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Littelfuse C&K SDE end-stackable SMT DIP switches. Reading Time: 6 mins read Littelfuse has introduced the C&K SDE series of end-stackable surface-mount DIP switches for low-power configuration circuits. The Littelfuse DIP switches family combines a 0.1-inch switch-position pitch with flush or extended actuators and gull-wing terminals. Side-by-side stacking supports configurable switch banks, while top-tape-sealed versions support washable board processing. Key features and benefits. * End-stackable construction supports adjacent switch packages on a standard 0.1-inch pitch. * Position counts cover 1 through 10 and 12, with independent single-pole, single-throw contacts. * Contact ratings distinguish 25 mA switching at 24 V DC from 100 mA non-switching duty. * Copper-alloy contacts have gold plating over nickel; maximum contact resistance is 100 mΩ. * Flush and extended actuators provide alternative mechanical arrangements for configuration access. * Top-tape-sealed versions support washable processing. Versions without tape are also available. * Tube and tape-and-reel packaging support different assembly flows. * All plastics are UL 94 V-0 grade. The series is RoHS compliant and halogen-free. Technical highlights. Electrical ratings and endurance. The switching and non-switching current ratings serve different duties. A contact carrying a static current within the 100 mA non-switching limit must still remain within the 25 mA switching limit when its position changes. This distinction matters where configuration settings can be adjusted while the board is powered. The insulation-resistance and dielectric-strength values are test characteristics, not alternative working-voltage ratings. Circuit selection should use the 24 V DC contact rating rather than the dielectric withstand value. The 1,000-cycle mechanical and electrical life makes expected adjustment frequency a selection factor. Installation and service settings should be assessed against the total number of changes anticipated over the equipment's operating life. Construction and assembly. The case and cover use PPS, and the actuator uses LCP. Both materials are UL 94 V-0 grade. Contacts use copper alloy with gold plating over nickel; the insert-moulded copper-alloy terminals have gold flash over nickel. The tape seal is polyimide. The package uses a moulded 0.3-inch integrated-circuit packing outline for automatic insertion. Gull-wing terminations provide the surface-mount connection, and the soldering reference is IPC/JEDEC J-STD-020D. Top-tape sealing is an ordering choice rather than a feature of every configuration. The sealing code is therefore important when washable processing forms part of the assembly route. Package options and ordering. The ordering structure separates position count, actuator, termination, contact material, sealing and packaging. For example, SDE04H0SBR is a four-position, flush-actuator version with gull-wing terminals, gold contacts, top-tape sealing and tape-and-reel packaging. SDE08H1SBDR is an eight-position version with an extended actuator, no tape seal and tape-and-reel packaging. Body length increases with position count. Selected dimensions illustrate the space required along the switch bank: End stacking allows packages to form a longer bank, but additional positions still require board length and corresponding connections. A PCB intended to support different populated configurations should reserve the necessary land patterns and actuator access from the outset. Typical applications and application fit. Target applications include industrial control equipment, garage door systems, security and fire systems, and IoT devices. Within these systems, the 24 V DC, 25 mA switching rating supports low-power configuration duties. The independent SPST contacts and available position counts allow the switch bank to match the number of configuration settings required. For industrial controls, the main selection points are contact voltage, current during adjustment and the required number of positions. Garage door, security and fire-system boards require the same separation between configuration switching and higher-current circuit functions. In IoT devices, package length and actuator access must be considered together. A flush actuator changes the mechanical arrangement, while an extended actuator changes access requirements; neither option removes the need to accommodate the selected position count. Design-in notes for engineers. * Check the electrical duty. Assess the voltage across an open contact and the current through a closed contact, including the conditions present when a setting changes. * Separate switching from static current. Apply the 25 mA switching limit during actuation rather than treating the 100 mA non-switching rating as an interchangeable limit. * Select the complete ordering code. Position count, actuator style, sealing and packaging must match the BOM and assembly route. * Use the SDE land pattern. Check terminal geometry, package tolerances and adjacent-package spacing before layout release. * Reserve actuator access. Account for neighbouring components, enclosure features and the intended adjustment method. * Match sealing to cleaning. Choose the top-tape-sealed configuration where washable processing is required. * Establish the assembly state. All switches are supplied in the OFF position; production programming and inspection should account for the required final settings. * Assess adjustment frequency against the 1,000-cycle mechanical and electrical life. * Validate final selection under the actual electrical, mechanical and assembly conditions before production release. Tube and tape-and-reel packaging are available. Samples can be requested through authorised Littelfuse distributors. This article is based on the Littelfuse product announcement and official product documentation. Engineers should refer to the current manufacturer datasheet for final design and qualification.

Ultra-low capacitance TVS diode arrays. 7 October 2026 Littelfuse has announced AQ4315-01ETG and SP4315-01WTG, two new Bidirectional TVS Diode Arrays (SPA Diodes) that combine industry-leading low clamping voltage with ultra-low capacitance to protect today's fastest automotive and consumer data interfaces from electrostatic discharge (ESD) without compromising signal integrity. High-speed interfaces such as automotive ADAS, DisplayPort, and USB4 are increasingly vulnerable to ESD damage as data-line voltages drop below 1 V to save energy and reduce EMI. Conventional TVS diodes force a trade-off between low clamping voltage and low capacitance, and many competing devices advertise a lower breakdown voltage while still clamping at levels that leave protected chips exposed to damage. The AQ4315-01ETG and SP4315-01WTG close that gap, holding clamping voltage to a typical 4.5V to 6.5V while suppressing ESD transients ranging from 8,000V to 20,000V down to well under 10V at the protected device, an 800- to 2,000-times reduction in the voltage and current reaching the IC and keeping it safely within its Safe Operating Area (SOA). "The industry is moving toward lower-voltage, higher-speed interfaces faster than traditional ESD protection can keep up," said Sophia Hu, Assistant Product Marketing Manager, Diode Arrays, Littelfuse Protection Business Unit. "The AQ4315-01ETG and SP4315-01WTG give designers an extremely low clamping voltage without the capacitance penalty, so they gain stronger ESD and surge protection while preserving the signal integrity and board space their next-generation automotive and consumer designs demand." Key features and benefits. Ultra-low clamping voltage: typical 4.5V to 6.5V during an ESD strike, as much as a tenfold improvement over comparable TVS diodes * Ultra-low capacitance: 0.25pF (AQ4315-01ETG) or 0.17pF (SP4315-01WTG) to preserve high-speed signal integrity * High ESD withstand: +/-15kV contact and +/-20kV air per IEC 61000-4-2; the AQ4315-01ETG also qualifies to ISO10605 * Automotive-grade reliability: AQ4315-01ETG is AEC-Q101 qualified and PPAP capable, rated -40°C to 150°C * Industry-standard packaging: SOD-882/DFN1006 (AQ4315-01ETG) and 0201 WLCSP flip-chip (SP4315-01WTG) for fast, easy design-in * Low leakage current: 50nA maximum to minimise power consumption in battery-powered and always-on designs * Broad protection margin: suppresses ESD transients of 8,000V to 20,000V to well under 10V at the protected device Target markets and applications. * Automotive ADAS, DisplayPort, and Gigabit Multimedia Serial Link (GMSL) interfaces * Gigabit Video Interface (GVIF) and Low Voltage Differential Signalling (LVDS) links * 2.5G/5G/10G automotive and consumer Ethernet * Thunderbolt 5.0, USB 3x, and USB4 consumer computing interfaces * Consumer DisplayPort and other high-speed data line interfaces * Industrial machine-to-machine communication protocols and legacy USB interfaces * Space-constrained wearable and portable consumer electronics The AQ4315-01ETG and SP4315-01WTG extend the Littelfuse SPA Diode portfolio into a new class of ultra-low-voltage ESD protection as automotive and consumer interfaces adopt progressively lower data-line voltages, some running below 1V. Both devices let design teams move quickly from inferior protection schemes to a solution engineered for today's most sensitive, highest-speed interfaces. Keep up to date with the most important news. Sensirion environmental sensors enable advanced air quality monitoring. Farnell to strengthen rugged connectivity solutions globally. 7 October 2026

Littelfuse launches new ultra-low capacitance TVS Diode Arrays. Published: 7 October 2026 Littelfuse, an industrial technology manufacturing company, has unveiled two new Bidirectional TVS Diode Arrays (SPA Diodes), the AQ4315-01ETG and SP4315-01WTG, that combine low clamping voltage with ultra-low capacitance to protect the fastest automotive and consumer data interfaces from electrostatic discharge (ESD) without compromising signal integrity High-speed interfaces, such as automotive ADAS, DisplayPort, and USB4, are increasingly vulnerable to ESD damage as data-line voltages drop below 1V to save energy and reduce EMI. Conventional TVS diodes force a trade-off between low clamping voltage and low capacitance. The AQ4315-01ETG and SP4315-01WTG can hold clamping voltage to a typical 4.5V to 6.5V while suppressing ESD transients ranging from 8,000V to 20,000V down to under 10V at the protective device, an 800- to 2,000-fold reduction in the voltage and current reaching the IC and keeping it within its Safe Operating Area (SOA). Sophia Hu, assistant product marketing manager, Diode Arrays, Littelfuse Protection Business Unit, said, "The industry is moving toward lower-voltage, higher-speed interfaces faster than traditional ESD protection can keep up. The AQ4315-01ETG and SP4315-01WTG give designers an extremely low clamping voltage without the capacitance penalty, so they gain stronger ESD and surge protection while preserving the signal integrity and board space their next-generation automotive and consumer designs demand." Key features and benefits. * Ultra-low clamping voltage: typical 4.5V to 6.5V during an ESD strike * Ultra-low capacitance: 0.25pF (AQ4315-01ETG) or 0.17pF (SP4315-01WTG) to preserve high-speed signal integrity * High ESD withstand: +/-15kV contact and +/-20kV air per IEC 61000-4-2; the AQ4315-01ETG also qualifies to ISO10605 * Automotive-grade reliability: AQ4315-01ETG is AEC-Q101 qualified and PPAP capable, rated -40°C to 150°C * Industry-standard packaging: SOD-882/DFN1006 (AQ4315-01ETG) and 0201 WLCSP flip-chip (SP4315-01WTG) * Low leakage current: 50nA maximum to minimise power consumption in battery-powered and always-on designs * Broad protection margin: suppresses ESD transients of 8,000V to 20,000V to under 10V at the protected device Target markets and applications. * Automotive ADAS, DisplayPort, and Gigabit Multimedia Serial Link (GMSL) interfaces * Gigabit Video Interface (GVIF) and Low Voltage Differential Signalling (LVDS) links * 2.5G/5G/10G automotive and consumer Ethernet * Thunderbolt 5.0, USB 3x, and USB4 consumer computing interfaces * Consumer DisplayPort and other high-speed data line interfaces * Industrial machine-to-machine communication protocols and legacy USB interfaces * Space-constrained wearable and portable consumer electronics The AQ4315-01ETG and SP4315-01WTG extend the Littelfuse SPA Diode portfolio into a new class of ultra-low-voltage ESD protection as automotive and consumer interfaces adopt progressively lower data-line voltages, some running below 1 V. Both devices let design teams adopt a solution engineered for sensitive, high-speed interfaces.