參數(shù)資料
型號: MAX555
廠商: Maxim Integrated Products, Inc.
英文描述: 300Msps, 12-Bit DAC with Complementary Voltage Outputs
中文描述: 300Msps、12位DAC,互補(bǔ)電壓輸出
文件頁數(shù): 8/12頁
文件大?。?/td> 98K
代理商: MAX555
M
300Msps, 12-Bit DAC with
Complementary Voltage Outputs
8
_______________________________________________________________________________________
and digital ground pins must be connected directly to
the analog ground plane at the MAX555, preferably with
a “star connection” at the LGND pins (15 and 16).
High-speed ECL inputs, as well as the output from the
MAX555, should employ good transmission-line tech-
niques, with terminations close to the device pins.
Separate power-supply buses for analog and digital
power supplies are recommended as good general
practice. Best results will be achieved by bypassing
the device pins with high-quality ceramic chip capaci-
tors connected physically close to the pins.
__________Applic ations Information
Referenc e Input
The MAX555 uses an internal op-amp circuit to buffer the
reference current. The input to the op amp may be driv-
en with a 1.25mA external current source or a 1V external
voltage reference. The reference input is the VREF pin.
The input impedance to the op amp is 800
. As shown
in Figure 1, VREF/2 is brought out externally with 400
of
impedance to the op amp. These reference inputs can
be used to vary the full-scale output for high-speed multi-
plying applications. R
OFFSET
must be connected to ana-
log ground. In addition, a 0.1μF capacitor should be
connected from VREF/2 to analog ground to reduce refer-
ence current noise.
Outputs
The analog outputs are laser trimmed to 50
. They can
be used either as a voltage drive with 50
impedance, or
to drive into a virtual null using a transimpedance amplifi-
er. Greater speed is achieved driving into 50
loads.
The differential outputs of the MAX555 may be used to
drive a balun for conversion to a single-ended output,
while at the same time greatly reducing the second-har-
monic content of the output.
Dynamic Performanc e
The Typical Operating Characteristics graphs show the
MAX555’s performance when used in direct digital synthe-
sis (DDS) applications for generating RF sine waves. The
first six graphs show the MAX555’s spurious-free dynam-
ic range (SFDR) for clock frequencies of 50MHz to
300MHz at various output frequencies. The seventh
graph shows the SFDR for clock frequencies from
50MHz to 350MHz while producing an output frequen-
cy of about 1/16 the clock frequency.
The last two graphs show the MAX555’s third and sec-
ond harmonic distortion while producing an output fre-
quency of about 1/5 f
CLK
for clock frequencies from
100MHz to 300MHz as a function of the reference volt-
age. The third harmonic content of the output can be
reduced at clock frequencies below about 200MHz by
reducing the reference voltage from its 1.000V nominal
value. At clock frequencies above about 200MHz, the
output’s third harmonic content is dominated by cou-
pling from the high-speed digital inputs to the output.
Reducing the reference voltage at these high clock
rates actually increases the third harmonic distortion in
the output, since the carrier amplitude drops but the
third harmonic level remains relatively constant.
The second harmonic distortion of the outputs is shown
as a function of clock frequency and reference voltage.
It is relatively constant for clock frequencies below
about 200MHz at different V
REF
values. As with the
third harmonic distortion, however, the second harmon-
ic distortion also increases at clock frequencies over
200MHz for lower V
REF
values. Minimize these effects
by bypassing the MAX555 heatspreader (pins 26 and
44) to V
EE
with a good-quality RF chip capacitor.
Reducing the swing of the input logic levels and/or
decreasing the rise time of the digital signals can also
improve the output’s harmonic content. Combining
these techniques achieves the best results. Some
experimentation may be required to optimize the
MAX555’s performance for a particular application.
Figure 3 shows the spectrum analyzer plots of the
MAX555 when used in DDS applications. These plots
show the MAX555’s output spectrum at clock frequen-
cies from 50MHz to 300MHz while producing various
output frequencies. Observing the output spectrum
while adjusting the reference voltage or varying the
logic levels is a sensitive method of optimizing MAX555
performance. The plots shown were obtained with a
+0.75V reference voltage with 500mV ECL logic
swings.
T ypic al Applic ation
Figure 4 shows a typical connection. With VOUT used
to drive a 50
line, the unused complementary output,
VOUT, should also be terminated to 50
. A 1V refer-
ence voltage at VREF gives a -0.5V full-scale voltage at
VOUT (when doubly terminated with 50
on the out-
put). Because some loads may represent a complex
impedance, be sure to match the output impedance
with the load. Mismatching the impedances can cause
reflections that will affect AC-performance parameters.
In all applications, the LOOPCRNT pin is always con-
nected to AGND, and compensation capacitors are
connected to pins ALTCOMPC, ALTCOMPIB, and
LBIAS. The LBIAS compensation is recommended for
non-multiplying applications. AC grounding the heat
spreader on the package (with pins 26 and 44)
reduces digital noise feedthrough and improves the
MAX555’s spurious performance at high data rates.
相關(guān)PDF資料
PDF描述
MAX555CQK 300Msps, 12-Bit DAC with Complementary Voltage Outputs
MAX560-MAX561 +3.3V Transceiver with Wow EIA/TIA-562 Receivers Active in Shutdown
MAX560CAI +3.3V Transceiver with Wow EIA/TIA-562 Receivers Active in Shutdown
MAX561CAI +3.3V Transceiver with Wow EIA/TIA-562 Receivers Active in Shutdown
MAX561CWI +3.3V Transceiver with Wow EIA/TIA-562 Receivers Active in Shutdown
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX5550ETE 功能描述:數(shù)模轉(zhuǎn)換器- DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時(shí)間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube
MAX5550ETE+ 功能描述:數(shù)模轉(zhuǎn)換器- DAC 10-Bit 2Ch Precision DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時(shí)間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube
MAX5550ETE+T 功能描述:數(shù)模轉(zhuǎn)換器- DAC 10-Bit 2Ch Precision DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時(shí)間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube
MAX5550ETE-T 功能描述:數(shù)模轉(zhuǎn)換器- DAC RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 DAC 輸出端數(shù)量:1 轉(zhuǎn)換速率:2 MSPs 分辨率:16 bit 接口類型:QSPI, SPI, Serial (3-Wire, Microwire) 穩(wěn)定時(shí)間:1 us 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-14 封裝:Tube
MAX5550EVKIT+ 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC 開發(fā)工具 MAX5548/50 Eval Kit RoHS:否 制造商:Texas Instruments 產(chǎn)品:Demonstration Kits 類型:ADC 工具用于評估:ADS130E08 接口類型:SPI 工作電源電壓:- 6 V to + 6 V