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

Diodes Incorporated UF1504S-B

Name: UF1504S-B
Brand: Diodes Incorporated
SKU: UF1504S-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: UF1504S-B

Manufacturer:: Diodes Incorporated

Category:: Single Diodes

Package:: DO-204AL, DO-41, Axial

Datasheet:: UF1504S-B.pdf

Description:: DIODE GEN PURP 400V 1.5A DO41

Quantity:: RFQ Add To RFQ list

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Inventory:9,876

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Product details

Overview

UF1504S-B from Diodes Incorporated is a 1.5A ultra-fast rectifier diode in DO-41 package, rated for 400V peak repetitive reverse voltage (V_RRM), 1.3V forward voltage at 1.5A (V_FM), and 50ns reverse recovery time (t_rr); used in high-frequency switching power supplies, AC/DC adapters, and flyback converter output stages.

For engineers reviewing the UF1504S-B datasheet, UF1504S-B pinout, UF1504S-B application, or UF1504S-B equivalent, key selection criteria include V_RRM, t_rr, I_FSM, thermal resistance (R_θJA = 70°C/W), and DO-41 mechanical compatibility in space-constrained board layouts.

Technical Context

This ultra-fast rectifier employs a diffused junction structure to achieve low reverse recovery charge and minimal switching losses in high-frequency (>50kHz) rectification circuits. Its 50ns t_rr enables efficient operation in SMPS secondary-side rectification where di/dt stress and ringing must be minimized.

Rated for 50A non-repetitive surge current (8.3ms half-sine), it withstands transient overloads common in input-stage rectification and inductive load commutation. The 1.3V V_FM at 1.5A balances conduction loss and thermal rise under continuous DC output conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	400 V - Maximum reverse voltage before breakdown; defines safe operating margin in 280V RMS bridge applications.
V_FM @ 1.5A	1.3 V - Forward conduction loss at rated average current; determines I²R heating and efficiency at full load.
t_rr	50 ns - Time to transition from forward conduction to reverse blocking; critical for minimizing switching noise and EMI in >100kHz designs.
I_FSM	50 A - Peak surge capability for 8.3ms; supports inrush current handling in capacitor-input filter stages.
R_θJA	70 °C/W - Junction-to-ambient thermal resistance; requires ≥9.5mm lead length at ambient for full 1.5A rating at 50°C.
I_R @ 25°C	5.0 µA - Reverse leakage at rated V_R; ensures low standby power loss in high-impedance bias networks.

Pinout & Package

DO-41 axial-leaded plastic package with cathode band marking; weight ≈0.35 g; UL 94V-0 flammability rating; moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward current entry point	Connected to transformer secondary or switch node; must handle 1.5A DC + ripple without excessive voltage drop.
Cathode	Forward current exit / reverse blocking terminal	Marked by band; ties to output capacitor positive rail; reverse voltage rating applies across this terminal and anode.

Key Features

Feature	Design Value
Ultra-fast recovery (50 ns)	Reduces switching losses and EMI generation in high-frequency SMPS, enabling smaller snubbers and lower RFI filtering cost.
50A surge rating	Supports reliable operation during cold-start inrush and line-voltage transients without degradation.
Low 5.0 µA reverse leakage	Minimizes standby power consumption in energy-efficient adapters meeting Level VI efficiency standards.
DO-41 RoHS-compliant package	Enables direct replacement of legacy rectifiers in existing through-hole production lines with no retooling.

Applications

AC/DC Adapter Output Rectification

Flyback Converter Secondary Side

Use Scenario: 12V/1.2A isolated offline adapter for consumer electronics with 60kHz switching frequency.

IC Role / Device Role / Timing Role: Primary output rectifier converting transformer secondary AC to regulated DC; operates in discontinuous conduction mode.

Use Value: 50ns t_rr prevents reverse recovery tail from overlapping with next switching cycle, reducing output ripple and transformer core loss.

Use Scenario: 5V/2A auxiliary supply in industrial PLC power module with 100kHz flyback topology.

IC Role / Device Role / Timing Role: Synchronous rectification alternative not required; ultra-fast diode provides cost-effective, robust output rectification.

Use Value: 1.3V V_FM limits conduction loss to <1.0W at full load, keeping junction temperature within 150°C limit with minimal heatsinking.

Capacitor-Input Filter Stage

DC Link Protection in Motor Drive

Use Scenario: 24V/1.0A medical-grade power supply using capacitor-input rectification with 50Hz line frequency.

IC Role / Device Role / Timing Role: Half-wave rectifier feeding bulk electrolytic capacitor; subjected to high peak currents during charging.

Use Value: 50A I_FSM rating accommodates 10× nominal current peaks without bond-wire fusing or parameter shift.

Use Scenario: 48V DC bus protection in brushed DC motor controller with regenerative braking spikes.

IC Role / Device Role / Timing Role: Freewheeling diode clamping inductive kickback from motor windings during PWM off-time.

Use Value: 400V V_RRM provides 2× margin over 48V bus + 100V transients, ensuring long-term reliability under repeated voltage stress.

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-fast rectifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STTH1L06U	Same 1.5A/600V rating but TO-220AC package; 60ns t_rr; higher V_F (1.7V @ 1.5A).	Requires PCB footprint change and thermal pad layout; better suited for higher-power, forced-air-cooled systems.	Select when higher V_RRM margin or surface-mount thermal management is needed; not drop-in compatible.
ES1D-E3/57T	SMA package; 1A rating; 35ns t_rr; 1.7V V_F @ 1A; lower I_FSM (30A).	Smaller footprint but derated current; suitable only for ≤1A loads with tighter t_rr requirements.	Choose for compact designs with lower current demand and priority on speed over surge robustness.

Compared with STTH1L06U and ES1D-E3/57T, UF1504S-B uniquely balances DO-41 through-hole compatibility, 400V rating, 50ns speed, and 50A surge tolerance-making it optimal for cost-sensitive, medium-power, high-reliability adapter and industrial power supply designs.

Availability

UF1504S-B is available at Aetrix Electronics and suitable for AC/DC adapters, flyback converters, capacitor-input rectifiers, and motor drive freewheeling circuits requiring stable component supply and long-lifecycle support.

Supply support for UF1504S-B 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-efficiency power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

UF1504S-B belongs to the UF150xS ultra-fast rectifier product line, engineered specifically for high-frequency switching power conversion where low recovery time and robust surge capability are essential.

FAQ

What is the maximum ambient temperature for full 1.5A operation?

UF1504S-B delivers its full 1.5A average rectified current only when leads are maintained at ambient temperature at a distance of 9.5mm from the case, up to TA = 50°C. Above 50°C, derating is required per Figure 1 in DS25006 - at 75°C ambient, maximum IO drops to approximately 1.1A.

Is UF1504S-B suitable for synchronous rectification designs?

No - UF1504S-B is a passive silicon PN junction diode and cannot be actively controlled like a MOSFET. It is intended for conventional diode rectification. For synchronous rectification, discrete N-channel MOSFETs or dedicated SR controllers (e.g., AP3410, MP6908) must be used instead.

How does its 50ns reverse recovery compare to standard recovery rectifiers?

Standard recovery rectifiers (e.g., 1N4007) exhibit t_rr > 2µs, causing significant switching loss and EMI above 20kHz. At 50ns, UF1504S-B reduces reverse recovery charge (Q_rr) by >95%, enabling clean turn-off in 50–500kHz SMPS without snubber networks.

Can UF1504S-B replace UF1503S or UF1505S in existing designs?

UF1504S-B (400V) can directly replace UF1503S (200V) if system reverse voltage remains ≤400V - offering higher margin. It cannot safely replace UF1505S (600V) in 600V-rated circuits due to insufficient V_RRM; doing so risks catastrophic failure under transient overvoltage conditions.

UF1504S-B Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: DO-204AL, DO-41, Axial

Packaging:: Bulk

Product Status:: Obsolete

Technology:: Standard

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

Current - Average Rectified (Io):: 1.5A

Voltage - Forward (Vf) (Max) @ If:: 1.3 V @ 1.5 A

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

Reverse Recovery Time (trr):: 50 ns

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

Capacitance @ Vr, F:: 35pF @ 4V, 1MHz

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-41

Operating Temperature - Junction:: -65°C ~ 150°C

UF1504S-B FAQ

1.How can I place an order for UF1504S-B through Aetrix?

Please submit a Request for Quotation (RFQ) for UF1504S-B 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 UF1504S-B reliable?

The price and inventory of UF1504S-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UF1504S-B is usually 5 days.

3.What payment methods are accepted for UF1504S-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UF1504S-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for UF1504S-B?

UF1504S-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your UF1504S-B 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 UF1504S-B?

For technical support, including UF1504S-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UF1504S-B requirements.

6.How does Aetrix verify that UF1504S-B is sourced from the original manufacturer or authorized distributors?

All UF1504S-B 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 UF1504S-B meets industry standards.

7.What is the process for return or replacement of UF1504S-B?

All UF1504S-B units undergo pre-shipment inspection (PSI). If there is an issue with UF1504S-B, 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 UF1504S-B part is unused and in its original packaging.

Return procedure for UF1504S-B:

1.Submit a request within 90 days.

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

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