BCR401UW6-7 - DIODES INC - Datasheet.Live

BCR401UW6

10 to 100mA LED CONSTANT CURRENT REGULATOR in SOT26 (SC74R)

Description

The BCR401U

monolithically integrates a transistor, diodes and

resistors to function as a Constant Current Regulator (CCR)

for LED

driving. The device regulates with a preset 10mA

nominal that can be

adjusted with external resistor up to 100mA. It is designed for driving

LEDs in strings and will reduce current at increasing temperatures

to

self-protect.

Operating as a series linear CCR for LED string current

control, it can be used in applications with supply voltages up to 40V.

With no need for additional external components, this CCR is fully

integrated into a SOT26 (SC74R)

minimizing PCB area and

component count.

Applications

Constant Current Regulation (CCR) in:

• Emergency Lighting

• Signage, Advertising, Decorative and Architectural Lighting

• Retail Lighting in Fridge, Freezer Case and Vending Machines

Features

• LED Constant Current Regulator Using PNP Emitter-Follower

with Emitter Resistor to Current Limit

• IOUT = 10mA ± 10% Constant Current (Preset)

• IOUT up to 100mA Adjustable with an External Resistor

• VS – 40V Supply Voltage

• PD up to 1W in SOT26 (SC74R)

• LED Dimming Using PWM up to 25kHz

• Negative Temperature Coefficient (NTC) Reduces IOUT with

Increasing Temperature

• Parallel Devices to Increase Regulated Current

• Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)

• Halogen and Antimony Free. “Green” Device (Note 3)

• For automotive applications requiring specific change

control (i.e.: parts qualified to AEC-Q100/101/200, PPAP

capable, and manufactured in IATF 16949 certified

facilities), please refer to the related automotive grade (Q-

suffix) part. A listing can be found at

https://www.diodes.com/products/automotive/automotive-

products/.

• This part is qualified to JEDEC standards (as references in

AEC-Q) for High Reliability.

https://www.diodes.com/quality/product-definitions/

• An Automotive-Compliant Part is Available Under Separate

Datasheet (BCR401UW6Q)

Mechanical Data

• Case: SOT26 (SC74R)

• Case Material: Molded Plastic. “Green” Molding Compound.

UL Flammability Rating 94V-0

• Moisture Sensitivity: Level 1 per J-STD-020

• Terminals: Finish – Matte Tin Plated Leads, Solderable per

MIL-STD-202, Method 208

• Weight: 0.018 grams (Approximate)

Ordering Information (Note 4)

Product

Marking

Reel Size (inches)

Tape Width (mm)

Quantity per Reel

BCR401UW6-7

401

7

8

3000

Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant.

2. See https://www.diodes.com/quality/lead-free/ for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"

and Lead-free.

3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl)

and <1000ppm antimony compounds.

4. For packaging details, go to our website at http://www.diodes.com/products/packages.html.

Pin Name

Pin Function

VS

Supply Voltage

OUT

Regulated Output Current

Rext

External resistor for

adjusting Output Current

GND

Power Ground

SOT26/SC74R

Top View

Pin-Out

Top View

Internal Device

Schematic

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Marking Information

Date Code Key

Year

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

2030

Code

H

I

J

K

L

M

N

O

P

Q

R

Month

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Code

1

2

3

4

5

6

7

8

9

O

N

D

Absolute Maximum Ratings (Voltage relative to GND, @TA = +25°C, unless otherwise specified.)

Characteristic

Symbol

Value

Unit

Supply Voltage

VS

40 V

Output Current

IOUT

100 mA

Output Voltage

VOUT

40

V

Reverse voltage between all terminals VR 0.5 V

Thermal Characteristics

Characteristic

Symbol

Value

Unit

Power Dissipation

(Note 5)

PD

1,190

mW

(Note 6)

912

Thermal Resistance, Junction to Ambient

(Note 5)

RθJA

105

°C/W

(Note 6)

137

Thermal Resistance, Junction to Lead

(Note 7)

RθJL

50

Recommended Operating Junction Temperature Range

TJ

-55 to +150 °C

Maximum Operating Junction and Storage Temperature Range

TJ , TSTG

-65 to +150

ESD Ratings (Note 8)

Characteristics

Symbols

Value

Unit

JEDEC Class

Electrostatic Discharge – Human Body Model

ESD HBM

800

V

1B

Electrostatic Discharge – Machine Model ESD MM 300 V B

Notes: 5. For a device mounted with the OUT leads on 50mm x 50mm 1oz copper that is on a single-sided 1.6mm FR4 PCB; device is measured under still

air conditions while operating in steady-state.

6. Same as Note 5, except mounted on 25mm x 25mm 1oz copper.

7. RθJL = Thermal resistance from junction to solder-point (at the end of the OUT leads).

8. Refer to JEDEC specification JESD22-A114 and JESD22-A115.

401 = Part Marking (See Ordering Information)

YM = Date Code Marking

Y = Year (ex:

H = 2020)

M = Month (ex: 9 = September)

401

SOT26 (SC74R)

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Electrical Characteristics (@TA = +25°C, unless otherwise specified.)

Characteristic

Symbol

Min

Typ

Max

Unit

Test Condition

Collector-Emitter Breakdown Voltage

BVCEO

40 — — V

IC = 1mA

GND (Enable) Current

IGND

340 420 500 µA

VS = 10V; VOUT = Open

GND (Enable) Current

IGND

— 380 — µA

VS = 10V; VOUT = 8.6V

DC Current Gain

hFE

100

220

470

—

IC = 50mA; VCE = 1V

Internal Resistor

RINT

78

91

104

Ω

IRINT = 10mA

Output Current (Nominal) IOUT 9 10 11 mA VOUT

= 8.6V; VS = 10V

Voltage Drop (V

REXT

) V

DROP

— 0.91 — V I

OUT

= 10mA

Lowest Sufficient Supply Voltage

(VS-VOUT)

VSMIN — 1.4 — V IOUT > 8mA

Output Current Change vs. Temperature

ΔIOUT/IOUT

—

-0.25

—

%/°C

VS = 10V

Output Current Change vs. Supply Voltage

ΔIOUT/IOUT

—

1

—

%/V

VS = 10V

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Typical Thermal Characteristics (@TA = +25°C, unless otherwise specified.)

100 1000

0

100

200

300

400

500

600

700

800

Rth(JA) VS Cu Area

Copper Area (mm2)

100µ 1m 10m 100m 110 100 1k

0

25

50

75

100

125

Tamb=25°C

50mm * 50mm

1oz Cu

Transient Thermal Impedance

D=0.5

D=0.2

D=0.1

Single Pulse

D=0.05

Thermal Resistance (°C/W)

Pulse Width (s)

100µ 1m 10m 100m 110 100 1k

1

10 Tamb=25°C

50mm * 50mm

1oz Cu

Single Pulse

Pulse Power Dissipation

Pulse Width (s)

Maximum Power (W)

100µ 1m 10m 100m 110 100 1k

0

25

50

75

100

125

150

Tamb=25°C

25mm * 25mm

1oz Cu

Transient Thermal Impedance

D=0.5

D=0.2

D=0.1

Single Pulse

D=0.05

Thermal Resistance (°C/W)

Pulse Width (s)

100µ 1m 10m 100m 110 100 1k

1

10

Single Pulse

Tamb=25°C

25mm * 25mm

1oz Cu

Pulse Power Dissipation

Pulse Width (s)

Maximum Power (W)

050 100 150

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Rth(JA) (°C/W)

25mm * 25mm

1oz Cu

50mm * 50mm

1oz Cu

Derating Curve

Temperature (°C)

Max Power Dissipation (W)

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Typical Electrical Characteristics (Continued) (@TA = +25°C, unless otherwise specified.)

0 5 10 15 20 25 30 35 40

0

2

4

6

8

10

12

14

20 40 60 80 100

0

10

20

30

40

50

60

510 15 20 25 30 35 40

1

20

40

60

80

-25 025 50 75 100 125 150

-20

0

20

40

60

80

0 5 10 15 20 25 30 35 40

0

5

10

15

0 5 10 15 20 25 30 35 40

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

V

S

-V

OUT

=1.4V to 2V

V

S

-V

OUT

=1V

V

S

=10V

V

S

-V

OUT

=1.4V & V

S

= 10V

150°C

85°C

25°C

-40°C

V

S

-V

OUT

=1.4V

I

S

(mA) I

OUT

(mA)

I

OUT

(mA) I

OUT

(mA)

I

OUT

(mA)

I

OUT

(mA)

R

ext

= 33 Ohms

V

S

vs I

S

V

S

(V)

V

S

vs I

OUT

V

S

vs I

OUT

V

S

(V)

T

J

vs I

OUT

T

J

(°C)

R

ext

(Ohms)

Rext=15 Ohms

R

ext

= 33 Ohms

R

ext

= 100

R

ext=22 Ohms

R

ext

=18 Ohms

Rext=51 Ohms

V

S

vs I

OUT

V

S

-V

OUT

=1.4V

V

S

(V)

R

ext

= 100

R

ext=51 Ohms

Rext=22 Ohms

R

ext

=18 Ohms

Rext=15 Ohms

R

ext

(Ohms)vs I

OUT

150°C

R

ext

= OPEN

V

S

-V

OUT

=1.4V

R

ext

= OPEN

85°C

25°C

-40°C

85°C

25°C -40°C

V

S

(V)

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Application Information

Figure 1. Typical Application Circuit for

BCR40x LED Driver

Figure 2. Application Circuit for Increasing LED Current

The BCR401/2/5 are designed for driving low-current LEDs with

typical LED currents of 10mA to 100mA. The devices provide a cost-

effective way for driving low-current LEDs compared with more

complex switching regulator solutions. Furthermore, they reduce the

PCB board area of the solution as there is no requirement for external

components like inductors, capacitors, and switching diodes.

Figure 1 shows a typical application circuit diagram for driving an LED

or string of LEDs. The devices come with an internal resistor (RINT) of

typically 91Ω, 44Ω, 16.5Ω which, in the absence of an external

resistor, sets an LED current of 10mA, 20mA, 50mA, respectively.

LED current can be increased to a desired value by choosing an

appropriate external resistor, REXT.

The REXT vs. IOUT graphs should be used to select the appropriate

resistor. Choosing a low tolerance REXT improves the overall accuracy

of the current sense formed by the parallel connection of RINT and

REXT.

The negative temperature coefficient of the BCR series allows easy

paralleling of BCR410/2/5s. In applications where current sharing is

required, either due to high current requirements of LED strings or for

power sharing, two or more BCR401/2/5s can be connected in parallel

as shown in Figure 2. Power dissipation capability must be factored

into the design with respect to the BCR401/2/5’s thermal resistance.

The maximum voltage across the device can be calculated by taking

the maximum supply voltage and subtracting the voltage across the

LED string.

VDEVICE = VS – VOUT

PD = (VDEVICE × ILED) + (VS × IGND)

As the output current of BCR401/2/5 increases, it is necessary to

connect an appropriate heat sink to the OUT pins of the device. The

power dissipation supported by the device is dependent upon the PCB

board material, the copper area, and the ambient temperature. The

maximum dissipation the device can handle is given by:

PD = (TJ(MAX) - TA) / RθJA

See the thermal characteristic graphs on page 4 for selecting the

appropriate PCB copper area.

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Application Information (continued)

PWM is the most pursued method for LED dimming. In the PWM method, dimming is achieved by turning the LEDs ON and OFF for a portion

of a single cycle. PWM dimming can be achieved by enabling/disabling the LED driver itself (see Figure 3a, Figure 3b) or by the switching the

power path on and off (see Figure 3c). The PWM signal can be provided by a microcontroller or analog circuitry. Figure 3 shows typical

circuits, and Figure 4 is a typical response of LED current vs. PWM duty cycle. The PWM method shown in Figure 3b is used for generating

the graphs.

Figure 3a Figure 3b

Figure 3c

Figure 3a, 3b, 3c. Application Circuits for LED Driver with PWM Dimming Functionality

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Application Information (cont.)

Figure 4. Typical LED Current Response vs. PWM Duty Cycle for

25kHz, 10kHz, and 1kHz PWM Frequency (see Figure 3b)

0

10

20

30

40

50

60

0 20 40 60 80 100

LED current (mA)

Duty ratio %

PWM resolution at 25kHz

calculated DC current

Measured DC current

0

10

20

30

40

50

60

0 20 40 60 80 100

LED current (mA)

Duty ratio %

PWM resolution at 10kHz

calculated DC current

Measured DC current

0

10

20

30

40

50

60

0 20 40 60 80 100

LED current (mA)

Duty ratio %

PWM resolution at 1kHz

calculated DC current

Measured DC current

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Application Information (Cont.)

The error between the calculated theoretical value and the measured value is due to the turn on and turn off times of the BCR401/2/5. There is

a small contribution from the switches (a pre-biased transistor or a MOSFET) shown in Figure 3a and Figure 3b towards the total turn-on and

turn-off times of the BCR401/2/5. It is recommended to keep the external switching delays to the lowest possible value to improve PWM

accuracy. The typical switching times of the BCR401/2/5 for the configuration shown in Figure 3b are:

Turn-On Time = 200ns

Turn-Off Time = 10µs

Please refer to the Figure 5 and Figure 6 for the switching time performance. The percentage contribution of these switching delays increases

with increasing frequency and decreasing duty ratio as shown in Figure 4.

Figure 5. Turn-On Time of BCR401/2/5 (PWM Method in Figure 3b)

Figure 6. Turn-On Time of BCR401/2/5 (PWM Method in Figure 3c)

Where possible, the switching performance of the BCR401/2/5 can be significantly improved by switching the power path as shown in Figure 3c.

Figure 7 shows the resulting turn-off time. This results in an improved PWM resolution at 25kHz as shown in Figure 8.

Turn-Off Time = ~200ns

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Application Information (Cont.)

Figure 7. Turn-Off Time of BCR401/2/5 while Switching the Power Path (see Figure 3c)

Yellow  PWM Signal

Green  LED Current

Blue  No Connection Made to this Probe Channel

Figure 8. PWM Resolution with Power Path Switching (see Figure 3c)

0

10

20

30

40

50

60

0 20 40 60 80 100

LED current (mA)

Duty ratio %

PWM resolution at 25kHz

calculated DC current

Measured DC current

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Application Information (Cont.)

To remove the potential of incorrect connection of the power supply

damaging the lamp’s LEDs, many systems use some form of

reverse polarity protection.

One solution for reverse input polarity protection is to simply use a

diode with a low VF in line with the driver/LED combination. The low

VF increases the available voltage to the LED stack and dissipates

less power. Figure 9 shows a circuit example wh

ich protects the

light engine, although it will not function until the problem is

diagnosed and corrected. An SDM10U45LP (0.1A/45V) is shown,

which provides exceptionally low VF

for its package size of 1mm x

0.6mm. Other reverse voltage ratings are available on Diodes

Incorporated’s website, such as the SBR02U100LP (0.2A/100V) or

SBR0220LP (0.2A/20V).

While

automotive applications commonly use this method for

reverse battery protection, Figure 10 shows an alternative approach

shown that

provides reverse polarity protection and corrects the

reversed polarity, allowing the light engine to function.

The BAS40BRW incorporates four low VF

Schottky diodes in a

single package, reducing the power dissipated and maximizing the

voltage across the LED stack.

Figure 9. Application Circuit for LED Driver

with Reverse Polarity Protection

Figure 10. Application Circuit for LED Driver with

Assured Operation Regardless of Polarity

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Package Outline Dimensions

Please see http://www.diodes.com/package-outlines.html for the latest version.

SOT26 (SC74R)

Dim

Min

Max

Typ

A1

0.013

0.10

0.05

A2

1.00

1.30

1.10

A3

0.70

0.80

0.75

b

0.35

0.50

0.38

c

0.10

0.20

0.15

D

2.90

3.10

3.00

e

-

0.95

e1

-

1.90

E

2.70

3.00

2.80

E1

1.50

1.70

1.60

L

0.35

0.55

0.40

a

-

8°

a1

-

7°

All Dimensions in mm

Suggested Pad Layout

Please see http://www.diodes.com/package-outlines.html for the latest version.

SOT26 (SC74R)

Dimensions

Value (in mm)

C

2.40

C1

0.95

G

1.60

X

0.55

Y

0.80

Y1

3.20

a1

D

e

E1 E

b

A2 A1

Seating Plane

L

c

a

e1

A3

C1

Y1 G

X

Y

C

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IMPORTANT NOTICE

DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,

INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).

Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes

without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the

application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or

trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall

assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes

Incorporated website, harmless against all damages.

Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales

channel.

Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify

and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of,

directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.

Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and

markings noted herein may also be covered by one or more United States, international or foreign trademarks.

This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is

the final and determinative format released by Diodes Incorporated.

LIFE SUPPORT

Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the

express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:

A. Life support devices or systems are devices or systems which:

1. are intended to implant into the body, or

2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the

labeling can be reasonably expected to result in significant injury to the user.

B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause

the

failure of the life support device or to affect its safety or effectiveness.

Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems,

and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products

and any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-

related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated

and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices

or systems.

www.diodes.com

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