- 您现在的位置：买卖IC网 > PDF目录10979 > AD9830ASTZ (Analog Devices Inc)IC DDS 10BIT 50MHZ CMOS 48-TQFP PDF资料下载
参数资料
| 型号： | AD9830ASTZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 2/16页 |
| 文件大小： | 0K |
| 描述： | IC DDS 10BIT 50MHZ CMOS 48-TQFP |
| 产品培训模块： | Direct Digital Synthesis Tutorial Series (1 of 7): Introduction Direct Digital Synthesizer Tutorial Series (7 of 7): DDS in Action Direct Digital Synthesis Tutorial Series (3 of 7): Angle to Amplitude Converter Direct Digital Synthesis Tutorial Series (6 of 7): SINC Envelope Correction Direct Digital Synthesis Tutorial Series (4 of 7): Digital-to-Analog Converter Direct Digital Synthesis Tutorial Series (2 of 7): The Accumulator |
| 标准包装： | 1 |
| 分辨率（位）： | 10 b |
| 主 fclk： | 50MHz |
| 调节字宽（位）： | 32 b |
| 电源电压： | 4.75 V ~ 5.25 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-LQFP |
| 供应商设备封装： | 48-LQFP（7x7） |
| 包装： | 托盘 |
| 产品目录页面： | 552 (CN2011-ZH PDF) |
| 配用： | EVAL-AD9830EBZ-ND - BOARD EVALUATION AD9830 |
AD9830
–10–
CIRCUIT DESCRIPTION
The AD9830 provides an exciting new level of integration
for the RF/Communications system designer. The AD9830
combines the Numerical Controlled Oscillator (NCO), SINE
Look-Up table, Frequency and Phase Modulators, and a
Digital-to-Analog Converter on a single integrated circuit.
The internal circuitry of the AD9830 consists of three main
sections. These are:
Numerical Controlled Oscillator (NCO) + Phase Modulator
SINE Look-Up Table
Digital-to-Analog Converter
The AD9830 is a fully integrated Direct Digital Synthesis
(DDS) chip. The chip requires one reference clock, two low
precision resistors and eight decoupling capacitors to provide
digitally created sine waves up to 25 MHz. In addition to the
generation of this RF signal, the chip is fully capable of a broad
range of simple and complex modulation schemes. These
modulation schemes are fully implemented in the digital do-
main allowing accurate and simple realization of complex
modulation algorithms using DSP techniques.
THEORY OF OPERATION
Sine waves are typically thought of in terms of their magnitude
form a (t) = sin (
ωt). However, these are nonlinear and not
easy to generate except through piece wise construction. On
the other hand, the angular information is linear in nature.
That is, the phase angle rotates through a fixed angle for each
unit of time. The angular rate depends on the frequency of the
signal by the traditional rate of
ω = 2πf
MAGNITUDE
PHASE
+1
0
–1
2
π
0
Figure 22. Sine Wave
Knowing that the phase of a sine wave is linear and given a ref-
erence interval (clock period), the phase rotation for that period
can be determined.
Phase = ωδt
Solving for
ω
ω = Phase/δt = 2πf
Solving for f and substituting the reference clock frequency for
the reference period (1/fMCLK =
δt)
f =
Phase × f
MCLK/2
π
The AD9830 builds the output based on this simple equation.
A simple DDS chip can implement this equation with three
major subcircuits.
Numerical Controlled Oscillator + Phase Modulator
This consists of two frequency select registers, a phase accumu-
lator and four phase offset registers. The main component of
the NCO is a 32-bit phase accumulator which assembles the
phase component of the output signal. Continuous time signals
have a phase range of 0 to 2
π. Outside this range of numbers,
the sinusoid functions repeat themselves in a periodic manner.
The digital implementation is no different. The accumulator
simply scales the range of phase numbers into a multibit digital
word. The phase accumulator in the AD9830 is implemented
with 32 bits. Therefore, in the AD9830, 2
π = 232. Likewise,
the
Phase term is scaled into this range of numbers 0 < Phase
< 2
32 –1. Making these substitutions into the equation above
f =
Phase × f
MCLK/2
32
where 0 <
Phase < 232
With a clock signal of 50 MHz and a phase word of 051EB852
hex
f = 51EB852
× 50 MHz/232 = 1.000000000931 MHz
The input to the phase accumulator (i.e., the phase step) can be
selected either from the FREQ0 Register or FREQ1 Register
and this is controlled by the FSELECT pin. NCOs inherently
generate continuous phase signals, thus avoiding any output
discontinuity when switching between frequencies. More com-
plex frequency modulation schemes can be implemented by up-
dating the contents of these registers. This facilitates complex
frequency modulation schemes, such as GMSK.
Following the NCO, a phase offset can be added to perform
phase modulation using the 12-bit PHASE Registers. The con-
tents of this register are added to the most significant bits of the
NCO. The AD9830 has four PHASE registers. The resolution
of the phase registers equals 2
π/4096.
Sine Look-Up Table (LUT)
To make the output useful, the signal must be converted from
phase information into a sinusoidal value. Since phase informa-
tion maps directly into amplitude, a ROM LUT converts the
phase information into amplitude. To do this, the digital phase
information is used to address a sine ROM LUT. Although the
NCO contains a 32-bit phase accumulator, the output of the
NCO is truncated to 12 bits. Using the full resolution of the
phase accumulator is impractical and unnecessary as this would
require a look-up table of 2
32 entries.
It is necessary only to have sufficient phase resolution in the
LUTs such that the dc error of the output waveform is domi-
nated by the quantization error in the DAC. This requires the
look-up table to have two more bits of phase resolution than the
10-bit DAC.
Digital-to-Analog Converter
The AD9830 includes a high impedance current source 10-bit
DAC, capable of driving a wide range of loads at different
speeds. Full-scale output current can be adjusted, for optimum
power and external load requirements, through the use of a
single external resistor (RSET).
The DAC can be configured for single or differential ended op-
eration. IOUT can be tied directly to AGND for single ended
operation or through a load resistor to develop an output volt-
age. The load resistor can be any value required, as long as the
REV. B
相关PDF资料 |
PDF描述 |
|---|---|
| VE-2WW-IY-F4 | CONVERTER MOD DC/DC 5.5V 50W |
| VE-2WW-IY-F1 | CONVERTER MOD DC/DC 5.5V 50W |
| VE-2WV-IY-F4 | CONVERTER MOD DC/DC 5.8V 50W |
| AD9959BCPZ | IC DDS QUAD 10BIT DAC 56LFCSP |
| VE-2WT-IY-F2 | CONVERTER MOD DC/DC 6.5V 50W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD9830ASTZ-REEL | 功能描述:IC DDS 10BIT 50MHZ CMOS 48TQFP RoHS:是 类别:集成电路 (IC) >> 接口 - 直接数字合成 (DDS) 系列:- 产品变化通告:Product Discontinuance 27/Oct/2011 标准包装:2,500 系列:- 分辨率（位）:10 b 主 fclk:25MHz 调节字宽（位）:32 b 电源电压:2.97 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:16-TSSOP 包装:带卷 (TR) |
| AD9831 | 制造商:AD 制造商全称:Analog Devices 功能描述:CMOS Complete DDS |
| AD9831AST | 制造商:Rochester Electronics LLC 功能描述:25 MHZ +5V/+3V, 10-BIT DDS DAC I.C. - Bulk 制造商:Analog Devices 功能描述:10BIT DAC DDS 25 MHZ +5V/+3V 9831 |
| AD9831AST-REEL | 制造商:Analog Devices 功能描述:Direct Digital Synthesizer 25MHz 1-DAC 10-Bit Parallel 48-Pin LQFP T/R 制造商:Rochester Electronics LLC 功能描述:25 MHZ +5V/+3V, 10-BIT DDS DAC I.C. - Tape and Reel |
| AD9831ASTZ | 功能描述:IC DDS 10BIT 25MHZ CMOS 48-LQFP RoHS:是 类别:集成电路 (IC) >> 接口 - 直接数字合成 (DDS) 系列:- 产品变化通告:Product Discontinuance 27/Oct/2011 标准包装:2,500 系列:- 分辨率（位）:10 b 主 fclk:25MHz 调节字宽（位）:32 b 电源电压:2.97 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:16-TSSOP 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。