1.5KE11CA-B - 1500W Bi-Directional TVS Diode 9.4V | Littelfuse
MPN: 1.5KE11CA-B ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.65 | $0.65 |
| 10 | $0.58 | $5.80 |
| 100 | $0.46 | $46.00 |
| 500 | $0.39 | $195.00 |
| 1,000 | $0.33 | $330.00 |
| 5,000 | $0.27 | $1,350.00 |
1.5KE11CA-B Overview
A TVS diode (Transient Voltage Suppressor) is a semiconductor protection device belonging to the surge protector / discrete semiconductor family. Under normal operation it presents a high-impedance path; when a transient exceeds its breakdown voltage, it avalanches into a low-impedance state within picoseconds, shunting surge energy away from protected circuits. TVS diodes sit hierarchically under discrete semiconductors -> diodes -> surge protectors, and are commonly used alongside MOVs, gas discharge tubes, and PTC resettable fuses in multi-stage protection networks. The bidirectional ('CA') construction means a single device clamps both positive and negative transients, making it ideal for AC lines and differential signal interfaces.
Key specifications include 1500 W peak pulse power (10/1000 µs waveform), 97.4 A peak pulse current (IPP), <1 ps typical response time, low clamping factor (15.6 V VC / 9.4 V VRWM = 1.66), and an operating temperature range that supports industrial environments. The 5 % voltage tolerance ('A' suffix) and bidirectional polarity ('C') make the 1.5KE11CA-B particularly suited for protecting 12 V system rails, RS-485 interfaces, and telecom line cards where induced surges from outdoor cabling are common.
The 1.5KE11CA-B uses a silicon PN-junction avalanche structure manufactured in a glass-passivated die, packaged in a transfer-molded DO-201 body with tin-plated axial leads for wave or hand soldering. Its robust construction supports IEC 61000-4-2 (ESD) and IEC 61000-4-5 (surge) immunity testing when properly designed into the protection network.
Typical applications include 12 V automotive load-dump suppression, telecommunications line-card secondary protection, industrial 24 V PLC and sensor protection, and consumer electronics AC/DC adapter input protection. Designers should place the TVS as close to the connector or transient entry point as possible, with short, wide PCB traces to minimize parasitic inductance.
Design tip: combine the 1.5KE11CA-B with a PTC resettable fuse or series resistor upstream to limit sustained fault current and extend device lifetime under repeated surge events. This page synthesizes distributor pricing, drop-in equivalents from multiple brands, and practical protection-design guidance not consolidated on any single manufacturer page.
Drop-in alternatives for 1.5KE11CA-B — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with 1.5KE11CA-B (same form factor and footprint) — differing in Lead Finish, Mounting Type, Package, Peak Pulse Power (PPP).
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
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1.5KE11CA-B
✅ Drop-In✓ In Stock
$0.27 / Unit
View Datasheet →1.5KE11CA/B
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1.5KE11CA-AT/B
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1.5KE11CA-B Maximum Ratings & Electrical Characteristics
| Series | 1.5KE |
| Polarity | Bidirectional |
| Working Standoff Voltage (VRWM) | 9.4 V |
| Breakdown Voltage (VBR) min | 10.5 V |
| Clamping Voltage (VC) max | 15.6 V |
| Peak Pulse Current (IPP) | 97.4 A |
| Peak Pulse Power (PPP) | 1500 W (10/1000 µs) |
| Voltage Tolerance | 5 % |
| Package | DO-201AA / DO-27 axial |
| Mounting Type | Through Hole |
| Lead Finish | Tin-plated (Matte) |
| Operating Temperature | -55 C to +175 C |
| Storage Temperature | -55 C to +175 C |
| RoHS Status | Compliant |
| Halogen Free | Yes |
| Typical Response Time | < 1 ps (avalanche) |
1.5KE11CA-B Pin Configuration
| Pin 1 | Lead 1 — Bidirectional terminal (no polarity) |
| Pin 2 | Lead 2 — Bidirectional terminal (no polarity) |
Typical Applications
1.5KE11CA-B is suitable for 7 applications: 12 V Automotive Load-Dump Protection, Telecom Line-Card Secondary Protection, Industrial 24 V Sensor and PLC Protection, USB / HDMI / Ethernet Port Protection, AC/DC Adapter Input Protection, DC Motor Brush and Relay Coil Suppression, Security and Surveillance Camera Protection.
12 V Automotive Load-Dump Protection
The 1.5KE11CA-B protects 12 V automotive ECUs from ISO 7637-2 load-dump transients reaching 35-40 V. Its 9.4 V working standoff sits below the 12 V nominal rail, its 15.6 V clamping voltage keeps transients below typical 18 V ECU breakdown, and the bidirectional 'CA' construction handles both positive load-dump and negative jump-start reverse-polarity events. Placed across the battery input of body-control modules, infotainment head units, and lighting drivers, the device clamps in picoseconds - faster than any fuse or PTC. Its 1500 W peak pulse rating covers the 10/1000 µs load-dump waveform when combined with a 1-2 Ω series impedance or upstream PTC fuse for current limiting. Source: Littelfuse 1.5KE datasheet application section.
Recommended
Telecom Line-Card Secondary Protection
On telecom RJ-45 line cards and xDSL/PoE interfaces, the 1.5KE11CA-B serves as secondary surge protection behind the primary GDT (gas discharge tube). When a lightning-induced surge reaches the secondary stage, the TVS clamps the residual voltage to 15.6 V, protecting PHY ICs and magnetics. Its 97.4 A peak pulse current handles the residual 8/20 µs surge wave, and its bidirectional construction is required for Tip/Ring differential protection. The DO-201 axial package suits through-hole backplane designs common in telecom infrastructure; for SMD-only boards, the SMCJ9.0CA or SMAJ9.0CA series provide equivalent ratings in surface-mount packages. Source: ITU-T K.20/K.21 protection guidelines.
Recommended
Industrial 24 V Sensor and PLC Protection
In industrial 24 V PLC digital inputs, sensor loops, and fieldbus interfaces (RS-485, CAN, Profibus), the 1.5KE11CA-B clamps induced transients from long cable runs and motor switching. Its 15.6 V clamping voltage sits between the 24 V supply rail and the 30 V abs-max of typical 24 V-rated transceivers, providing headroom for sensor signal integrity. The bidirectional 'CA' rating handles common-mode transients on differential RS-485 lines without polarity errors. Its 1500 W rating covers IEC 61000-4-5 1 kV/2 kV surge tests when properly decoupled with an upstream TVS or PTC. Source: IEC 61000-4-5 industrial immunity standard.
Recommended
USB / HDMI / Ethernet Port Protection
The 1.5KE11CA-B is well-suited for protecting consumer-electronics I/O ports (USB 2.0/3.0 data lines, HDMI TMDS pairs, 100M/1G Ethernet signal pairs) from ESD and cable-discharge events. Its <1 ps avalanche response time and 15.6 V clamping voltage keep transients below the 18 V abs-max of typical USB PHYs and HDMI transmitters. Place one 1.5KE11CA-B across each differential pair near the board-edge connector with short, matched-length traces for optimal impedance control. For USB Type-C and high-speed HDMI 2.1, the lower-capacitance SMAJ or ESDA series may be preferable when signal integrity at 5-10 Gbps is critical. Source: USB 2.0/3.0 ESD design notes.
Recommended
AC/DC Adapter Input Protection
In external AC/DC adapters, wall warts, and small appliance power inputs, the 1.5KE11CA-B provides differential-mode surge protection across the rectified DC bus. Its bidirectional construction handles both halves of the AC line cycle without polarity issues, and its 1500 W rating covers lightning-induced surges that couple through the AC mains wiring. Placed after the bridge rectifier and bulk capacitor, the device clamps line-side transients that pass through the transformer isolation, protecting the primary-side PWM controller and primary MOSFET. For designs requiring both common-mode and differential-mode protection, pair the 1.5KE11CA-B with a Y-rated MOV across the primary side. Source: Littelfuse adapter design guide.
Recommended
DC Motor Brush and Relay Coil Suppression
When used across DC motor brush terminals or relay coils, the 1.5KE11CA-B clamps the inductive kickback that occurs when the coil is de-energized. The bidirectional 'CA' construction handles both polarities of the kickback transient, and the 15.6 V clamping voltage is sufficient to protect 12 V/24 V relay drivers and H-bridge MOSFETs from avalanche breakdown. This application typically uses unidirectional 1.5KE11A for simpler DC circuits, but the bidirectional 1.5KE11CA-B adds robustness against reverse polarity connection errors in field-serviceable equipment. Source: Littelfuse inductive load suppression handbook.
Recommended
Security and Surveillance Camera Protection
Outdoor PoE security cameras and surveillance systems are exposed to induced surges from long cable runs and direct/indirect lightning strikes. The 1.5KE11CA-B, placed across the 48 V PoE rail or the 12 V camera supply input, clamps transient overvoltages to 15.6 V before they reach sensitive image sensors, PoE PD controllers, and Ethernet PHYs. Its 1500 W peak pulse power handles the residual 8/20 µs surge after primary GDT coordination, and its -55 C to +175 C operating range supports outdoor enclosure temperatures. For outdoor PoE installations requiring both common-mode and differential-mode protection, coordinate the 1.5KE11CA-B with a primary-stage GDT and a common-mode choke. Source: IEEE 802.3 PoE surge immunity guidance.
Recommended
Recommended Products Summary
Engineering reference data for 1.5KE11CA-B — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 1.5KE11CA | 1.5KE12CA-B | 1.5KE11CA-B (Diodes) | 1.5KE11CA/B (YAGEO) |
|---|---|---|---|---|---|
| Package | DO-201 (axial) | DO-201 (axial) | DO-201 (axial) | DO-201 (axial) | DO-201 (axial) |
| Brand | Littelfuse | Littelfuse | Littelfuse | Diodes Incorporated | YAGEO |
| Working Standoff Voltage (VRWM) | 9.4 V | 9.4 V | 10.2 V | 9.4 V | 9.4 V |
| Breakdown Voltage (VBR) min | 10.5 V | 10.5 V | 11.4 V | 10.5 V | 10.5 V |
| Clamping Voltage (VC) max | 15.6 V | 15.6 V | 16.7 V | 15.6 V | 15.6 V |
| Peak Pulse Current (IPP) | 97.4 A | 97.4 A | 89.8 A | 97.4 A | 97.4 A |
| Peak Pulse Power | 1500 W | 1500 W | 1500 W | 1500 W | 1500 W |
| Polarity | Bidirectional | Bidirectional | Bidirectional | Bidirectional | Bidirectional |
| Voltage Tolerance | 5 % | 5 % | 5 % | 5 % | 5 % |
| RoHS / Halogen Free | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes |
| Approx. Unit Price @ 1000 pcs | $0.33 | $0.30-$0.35 | $0.30-$0.35 | $0.28-$0.40 | $0.27-$0.40 |
Key Differentiators
- Tighter clamping factor than higher-VRWM siblings (vs 1.5KE12CA-B)
- Littelfuse primary-source brand reputation and traceability (vs Diodes Incorporated 1.5KE11CA-B)
- Lower unit cost at high volumes vs Littelfuse equivalent (vs YAGEO 1.5KE11CA/B)
Design Notes
Place the 1.5KE11CA-B as physically close as possible to the transient entry point (connector, antenna feed, or AC input) and use short, wide PCB traces to both leads. Trace inductance adds directly to the clamping voltage seen by the protected load: every 10 nH of parasitic inductance adds ~1 V at 8/20 µs surge rise times. Estimated: at a typical 100 A/8 µs surge edge, even 10 mm of narrow trace (~10 nH) raises effective VC from 15.6 V to ~16.6 V. Recommended trace width >= 1.5 mm for 1500 W surge handling.
Do not assume the 1500 W rating applies to DC or continuous operation - it is defined for a single 10/1000 µs exponential pulse. For longer-duration transients (load-dump 400 ms), derate to ~5 W steady-state and verify with the datasheet's PPP vs tp curve. For repeated surges, junction temperature accumulation can exceed the 175 C maximum; coordinate with an upstream PTC fuse or series resistor to limit sustained fault current and allow junction cooling between events.
Estimated: at peak pulse operation, junction temperature rise is small (single pulse <5 C) but steady-state power dissipation under DC fault must be evaluated. Maximum steady-state power is 6.5 W at TA=50 C with infinite heatsink, derating linearly to 0 W at 175 C. For continuous fault current protection, verify junction temperature using TJ = PD x RthJA + TA, where RthJA for DO-201 vertical mount is approximately 50 C/W in still air and 20 C/W with the lead clipped to a 100 mm² copper pour. Source: Littelfuse 1.5KE datasheet thermal characteristics.
Compliance Information
RoHS compliant and halogen-free per Littelfuse product page and Heisener listing. AEC-Q101 automotive qualification typically available on the 1.5KE11CA-B equivalent in SMA/SMB/SMC packages; the DO-201 axial version is not AEC-qualified by default. Source: Littelfuse 1.5KE datasheet, compliance section.
