LTC3205EUF Linear Technology, LTC3205EUF Datasheet - Page 5

• Manufacturer Part Number: LTC3205EUF
• Description: IC LED DRVR WT/RGB BCKLGT 24-QFN
• Manufacturer: Linear Technology
• Type: Backlight, White LED, RGB (Serial Interface)r

Specifications of LTC3205EUF

• Topology: PWM, Step-Down (Buck), Step-Up (Boost), Switched Capacitor (Charge Pump)
• Number Of Outputs: 9
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: RGB, White LED
• Frequency: 600kHz ~ 1.1MHz
• Voltage - Supply: 2.8 V ~ 4.5 V
• Mounting Type: Surface Mount
• Package / Case: 24-QFN
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 250mA
• Internal Switch(s): Yes
• Efficiency: 92%
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Voltage - Output: -

PI FU CTIO S
MAIN1-MAIN4 (Pins 2, 1, 24, 23): Current Source
Outputs for the Main Display White LEDs. The current for
the main display is controlled by the resistor on the I
pin. The LEDs on the main display can be set to 100%,
50%, 25% or 0% of full-scale programmed current under
software control. See Tables 1 and 2.
C1
Capacitor Pins. A 1 F X7R or X5R ceramic capacitor should be
connected from C1
D
is shifted in one bit per clock to control the LTC3205 (see
Table 1). The logic level for D
SCLK (Pin 8): Clock Input for the 16-Bit Serial Port (see
Figure 3). The logic level for SCLK is referenced to DV
LD (Pin 9): Load Input for the 16-Bit Serial Port. Command
data is loaded into the command latch on the falling edge
of LD (see Figure 3). The logic level for LD is referenced to
DV
ENRGB (Pin 10): This pin is used to enable and disable the
red, green and blue current sources. Once ENRGB is brought
high, the LTC3205 illuminates the RGB display with the color
combination that was previously programmed via the serial
port. When the main and sub displays are off and ENRGB is
low, the LTC3205 will be in shutdown. The logic level for
ENRGB is referenced to DV
TYPICAL PERFOR A CE CHARACTERISTICS
IN
3.9
3.7
3.5
3.3
3.1
2.9
2.7
2.5
+
U
CC
, C1
(Pin 7): Input Data for the 16-Bit Serial Port. Serial data
25
.
Input Supply Voltage Required for
Higher LED Currents
T
A
–
= 25 C
50
, C2
U
I
MS
75
+
, C2
OR I
100
RGB
–
+
125
(Pins 5, 4, 6, 3): Charge Pump Flying
to C1
CURRENT ( A)
U
I
MS
175
–
and another from C2
CC
200
I
RGB
W
.
IN
225
3205 G14
is referenced to DV
U
250
120
100
80
60
40
20
0
+
Compliance Voltage for Higher
LED Currents
0
to C2
V
T
A
IN
= 25 C
= 3.6V
0.2
CC
–
.
.
CC
MS
LED PIN VOLTAGE (V)
.
0.4
STEPUP (Pin 11): A logic high on this pin forces the
LTC3205’s charge pump to operate in 2:3 step-up mode,
thereby eliminating any possibility of the device switching
from 1:1 mode to 2:3 mode during critical communication
periods. The logic level for STEPUP is referenced to DV
DV
LTC3205.
I
at the RED, GREEN and BLUE LED pins. The I
servos to 1.223V when there is a resistor to ground. The
current in the RED, GREEN and BLUE LEDs will be 400
times the current at the I
scale (see Tables 1 and 3).
I
LED current in both the main and sub LED displays. The
I
ground. The currents in the main and sub display LEDs will
be 100, 200 or 400 times the current at the I
depending on which setting is chosen from the serial port.
CPO (Pin 15): Output of the Charge Pump. This output
should be used to power white, blue and “true” green
LEDs. Red LEDs can be powered from V
or X7R low impedance (ceramic) 1 F charge storage
capacitor is required on CPO.
RGB
MS
MS
0.6
CC
(Pin 14): This pin controls the maximum amount of
pin servos to 1.223V when there is a resistor to
(Pin 13): This pin controls the amount of LED current
I
I
I
I
I
RGB
RGB
RGB
RGB
RGB
(Pin 12): This pin sets the logic reference level of the
= 250 A
= 200 A
= 150 A
= 100 A
= 50 A
0.8
3205 G15
1.0
3mA/DIV
0mA
I
RGB
LED
RGB LED Turn On and Off
Characteristics
pin when programmed to full
IN
LTC3205
5 s/DIV
or CPO. An X5R
RGB
MS
3205 G011
5
3205f
pin
pin
CC
.