MP1521

High Efficiency

White LED Driver

MP1521 Rev 2.7 10/06/04

www.monolithicpower.com

2

Monolithic Power Systems

Absolute Maximum Ratings

28V

Switch Voltage to GND

-0.5V to 28V

–0.3V to 6V

Storage Temperature

-55

°C to +150°C

Recommended Operating Conditions

2.7V to 25V

Operating Temperature

-20

°C to +85°C

Switch Voltage to GND

-0.5V to 25V

Package Thermal Characteristics

150°C/W

60°C/W

Parameters

Symbol

Condition

Min

Typ

Max

Units

Supply Current (shutdown)

1

3

µA

Supply Current (quiescent)

550

700

µA

Minimum Off Time, normal

operation

400

500

700

nS

Minimum Off Time, start-up

(Note 1)

1.5

2.4

µS

UVLO

2.1

2.6

V

Under Voltage Lockout

1.9

2.4

V

Enable

Threshold

0.8

1.0

2.0

V

Hysterisis

60

mV

Leakage Current

1

µA

Open Load Shutdown

Threshold

Measured at OLS Pin

26

29

V

1

µA

Leakage Current

45

70

µA

Reference

Output Voltage

1.20

1.235 1.27

V

Load Regulation

2.5

5

mV

Line Regulation

2.5

5

mV

Feedback Comparator

Threshold

V

380

400

420

mV

Hysterisis (Note 2)

30

mV

FB Input Bias Current

-150

-50

0

nA

PWM Mode

Output-Off Threshold

0.18

0.26

V

BRT Input Bias

-100

-30

0

nA

BRT Full Scale Threshold

(Note 3)

1.2

V

Output Switch

0.5

0.6

Ω

Switch Current Limit

300

400

mA

Leakage Current

5

µA

Thermal Shutdown (Note 2)

160

°C

Notes:

1) First 64 pulses after EN switches high.

2) Guaranteed by design.

3) The output current is off when BRT is driven below the output-off threshold and full-scale when driven above the full-scale

threshold. To PWM the output drive BRT above and below these thresholds.