LT3595
APPLICATIONS INFORMATION
LED string depends on the number of LEDs and can vary
from 0.47μF to 1μF. Refer to Table 2 for proper output
capacitor selection.
Open LED Detection
The LT3595 detects an open LED on any channel and
reports it to the OPENLED pin. The fault also reports dur-
ing startup until the output voltage and LED current are
in regulation. Therefore, it can also be used as a “power
ok” signal.
Table 2. Recommended Output Capacitor Values (VLED = 3.5V)
# LEDs
3-10
1-2
C
(μF)
OUT
0.47
1
Programming LED Current
The set resistor (R
in the Block Diagram) controls
Table 3. Recommended Ceramic Capacitor Manufacturers
SET
the LED current in all sixteen channels. LED current as
a function of the R resistance is shown in the Typical
PerformanceCharacteristics.CommonvaluesforLEDcur-
rent and their required resistor values are listed in Table 4.
SinceresistorerrordirectlytranslatestoLEDcurrenterror,
precision resistors are preferred (1% is recommended).
The maximum allowed resistor value is 150k.
Taiyo Yuden
(408) 573-4150
www.t-yuden.com
SET
TDK
(847) 803-6100
www.component.tdk.com
Murata
Kemet
(714) 852-2001
www.murata.com
(408)-986-0424
www.kemet.com
Table 4. LED Current vs RSET Resistance
Table 3 shows a list of several ceramic capacitor manufac-
turers. Consultthemanufacturersfordetailedinformation
on their entire selection of ceramic parts.
R
SET
(kΩ)
I
(mA)
LED
150
10
75.0
49.9
37.4
30.1
20
30
40
50
3595f
10
Linear [ Linear ]
