
LT8500
20
8500f
Typical applicaTions
Four typical applications are shown in Figures 7 to 10.
Figures 7 and 8 illustrate the 5-pin and 4-pin topologies
for daisy chains as discussed earlier in this data sheet.
Figure 9 illustrates a single LT8500 controlling 48 resistor
ballasted LED strings. Figure 10 illustrates a novel use of
the LT8500 as a 48-channel digital-to-analog converter
(DAC). Using a simple RC filter on each PWM output, the
resulting converter has very good error characteristics
as shown in the accompanying differential linearity error
(DLE) and integrated linearity error (ILE) charts (Figures
11 and 12). The DLE measurements were taken from an
all codes test, and were compensated for power supply
variation on VCC of less than ±0.01% over the course of
the test. The ILE is simply the sum of all previous com-
pensated DLE measurements. The units of the DLE and
ILE measurements are in PWM LSB’s.