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| 型号： | AD9859YSVZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 3/24页 |
| 文件大小： | 0K |
| 描述： | IC DDS DAC 10BIT 400MSPS 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： | 400MHz |
| 调节字宽（位）： | 32 b |
| 电源电压： | 1.71 V ~ 1.96 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-TQFP 裸露焊盘 |
| 供应商设备封装： | 48-TQFP 裸露焊盘（7x7） |
| 包装： | 托盘 |
| 产品目录页面： | 552 (CN2011-ZH PDF) |
AD9859
Rev. A | Page 11 of 24
THEORY OF OPERATION
COMPONENT BLOCKS
DDS Core
The output frequency (fO) of the DDS is a function of the
frequency of the system clock (SYSCLK), the value of the
frequency tuning word (FTW), and the capacity of the
accumulator (232 in this case). The exact relationship is given
below with fS defined as the frequency of SYSCLK.
31
32
2
0
2
/
FTW
with
f
FTW
f
S
O
1
–
2
/
–
1
32
31
32
FTW
with
FTW
f
S
O
The value at the output of the phase accumulator is translated to
an amplitude value via the COS(x) functional block and routed
to the DAC.
In certain applications, it is desirable to force the output signal
to zero phase. Simply setting the FTW to 0 does not accomplish
this; it only results in the DDS core holding its current phase
value. Thus, a control bit is required to force the phase accumula-
tor output to zero.
At power-up, the clear phase accumulator bit is set to Logic 1,
but the buffer memory for this bit is cleared (Logic 0). There-
fore, upon power-up, the phase accumulator remains clear until
the first I/O UPDATE is issued.
Phase-Locked Loop (PLL)
The PLL allows multiplication of the REFCLK frequency.
Control of the PLL is accomplished by programming the 5-bit
REFCLK multiplier portion of Control Function Register No. 2,
Bits <7:3>.
When programmed for values ranging from 0x04 to 0x14
(4 decimal to 20 decimal), the PLL multiplies the REFCLK
input frequency by the corresponding decimal value. However,
the maximum output frequency of the PLL is restricted to
400 MHz. Whenever the PLL value is changed, the user should
be aware that time must be allocated to allow the PLL to lock
(approximately 1 ms).
The PLL is bypassed by programming a value outside the range
of 4 to 20 (decimal). When bypassed, the PLL is shut down to
conserve power.
Clock Input
The AD9859 supports various clock methodologies. Support for
differential or single-ended input clocks and enabling of an
on-chip oscillator and/or a phase-locked loop (PLL) multiplier
are all controlled via user programmable bits. The AD9859 may
be configured in one of six operating modes to generate the system
clock. The modes are configured using the CLKMODESELECT
pin, CFR1<4>, and CFR2<7:3>. Connecting the external pin
CLKMODESELECT to Logic High enables the on-chip crystal
oscillator circuit. With the on-chip oscillator enabled, users of
the AD9859 connect an external crystal to the REFCLK and
REFCLKB inputs to produce a low frequency reference clock in
the range of 20 MHz to 30 MHz. The signal generated by the
oscillator is buffered before it is delivered to the rest of the chip.
This buffered signal is available via the CRYSTAL OUT pin. Bit
CFR1<4> can be used to enable or disable the buffer, turning on
or off the system clock. The oscillator itself is not powered
down in order to avoid long startup times associated with
turning on a crystal oscillator. Writing CFR2<9> to Logic High
enables the crystal oscillator output buffer. Logic Low at
CFR2<9> disables the oscillator output buffer.
Connecting CLKMODESELECT to Logic Low disables the
on-chip oscillator and the oscillator output buffer. With the
oscillator disabled, an external oscillator must provide the
REFCLK and/or REFCLKB signals. For differential operation,
these pins are driven with complementary signals. For single-
ended operation, a 0.1 μF capacitor should be connected
between the unused pin and the analog power supply. With the
capacitor in place, the clock input pin bias voltage is 1.35 V. In
addition, the PLL may be used to multiply the reference
frequency by an integer value in the range of 4 to 20. Table 4
summarizes the clock modes of operation. Note that the PLL
multiplier is controlled via the CFR2<7:3> bits, independent of
the CFR1<4> bit.
Table 4. Clock Input Modes of Operation
CFR1<4>
CLKMODESELECT
CFR2<7:3>
Oscillator Enabled?
System Clock
Frequency Range (MHz)
Low
High
3 < M < 21
Yes
FCLK = FOSC × M
80 < FCLK < 400
Low
High
M < 4 or M > 20
Yes
FCLK = FOSC
20 < FCLK < 30
Low
3 < M < 21
No
FCLK = FOSC × M
80 < FCLK < 400
Low
M < 4 or M > 20
No
FCLK = FOSC
10 < FCLK < 400
High
X
No
FCLK = 0
N/A
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD9859YSVZ | 制造商:Analog Devices 功能描述:IC 400 MSPS DDS 制造商:Analog Devices 功能描述:IC, 400 MSPS DDS |
| AD9859YSVZ | 制造商:Analog Devices 功能描述:DIRECT DIGITAL SYNTHESIZER |
| AD9859YSVZ1 | 制造商:AD 制造商全称:Analog Devices 功能描述:400 MSPS, 10-Bit,1.8 V CMOS Direct Digital Synthesizer |
| AD9859YSVZ-REEL7 | 功能描述:IC DDS DAC 10BIT 400MSPS 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) |
| AD9859YSVZ-REEL71 | 制造商:AD 制造商全称:Analog Devices 功能描述:400 MSPS, 10-Bit, 1.8 V CMOS Direct Digital Synthesizer |
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