MAX5165
32-Channel Sample/Hold Amplifier
with a Single Multiplexed Input
10 ______________________________________________________________________________________
Figure 5. Multiplexing a DAC
Chip Information
TRANSISTOR COUNT: 5077
Multiplexed DAC
Figure 5 shows a typical demultiplexer application.
Different digital codes are converted by the digital-to-
analog converter (DAC) and then stored on 32 different
channels of the MAX5165. The 100mV/sec (max) droop
rate requires refreshing the hold capacitors every
100ms before the voltage drops by 1/2LSB for an 8-bit
DAC with a 5V full-scale voltage.
Powering the MAX5165
The MAX5165 does not require a special power-up
sequence to avoid latchup. The device requires three
separate supply voltages for operation; however, when
one or two of the voltages are not available, DC-DC
charge-pump (switched-capacitor) converters provide
a simple, efficient solution. The MAX860 provides volt-
age doubling or inversion, ideal for conversions from
+5V to +10V or from +5V to -5V. The MAX860 also
functions as a voltage divider to provide conversion
from +10V to +5V.
