AD8334 Datasheet | Analog Devices

FEATURES Ultralow noise preamplifier (preamp) Voltage noise = 0.74 n V/√Hz Current noise = 2.5 p A/√Hz 3 d B bandwidth AD8331: 120 MHz AD8332, AD8334: 100 MHz Low power AD8331: 125 m W/channel AD8332, AD8334: 145 m W/channel Wide gain range with programmable postamp - 4.5 d B to +43.5 d B in LO gain mode 7.5 d B to 55.5 d B in HI gain mode Low output-referred noise: 48 n V/√Hz typical Active input impedance matching Optimized for 10-bit/12-bit ADCs Selectable output clamping level Single 5 V supply operation AD8332 and AD8334 available in lead frame chip scale package APPLICATIONS Ultrasound and sonar time-gain controls High performance automatic gain control (AGC) systems I/Q signal processing High speed, dual ADC drivers GENERAL DESCRIPTION The AD8331/AD8332/AD8334 are single-, dual-, and quadchannel, ultralow noise linear-in-d B, variable gain amplifiers (VGAs). Optimized for ultrasound systems, they are usable as a low noise variable gain element at frequencies up to 120 MHz. Included in each channel are an ultralow noise preamp (LNA), an X-AMP® VGA with 48 d B of gain range, and a selectable gain postamp with adjustable output limiting. The LNA gain is 19 d B with a single-ended input and differential outputs. Using a single resistor, the LNA input impedance can be adjusted to match a signal source without promising noise performance. The 48 d B gain range of the VGA makes these devices suitable for a variety of applications. Excellent bandwidth uniformity is maintained across the entire range. The gain control interface provides precise linear-in-d B scaling of 50 d B/V for control voltages between 40 m V and 1 V. Factory trim ensures excellent part-to-part and channel-to-channel gain matching. FUNCTIONAL BLOCK DIAGRAM LON LOP VIP VIN HILO LNA INH 19d B VMID 3.5d B OR 15.5d B - 48d B ATTENUATOR + 21d B VOH VOL VCM BIAS VGA BIAS AND INTERPOLATOR GAIN CONTROL INTERFACE CLAMP AD8331/AD8332/AD8334 RCLMP 03199-001 ENB GAIN Figure 1. Signal Path Block...