring . . . .
3.5.1 Power Supply Diagnostics. . .
3.5.2 Over-Temperature Diagnostics .
3.5.3 Over-Current Diagnostics . . .
3.5.4 Open-Circuit Diagnostics . . .
3.5.5 Communication Error Diagnostics
3.5.6 Channel Status Monitoring . .
3.6 Serial Peripheral Interface . . . .
3.6.1 SPI Register Map . . . . .
3.6.2 SPI Communication Transactions
3.6.3 SPI Read Operation . . . . .
3.6.4 SPI Write Operation . . . . .
3.6.5 SPI Daisy Chain Organization .
3.6.6 SPI Timing Behavior . . . .
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4. Application Information
. . . . . . . . . . . . . . . . . . . . . . . . . . 36
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.36
.36
.38
.39
.41
.42
4.1 Recommended Application Circuits . . . . . . . . . . .
4.1.1 Isolated Switch with Parallel Inputs and Diagnostic Indicators .
4.1.2 Isolated High-Side Switch with Parallel Inputs and Fault Control
4.1.3 Isolated High-Side Switch with SPI . . . . . . . . . .
4.2 Layout Considerations .
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4.3 Power Dissipation Considerations
5. Electrical Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . . 44
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.54
5.1 Typical Operating Characteristics.
6. Pin and Package Descriptions . . . . . . . . . . . . . . . . . . . . . . . . 59
6.1 Pin Descriptions
6.3 Land Pattern.
6.4 Top Marking .
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.59
.63
.65
.66
6.2 Package Drawing .
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7. Revision History
7.1 Revision 0.5 .
.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
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.67
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Rev. 0.5 | 4
Si834x Data Sheet
System Overview
2. System Overview
A single channel of the Si834x Isolated Smart Switch is analogous to that of an optocoupler and a relay driver, except that an RF carrier
is modulated across the isolation barrier instead of light. This simple architecture provides a robust isolation path and requires no spe-
cial considerations or initialization at startup. The RF carrier is modulated using methods that optimize fault tolerance and propagation
delay across the isolation barrier.
Switch
Control
4 Parallel Channels
Figure 2.1. Parallel/SPI Sourcing Device System Diagram
The fundamental channel structure described above is augmented using a number of innovative technologies. The output switch is a
low ON-State Resistance (R
ON
) device capable of driving inductive and resistive loads at continuous currents of 700 mA. It includes
precise voltage, current, and temperature sensors that continuously monitor the switch and load conditions, protecting the device by
reducing driver performance or forcing a controlled shutdown when necessary.
The switch uses a sophisticated multi-voltage output clamp, called a “smart output clamp”, that both protects the switch from harmful
inductive kickback voltage (or back EMF) while still offering fast demagnetization of inductors to reduce contact arcing and increase
switching speed.
Four identical channels are packaged together into an Si834x device, each with its own set of sensors. Switches are controlled using
dedicated isolation channels which increase reliability and timing performance. A bidirectional, fault-tolerant isolation channel is also
implemented between the switch and logic interface, allowing the host controller to configure, monitor, and diagnose the switches and
their loads.
The logic interface offers dedicated parallel input channels and an asynchronous output enable (OE) pin for high speed switch control
as well as a rich SPI for diagnostics and monitoring. Eight different diagnostic reports are available in the device status registers ac-
cessed via SPI which provide a complete picture of device and load condition. See
Diagnostics and Monitoring
for more information on
the available reports.
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