描述 Description

The AFE5851 is an analog front-end targeting applications where the power and level of integration are critical. The device contains 16 variable gain amplifiers (VGA), followed by an octal high speed (up to 65 MSPS) analog to digital converter (ADC). Each of the 16 single ended inputs is buffered, accepts up to 1VPP maximum input swing and it is followed by a VGA with a gain range from –5dB to 31dB. The VGA gain is digitally controlled and the gain curves versus time can be stored in memory, integrated within the device using the serial interface. A selectable clamping and anti-alias low pass filter (with 3dB attenuation at 7.5, 10 or 14MHz) is also integrated between the VGA and ADC for every channel. The VGA/anti-alias filter outputs are differential (limited to 2 VPP) and drive the on-board 12-bit 65MSPS ADC that is shared between two VGAs to optimize the power dissipation. Each VGA output is sampled at alternate clock cycles, making the effective sampling frequency half the input clock rate. The ADC also scales down its power consumption should a lower sampling rate be selected. The ADC outputs are serialized in LVDS streams further minimizing power and board area. The AFE5851 is available in a 64-pin QFN package (9x9mm2) and is specified over the full industrial temperature range (–40°C to 85°C).

特性 Features

? 16 Variable Gain Amplifiers (VGA)
? 16 Single-Ended Buffered Inputs With 1VPP Maximum Swing
? 5.5nV/√Hz VCA Input Noise (31dB Gain).
? Variable Gain –5dB to 31dB With 0.125dB Steps
? Digital Gain Control

? 3rd Order Anti-Aliasing Filter With Programmable Cut-Off Frequency (7.5, 10 and 14MHz).
? Clamping
? Analog-to-Digital Converter (ADC)
? Octal channel 12-bit, 65 MSPS
? 32.5 MSPS Maximum per Input Channel
? 2 VGA Outputs Alternately Sampled by Each ADC
? Internal and External Reference Support
? No External Decoupling Required for References
? Serial LVDS Outputs

? 1.8V and 3.3V Supply
? 39 mW Total Power per Channel at 32.5 MSPS
? 64-QFN Package (9mm × 9mm)
? APPLICATIONS
? Imaging: Ultrasound, PET

? RELATED DEVICES
? AFE5801: Octal VGA+ADC, 65 MSPS/channel