DONGWOON DW8505A Low Dropout Linear LED Constant Current Driver IC | 100mA Adjustable / SOT23-5L / Compact Package for Backlight Application | Pin-to-Pin Replacement for BCR401W/BCR420U/DW8506
Core Parameter Summary: DW8505A is an original low dropout linear constant current LED driver IC manufactured by DONGWOON (South Korea). Wide input voltage range: 5~40V | 0~100mA adjustable constant current | Ultra-low dropout voltage: 0.1V @ 60mA | Built-in thermal foldback protection | PWM dimming support | SOT23-5L package | Low EMI interference | Direct pin-to-pin replacement for BCR401W/BCR420U/DW8506. Authorized distributor with stock available, samples and technical support provided.
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Product Description: DW8505A is a fast-switching low dropout linear LED constant current driver IC launched by DONGWOON Korea. It features 5~40V wide input voltage, maximum 100mA adjustable output current, built-in thermal foldback protection and 0~100% PWM dimming function. The output current is set by a single external resistor with minimal peripheral circuits and low EMI noise. It is ideally designed for LED lamps, indicator & decorative lighting, panel backlight, RGB backlight, automotive lighting and general constant current source applications. It can directly replace mainstream models including BCR401W, BCR420U and DW8506 with higher constant current accuracy, lower dropout voltage and superior reliability.
DW8505A Linear LED Constant Current Driver IC Core Advantages
● Wide input voltage 5~40V, compatible with 12V/24V industrial and backlight power supply systems
● 0~100mA adjustable output current, precise current setting via single resistor, constant current accuracy ±3%
● Ultra-low dropout voltage: 0.1V max @ 60mA, lower heat generation and higher efficiency
● Built-in thermal foldback protection, current automatically reduces under high temperature for long-term reliable operation
● PWM dimming support (≤30kHz), flicker-free precise dimming from 0 to 100%
● Only one external resistor required, simplified circuit design, lower cost and easy PCB layout
● Compact SOT23-5L package, small footprint, good heat dissipation and easy for SMT production
● Low EMI interference, easily pass various safety and EMC compliance tests
DW8505A Key Electrical Parameters | Specifications
| Parameter | Typical Value | Unit |
| Input Voltage | 5~40 | V |
| Output Current | 0~100 | mA |
| Dropout Voltage | 0.1 @ 60mA | V |
| Constant Current Accuracy | ±3% | -- |
| Thermal Foldback Threshold | 140 | ℃ |
| Dimming Method | PWM | -- |
| Package Type | SOT23-5L | -- |
DW8505A Pinout & Package Dimension | Pin Diagram
| Pin No. | Pin Name | Function Description |
| 1 | EN | Output enable pin, active high for PWM dimming, recommended frequency ≤30kHz |
| 2 | GND | Ground |
| 3 | RS | Output current setting pin, connect external resistor to GND |
| 4 | VDD | Power supply input |
| 5 | OUT | LED constant current output |
DW8505A Internal Block Diagram | Internal Structure
DW8505A Typical Application Circuit | Reference Design
DW8505A Application Fields | Applicable Industries
● LED bulbs, residential lighting and small lighting equipment
● Indicator signs, advertising signage and decorative LED lighting
● Panel displays, home appliance panels and general backlight lighting
● RGB backlight, colorful lighting and ambient light drivers
● Constant current modules matched with DC/DC & AC/DC power supplies
● Automotive interior lights, daytime running lights, signal lights and vehicle lighting
● General constant current sources, industrial control and instrumentation power supply
Compatible Replacement Models & Advantages Comparison
DONGWOON DW8505A supports direct pin-to-pin replacement for: DW8506, BCR401W, BCR420U
● Advantage 1: Wider operating voltage range 5~40V, covering more industrial and backlight scenarios
● Advantage 2: Lower dropout voltage (0.1V @ 60mA), higher efficiency and less heat dissipation
● Advantage 3: Built-in thermal foldback protection, higher reliability compared with competitors without protection
● Advantage 4: ±3% constant current accuracy, stable output against voltage and temperature fluctuation
● Advantage 5: PWM dimming supported while BCR401W does not, broader application coverage
Parameter Comparison with Similar Products | Replacement Comparison
| Item | DW8505A | DW8506 | BCR401W | BCR420U | Advantage Description |
| Brand | DONGWOON | DONGWOON | Infineon | Infineon | Stable original supply |
| Operating Voltage | 5~40V | 6.5~40V | Up to 18V | Up to 40V | Broader voltage range |
| Max Output Current | 100mA | 100mA | 60mA | 150mA | Flexible current matching |
| Dropout Voltage | 0.1V @ 60mA | 0.5V @ 50mA | 1.2V | 1.4V | Lower dropout & higher efficiency |
| Thermal Protection | Yes | Yes | No | No | Safer operation under high temperature |
| Constant Current Accuracy | ±3% | ±5% | ±10% | ±10% | Higher accuracy & better stability |
| PWM Dimming | Supported | Not Supported | Not Supported | Supported | More flexible dimming performance |
Demo Board Test Comparison
| DW8505A | DW8506 | BCR401W | BCR420U |
| EVB |  |  |  |  |
| RSET (20mA) | 36Kohm | 6.04Kohm | 80ohm | 100ohm |
Output Current Characteristics vs Output Voltage
Test Condition: Input 12V, Output Current 20mA
| Item | DW8505A | DW8506 | BCR420U | BCR401W | Remark |
| Dropout Voltage | 0.2V | 0.3V | 1V | 1.2V | Output current at 90% rated value |
DW8505A and DW8506 enable multiple LED modules to be installed on a single 12VDC power supply, thanks to their much lower dropout voltage compared with BCR401W and BCR420U.
IC Temperature Characteristics vs Output Voltage
Test Condition: Input 12V, Output Current 20mA
| Item | DW8505A | DW8506 | BCR420U | BCR401W |
| IC Temperature (℃) | 53.7 | 54.3 | 58.4 | 51.2 |
Output Current Characteristics vs Ambient Temperature
Test Condition: Input 12V, Output Current 20mA, Temperature Range -45℃~145℃
| LED Vf | DW8505A | DW8506 | BCR420U | BCR401W | Remark |
| 2.6V | 4.53~-5.84% | -1.82~3.41% | 10.64~-20.39% | 14.89~-17.30% | DW8505A/DW8506 Equipped with thermal foldback |
| 3.2V | 4.42~-5.70% | -1.81~3.39% | 10.56~-20.42% | 14.81~-18.63% |
When the junction temperature of DW8505A and DW8506 reaches 125℃, thermal foldback protection activates and reduces the output current to 1/4 of the set value, which effectively lowers chip temperature.
BCR420U and BCR401W have no built-in thermal protection circuit.
Output Current Characteristics vs EN Pin Voltage
Test Condition: Input 40V, Output Current 20mA, Variable EN Pin Voltage
| EN (V) | BCR420U | DW8505A |
|---|
| Iout [mA] | Accuracy [%] | Iout [mA] | Accuracy [%] |
|---|
| 5 | 16.79 | 0.00 | 20.01 | 0.00 |
| 10 | 17.89 | 6.56 | 20.01 | 0.00 |
| 15 | 18.42 | 9.67 | 20.02 | 0.03 |
| 20 | 18.76 | 11.74 | 20.02 | 0.02 |
| 25 | 19.01 | 13.23 | 20.02 | 0.05 |
| 30 | 19.21 | 14.37 | 20.02 | 0.02 |
| 35 | 19.38 | 15.38 | 19.99 | -0.09 |
DW8505A maintains stable 20mA constant current output with varying EN pin voltage, while BCR420U cannot keep constant output current.
Within EN pin voltage range 5V~35V, the output current variation of DW8505A is only -0.09%, compared with 15.38% of BCR420U.
DONGWOON Korea Linear Constant Current Driver Solution Recommendation
| DW8501 | DW8502 | DW8505A | DW8506 | DW8506A | DW3505A |
| Input Voltage (V) | 5~40 | 5~40 | 5~40 | 6.5~40 | 6.5~40 | 5~40 |
| Output Current | Adjustable up to 1.5A | Adjustable up to 2.5A | Adjustable up to 100mA | Adjustable up to 100mA | Fixed 60mA | Adjustable up to 300mA |
| Dropout Voltage | Max.0.3V @ 300mA | Max.1V @ 1A | Max.0.1V @ 60mA | Max.0.5V @ 50mA | Max.0.6V @ 60mA | Max.0.2V @ 60mA |
| Dimming Function | PWM | PWM | PWM | -- | -- | PWM |
| Protection | Thermal Foldback | Thermal Foldback | Thermal Foldback | Thermal Foldback | Thermal Foldback | Thermal Foldback |
| Package | SOT223-5L/TO252-5L | TO263-5L/TO220-5L | SOT23-5L | SOT23-5L | WLCSP | SOT89-5L |
| Typical Circuit |  |  |  |  |  |  |
Authorized Distributor & Service
GS Micro Semiconductor (Shenzhen) Co., Ltd. is the official authorized distributor of DONGWOON Korea. We focus on promoting linear constant current drivers and power management ICs, providing complete datasheets, application solutions, sample testing and professional technical after-sales support to accelerate customers' mass production.
Official Website: https://www.gs-micro.com
Frequently Asked Questions (FAQ)
Can DW8505A directly replace BCR401W, BCR420U or DW8506?
Yes. DW8505A shares identical pinout and SOT23-5L package with BCR401W, BCR420U and DW8506. It features wider 5~40V input voltage, ultra-low dropout voltage (0.1V @ 60mA) and PWM dimming function. No PCB modification is required for direct replacement, with higher constant current accuracy and reliability.
What is the PWM dimming frequency limit of DW8505A?
The recommended PWM dimming frequency is ≤30kHz, with full dimming range from 0% to 100%. Dimming is realized via EN pin with flicker-free and high linearity performance. When EN pin voltage varies from 5V to 35V, the output current deviation of DW8505A is only -0.09%, much better than 15.38% of BCR420U.
What is the trigger temperature of thermal foldback protection?
The thermal foldback protection activates when chip junction temperature reaches approximately 125℃~140℃, and the output current will drop to 1/4 of the preset value to reduce chip heat generation. BCR420U and BCR401W have no thermal protection circuit.
Are SOT23-5L and SOT-25 packages interchangeable?
Yes. SOT23-5L and SOT-25 refer to the same 5-pin small outline transistor package with consistent pin assignment, which can be used interchangeably. Please note that minor internal structure differences may exist among products from different manufacturers.
How to request DW8505A samples or get bulk quotation?
Please contact our sales team via phone: +86 18018703531 (Contact: He Long), or send email to sales@gs-micro.com. We will provide samples, technical support and bulk price quotation promptly.
