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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

STMicroelectronics STTH1R04AY

Name: STTH1R04AY
Brand: STMicroelectronics
SKU: STTH1R04AY
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STTH1R04AY

Manufacturer:: STMicroelectronics

Category:: Single Diodes

Package:: DO-214AC, SMA

Datasheet:: STTH1R04AY.pdf

Description:: DIODE GEN PURP 400V 1A SMA

Quantity:: RFQ Add To RFQ list

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Inventory:25,263

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Product details

Overview

STTH1R04AY from STMicroelectronics is an automotive-grade ultrafast recovery silicon diode using planar Pt-doped technology, rated for 400 V repetitive peak reverse voltage and 1 A average forward current, with typical reverse recovery time of 14 ns and forward voltage drop of 0.9 V at 25 °C - deployed in low-voltage, high-frequency inverters and polarity protection circuits in engine control units and body electronics.

For engineers reviewing the STTH1R04AY datasheet, STTH1R04AY pinout, STTH1R04AY application, or STTH1R04AY equivalent, key selection criteria include AEC-Q101 qualification, junction temperature capability up to 175 °C, negligible switching losses, and dual SMB/SMA package options with validated thermal resistance (R_th(j-l) = 25 °C/W for SMB, 30 °C/W for SMA).

Technical Context

This diode employs platinum diffusion for precise carrier lifetime control, enabling ultrafast soft recovery with low reverse recovery charge (Q_RR) and minimal reverse recovery current (I_RM ≤ 3.5 A at dI_F/dt = −200 A/µs). Its dynamic performance is characterized across −40 °C to +175 °C operating range.

The device operates as a unidirectional freewheeling or clamping element in synchronous rectification and flyback topologies, where low V_F reduces conduction loss and fast t_rr minimizes switching node ringing - critical for EMI-sensitive automotive power stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	400 V - supports 24 V and 48 V automotive bus systems with ≥2× safety margin against transients
I_F(AV)	1 A - enables continuous operation in compact DC-DC converters without forced cooling
t_rr (typ.)	14 ns - limits turn-off energy loss and enables >500 kHz switching in SMPS designs
V_F (typ., 25 °C)	0.9 V - reduces conduction loss to ~0.9 W at 1 A average current
T_j(max)	175 °C - allows placement near hot components (e.g., power MOSFETs) in under-hood ECUs
R_th(j-l) (SMB)	25 °C/W - enables direct PCB copper heatsinking without external thermal pads
I_FSM	37 A (8.3 ms) - withstands load dump and jump-start surge events per ISO 7637-2

Pinout & Package

STTH1R04AY is available in SMA and SMB surface-mount packages. The SMA variant uses a single-diode configuration with cathode-anode terminals; the SMB variant shares identical electrical behavior but offers lower thermal resistance due to larger lead frame area.

Pin/Terminal	Circuit Role	Design Meaning
Anode (A)	Forward current entry point	Connected to low-side switch node or return path in freewheeling configurations
Cathode (K)	Forward current exit / reverse blocking terminal	Connected to positive rail or inductive load high side; blocks 400 V reverse bias during off-state

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive use including temperature cycling, humidity testing, and mechanical shock per stress test requirements
Ultrafast soft recovery	t_rr = 14 ns with low I_RM and Q_RR, reducing EMI generation and snubber component count
High T_j capability	175 °C max junction temperature enables operation in sealed enclosures without derating at ambient >125 °C
ECOPACK®2 compliance	Lead-free, halogen-free construction meeting RoHS and ELV directives for global vehicle production
Low V_F at elevated T_j	V_F = 0.90 V (typ.) at 150 °C - maintains efficiency in thermally constrained layouts

Applications

Engine Control Unit (ECU) Power Supply

Automotive LED Headlamp Driver

Use Scenario: Freewheeling path in buck-derived auxiliary power supply feeding microcontroller and sensors.

IC Role / Device Role / Timing Role: Unidirectional current path during high-side switch off-time; recovers before next switching cycle.

Use Value: 14 ns t_rr prevents cross-conduction loss and enables stable 300 kHz operation without snubber.

Use Scenario: Polarity protection and reverse-current blocking in constant-current LED driver output stage.

IC Role / Device Role / Timing Role: Standby blocking element; conducts only during fault conditions or reverse battery connection.

Use Value: 400 V V_RRM and 175 °C T_j ensure reliability under load dump (ISO 7637-2 Pulse 5a) and under-hood thermal stress.

Start-Stop System DC-DC Converter

Body Control Module (BCM) Inverter

Use Scenario: Output rectifier in synchronous boost converter supplying 12 V rail from 48 V mild-hybrid battery.

IC Role / Device Role / Timing Role: Secondary-side clamp diode managing inductive kickback during MOSFET commutation.

Use Value: Low 0.9 V V_F minimizes conduction loss at 1 A average current, improving overall conversion efficiency by ~1.2%.

Use Scenario: High-frequency inverter driving small BLDC motors for HVAC actuators or window lifters.

IC Role / Device Role / Timing Role: Fast freewheeling diode across motor phase windings to manage back-EMF during PWM dead-time.

Use Value: Soft recovery characteristic suppresses voltage overshoot spikes >20 V, eliminating need for TVS clamps on motor drivers.

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultrafast recovery diode applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STTH1L04Y	Same 400 V rating but 1.0 A I_F(AV) and 35 ns t_rr; uses different doping process	Higher t_rr increases switching loss in >200 kHz designs; suitable for cost-sensitive non-AEC-Q101 modules	Select when AEC-Q101 is not required and thermal budget allows higher loss
VS-1EYH04-M3	Vishay part with 400 V V_RRM, 1 A I_F(AV), 25 ns t_rr, and SMB package; not AEC-Q101 qualified	Lacks automotive qualification; exhibits higher V_F (1.15 V typ.) and reduced T_j(max) (150 °C)	Acceptable for industrial or consumer-grade 24 V supplies where qualification is optional

Compared with STTH1L04Y and VS-1EYH04-M3, STTH1R04AY delivers superior high-frequency efficiency and automotive reliability via its 14 ns t_rr, AEC-Q101 certification, and 175 °C junction rating - making it the preferred choice for safety-critical, thermally dense automotive power nodes.

Availability

STTH1R04AY is available at Aetrix Electronics and suitable for engine control units, LED headlamp drivers, start-stop DC-DC converters, and body control module inverters requiring stable component supply across extended automotive lifecycles.

Supply support for STTH1R04AY 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, MCU, and sensor solutions for automotive, industrial, and consumer markets.

STTH1R04AY belongs to ST's automotive ultrafast diode product line, engineered specifically for high-reliability, high-efficiency power conversion in harsh-temperature automotive environments - emphasizing low-loss switching, robust transient immunity, and long-term parametric stability.

FAQ

What is the maximum allowable case temperature for STTH1R04AY in SMB package?

The maximum junction temperature is 175 °C. With R_th(j-l) = 25 °C/W and typical PCB copper area (≥1 cm² per lead), case temperature remains ≤125 °C at 1 A average current and 25 °C ambient - verified per Figure 13 in the datasheet. Derating is required above 100 °C ambient.

Does STTH1R04AY support bidirectional current flow?

No. STTH1R04AY is a unidirectional silicon PN junction diode. It conducts only from anode to cathode under forward bias and blocks current in reverse direction up to 400 V. Bidirectional operation requires external circuitry such as back-to-back diodes or a dedicated bridge configuration.

Can STTH1R04AY replace a standard FR107 in an automotive design?

No. While both are 1 A, 1000 V diodes, FR107 has ~500 ns t_rr and no AEC-Q101 qualification. STTH1R04AY's 14 ns t_rr, 400 V rating, and automotive qualification make it incompatible as a drop-in replacement - redesign of snubbers, layout, and thermal management is required.

Is the STTH1R04AY marking "HR4Y" consistent across all reels?

Yes. Per Table 8 in the datasheet, STTH1R04AY is marked "HR4Y" on the SMA package body. This 4-character laser marking is standardized for traceability and matches ST's internal lot coding system - confirmed on production reels and verified in ST's packaging documentation DocID024449 Rev 2.

STTH1R04AY Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: DO-214AC, SMA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Technology:: Standard

Voltage - DC Reverse (Vr) (Max):: 400 V

Current - Average Rectified (Io):: 1A

Voltage - Forward (Vf) (Max) @ If:: 1.6 V @ 1 A

Speed:: Fast Recovery =< 500ns, > 200mA (Io)

Reverse Recovery Time (trr):: 30 ns

Current - Reverse Leakage @ Vr:: 5 µA @ 400 V

Capacitance @ Vr, F:: -

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SMA

Operating Temperature - Junction:: -40°C ~ 175°C

STTH1R04AY FAQ

1.How can I place an order for STTH1R04AY through Aetrix?

Please submit a Request for Quotation (RFQ) for STTH1R04AY 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 STTH1R04AY reliable?

The price and inventory of STTH1R04AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STTH1R04AY is usually 5 days.

3.What payment methods are accepted for STTH1R04AY?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STTH1R04AY transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STTH1R04AY?

STTH1R04AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STTH1R04AY 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 STTH1R04AY?

For technical support, including STTH1R04AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STTH1R04AY requirements.

6.How does Aetrix verify that STTH1R04AY is sourced from the original manufacturer or authorized distributors?

All STTH1R04AY 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 STTH1R04AY meets industry standards.

7.What is the process for return or replacement of STTH1R04AY?

All STTH1R04AY units undergo pre-shipment inspection (PSI). If there is an issue with STTH1R04AY, 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 STTH1R04AY part is unused and in its original packaging.

Return procedure for STTH1R04AY:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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