MAX5167
both of the 32-channel devices. The A5 line toggles the
SELECT pins of both devices to select the active one.
The device that has CONFIG tied high responds to the
lower 32 addresses (000000 through 011111). The
device that has CONFIG grounded responds to the
upper 32 addresses (100000 through 111111).
Input Drive Requirements
The input of the MAX5167 feeds the inputs of 32 high-
impedance buffers. These buffers are what charge the
sample/hold capacitor through the multiplexer switch
resistance. The bias current of a selected buffer is
10µA, and this feeds into the 10pF input capacitance.
Figure 5 shows an equivalent input circuit. The bias cur-
rents of the other 31 sample and holds are very small in
comparison to the bias current of the selected channel.
Powering the MAX5167
The MAX5167 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.
Chip Information
TRANSISTOR COUNT: 6961
32-Channel Sample/Hold Amplifier
with Output Clamping Diodes
10 ______________________________________________________________________________________
