MAX1276EVKIT Maxim Integrated, MAX1276EVKIT Datasheet - Page 10

• Manufacturer Part Number: MAX1276EVKIT
• Description: Data Conversion IC Development Tools Evaluation Kit/Evaluation System for the MAX1070/71/72/75#79/MAX1224/25/MAX1274#79
• Manufacturer: Maxim Integrated
• Series: MAX1276, MAX1278r

Specifications of MAX1276EVKIT

• Interface Type: QSPI, Serial (SPI, Microwire)

The EV kit can be readily configured to evaluate the DC
performance of the DUT using the on-board buffer cir-
cuitry. In this configuration, no ACIN signal is required
and the DC common-mode pads CMP/CMM can be
used to apply arbitrary DC voltages to the test device.
When evaluating unipolar parts, a direct ground connec-
tion is also supported for AIN-. When performing DC
evaluations of the test device, be sure to verify the levels
actually present at the device inputs using the supplied
AIN+ and AIN- SENSE pads. When monitoring voltages
through the SENSE pads, be sure to set the voltmeter to
high-impedance mode, as current drawn through the iso-
lation resistors can cause measurement errors.
The MAX1276 family requires the following conditions
for accurate operation:
• VREF > (AIN+ - AIN-) > 0 for unipolar parts.
• VREF / 2 > (AIN+ - AIN-) > - VREF / 2 for bipolar parts.
• VDD > AIN+ > 0 and VDD > AIN- > 0 for all parts.
Unipolar AC operation can be realized in both single-
ended and fully differential modes. For single-ended
mode, ACIN is supplied to either buffer U2 or U3, with
the other buffer AC input connected to ground. A spe-
cial case of unipolar single-ended operation can be
realized with AIN- connected directly to ground. For dif-
ferential operation, ACIN is supplied to both buffers
along with selected common modes to realize the
waveforms shown in case UD of
DC common mode(s) CMP and CMM should be select-
ed such that:
Note that input settings where (AIN+ < AIN-) produce
zero code outputs for unipolar parts.
three possible waveforms for proper unipolar operation.
All three are phased so that the resulting differential
input (and converted output) for each waveform pair
are equivalent.
Bipolar AC operation can be achieved in both single-
ended and fully differential modes. For single-ended
mode, ACIN is supplied to either buffer U2 or U3, with
MAX1276 Evaluation Kit/Evaluation System
10
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VREF > (AIN+ - AIN-) > 0
VDD > AIN+ > 0
VDD > AIN- > 0
Buffered DC Operation
Unipolar AC Operation
Bipolar AC Operation
Figure
5.
Figure
5 shows
the other buffer’s AC input connected to ground. For
fully differential operation, ACIN is supplied to both
buffers along with selected common modes to produce
the waveforms shown in case BD of
DC common mode(s) CMP and CMM should be select-
ed such that:
Figure
bipolar operation. All three are phased so that the
resulting differential input (and converted output) for
each waveform pair are equivalent.
In addition to providing on-board buffering for the test
device inputs, the EV kit also provides pads for direct
connection of external sources to the ADC inputs.
Before using these options, read about the input
buffers in the Detailed Description of Hardware section.
The direct-drive option is intended for use with external
sources capable of adequately driving the MAX1276
input section. In most cases, peak performance
requires the use of the on-board or similar external
buffers when evaluating both AC and DC performance.
The MAX1276 EV kit provides several options for sup-
plying and monitoring reference voltages to and from
the MAX1276 family of devices. For all options, users
should monitor the actual reference value appearing at
the test device through the VREF_SENSE and
RGND_SENSE pads. When monitoring voltages
through the SENSE pins, be sure to use a high-imped-
ance voltmeter. Also, be sure to select a mode of oper-
ation compatible with your selection of ADC.
In this mode of operation, parts with internal references
can be easily evaluated. The internal reference output
level is made available at the VREF pad. If a user wishes
to use the internal reference level to drive additional cir-
cuitry, be sure to consult the MAX1276 family data sheets
to ensure that the internal reference specifications for cur-
rent capability and load regulation are considered. When
used externally, most dynamic applications require that
the VREF output be actively buffered to prevent interfer-
ence with the operation of the ADC circuitry.
Internal Reference Operation (Default)
6 shows three possible waveforms for proper
+VREF / 2 > (AIN+ - AIN-) > - VREF / 2
Reference Setup Procedure
VDD > AIN+ > 0
VDD > AIN- > 0
Direct-Drive Operation
Figure
6.