Linear Technology LTC3220 Quick Start Manual

DESCRIPTION
Do not look directly at operating LED.
This circuit produces light that can damage eyes.
Demonstration circuit 1265 is a 360mA Universal 18-
Channel LED Driver with twelve white LEDs and two RGB
LEDs featuring the LTC3220/LTC3220-1.
The LTC3220/LTC3220-1 is a low noise charge pump
designed to drive 18 universal LED (ULED) current
sources. The LTC3220/LTC3220-1 requires only five
small ceramic capacitors to form a complete LED power
supply and current controller.
The maximum display currents are set with an internal
precision current reference. On/Off blinking, gradation,
intensity, and a software controlled shutdown are ac-
PERFORMANCE SUMMARY
PARAMETER
Input Supply Range (V
VIN Shutdown Current
DV Operating Voltage
CC
DV Shutdown Current
CC
CPO Regulation Voltage
Full-Scale LED Current
Absolute Maximum LED Current
Minimum (I ) LED Current Step
LSB
Minimum Programmable Current
LED Current Matching
LED Dropout Voltage
LED Turn-on Delay
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WARNING!
CONDITIONS
)
IN
1.5x Mode, I = 20mA
CPO
2x Mode, I = 20mA
CPO
ULED = 1V
Strong GPO Mode, external current limit needed
ULED Data Register Programmed to 0b00000001
Any Two Outputs, 50% Full-Scale
I = Full-Scale
LED
From Stop Bit, Part Enabled
360mA Universal 18-Channel
complished via an I
LTC3220/LTC3220-1 data sheet for more information on
this process. There are 64 dimming states available for
the universal LEDs.
The charge pump optimizes efficiency based on the volt-
age across the LED current sources. The part powers up
in 1x mode and will automatically switch to boost mode
whenever any enabled LED current source begins to drop
out. The first dropout switches the part to 1.5x mode and
a subsequent dropout switches the part into 2x mode.
The part resets to 1x mode whenever a data byte is up-
dated via the I
Design files for this circuit board are available. Call
the LTC factory.
L
, LTC, LTM, LT are registered trademarks of Linear Technology Corporation. Other product
names may be trademarks of the companies that manufacture the products.
Specifications are at T A = 25°C
Demo Circuit 1265
QUICK START GUIDE
LTC3220/LTC3220-1
LTC3220/LTC3220-1
LED Driver
2
C serial interface. See the
2
C port.
MIN TYP MAX
2.9 5.5
3.2 7
1.5 5.5
1
4.5
5.03
18 20 22
25
0.314
0.395
1.5
120
4
UNITS
V
uA
V
μA
V
V
mA
mA
mA
mA
%
mV
uS
1