AD9864

The AD9864 1 is a general-purpose IF subsystem that digitizes a low level, 10 MHz to 300 MHz IF input with a signal bandwidth ranging from 6.8 kHz to 270 kHz. The signal chain of the AD9864 consists of a low noise amplifier (LNA), a mixer, a band-pass Σ-∆ analog-to-digital converter (ADC), and a decimation filter with programmable decimation factor. An automatic gain control (AGC) circuit gives the AD9864 12 dB of continuous gain adjustment. Auxiliary blocks include both clock and local oscillator (LO) synthesizers.

The high dynamic range of the AD9864 and inherent antialiasing provided by the band-pass Σ-∆ converter allow the device to cope with blocking signals up to 95 dB stronger than the desired signal. This attribute often reduces the cost of a radio by reducing IF filtering requirements. Also, it enables multimode radios of varying channel bandwidths, allowing the IF filter to be specified for the largest channel bandwidth.

The SPI port programs numerous parameters of the AD9864, allowing the device to be optimized for any given application. Programmable parameters include synthesizer divide ratios, AGC attenuation and attack/decay time, received signal strength level, decimation factor, output data format, 16 dB attenuator, and the selected bias currents.

The AD9864 is available in a 48-lead LFCSP package and operates from a single 2.7 V to 3.6 V supply. The total power consumption is typically 56 mW and a power-down mode is provided via serial interfacing.

10 MHz to 300 MHz input frequency 6.8 kHz to 270 kHz output signal bandwidth 7.5 dB single sideband noise figure (SSB NF) -7.0 dBm input third-order intercept (IIP3) AGC free range up to -34 dBm 12 dB continuous AGC range 16 dB front -end attenuator Baseband I/Q 16-bit (or 24-bit) serial digital output LO and sampling clock synthesizers Programmable decimation factor, output format, AGC, and synthesizer settings 370 Ω input impedance 2.7 V to 3.6 V supply voltage Low current consumption: 17 mA 48-lead LFCSP package

Multimode narrow-band radio products Analog/digital UHF/VHF FDMA receivers TETRA, APCO25, GSM/EDGE Portable and mobile radio products SATCOM terminals

1 Protected by U.S. Patent No. 5,969,657; other patents pending.

04319-0-002

Figure 2. 48-Lead LFCSP Pin Configuration

Figure 2. 48-Lead LFCSP Pin Configuration

Table 5. 48-Lead Lead Frame Chip Scale Package (LFCSP) Pin Function Descriptions

Table 3. AD9864 Absolute Maximum Ratings

Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability.

θ JA is specified for the worst-case conditions, that is, θ JA is specified for device soldered in circuit board for surface-mount packages.