MAX1338 Datasheet, PDF (13/24 Pages) Maxim Integrated Products – 14-Bit, 4-Channel, Software-Programmable, Multiranging, Simultaneous-Sampling ADC

14-Bit, 4-Channel, Software-Programmable,
Multiranging, Simultaneous-Sampling ADC
AV_DD
AIN0+
S/H
AIN0-
AIN3+
S/H
AIN3-
REFP2
REFP1
COM2
COM1
REFN2
REFN1
REFADC
INTCLK/EXTCLK
AGND
MAX1338
4x1
14-BIT
MUX
ADC
4 x 14
OUTPUT
SRAM
DRIVERS
5kΩ
2.500V
CONFIGURATION
REGISTER
INTERFACE
AND
CONTROL
DV_DD
DRV_DD
D13
D8
D7
D0
WR
CS
RD
CONVST
SHDN
CLK
STANDBY
EOC
EOLC
DRGND
DGND
Figure 2. Functional Diagram
Power-Supply Inputs
Three separate power supplies power the MAX1338. A
+5V analog supply, AV_DD, powers the analog input and
converter sections. A +5V digital supply, DV_DD, powers
the internal logic circuitry, and a +2.7V to +5V digital
supply (DRV_DD), powers the parallel I/O and the control
I/O (see the Typical Operating Circuit). Bypass the
power supplies as indicated in the Layout, Grounding,
and Bypassing section. Power-supply sequencing is
not required for the MAX1338.
Analog Inputs
Software-Selectable Input Range
The MAX1338 provides four independent, software-
selectable, analog input voltage ranges for each chan-
nel. The selectable input ranges are ±V_REF x 4 (the
power-up default condition), ±V_REF x 2, ±V_REF, and
±V_REF x 0.5. Using the 2.5V internal reference, the
selectable input ranges are ±10V (power-up default),
±5V, ±2.5V, and ±1.25V. Program the analog input
ranges with the configuration register through the
parallel I/O. See the Configuration Register section for
programming details.
Input Protection
Protection at the analog inputs provides ±17V fault
immunity for the MAX1338. This protection circuit limits
the current at the analog inputs to less than ±2mA.
Input fault protection is active in standby, in shutdown,
during normal operation, and over all input ranges.
Track and Hold (T/H)
To preserve relative phase information between input
channels, each input channel has a dedicated T/H
amplifier. The rising edge of CONVST represents the
sampling instant for all channels. All samples are taken
within an aperture delay (t_AD) of 16ns. The aperture
delay of all channels is matched to within 100ps.
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