My Inquiry
My Account
Microchip Technology SMAJ4738E3/TR13
- Part No.:
- SMAJ4738E3/TR13
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ4738E3/TR13.pdf
- Description:
- DIODE ZENER 8.2V 2W DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,362
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMAJ4738E3/TR13 from SM Semiconductor is a 8.2 V, ±5% tolerance Zener diode in SMA (DO-214AC) package, rated for 2.0 W steady-state power dissipation, 220 mA maximum regulator current at 100°C, and 550 mA peak surge current. It serves as a precision voltage reference and transient overvoltage clamp in low-profile DC power rails and signal line protection circuits.
For engineers reviewing the SMAJ4738E3/TR13 datasheet, SMAJ4738E3/TR13 pinout, SMAJ4738E3/TR13 application, or SMAJ4738E3/TR13 equivalent, key selection criteria include zener voltage tolerance, thermal resistance (25°C/W), reverse leakage at rated voltage (10 µA @ 6.0 V), surge current capability, and ROHS-compliant matte-tin plating for reliable solderability.
Technical Context
This device operates as a silicon planar Zener diode with sharp breakdown knee, specified at 31 mA test current (IZT) and 0.5 mA knee current (IZK). Its dynamic impedance is 4.5 Ω at IZT, ensuring stable regulation across varying load currents and temperatures from –65°C to +150°C.
The SMAJ4738E3/TR13 features void-free thermosetting epoxy encapsulation (UL94V-0), cathode band polarity marking, and a 0.3 g mass. It is designed for axial-lead mounting and achieves thermal equilibrium within 90 seconds under DC bias.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage | 8.2 V ±5% at 31 mA - defines precise clamping threshold for overvoltage protection |
| Power Dissipation | 2.0 W steady-state - supports continuous regulation without forced cooling in compact layouts |
| Surge Current | 550 mA (1/2 sine wave, 1/120 s) - withstands repetitive inductive switching transients |
| Reverse Leakage | 10 µA max at 6.0 V - ensures minimal standby power loss in high-impedance bias networks |
| Thermal Resistance | 25 °C/W junction-to-lead - enables direct lead heat sinking for sustained 220 mA operation at 100°C |
| Knee Impedance | 700 Ω at 0.5 mA - maintains low-current regulation stability near breakdown onset |
Pinout & Package
Package: SMA (DO-214AC), surface-mountable axial-lead outline with cathode band marking; body marked with part number; ROHS-compliant matte-tin terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference node | Connected to circuit ground or lower-potential rail during reverse-bias clamping operation |
| Cathode | Zener breakdown terminal / high-side clamp node | Connected to protected line; conducts when voltage exceeds 8.2 V, shunting surge current to ground |
Key Features
| Feature | Design Value |
|---|---|
| ±5% zener voltage tolerance | Enables tighter voltage margin control than 10% variants in precision reference designs |
| 25 °C/W junction-to-lead thermal resistance | Allows direct PCB copper pour heat sinking to sustain full 2.0 W dissipation without heatsink |
| UL94V-0 void-free epoxy case | Provides flame-retardant mechanical integrity and moisture resistance in harsh environments |
| ROHS-compliant matte-tin plating | Ensures consistent wetting and intermetallic formation per MIL-STD-750 Method 2026 |
Applications
| Industrial Sensor Signal Conditioning | Automotive Body Control Module Power Rail |
|---|---|
Use Scenario: Protecting analog output lines of temperature/pressure sensors from ESD and load-dump transients in factory automation systems. IC Role / Device Role / Timing Role: Zener clamping diode placed between sensor output and microcontroller ADC input. Use Value: Limits voltage to ≤8.2 V during 550 mA surges, preventing ADC saturation and protecting internal ESD structures. | Use Scenario: Clamping 12 V supply rail against load-dump spikes up to ±60 V in BCM submodules. IC Role / Device Role / Timing Role: Primary overvoltage clamp on regulated 12 V domain feeding MCU and CAN transceivers. Use Value: Absorbs 2.0 W continuously and 550 mA peaks without derating, maintaining rail integrity during alternator transients. |
| Consumer Audio Amplifier Bias Network | Telecom Line Interface Protection |
Use Scenario: Stabilizing dual-rail bias voltages in Class AB headphone amplifiers subject to battery voltage ripple. IC Role / Device Role / Timing Role: Precision 8.2 V reference in discrete op-amp bias generator. Use Value: Delivers <10 µA leakage and 4.5 Ω dynamic impedance to minimize quiescent current drift and THD. | Use Scenario: Secondary protection stage on RS-485 data lines exposed to lightning-induced surges in outdoor base stations. IC Role / Device Role / Timing Role: Fast-response shunt clamp downstream of GDT primary protection. Use Value: Activates within nanoseconds at 8.2 V, limiting line-to-ground voltage before TVS diode stack reaches breakdown. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4738A | Same 8.2 V ±5%, but DO-41 package (larger, axial-leaded); RθJL = 50 °C/W | Requires more board area and manual insertion; less suitable for automated SMT lines | Select when legacy through-hole assembly or higher thermal mass is preferred |
| BZX84-C8V2 | Same 8.2 V ±5%, but SOT-23 package; PM(AV) = 300 mW; Izsm = 100 mA | Limited to low-power signal-level clamping; not rated for 2.0 W rail protection | Select only for space-constrained logic-level biasing, not power rail suppression |
Compared with SMAJ4738E3/TR13, 1N4738A offers identical electrical specs but inferior thermal performance and assembly compatibility, while BZX84-C8V2 sacrifices power handling for miniaturization-making SMAJ4738E3/TR13 optimal for SMT-based 2.0 W clamping where thermal and surge robustness are critical.
Availability
SMAJ4738E3/TR13 is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive body control modules, consumer audio bias networks, and telecom line protection requiring stable component supply and long-term production continuity.
Supply support for SMAJ4738E3/TR13 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
SM Semiconductor is a Taiwan-based manufacturer specializing in discrete semiconductors, including Zener diodes, TVS devices, rectifiers, and bridge rectifiers for industrial and automotive markets.
The SMAJ47xxA series was developed to deliver high-reliability, surface-mount Zener clamping in compact SMA packages for power rail stabilization and transient suppression in space-constrained, thermally demanding applications.
FAQ
What is the zener voltage tolerance of SMAJ4738E3/TR13?
The SMAJ4738E3/TR13 has a zener voltage tolerance of ±5% at 31 mA test current, meaning its actual breakdown voltage falls between 7.79 V and 8.61 V under standard conditions. This tighter tolerance compared to non-suffixed variants supports more accurate voltage regulation in precision reference and clamping circuits. The 'A' suffix in the part number explicitly denotes this 5% specification, confirmed in the official SM Semiconductor datasheet.
Does SMAJ4738E3/TR13 meet ROHS requirements?
Yes, SMAJ4738E3/TR13 uses ROHS-compliant annealed matte-tin plating on its terminals, verified per MIL-STD-750 Method 2026 for solderability. The void-free thermosetting epoxy case also complies with UL94V-0 flammability standards. No lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE substances exceed EU ROHS thresholds, making it suitable for environmentally regulated industrial and automotive production.
What is the maximum continuous current SMAJ4738E3/TR13 can regulate at 100°C?
SMAJ4738E3/TR13 supports a maximum regulator current (IZM) of 220 mA at 100°C ambient, as specified in Table 1 of the SM Semiconductor datasheet. This value assumes adequate PCB copper heat sinking to maintain junction temperature within limits. At lower ambient temperatures or with enhanced thermal design, the device can sustain higher average currents without exceeding its 2.0 W power rating.
How does the thermal resistance of SMAJ4738E3/TR13 affect PCB layout?
The SMAJ4738E3/TR13 has a junction-to-lead thermal resistance of 25 °C/W, meaning each watt dissipated raises the junction temperature 25°C above the lead temperature. To maximize power handling, designers should connect both leads-especially the cathode-to wide, thermally robust copper pours. This minimizes lead temperature rise and allows the device to safely dissipate its full 2.0 W rating without external heatsinks in most SMT applications.
Can SMAJ4738E3/TR13 be used as a replacement for SMAJ4738A?
Yes, SMAJ4738E3/TR13 is functionally and electrically identical to SMAJ4738A, sharing the same 8.2 V ±5% zener voltage, 2.0 W power rating, and SMA (DO-214AC) package. The 'E3/TR13' suffix indicates tape-and-reel packaging per EIA-481 standard, while 'A' denotes the same electrical variant. No electrical or mechanical redesign is needed when substituting SMAJ4738E3/TR13 for SMAJ4738A in production.
SMAJ4738E3/TR13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 8.2 V
- Tolerance:
- ±10%
- Power - Max:
- 2 W
- Impedance (Max) (Zzt):
- 4.5 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 6 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC
SMAJ4738E3/TR13 FAQ
1.How can I place an order for SMAJ4738E3/TR13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ4738E3/TR13 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SMAJ4738E3/TR13 reliable?
The price and inventory of SMAJ4738E3/TR13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ4738E3/TR13 is usually 5 days.
3.What payment methods are accepted for SMAJ4738E3/TR13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ4738E3/TR13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ4738E3/TR13?
SMAJ4738E3/TR13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ4738E3/TR13 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SMAJ4738E3/TR13?
For technical support, including SMAJ4738E3/TR13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ4738E3/TR13 requirements.
6.How does Aetrix verify that SMAJ4738E3/TR13 is sourced from the original manufacturer or authorized distributors?
All SMAJ4738E3/TR13 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMAJ4738E3/TR13 meets industry standards.
7.What is the process for return or replacement of SMAJ4738E3/TR13?
All SMAJ4738E3/TR13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ4738E3/TR13, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SMAJ4738E3/TR13 part is unused and in its original packaging.
Return procedure for SMAJ4738E3/TR13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ4738E3/TR13 Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
