Fairchild FAN5333A, FAN5333B service manual

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FAN5333A/FAN5333B High Efficiency, High Current Serial LED Driver with 30V Integrated Switch

August 2005

FAN5333A/FAN5333B
High Efficiency, High Current Serial LED Driver with 30V
Integrated Switch

Features

1.5MHz Switching Frequency

Low Noise

Adjustable Output Voltage

Up to 1.5A Peak Switch Current

1.5W Output Power Capability

Low Shutdown Current: <1µA

Cycle-by-Cycle Current Limit

Low Feedback Voltage

Over-Voltage Protection

Fixed-Frequency PWM Operation

Internal Compensation

FAN5333A has 110mV Feedback Voltage

FAN5333B has 315mV Feedback Voltage

Thermal Shutdown

5-Lead SOT23 Package

Applications

Cell Phones

PDAs

Handheld Equipment

Display Bias

LED Bias

Flash LED

Description

The FAN5333A/FAN5333B is a general purpose LED driver that
features fixed frequency mode operation and an integrated FET
switch. The device’s high output power makes it suitable to drive
flash LEDs in serial connections. This device is designed to
operate at high switching frequencies in order to minimize
switching noise measured at the battery terminal of hand-held
communications equipment. Quiescent current in both normal
and shutdown mode is designed to be minimal in order to
extend battery life. Normal or shutdown mode can be selected
by a logic level shutdown circuitry.

The low ON-resistance of the internal N-channel switch ensures
high efficiency and low power dissipation. A cycle-by-cycle cur­rent limit circuit keeps the peak current of the switch below a
typical value of 1.5A. The FAN5333A/FAN5333B is available in
a 5-lead SOT23 package.

Typical Application

VIN

©2005 Fairchild Semiconductor Corporation

FAN5333A/FAN5333B Rev. 1.0.1

4.7µF
to
10µF

ON

C

OFF

L

5

6.8µH to 10µH

V

IN

SW

FB

IN

BAT54

C

OUT

0.1µF
to

2.2µF

1

3

I

LED

I

LED1

I

LED2

V

OUT

FAN5333

4

SHDN

GND

2

R

R1

R2

Figure 1. Typical Application Diagram

1

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Pin Assignment

FAN5333A/FAN5333B High Efficiency, High Current Serial LED Driver with 30V Integrated Switch

Top View

SW

GND

FB

V

IN

SHDN

5-Lead SOT-23

Figure 2. Pin Assignment

Pin Description

Pin No. Pin Name Pin Description

1SW

2 GND

3FB

4 SHDN

5V

IN

Switching Node .

Analog and Power Ground .

Feedback Pin. Feedback node that connects to an external current set resistor.

Shutdown Control Pin. Logic HIGH enables, logic LOW disables the device.

Input Voltage Pin .

FAN5333A/FAN5333B Rev. 1.0.1

2

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FAN5333A/FAN5333B High Efficiency, High Current Serial LED Driver with 30V Integrated Switch

Absolute Maximum Ratings (

Note1)

Parameter Min Max Unit

V

to GND 6.0 V

IN

FB, SHDN

SW to GND -0.3 35 V

Lead Soldering Temperature (10 seconds) 300 °C

Junction Temperature 150 °C

Storage Temperature -55 150 °C

Thermal Resistance ( Θ

Electrostatic Discharge Protection (ESD) Level (Note 2) HBM 2 kV

to GND -0.3 V

) 210 °C/W

JA

CDM 1

+ 0.3 V

IN

Recommended Operating Conditions

Parameter Min Typ Max Unit

Input Voltage 1.8 5.5 V

Output Voltage V

Operating Ambient Temperature -40 25 85 °C

Output Capacitance Rated at the Required Output (Note 3) for maximum load
current

Notes:

1. Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or any other conditions above those indicated in the operational section
of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device
reliability. Absolute maximum ratings apply individually only, not in combination.

2. Using EIA/JESD22A114B (Human Body Model) and EIA/JESD22C101-A (Charge Device Model).

3. This load capacitance value is required for the loop stability. Tolerance, temperature variation, and voltage dependency of the
capacitance must be considered. Typically a 1µF ceramic capacitor is required to achieve specified value at V

IN

0.47 µF

30 V

= 30V.

OUT

FAN5333A/FAN5333B Rev. 1.0.1

3

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≤

Ω

Ω

µ

≤

µ

Electrical Characteristics

Unless otherwise noted, V
T

= 25°C, Test Circuit, Figure 3.

A

Parameter Conditions Min. Typ. Max. Units

Feedback Voltage FAN5333A 99 110 121 mV

Switch Current Limit V

Load Current Capability V

Switch On-resistance V

Quiescent Current V

OFF Mode Current V

Shutdown Threshold Device ON 1.5 V

Shutdown Pin Bias Current V

Feedback Pin Bias Current 1 300 nA

Feedback Voltage Line Regulation 2.7V < V

Switching Frequency 1.2 1.5 1.8 MHz

Maximum Duty Cycle 87 93 %

Switch Leakage Current No Switching, V

OVP 15 %

Thermal Shutdown Temperature 150 °C

= 3.6V, V

IN

OUT

= 20V, I

= 20mA, T

LED

= -40°C to 85°C, Typical values are at

A

FAN5333B 299 315 331 mV

= 3.2V 1.1 1.5 A

IN

20V, V

OUT

= 5V 0.6

IN

V

= 3.6V 0.7

IN

= 3.6V, No Switching 0.6 mA

SHDN

= 0V 0.1 3

SHDN

= 3.2V 65 mA

IN

Device OFF 0.5 V

SHDN

= 0V or V

< 5.5V, V

IN

= 5.5V 1 300 nA

SHDN

20V 0.3 %

OUT

= 5.5V 1

IN

FAN5333A/FAN5333B High Efficiency, High Current Serial LED Driver with 30V Integrated Switch

A

A

Test Circuit

VIN

C

10µF

ON

L

IN

5

10µH

SW

V

IN

FB

BAT54

C

OUT

1µF

I

1

3

LED

V

OUT

Electronic Load

FAN5333

R

OFF

4

SHDN

GND

Figure 3. Test Circuit

2

FAN5333A/FAN5333B Rev. 1.0.1

4

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