MAX5165NECM Maxim Integrated, MAX5165NECM Datasheet - Page 8

• Manufacturer Part Number: MAX5165NECM
• Description: Sample & Hold Amplifiers
• Manufacturer: Maxim Integrated
• Series: MAX5165r

Specifications of MAX5165NECM

• Number Of Channels: 32
• Acquisition Time: 4 us
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: TQFP-48
• Minimum Dual Supply Voltage: - 4.75 V, + 9.5 V

32-Channel Sample/Hold Amplifier
with Four Multiplexed Inputs
Figure 2. Timing Performance
The MAX5166 contains a separate input for each 1-to-8
multiplexer. Externally connect the input pins to form
larger multiplexers. When all four inputs are connected
to the same source, the MAX5166 is functionally equiv-
alent to the MAX5165, except the MAX5166 does not
contain output clamping diodes.
The MAX5166 contains four separate 1-to-8 multiplexers
and individual mode selectors for each multiplexer. When
sampling one channel at a time, use an external 2-to-4
decoder (with active-low outputs) to reduce the number
of digital control lines from seven to five (Figure 3).
Individually control the four mode/multiplexer-select
pins to simultaneously sample on four channels, the
same channel for each multiplexer (Figure 4). Each
mode-select pin controls sampling on one of the 1-to-8
multiplexers, while the 3-bit address selects one of the
eight channels on all the multiplexers (Tables 1 and 2).
Setting any combination of the mode-select pin low
enables sampling on the addressed channels for the
selected multiplexers.
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__________Applications Information
_______________________________________________________________________________________
Single vs. Simultaneous Sampling
ADDRESS
OUTPUT
(A0–A2)
SELECT
MODE
INPUT
Control-Line Reduction
Combining Inputs
t
AQ
t
H
t
PW
Simultaneously sampling two or more channels reduces
offset voltage but increases acquisition time. Multiply
the single-channel acquisition time by the number of
channels sampling.
Figure 5 shows a typical demultiplexer application.
Different digital codes are converted by the digital-to-
analog converter (DAC) and then stored on eight differ-
ent channels, or as many as 32 different channels
when all four inputs are active. 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.
The MAX5166 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.
t
DH
t
AP
HOLD STEP
t
DS
Powering the MAX5166
Multiplexed DAC