MAX1316_08 Datasheet, PDF (13/27 Pages) Maxim Integrated Products – 8-/4-/2-Channel, 14-Bit, Simultaneous-Sampling ADCs with ±10V, ±5V, and 0 to +5V Analog Input Ranges

8-/4-/2-Channel, 14-Bit, Simultaneous-Sampling ADCs
with ±10V, ±5V, and 0 to +5V Analog Input Ranges
AV_DD
CH0
S/H
CH7
S/H
MSV
*
REF+
COM
REF-
REF
REF_MS
INTCLK/EXTCLK
AGND
MAX1316–MAX1318
MAX1320–MAX1322
MAX1324–MAX1326
8x1
MUX
14-BIT
ADC
8 x 14
SRAM
OUTPUT
DRIVERS
5kΩ
5kΩ
2.500V
CONFIGURATION
REGISTER
INTERFACE
AND
CONTROL
DV_DD
D13
D8
D7
D0
WR
CS
RD
CONVST
SHDN
CLK
ALLON
EOC
EOLC
DGND
*SWITCH CLOSED ON UNIPOLAR DEVICES, OPEN ON BIPOLAR DEVICES
Figure 1. Functional Diagram
Detailed Description
The MAX1316–MAX1318/MAX1320–MAX1322/MAX1324-
MAX1326 are 14-bit ADCs. They offer two, four, or eight
(independently selectable) input channels, each with its
own T/H circuitry. Simultaneous sampling of all active
channels preserves relative phase information, making
these devices ideal for motor control and power monitor-
ing. These devices are available with 0 to +5V, ±5V, and
±10V input ranges. The 0 to +5V devices feature ±6V
fault-tolerant inputs. The ±5V and ±10V devices feature
±16.5V fault-tolerant inputs. Two channels convert in 2µs;
all eight channels convert in 3.8µs, with a maximum 8-
channel throughput of 263ksps per channel. Internal or
external reference and internal- or external-clock capabil-
ity offer great flexibility and ease of use. A write-only con-
figuration register can mask out unused channels, and a
shutdown feature reduces power. A 16.6MHz, 14-bit, par-
allel data bus outputs the conversion result. Figure 1
shows the functional diagram of these devices.
Analog Inputs
T/H
To preserve phase information across these multichan-
nel devices, each input channel has a dedicated
T/H amplifier.
Use a low-input source impedance to minimize gain-
error harmonic distortion. The time required for the T/H
to acquire an input signal depends on the input source
impedance. If the input signal’s source impedance is
high, the acquisition time lengthens and more time
must be allowed between conversions. The acquisition
time (t₁) is the maximum time the device takes to
acquire the signal. Use the following formula to calcu-
late acquisition time:
t₁ = 10 (R_S + R_IN) x 6pF
where R_IN = 2.2kΩ, R_S = the input signal’s source
impedance, and t₁ is never less than 180ns. A source
impedance of less than 100Ω does not significantly
affect the ADC’s performance.
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