Integration : IA2505

Four Channel LED Current Source for Flash and Backlighting

The IA2505 is a high-efficiency, low-cost, high-current, parallel LED driver current source specifically designed for running flash and backlighting LEDs. The LED current can be set from 5mA to 80mA on each channel, and the individual LED currents are matched to within +/-10%. LED pulse current can be as high as 200mA for duration of 20msec or less.

LED brightness can be varied up to the programmed LED current by applying a Pulse Width Modulated (PWM) signal to the EN pin of the device. The LED output current of the IA2505 is tightly controlled over temperature and voltage.

The input supply range is from 2.7V to 5.5V which is ideally suited for single-cell Li-Ion battery supplies. Dropout voltage is only 30mV at 20mA, permitting direct operation from a Li-Ion battery. The IA2505 can also be operated from two or three Alkaline batteries. The only external component required is a resistor that sets the current on each of the four channels.

The IA2505 typically draws only 40µA when operating in the no-load condition and draws less than 0.01µA when the device is shutdown.

The IA2505 is available in a space-saving 3mm x 3mm DFN package.

Parameter	Condition	Min	Typ	Max	Units
Supply Current	EN=0V		0.01	1	µA
Supply Current	EN≥4.5V(No Load) with Rset=open		40	55	µA
Enable Threshold	Logic Low			0.8	V
Enable Threshold	Logic High	0.9VCC			V
Sink Current	Rset=60KΩ	15	20	25	mA
Sink Current	Rset=15KΩ	70	80	90	mA
Dropout Voltage (Note 1)	Rset=60KΩ		30	50	mV
Iset Voltage	Rset=60KΩ, VCC=5V	1.12	1.20	1.32	V
LED Current Set Factor, α	Rset=60KΩ, α=Iled*Rset	900	1200	1500
Thermal Shutdown			160		°C
Thermal Shutdown Hysteresis			10		°C

Note 1: Dropout voltage is defined as the LED pin voltage at which the LED current is 80% of the LED nominal current at VCC=5V

High efficiency of 83% at VCC = 3.6V for VF = 3V
30mV dropout at 20mA allows operation at low Vin
No internal switching signals - Eliminates EMI
LED current settable from 5mA to 80mA with single resistor
Capable of 200mA/LED pulse current with duration of 20msec or less
Currents matched to within ±10%
Minimum external components
Input voltage from 2.7V to 5.5V
1µA maximum shutdown current
Brightness control using PWM signals
Rated at -40°C to +85°C operating temperature range
3mm x 3mm DFN packages

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