Features and Benefits
- 2 synchronized DDS channels at 500 MSPS
- Independent frequency/phase/amplitude control between channels
- Matched latencies for frequency/phase/amplitude changes
- Excellent channel-to-channel isolation (>72 dB)
- Linear frequency/phase/amplitude sweeping capability
- Up to 16 levels of frequency/phase/amplitude modulation (pin-selectable)
- 2 integrated 10-bit digital-to-analog converters (DACs)
- Individually programmable DAC full-scale currents
- 0.12 Hz or better frequency tuning resolution
- 14-bit phase offset resolution
- 10-bit output amplitude scaling resolution
- Serial I/O port interface (SPI) with 800 Mbps data throughput
- Software-/hardware-controlled power-down
- Dual supply operation (1.8 V DDS core/3.3 V serial I/O)
- Multiple device synchronization
- Selectable 4× to 20× REFCLK multiplier (PLL)
- Selectable REFCLK crystal oscillator
- 56-lead LFCSP
The AD9958 consists of two DDS cores that provide independent frequency, phase, and amplitude control on each channel. This flexibility can be used to correct imbalances between signals due to analog processing, such as filtering, amplification, or PCB layout related mismatches. Because both channels share a common system clock, they are inherently synchronized. Synchronization of multiple devices is supported.
The AD9958 can perform up to a 16-level modulation of frequency, phase, or amplitude (FSK, PSK, ASK). Modulation is performed by applying data to the profile pins. In addition, the AD9958 also supports linear sweep of frequency, phase, or amplitude for applications such as radar and instrumentation.
The AD9958 serial I/O port offers multiple configurations to provide significant flexibility. The serial I/O port offers an SPIcompatible mode of operation that is virtually identical to the SPI operation found in earlier Analog Devices, Inc., DDS products. Flexibility is provided by four data pins (SDIO_0 / SDIO_1 / SDIO_2 / SDIO_3) that allow four programmable modes of serial I/O operation.
The AD9958 uses advanced DDS technology that provides low power dissipation with high performance. The device incorporates two integrated, high speed 10-bit DACs with excellent wideband and narrow-band SFDR. Each channel has a dedicated 32-bit frequency tuning word, 14 bits of phase offset, and a 10-bit output scale multiplier.
The DAC outputs are supply referenced and must be terminated into AVDD by a resistor or an AVDD center-tapped transformer. Each DAC has its own programmable reference to enable different full-scale currents for each channel.
The DDS acts as a high resolution frequency divider with the REFCLK as the input and the DAC providing the output. The REFCLK input source is common to both channels and can be driven directly or used in combination with an integrated REFCLK multiplier (PLL) up to a maximum of 500 MSPS. The PLL multiplication factor is programmable from 4 to 20, in integer steps. The REFCLK input also features an oscillator circuit to support an external crystal as the REFCLK source. The crystal must be between 20 MHz and 30 MHz. The crystal can be used in combination with the REFCLK multiplier.
The AD9958 comes in a space-saving 56-lead LFCSP package. The DDS core (AVDD and DVDD pins) is powered by a 1.8 V supply. The digital I/O interface (SPI) operates at 3.3 V and requires the pin labeled DVDD_I/O (Pin 49) be connected to 3.3 V.
The AD9958 operates over the industrial temperature range of −40°C to +85°C.
- Agile local oscillators
- Phased array radars/sonars
- Synchronized clocking
- RF source for AOTF
- Single-side band suppressed carriers
- Quadrature communications
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Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Application Notes (19)
Tools & Simulations
ADIsimDDS uses mathematical equations to model and illustrate the overall performance of the selected device. ADIsimDDS calculates the required FTW, given the reference clock frequency and desired output frequency. This tool also models an estimate of the overall spectral performance, and allows the user to explore the effects of external reconstruction filters.
Reference Designs (1)
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Features & Benefits
- Switch frequencies without losing phase information
- Precision tuning range with digital programming
Technical Articles (24)
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