My Inquiry
My Account
onsemi SZ1SMA5938BT3G
- Part No.:
- SZ1SMA5938BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SZ1SMA5938BT3G.pdf
- Description:
- DIODE ZENER 36V 1.5W SMA
- Quantity:
- Payment:
- Shipping:
Inventory:2,183
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SZ1SMA5938BT3G from onsemi is a 1.5 W surface-mount Zener diode with nominal zener voltage 36 V, ±5% tolerance, 10.4 Ω dynamic impedance at 38 mA test current, and 0.25 μA leakage current at 27.4 V reverse voltage. It serves as a precision voltage reference or overvoltage clamp in automotive power rails and industrial sensor signal conditioning circuits.
For engineers reviewing the SZ1SMA5938BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage stability across temperature (±0.085%/°C typical), AEC-Q101 qualification for automotive use, low-profile SMA package compatibility with automated placement, and 16 kV HBM ESD rating for robust board-level handling.
Technical Context
This device operates in reverse breakdown mode with specified regulation at IZT = 38 mA and exhibits a positive temperature coefficient of +0.085%/°C for VZ between 33 V and 37.8 V. Its thermal resistance junction-to-lead is 50 °C/W, enabling 1.5 W dissipation at TL = 75°C with proper PCB copper pad design.
The SMA package supports top-slide or bottom-board mounting and features a flat handling surface for accurate pick-and-place. Polarity is marked by a molded cathode band, and the device is Pb-free per J-STD-020 and RoHS-compliant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 36 V nominal, 34.2–37.8 V range at IZT = 38 mA - defines stable regulation point for feedback loops |
| Zener Impedance (ZZT) | 10.4 Ω max at IZT = 38 mA - ensures minimal output voltage variation under load transients |
| Leakage Current (IR) | 0.25 μA max at VR = 27.4 V - guarantees low standby power loss in high-impedance bias networks |
| Power Dissipation (PD) | 1.5 W at TL = 75°C - requires ≥1 in² FR-4 copper pad for thermal management |
| ESD Rating | Class 3 (>16 kV) per HBM - eliminates need for external ESD protection in handling-sensitive assembly lines |
| AEC-Q101 Qualified | Validated for automotive applications - enables use in engine control modules and ADAS power supervisors without requalification |
Pinout & Package
The SZ1SMA5938BT3G uses the SMA (DO-214AC) package, case outline 403D, with cathode indicated by a molded band. It has two terminals: Pin 1 (cathode) and Pin 2 (anode).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Regulated output node | Connected to voltage rail being stabilized; sinks current during regulation |
| Anode | Reference/ground return | Tied to system ground or lower-potential node; completes conduction path |
Key Features
| Feature | Design Value |
|---|---|
| ±5% VZ tolerance | Enables direct replacement in legacy 36 V reference designs without recalibration |
| Flat handling surface | Reduces misalignment risk in high-speed SMT placement at >25,000 CPH |
| Low-profile SMA package | Supports 1.0 mm max board height in space-constrained modules like telematics units |
| Pb-free and RoHS-compliant | Meets IPC-J-STD-020 moisture sensitivity level 1 - no bake required before reflow |
| Top-slide or bottom-mount capability | Allows flexible layout routing on double-sided PCBs with thermal vias under anode pad |
Applications
| Automotive Engine Control Unit (ECU) Power Monitoring | Industrial 4–20 mA Loop Transmitter Reference |
|---|---|
Use Scenario: Monitoring 12 V battery rail voltage in real time to detect undervoltage or overvoltage faults. IC Role / Device Role / Timing Role: Zener diode provides stable 36 V reference for comparator input in fault-detection circuitry. Use Value: AEC-Q101 qualification ensures reliability over 15-year vehicle lifetime; 16 kV HBM ESD withstand prevents damage during service bay handling. | Use Scenario: Generating precise 36 V reference for DAC-based current source calibration in field transmitter modules. IC Role / Device Role / Timing Role: Acts as shunt regulator to maintain constant voltage across precision resistor network defining loop current. Use Value: 10.4 Ω ZZT minimizes current error drift under varying load conditions; ±5% tolerance avoids post-calibration trimming. |
| Medical Infusion Pump Power Supply Clamp | Telecom Base Station DC-DC Feedback Divider |
Use Scenario: Clamping transient spikes on isolated 24 V auxiliary supply feeding microcontroller peripherals. IC Role / Device Role / Timing Role: Shunt protector that conducts only above 37.8 V, diverting surge energy away from downstream ICs. Use Value: 1.5 W power rating handles 100 ms surges per IEC 61000-4-5; low leakage (<0.25 μA) prevents false triggering in sleep mode. | Use Scenario: Setting output voltage of isolated flyback converter via optocoupler feedback network. IC Role / Device Role / Timing Role: Provides stable reference voltage for TL431-like feedback divider, improving output regulation accuracy. Use Value: Temperature coefficient of +0.085%/°C reduces output drift over −40°C to +125°C ambient range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMA5938BT3G | No AEC-Q101 qualification; same electrical specs and package | Restricted to commercial/industrial use; not approved for automotive production | Select when automotive qualification is unnecessary and cost is primary driver |
| MMSZ5245B-TP | 500 mW rating, 33 V nominal, SOD-123 package, 35 Ω ZZT | Lower power handling and higher impedance limit use to low-current bias networks | Select for space-constrained consumer electronics where 36 V precision is secondary to footprint size |
Compared with 1SMA5938BT3G and MMSZ5245B-TP, the SZ1SMA5938BT3G delivers automotive-grade reliability and 1.5 W power handling in the same SMA footprint - critical for ECU voltage supervisors requiring long-term stability under thermal cycling.
Availability
SZ1SMA5938BT3G is available at Aetrix Electronics and suitable for automotive power monitoring, industrial loop transmitter calibration, and medical infusion pump surge protection requiring stable component supply and full traceability.
Supply support for SZ1SMA5938BT3G 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
onsemi is a global semiconductor supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications.
The 1SMA59xxBT3G/SZ1SMA59xxBT3G series was designed specifically for high-reliability voltage regulation in automotive ECUs and industrial control systems where AEC-Q101 compliance and robust thermal performance are mandatory.
FAQ
What is the zener voltage tolerance for SZ1SMA5938BT3G?
The SZ1SMA5938BT3G has a ±5% zener voltage tolerance, meaning its regulated breakdown voltage falls between 34.2 V and 37.8 V at the specified test current of 38 mA. This tolerance is guaranteed at thermal equilibrium and applies across the full operating temperature range of −65°C to +150°C. The SZ1SMA5938BT3G datasheet confirms this value in the Electrical Characteristics table on page 2.
Is SZ1SMA5938BT3G qualified for automotive applications?
Yes, the SZ1SMA5938BT3G is AEC-Q101 qualified and PPAP capable, making it suitable for automotive powertrain, body electronics, and ADAS systems. The "SZ" prefix explicitly denotes automotive-grade manufacturing controls and site-specific change management. This qualification is documented in the Features section of the onsemi datasheet (Rev. 11, August 2021), and the device meets all stress tests including temperature cycling, humidity bias, and mechanical shock.
What is the maximum power dissipation for SZ1SMA5938BT3G at 25°C ambient?
The SZ1SMA5938BT3G has a maximum DC power dissipation of 0.5 W at TA = 25°C, derating linearly at 4.0 mW/°C above that temperature. This is significantly lower than its 1.5 W rating at TL = 75°C, reflecting the importance of PCB thermal design. To achieve full 1.5 W operation, the device must be mounted on a 1 in² copper pad per the onsemi recommended footprint - a requirement clearly stated in Note 2 of the Maximum Ratings table.
What does the marking "838B" indicate on SZ1SMA5938BT3G?
The marking "838B" on the SZ1SMA5938BT3G corresponds to its device code as defined in the onsemi datasheet's Electrical Characteristics table. It uniquely identifies the 36 V zener variant within the 1SMA59xxBT3G family and distinguishes it from other voltages such as 837B (33 V) or 839B (39 V). The "B" suffix indicates ±5% tolerance, consistent across the entire SZ1SMA59xxBT3G series.
Can SZ1SMA5938BT3G replace older MELF-style zeners in existing layouts?
Yes, the SZ1SMA5938BT3G is explicitly positioned as an ideal replacement for MELF packages due to its low-profile SMA (DO-214AC) form factor, flat handling surface, and compatible thermal performance. Unlike cylindrical MELF devices, the SMA package enables automated top-slide placement and eliminates orientation concerns. The datasheet states this compatibility directly in the Features section, confirming mechanical and functional interchangeability without PCB redesign.
SZ1SMA5938BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- SZ1SMA59xxBT3G
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 36 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 38 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 27.4 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
SZ1SMA5938BT3G FAQ
1.How can I place an order for SZ1SMA5938BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMA5938BT3G 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 SZ1SMA5938BT3G reliable?
The price and inventory of SZ1SMA5938BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMA5938BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMA5938BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMA5938BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMA5938BT3G?
SZ1SMA5938BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMA5938BT3G 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 SZ1SMA5938BT3G?
For technical support, including SZ1SMA5938BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMA5938BT3G requirements.
6.How does Aetrix verify that SZ1SMA5938BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMA5938BT3G 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 SZ1SMA5938BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMA5938BT3G?
All SZ1SMA5938BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMA5938BT3G, 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 SZ1SMA5938BT3G part is unused and in its original packaging.
Return procedure for SZ1SMA5938BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SZ1SMA5938BT3G 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
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
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…
