LTC6421-20 Datasheet, PDF (1/16 Pages) Linear Technology – Dual Matched 1.3GHz Differential Amplifi ers/ADC Drivers

FEATURES
n _{Matched Gain ±0.1dB}
n _{Matched Phase ±0.2° at 100MHz}
n _{Channel Separation 80dB at 100MHz}
n _{1.3GHz –3dB Bandwidth; Fixed Gain of 10V/V (20dB)}
n _{IMD3 = –76dBc at 100MHz, 2VP-P}
n _{Equivalent OIP3 = 42dBm at 100MHz}
n _{1nV/√Hz Internal Op Amp Noise}
n _{6.2dB Noise Figure}
n _{Differential Inputs and Outputs}
n _{Rail-to-Rail Output Swing}
n _{40mA Supply Current (120mW) per Amplifier}
n _{1V to 1.6V Output Common Mode Voltage,}
Adjustable
n _{DC- or AC-Coupled Operation}
n _{20-Lead 3mm × 4mm × 0.75mm QFN Package}
APPLICATIONS
n _{Differential ADC Driver}
n _{Differential Driver/Receiver}
n _{Single Ended to Differential Conversion}
n _{IF Sampling (Diversity) Receivers}
LTC6421-20
Dual Matched
1.3GHz Differential
Amplifiers/ADC Drivers
DESCRIPTION
The LTC^®6421-20 is a dual high speed differential amplifier
targeted at processing signals from DC to 140MHz. The
part has been specifically designed to drive 12-, 14- and
16-bit ADCs with low noise and low distortion, but can also
be used as a general-purpose broadband gain block.
The LTC6421-20 is easy to use, with minimal support
circuitry required. The output common mode voltage
is set using an external pin, independent of the inputs,
which eliminates the need for transformers or AC-coupling
capacitors in many applications. The gain is internally
fixed at 20dB (10V/ V).
The LTC6421-20 saves space and power compared to
alternative solutions using IF gain blocks and transformers.
The LTC6421-20 is packaged in a compact 20-lead
3mm × 4mm QFN package and operates over the – 40°C
to 85°C temperature range.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Matched Dual Amplifiers with Output Common Mode Biasing
3V
1000pF 0.1μF
V_OCMA
V+ A
Z_IN = 200Ω _LTC6421-20
0.1μF
–INA ^100Ω
V_INA
0.1μF
+INA ^100Ω
V^–
V_OCMA
1000Ω
1000Ω
0.1μF
+INB ^100Ω
1000Ω
V_INB
0.1μF
– INB ^100Ω
Z_IN = 200Ω
V+ B
1000pF 0.1μF
1000Ω
V_OCMB
V_OCMB
ENABLEA
12.5Ω _+OUTA
12.5Ω _{– OUTA}
V^–
12.5Ω _{– OUTB}
12.5Ω _+OUTB
V_OCMA
V_OCMA
±0.1dB GAIN MATCHING
±0.1° PHASE MATCHING
AT 100MHz
V_OCMB
V_OCMB
ENABLEB
642120 TA01a
3V
Distribution of Gain Match
40
35
30
25
20
15
10
5
0
– 0.25 – 0.15 – 0.05 0.05 0.15 0.25
CHANNEL-TO-CHANNEL GAIN MATCH (dB)
642120 TA01b
642120fa
1