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MAX5858A
Dual, 10-Bit, 300Msps, DAC with 4x/2x/1x
Interpolation Filters and PLL
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The MAX5858A is packaged in a 48-pin TQFP-EP pack-
age, providing design flexibility, increased thermal effi-
ciency, and optimized AC performance of the DAC. The
EP enables the implementation of grounding techniques,
which are necessary to ensure highest performance
operation.
In this package, the data converter die is attached to
an EP leadframe with the back of the frame exposed at
the package bottom surface, facing the PC board side
of the package. This allows a solid attachment of the
package to the PC board with standard infrared (IR)-
flow soldering techniques. A specially created land pat-
tern on the PC board, matching the size of the EP,
ensures the proper attachment and grounding of the
DAC. Designing vias* into the land area and imple-
menting large ground planes in the PC board design
achieve optimal DAC performance. Use an array of 3
3 (or greater) vias (0.3mm diameter per via hole and
1.2mm pitch between via holes) for this 48-pin TQFP-
EP package.
Dynamic Performance Parameter
Definitions
Adjacent Channel Leakage Ratio (ACLR)
Commonly used in combination with wideband code-
division multiple-access (WCDMA), ACLR reflects the
leakage power ratio in dB between the measured
power within a channel relative to its adjacent channel.
ACLR provides a quantifiable method of determining
out-of-band spectral energy and its influence on an
adjacent channel when a bandwidth-limited RF signal
passes through a nonlinear device.
Total Harmonic Distortion (THD)
THD is the ratio of the RMS sum of all essential harmon-
ics (within a Nyquist window) of the input signal to the
fundamental itself. This can be expressed as:
where V1 is the fundamental amplitude, and V2 through
VN are the amplitudes of the 2nd through Nth-order
harmonics.
Spurious-Free Dynamic Range (SFDR)
SFDR is the ratio of RMS amplitude of the carrier fre-
quency (maximum signal component) to the RMS value
of the next-largest spectral component. SFDR is usually
measured in dBc with respect to the carrier frequency
amplitude or in dB FS with respect to the DAC’s full-
scale range. Depending on its test condition, SFDR is
observed within a predefined window or to Nyquist.
Multitone Power Ratio (MTPR)
A series of equally spaced tones are applied to the DAC
with one tone removed from the center of the range.
MTPR is defined as the worst-case distortion (usually a
3rd-order harmonic product of the fundamental frequen-
cies), which appears as the largest spur at the frequency
of the missing tone in the sequence. This test can be per-
formed with any number of input tones; however, four and
eight tones are among the most common test conditions
for CDMA- and GSM/EDGE-type applications.
Intermodulation Distortion (IMD)
The two-tone IMD is the ratio expressed in dBc of either out-
put tone to the worst 3rd-order (or higher) IMD products.
Static Performance Parameter Definitions
Integral Nonlinearity (INL)
Integral nonlinearity (INL) is the deviation of the values
on an actual transfer function from a line drawn
between the end points of the transfer function, once
offset and gain errors have been nullified. For a DAC,
the deviations are measured at every individual step.
Differential Nonlinearity (DNL)
Differential nonlinearity (DNL) is the difference between
an actual step height and the ideal value of 1 LSB. A
DNL error specification no more negative than -1 LSB
guarantees monotonic transfer function.
Offset Error
Offset error is the current flowing from positive DAC
output when the digital input code is set to zero. Offset
error is expressed in LSBs.
THD
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*Vias connect the land pattern to internal or external copper planes.