The MAX12557 is a dual 3.3V, 14-bit analog-to-digital
converter (ADC) featuring fully differential wideband
track-and-hold (T/H) inputs, driving internal quantizers.
The MAX12557 is optimized for low power, small size,
and high dynamic performance in intermediate frequency
(IF) and baseband sampling applications. This dual
ADC operates from a single 3.3V supply, consuming
only 610mW while delivering a typical 72.5dB signal-to-noise
ratio (SNR) performance at a 175MHz input frequency.
The T/H input stages accept single-ended or
differential inputs up to 400MHz. In addition to low operating
power, the MAX12557 features a 166µW powerdown
mode to conserve power during idle periods.
A flexible reference structure allows the MAX12557 to
use the internal 2.048V bandgap reference or accept
an externally applied reference and allows the reference
to be shared between the two ADCs. The reference
structure allows the full-scale analog input range
to be adjusted from ±0.35V to ±1.15V. The MAX12557
provides a common-mode reference to simplify design
and reduce external component count in differential
analog input circuits.
The MAX12557 supports either a single-ended or differential
input clock. User-selectable divide-by-two (DIV2)
and divide-by-four (DIV4) modes allow for design flexibility
and help eliminate the negative effects of clock jitter.
Wide variations in the clock duty cycle are compensated
with the ADC's internal duty-cycle equalizer (DCE).
The MAX12557 features two parallel, 14-bit-wide,
CMOS-compatible outputs. The digital output format is
pin-selectable to be either two's complement or Gray
code. A separate power-supply input for the digital outputs
accepts a 1.7V to 3.6V voltage for flexible interfacing
with various logic levels. The MAX12557 is available
in a 10mm x 10mm x 0.8mm, 68-pin thin QFN package
with exposed paddle (EP), and is specified for the
extended (-40°C to +85°C) temperature range.
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