Rainbow Electronics MAX1168 User Manual

Page 13

The MAX1168 features a 16-bit-wide data-transfer
mode that includes a longer acquisition time (11.5
clock cycles). Longer acquisition times are useful in
applications with input source resistances greater than
1k

Ω. Noise increases when using large source resis-

tances. To improve the input signal bandwidth under
AC conditions, drive AIN_ with a wideband buffer
(>10MHz) that can drive the ADC’s input capacitance
and settle quickly.

Input Bandwidth

The ADC’s input-tracking circuitry has a 4MHz small-
signal bandwidth, making possible the digitization of
high-speed transient events and the measurement of

periodic signals with bandwidths exceeding the ADC’s
sampling rate by using undersampling techniques. To
avoid aliasing of unwanted, high-frequency signals into
the frequency band of interest, use anti-alias filtering.

Analog Input Protection

Internal protection diodes, which clamp the analog
input to AV

or AGND, allow the input to swing from

(AGND - 0.3V) to (AV

+ 0.3V) without damaging the

device. If the analog input exceeds 300mV beyond the
supplies, limit the input current to 10mA.

MAX1167/MAX1168

Multichannel, 16-Bit, 200ksps Analog-to-Digital

Converters

______________________________________________________________________________________

REFERENCE

REF

REFCAP

AGND

DGND

AIN0

AIN1

AIN2

AIN3

SCLK

DIN

ANALOG-INPUT

MULTIPLEXER

CONTROL

ACCUMULATOR

MEMORY

INPUT REGISTER

BIAS

OSCILLATOR

OUTPUT

DOUT

EOC

ANALOG-SWITCH FINE TIMING

SUCCESSIVE-APPROXIMATION

MAX1168

DAC

BUFFER

AIN4

AIN5

AIN6

AIN7

RAIL

COMPARATOR

DSPX

DSEL

DSPR

Figure 4. MAX1168 Functional Diagram