Rainbow Electronics MAXQ3120 - Manual (Page 28)

MAXQ3120
Applications Information
The low-power, high-performance RISC architecture of
the MAXQ3120 makes it an excellent fit for many
portable or battery-powered applications that require
cost-effective computing. The high-throughput core is
complemented by a dual-differential channel, 16-bit
sigma-delta ADC, and 16-bit hardware multiplier-accu-
mulator, allowing the implementation of sophisticated
computational algorithms. Applications benefit from a
wide range of peripheral interfaces, allowing the micro-
controller to communicate with many external devices.
With integrated LCD support of up to 112 segments (4 x
28), applications can support complex user interfaces.
Displays are driven directly with no additional external
hardware required. Contrast can be adjusted using a
built-in, adjustable resistor. The simplified architecture
reduces component count and board space, critical
factors in the design of portable systems.
The MAXQ3120 is ideally suited for single-phase elec-
tricity metering applications as well as other applica-
tions that require high-precision analog-to-digital
conversion and signal processing.
Additional Documentation
Designers must have four documents to fully use all the
features of this device. This data sheet contains pin
descriptions, feature overviews, and electrical specifi-
cations. Errata sheets contain deviations from pub-
lished specifications. The user’s guides offer detailed
information about programming, device features, and
operation. The following documents can be down-
loaded from www.maxim-ic.com/microcontrollers.
• The MAXQ3120 data sheet, which contains electri-
cal/timing specifications and pin descriptions, avail-
able at www.maxim-ic.com/MAXQ3120.
• The MAXQ3120 errata sheet, available at
www.maxim-ic.com/errata.
• The MAXQ Family User’s Guide, which contains
detailed information on core features and operation,
including programming, avaliable at www.maxim-
ic.com/MAXQUG.
• The MAXQ Family User’s Guide: MAXQ3120
Supplement, which contains detailed information on
features specific to the MAXQ3120, available at
www.maxim-ic.com/MAXQ3120UG.
Development and Technical Support
A variety of highly versatile, affordably priced develop-
ment tools for this microcontroller are available from
Maxim/Dallas Semiconductor and third-party suppliers,
including:
• Compilers
• In-circuit emulators
• Integrated development environments (IDEs)
• JTAG-to-serial converters for programming and
debugging
A partial list of development tool vendors can be found
on our website at www.maxim-ic.com/microcontrollers.
Technical support is available through email at
[email protected].
Definitions
Offset Error
For an ideal converter, the first transition occurs at 0.5
LSB above zero. Offset error is the amount of deviation
between the measured first transition point and the
ideal point.
Gain Error
With a full-scale analog voltage applied to the ADC
(resulting in all ones in the digital code), gain error is
defined as the amount of deviation between the ideal
transfer function and the measured transfer function
(with the offset error removed). Gain error is usually
expressed in LSB or as a percentage of full-scale
range (%FSR).
Power-Supply Rejection Ratio
Power-supply rejection ratio (PSRR) is the ratio of
changes in the power supply (V) to changes in the con-
verter output (V). It is typically measured in decibels.
High-Precision ADC
Mixed-Signal Microcontroller
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