LT5554 Datasheet | Linear Technology

Features n 1GHz Bandwidth at all Gains n 48d Bm OIP3 at 200MHz, 2VP-P into 50Ω, ROUT = 100Ω n - 88d Bc IMD3 at 200MHz, 2VP-P into 50Ω, ROUT = 100Ω n 1.4n V/√Hz Input-Referred-Noise (RTI) n 20d Bm Output P1d B at 70MHz, ROUT = 130Ω n 2d B to 18d B Gain Range (ROUT = 50Ω) n 0.125d B Gain Step Size n 30ps Group Delay Variation n 5ns Fast Gain Settling Time n 5ns Fast Overdrive Recovery n - 80d B Reverse Isolation APPLICATIONS n Differential ADC Driver n IF Sampling Receivers n VGA IF Power Amplifier n 50Ω Driver n Instrumentation L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Broadband Ultra Low Distortion 7-Bit Digitally Controlled VGA DESCRIPTION The LT®5554 is a 7-bit digitally controlled programmable gain (PG) amplifier with 16d B gain control range. It consists of a 50Ω input variable attenuator, followed by a high linearity variable transconductance amplifier. The coarse 4d B input attenuator step is implemented via 2-bits of digital control (PG5, PG6). The fine transconductance amplifier 0.125d B step within 3.875d B gain control range is set via 5-bits digital control (PG0 to PG4). The LT5554 gain control inputs (PGx) and the STROBE input can be directly coupled to TTL or ECL drivers. The seven parallel gain control inputs time skew can be eliminated by using the STROBE input positive transition. The internal output resistor RO = 400Ω limits the maximum overall gain to 36d B for open outputs. The internal circuitry of open output collectors enables the LT5554 to be unconditionally stable over any loading conditions (including external SAW filters) and provides - 80d B reverse isolation at 300MHz. The LT5554 is internally protected during overdrive and has an on-chip power supply regulator. With 0.125d B step resolution and 5ns settling time, the LT5554 is suitable in applications where continuous gain control is required. TYPICAL APPLICATION RF INPUT 5V VCC MODE 0.1μF IF...