LTC3205_15 Datasheet, PDF (6/16 Pages) Linear Technology – Multidisplay LED Controller

LTC3205
PI FU CTIO S
V_IN (Pin 16): Supply Voltage for the Charge Pump. The V_IN
pin should be connected directly to the battery and by-
passed with a 1µF X5R or X7R ceramic capacitor.
SGND (Pin 17): Ground for the Control Logic. This pin
should be connected directly to a low impedance ground
plane.
RED, GREEN, BLUE (Pins 18, 19, 20): Current Source
Outputs for the RGB Illuminator LEDs. The currents for
the RGB LEDs are controlled by the resistor on the I_RGB
pin. The RGB LEDs can independently be set to any duty
cycle from 0/15 through 15/15 under software control
giving a total of 16 shades per LED and a total of 4096
colors for the illuminator. See Tables 1 and 3. The RGB
LEDs are modulated at 1/240 the speed of the charge
pump oscillator.
SUB1, SUB2 (Pins 22, 21): Current Source Outputs for
the Sub Display White LEDs. The current for the sub
display is controlled by the resistor on the I_MS pin. The
LEDs on the sub display can be set to 100%, 50%, 25% or
0% of full scale under software control. See Tables 1
and␣ 2.
PGND (Pin 25, Exposed Pad): Power Ground for the
Charge Pump. The exposed pad should be connected
directly to a low impedance ground plane.
BLOCK DIAGRA
V_IN 16
800kHz
OSCILLATOR
C1⁺
C1^–
C2⁺
C2^–
5
4
6
3
1:1 AND 2:3 CHARGE PUMP
25 PGND
15 CPO
ENABLECP
6
I_MS 14
I_RGB 13
SGND 17
DV_CC 12
STEPUP 11
ENRGB 10
LD 9
D_IN 7
SCLK 8
2
2
CONTROL
LOGIC
2
2
PWM
444
COMMAND LATCH
16
SHIFT REGISTER
2 MAIN1
1 MAIN2
24 MAIN3
23 MAIN4
22 SUB1
21 SUB2
18 RED
19 GREEN
20 BLUE
3205 BD
3205f