MAX121
EVALUATION KIT AVAILABLE
308ksps ADC with DSP Interface and 78dB SINAD
General Description
The MAX121 is a complete, BiCMOS, serial-output,
sampling 14-bit analog-to-digital converter (ADC) that
combines an on-chip track/hold and a low-drift, low-
noise, buried-zener voltage reference with fast conversion
speed and low power consumption. The throughput rate
is as high as 308k samples per second (ksps). The full-
scale analog input range is ±5V.
The MAX121 utilizes the successive-approximation archi-
tecture with a high-speed DAC to achieve both fast
conversion speeds and low-power operation. Operating
with +5V and -12V or -15V power supplies, power con
sumption is only 210mW.
The MAX121 can be directly interfaced to the serial port
of most popular digital-signal processors, and comes
in space-saving 16-pin DIP and SO and smaller 20-pin
SSOP packages. The MAX121 operates with TTL- and
CMOS-compatible clocks in the frequency range from
1.1MHz to 5.5MHz. All logic inputs and outputs are TTL-
and CMOS-compatible. This data sheet includes applica-
tion notes for easy interface to TMS320, µPD77230, and
ADSP2101 digital-signal processors, as well as µPs using
the Motorola SPI and QSPI interface standards.
Applications
●● Digital Signal Processing
●● Audio and Telecom Processing
●● Speech Recognition and Synthesis
●● DSP Servo Control
●● Spectrum Analysis
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part, refer
to www.maximintegrated.com/MAX121.related.
Benefits and Features
●● 14-Bit Resolution
●● 2.9µs Conversion Time/308ksps Throughput
●● 400ns Acquisition Time
●● Low Noise and Distortion
• 78d8 SINAD
• -85dB THD
●● ±5V Bipolar Input Range, Overvoltage Tolerant to
±15V
●● 210mW Power Dissipation
●● Continuous-Conversion Mode Available
●● 30ppm/°C, -5V Internal Reference
●● Interfaces to DSP Processors
●● 16-Pin DIP and SO Packages,
20-Pin SSOP Package
Functional Diagram
AIN
3kΩ
MAX121
BUFFER
SAMPLING
COMPARATOR
TRACK/HOLD
7pF
VREF
3kΩ
-5V
DAC
VDD
AGND
DGND
VSS
SAR
REFERENCE
CLIKIN
CONVST
CONTROL LOGIC
CS
MODE
INVCLK
INVFRM
SDATA
SCLK
FSTRT
SFRM
19-0108; Rev 3; 1/12