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FAN5701

Compact 6-LED Driver for Mobile Platforms

Fairchild Semiconductor 

Electrical Specifications

Unless otherwise specified; VIN = 2.7V to 5.5V, TA = -40°C to +85°C, and EN = VIN. Typical values are VIN = 3.6V, TA = 25°C,

ILED = 20mA, and LED cathode terminals = 0.4V. Circuit and components are according to Figure 1.

Symbol

Parameter

Conditions

Min. Typ. Max. Units

Power Supplies and Thermal Protection

IQ

Quiescent Supply Current

1.5x Mode, No LEDs

1x Mode, No LEDs

4.4

mA

0.7

mA

ISD

VUVLO

VUVHYST

Shutdown Supply Current

Under-Voltage Lockout

Threshold

Under-Voltage Lockout

Hysteresis

EN = 0, VIN = 4.5V, TA=-40°C to +85°C

1.5

4.0

μA

VIN Rising

VIN Falling

2.55 2.70

V

2.20 2.40

150

mV

OVP Over-Voltage Protection

6

V

TLIMIT Thermal Shutdown

THYST Thermal Shutdown Hysteresis

LED Current Sinks

150

°C

20

°C

ILED

ILED(MAX)

ILED_MATCH

VDTH

VHR

Absolute Current Accuracy

Maximum Diode Current (3)

LED Current Matching (4)

1x to 1.5x Gain Transition

Threshold

Current Sink Headroom (5)

Charge Pump

VCATHODE=0.4V, See Options for ISET

ILED= ISET

VCATHODE=0.4V, ILED= ISET

LED Cathode Voltage Falling

ILED = 90% ILED(NOMINAL)

–10% ISET +10% mA

30

mA

0.4

3.0

%

100

mV

65

mV

ROUT Output Resistance

1.5x Mode

1x Mode

2.4

Ω

0.9

Ω

fSW

tSTART

Switching Frequency

Startup Time

VOUT = 90% of Steady State

0.9

1.2

1.5

MHz

250

μs

PWM Dimming

fPWM PWM Dimming Frequency

DPWM PWM Duty-Cycle

Logic Inputs (EN, PWMA, PWMB)

tON_LED = 15µs (Minimum)

fPWM = 100Hz

20

kHz

0.15

100.00 %

VIH

HIGH-Level Input Voltage

1.2

V

VIL

LOW-Level Input Voltage

0.4

V

VIMAX Maximum Input Voltage

1.8

5.5

V

IIN

Input Bias Current

Input Tied to GND or VIN

0.01 1.00

μA

Notes:

3. The maximum total output current for the IC should be limited to 180mA. The total output current can be split between the

two groups (IDxA = IDxB = 30mA maximum). Under maximum output current conditions, special attention must be given

to input voltage and LED forward voltage to ensure proper current regulation. See the Maximum Output Current section of

the datasheet for more information.

4. For the two groups of current sinks on a part (GroupA and GroupB), the following are determined: the maximum sink

current in the group (MAX), the minimum sink current in the group (MIN), and the average sink current of the group (AVG).

For each group, two matching numbers are calculated: (MAX-AVG)/ AVG and (AVG-MIN)/AVG. The largest number of the

two (worst case) is considered the matching figure for the group. The matching figure for a given part is considered to be

the highest matching figure of the two groups. The typical specification provided is the most likely norm of the matching

figure for all parts.

5. For each Dxx pin, headroom voltage is the voltage across the internal current sink connected to that pin. VHRx = VOUT -

VLED. If headroom voltage requirement is not met, LED current regulation is compromised.

© 2009 Fairchild Semiconductor Corporation

FAN5701 • Rev. 1.0.3

6

www.fairchildsemi.com

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