Datasheet SP6690 Datasheet (Sipex)

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Page 1

SP6690

Micro Power Boost Regulator Series White LED Driver

FEATURES

■ High Output Voltage: Up to 30V

■ Optimized for Single Supply,

2.7V - 4.2V Applications

■ Operated Down to 1V

■ High Efficiency: Greater Than 75%

■ Low Quiescent Current: 20µA

■ Ultra Low Shutdown Current: 10nA

■ Single Battery Cell Operation

■ Programmable Output Voltage

■ 1Ω switch (250mV at 250mA)

■ Miniature Package: 8 Pin DFN,

5 Pin TSOT or 5 Pin SOT-23

APPLICATIONS

■ White LED Driver

■ High Voltage Bias

■ Digital Cameras

■ Cell Phone

■ Battery Backup

■ Handheld Computers

SP6690

8 Pin DFN

SHDN

GND

Now Available in Lead Free Packaging

DESCRIPTION

The SP6690 is a micro power boost regulator that is specifically designed for powering series configuration white LED. The part utilizes fixed off time architecture and consumes only 10nA quiescent current in shutdown. Low voltage operation, down to 1V, fully utilizes maximal battery life. The SP6690 is offered in a 8 pin DFN, 5 pin TSOT or 5 pin SOT-23 package and enables the construction of a complete regulator occupying < 0.2 in2 board space.

TYPICAL APPLICATION CIRCUIT

10µH

2.7 to 4.2V

SHDN

4.7µF

SP6690

GND

20mA

2.2 µF

Rb 60.4

Page 2

ABSOLUTE MAXIMUM RATINGS

VIN....................................................................... 15V

SW Voltage .............................................. -0.4 to 34V

FB Voltage ......................................................... 2.5V

All other pins ................................... -0.3 to V

Current into FB ................................................. ±1mA

Max ............................................................. 125°C

Operating Temperature Range ............ -40°C to 85°C

+ 0.3V

Peak Output Current < 10us SW .................... 500mA

Storage Temperature ...................... -65°C to +150°C

Power Dissipation. ......................................... 200mW

ESD Rating ................................................. 2kV HBM

These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.

ELECTRICAL CHARACTERISTICS

Specifications are at TA = 25°C, V

= 3.3, V

SHDN

temperature range, unless otherwise specified.

PARAMETER SYMBOL MIN TYP MAX UNITS CONDITIONS

Input Voltage V

Supply Current I

Reference Voltage V

FB Hysteresis HYST 8 mV

VFB Input Bias Current I

Line Regulation ∆Vo/∆V

Switch Off Time T

Switch Saturation Voltage V

Switch Current Limit I

SHDN Bias Current I

SHDN High Threshold (on) V

SHDN Low Threshold (off) V

Switch Leakage Current I

OFF

CESAT

LIM

SHDN

SWLK

♦♦

= VIN,

♦ denotes the specifications which apply over the full operating

♦♦

1.0 13.5 V

20 30 µA

0.01 1 µA

1.17 1.22 1.27 V

15 80 nA

♦♦

♦ No Switching

♦♦

♦ SHDN = 0V (off)

♦♦

♦

♦♦

♦ V

♦♦

= 1.22V

0.1 0.3 %/V 1.2 ≤ V

250 nS V

1200 nS V

170 350 mV

250 350 450 mA

512µA

♦♦

♦ ISW = 250mA

♦♦

♦

♦♦

♦ V

♦♦

> 1V

< 0.3V

SHDN

= 3.3V

0.9 V

0.25 V

0.01 5 µA

♦♦

♦ Switch Off, VSW = 5V

♦♦

≤ 13.5V

Page 3

PIN DESCRIPTION

SP6690

3 Pin SOT-23

GND

SHDN

PIN NUMBER PIN NAME 8 PIN DFN DESCRIPTION

1NCNo connect.

2FBFeedback.

3NCNo connect.

3SWSwitch input to the internal power switch

5 GND Ground

6VINInput Voltage. Bypass this pin with a capacitor as close to the device

as possible.

7 SHDN Shutdown. Pull high (on) to enable. Pull low (off) for shutdown.

8NCNo connect.

PIN NUMBER PIN NAME 5 PIN SOT-23 / TSOT DESCRIPTION

1SWSwitch input to the internal power switch.

2 GND Ground

3FBFeedback

4 SHDN Shutdown. Pull high (on) to enable. Pull low (off) for shutdown.

5VINInput Voltage. Bypass this pin with a capacitor as close to the device

as possible.

SHDN

SP6690

5 Pin TSOT

123

GND

SP6690

8 Pin DFN

SHDN

GND

PACKAGE: PINOUTS

Page 4

FUNCTIONAL DIAGRAM

VIN

SHDN

Shutdown Logic

General Overview:

Operation can be best understood by referring to the functional diagram above and the typical application circuit on the front page. Q1 and Q2 along with R3 and R4 form a band gap reference. The input to this circuit completes a feedback path from the high voltage output through a voltage divider, and is used as the regulation control input. When the voltage at the FB pin is slightly above 1.22V, comparator X1 disables most of the internal circuitry. Current is then provided by capacitor C2, which slowly discharges until the voltage at the FB pin drops below the lower hysteresis point of X1, about 6mV. X1 then enables the internal circuitry, turns on chip power, and the current in the inductor begins to ramp up. When the current through the driver transistor reaches about 350mA, comparator X2 clears the latch, which turns off the driver transistor for a preset 250nS. At the instant of shutoff, inductor current is diverted to the output through diode D1. During this 250nS time limit, inductor current decreases while its energy charges C2.

DISABLE

SET

250ns

ONE-SHOT

CLEAR

DRIVER

POWER

TRANSISTOR

52.5mV

0.15

GND

THEORY OF OPERATION

At the end of the 250ns time period, driver transistor is again allowed to turn on which ramps the current back up to the 350mA level. Comparator X2 clears the latch, it’s output turns off the driver transistor, and this allows delivery of L1’s stored kinetic energy to C2. This switching action continues until the output capacitor voltage is charged to the point where FB is at band gap (1.22V). When this condition is reached, X1 turns off the internal circuitry and the cycle repeats. The SP6690 contains circuitry to provide protection during start-up and while in short-circuit conditions. When FB pin voltage is less than approximately 300mV, the switch off time is increased to about 1.2uS and the current limit is reduced to about 70% of its normal value. While in this mode, the average inductor current is reduced and helps minimize power dissipation in the SP6690, the external inductor and diode.

Page 5

Refer to the typical application circuit, T

= 25°C, unless otherwise specified.

PERFORMANCE CHARACTERISTICS

AMB

Efficiency (%)

020406080100 120 140

Iout (mA)

Figure 1. 12V Output Efficiency

Vout = 15V Efficiency

Vout = 12V Efficiency

Efficiency (%)

0102030405060708090100

Iout (mA)

Figure 3. 15V Output Efficiency

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

13.0

12.5

12.0

Vout = 12V Load Regulation

Vout (V)

11.5

11.0

020406080100 120 140

Iout (mA)

Figure 2. 12V Output Load Regulation

Vout = 15V Load Regulation

16.0

15.5

15.0

Vout (V)

14.5

14.0 0102030405060708090100

Iout (mA)

Figure 4. 15V Output Load Regulation

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Vout = 18V Efficiency

Efficiency (%)

01020304050607080

Iout (mA)

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Figure 5. 18V Output Efficiency

19.0

18.5

18.0

Vout (V)

17.5

17.0

Figure 6. 18V Output Load Regulation

Vout = 18V Load Regulation

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

01020304050607080

Iout (mA)

Page 6

Refer to the typical application circuit, T

= 25°C, unless otherwise specified.

PERFORMANCE CHARACTERISTICS

AMB

Efficiency (%)

0102030405060

Iout (mA)

Figure 7. 21V Output Efficiency

Vout = 24V Efficiency

Vout = 21V Efficiency

Efficiency (%)

051015 20 25 30 35 40

Iout (mA)

Figure 9. 24V Output Efficiency

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

21.5

21.0

20.5

Vout (V)

20.0

19.5

0102030405060

Iout (mA)

Figure 8. 21V Output Load Regulation

Vout = 21V Load Regulation

Vout = 24V Load Regulation

24.5

24.0

23.5

Vout (V)

23.0

22.5 051015 20 25 30 35 40

Iout (mA)

Figure 10. 24V Output Load Regulation

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Vin = 5.0V Vin = 4.2V Vin = 3.3V Vin = 2.7V

Efficiency (%)

051015 20 25 30

Iout (mA)

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

Figure 11. 30V Output Efficiency

30.5

30.0

29.5

Vout (V)

29.0

28.5

Figure 12. 30V Output Load Regulation

Vout = 30V Efficiency

Vout = 30V Load Regulation

Vin = 5.0V

Vin = 4.2V

Vin = 3.3V

Vin = 2.7V

051015 20 25 30

Iout (mA)

Page 7

Refer to the typical application circuit, T

= 25°C, unless otherwise specified.

PERFORMANCE CHARACTERISTICS

AMB

Quiescent Current (uA)

1.2 1.8 2.4 3 3.6 4.2 4.8 5.4

Input Voltage (V)

Figure 13. Quiescent Current IQ vs. V

600

500

400

300

200

Ipk Current Limit (mA)

100

1.2 1.8 2.4 3 3.6 4.2 4.8 5.4

Input Voltage (V)

Tamb=-25C

Tamb=25C

Tamb=85C

Shutdown Pin Current (µA)

1.2 1.8 2.4 3 3.6 4.2 4.8 5.4

Input Voltage (V)

Figure 14. Shutdown Pin Current vs. V

400

350

300

250

200

150

100

Switch Saturation Voltage (mV)

-30 -10 10 30 50 70 90

Temperature (°C)

Figure 15. I

1.25

1.24

1.23

1.22

1.21

Feedback Voltage (V)

1.20

Figure 17. Feedback Voltage vs. Temperature

Current Limit vs. V

-30 -10 10 30 50 70 90

Temperature (°C)

Figure 16. Switch Saturation Voltage V Temperature (I

Average Output Current (mA)

020406080100

= 350mA)

PWM Duty Cycle (%)

CESAT

vs.

Figure 18. Average IO vs. SHDN Duty Cycle (VIN =

3.3V, Standard 4x20mA WLED Evaluation Board, PWM Frequency 100Hz)

Page 8

Refer to the typical application circuit, T

= 25°C, unless otherwise specified.

PERFORMANCE CHARACTERISTICS

AMB

OUT

IIN (0.2A/DIV)

Figure 19. Startup Waveform (VIN=3.3V, V I

=20mA)

OUT

(10mA/DIV)

OUT

(AC)

OUT

(0.5A/DIV)

OUT

=15V,

IL (0.5A/DIV)

OUT

Figure 20. Typical Switching Waveforms (VIN=3V, V

OUT

=15V, I

OUT

=20mA)

(AC)

Figure 21. Load Step Transient (VIN=3V, V

OUT

=21V,

1∼15mA Load Step

Page 9

APPLICATION INFORMATION

Inductor Selection

For SP6690, the internal switch will be turned off only after the inductor current reaches the typical dc current limit (I

=350mA). How-

LIM

ever, there is typically propagation delay of 200nS between the time when the current limit is reached and when the switch is actually turned off. During this 200nS delay, the peak inductor current will increase, exceeding the current limit by a small amount. The peak inductor current can be estimated by:

IPK = I

LIM

IN(MAX)

• 200nS

The larger the input voltage and the lower the inductor value, the greater the peak current.

In selecting an inductor, the saturation current specified for the inductor needs to be greater than the SP6690 peak current to avoid saturating the inductor, which would result in a loss in efficiency and could damage the inductor.

Choosing an inductor with low DCR decreases power losses and increase efficiency.

Refer to Table 1 for some suggested low ESR inductors.

Table 1. Suggested Low ESR inductor

MANUF. PART NUMBER DCR Current

MURATA LQH32CN100K11 0.3 450 770-436-1300 (10µH)

TDK NLC453232T-100K 0.55 500 847-803-6100 (10µH)

Diode Selection

(Ω) Rating

(mA)

A schottky diode with a low forward drop and fast switching speed is ideally used here to achieve high efficiency. In selecting a Schottky diode, the current rating of the schottky diode should be larger than the peak inductor current. Moreover, the reverse breakdown voltage of the schottky diode should be larger than the output voltage.

Capacitor Selection

Ceramic capacitors are recommended for their inherently low ESR, which will help produce low peak to peak output ripple, and reduce high frequency spikes.

For the typical application, 4.7µF input capacitor and 2.2µF output capacitor are sufficient. The input and output ripple could be further reduced by increasing the value of the input and output capacitors. Place all the capacitors as close to the SP6690 as possible for layout. For use as a voltage source, to reduce the output ripple, a small feedforward (47pF) across the top feedback resistor can be used to provide sufficient overdrive for the error comparator, thus reduce the output ripple.

Refer to Table 2 for some suggested low ESR capacitors.

Table 2. Suggested Low ESR Capacitor

MANUF. PART NUMBER CAP SIZE

MURATA GRM32RR71E 2.2µF 1210 770-436-1300 225KC01B /25V /X5R

MURATA GRM31CR61A 4.7µF 1206 770-436-1300 475KA01B /10V /X5R

TDK C3225X7R1E 2.2µF 1210 847-803-6100 225M /25V /X7R

TDK C3216X5R1A 4.7µF 1206 847-803-6100 475K /10V /X5R

LED Current Program

/VOLTAGE /TYPE

In the white LEDs application, the SP6690 is generally programmed as a current source. The bias resistor Rb, as shown in the typical application circuit is used to set the operating current of the white LED using the equation:

Rb = I

where V

is the feedback pin voltage (1.22V),

IF is the operating current of the White LEDs. In order to achieve accurate LED current, 1%

Page 10

APPLICATION INFORMATION

precision resistors are recommended. Table 3 below shows the R

selection for different white

LED currents. For example, to set the operating current to be 20mA, R

is selected as 60.4 Ω, as

shown in the schematic.

Table 3. Bias Resistor Selection

IF (mA) Rb (Ω)

5 243

10 121

12 102

15 80.6

20 60.4

Output Voltage Program

The SP6690 can be programmed as either a voltage source or a current source. To program the SP6690 as voltage source, the SP6690 requires 2 feedback resistors R1 & R2 to control the output voltage. As shown in Figure 22.

VIN

Figure 22. Using SP6690 as Voltage Source

SP6690

VOUT

FBSHDN

1.22V

The formula and table for the resistor selection are shown below:

Table 4. Divider Resistor Selection

(V) R1 (Ω)R

OUT

(Ω)

12 1M 113K

15 1M 88.7K

18 1M 73.2K

21 1M 61.9K

30 1M 42.2K

Brightness Control

Dimming control can be achieved by applying a PWM control signal to the SHDN pin. The brightness of the white LEDs is controlled by increasing and decreasing the duty cycle of The PWM signal. A 0% duty cycle corresponds to zero LED current and a 100% duty cycle corresponds to full load current. While the operating frequency range of the PWM control is from 60Hz to 700Hz, the recommended maximum brightness frequency range of the PWM signal is from 60Hz to 200Hz. A repetition rate of at least 60Hz is required to prevent flicker. The magnitude of the PWM signal should be higher than the minimum SHDN voltage high.

Open Circuit Protection

When any white LED inside the white LED module fails or the LED module is disconnected from the circuit, the output and the feedback control will be open, thus resulting in a high output voltage, which may cause the SW pin voltage to exceed it maximum rating. In this case, a zener diode can be used at the output to limit the voltage on the SW pin and protect the part. The zener voltage should be larger than the maximum forward voltage of the White LED module.

R1 =(

1.22

OUT

- 1 ) • R

Page 11

Layout Consideration

Both the input capacitor and the output capacitor should be placed as close as possible to the IC.

This can reduce the copper trace resistance which directly effects the input and output ripples. The feedback resistor network should be kept close to the FB pin to minimize copper trace connections that can inject noise into the system. The ground connection for the feedback resistor network should connect directly to the GND pin or to an analog ground plane that is tied directly to the GND pin. The inductor and the schottky diode should be placed as close as possible to the switch pin to minimize the noise coupling to the other circuits, especially the feedback network.

Power Efficiency

For the typical application circuit, the output efficiency of the circuit is expressed by

• I

OUT

η =

Where VIN , IIN, V

OUT

• I

, I

OUT

are the input and

OUT

output voltage and current respectively.

While the white LED efficiency is expressed by

- 1.22) • I

η =

OUT

IN • IIN

OUT

APPLICATION INFORMATION

2.7-4.2V

Murata LQH32CN100K11

4.7uF

L1 10uH 0.45A

SP6690

GND

MBR0530

2.2uF

FBSHDN

1.22V

150Kohm

DIODE

White LED Module

0.7V

34.8ohm

VIN

method.

Figure 23. Improve Efficiency with Diode in Feedback Loop

To further improve the efficiency and reduce the effects of the ambient temperature on the diode D1 used in method 1, an op amp circuit can be used as shown in Figure 24. The gain of the op amp circuit can be calculated by:

R1 + R

Av =

If the voltage across the bias resistor is set to be

0.1V the current through R1 and R2 to be around 100µA, R1 and R2 can be selected as 1K and

11.2K respectively. LMV341 can be used because of its small supply current, offset voltage and minimum supply voltage. By using this method, the efficiency can be increased around

This equation indicates that the white LED efficiency will be much smaller than the output efficiency of the circuit when V

is not very

OUT

large, compared to the feedback voltage (1.22V).

The other power is consumed by the bias resistor. To reduce this power loss, two circuits can be used, as shown in Figure 23 and Figure 24. In Figure 23, a general-purpose diode (for example, 1N4148) is used to bring the voltage

Vbattery

2.7-4.2V

Murata LQH32CN100K11

4.7uF

L1 10uH 0.45A

SP6690

MBR0530

2.2uF

1 S

FBSHDN

1.22V

Vbattery

White LED Module

LMV341

OUT

11.2K

0.1V

5.1Ω

across the bias resistor to be around 0.7V. R1 is used to create a loop that provides around 100µA operating current for the diode. 3% efficiency improvement can be achieved by using this

7%.

Figure 24. Improve Efficiency with Op Amp in Feedback Loop

Page 12

PACKAGE: 5 PIN TSOT

INDEX AREA (D/2 X E1/2)

E1/2

N/2 +1

N/22

5 Pin TSOT JEDEC MO-193 (AB) Variation

SYMBOL

MIN NOM MAX

A--1.1 A1 0 - 0.1 A2 0.7 0.9 1

b 0.3 - 0.5

c 0.08 - 0.2

e e1

E E1

2.90 BSC

0.95 BSC

1.90 BSC

2.80 BSC

1.60 BSC

L 0.3 0.45 0.6 L1 L2

0.60 REF

0.25 BSC

ø0º4º8º ø1 4º 10º 12º

E/2

SEE VIEW C

VIEW A-A

Ø1

Gauge Plane

Seating Plane

ø1

VIEW C

WITH PLATING

SEATING PLANE

SIDE VIEW

Note: Dimensions in (mm)

BASE METAL

B-BSection

Page 13

PACKAGE: 5 PIN SOT-23

E1/2

N/2 +1

N/22

5 Pin SOT-23 JEDEC MO-178 (AA) Variation

SYMBOL

MIN NOM MAX

A--1.45

A1 0 - 0.15 A2 0.9 1.15 1.3

b 0.3 - 0.5

c 0.08 - 0.22

E E1

e e1

2.90 BSC

2.80 BSC

1.60 BSC

0.95 BSC

1.90 BSC

L 0.3 0.45 0.6 L1 L2

0.60 REF

0.25 BSC

Ø0º4º8º

ø5º10º 15º

Note: Dimensions in (mm)

E/2

SEE VIEW C

VIEW A-A

Gauge Plane

Seating Plane

VIEW C

WITH PLATING

Seating Plane

SIDE VIEW

BASE METAL

SECTION B-B

Page 14

PACKAGE: 8 PIN DFN

D/2

Top View

E/2

Side View

2x3 8 Pin DFN JEDEC MO-229 (VCED-2)

VARIATION

SYMBOL

MIN NOM MAX

A 0.8 0.9 1 A1 0 0.02 0.05 A3

b 0.18 0.25 0.3

0.20 REF

2.00 BSC

D2 1.5 1.75

e-0.5 -

3.00 BSC

E2 1.6 - 1.9

K 0.2 - -

L 0.3 0.4 0.5

Note: Dimensions in (mm)

Bottom View

Page 15

ORDERING INFORMATION

Part Number Topmark Temperature Range Package Type

SP6690EK1 ....................... P3WW ...................... -40˚C to +85˚C ............................. 5 Pin TSOT

SP6690EK1/TR .................. P3WW ...................... -40˚C to +85˚C ............................ 5 Pin TSOT

SP6690EK ......................... C3WW ...................... -40˚C to +85˚C .......................... 5 Pin SOT-23

SP6690EK/TR .................... C3WW ...................... -40˚C to +85˚C ......................... 5 Pin SOT-23

SP6690ER ........................ 6690ES ..................... -40˚C to +85˚C ............................... 8 Pin DFN

SP6690ER/TR .................. 6690ES ..................... -40˚C to +85˚C .............................. 8 Pin DFN

Available in lead free packaging. To order add "-L" suffix to part number.

Example: SP6690ER/TR = standard; SP6690ER-L/TR = lead free

/TR = Tape and Reel

Pack quantity is 2,500 for TSOT or SOT-23 and 3,000 for DFN.

CLICK HERE TO ORDER SAMPLES

Corporation

ANALOG EXCELLENCE

Sipex Corporation

Headquarters and Sales Office

233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.