THS770006 Datasheet, PDF (17/39 Pages) National Semiconductor (TI) – Broadband, Fully-Differential, 14-/16-Bit ADC DRIVER AMPLIFIER

THS770006
www.ti.com
SBOS520B – JULY 2010 – REVISED JANUARY 2012
Transient Response, Slew Rate, Overdrive Recovery
The standard EVM is used with T1 and T2 removed and jumpers placed across terminals 3 to 4 and 1 to 6; R15,
R17, and R25 = 49.9Ω; C1, C2, C9, and C13 = 0Ω; and R5, R6, R16, and R21 = open. A differential waveform
generator is connected to the input of the EVM with 50Ω coaxial cables at J1 and J2. The differential output at J3
and J4 is connected with 50Ω coaxial cables to an oscilloscope to measure the outputs. Waveform math in the
oscilloscope is used to combine the differential output of the device.
Power-Down
The standard EVM is used with T1 and T2 removed, jumpers placed across terminals 3 to 4 and 1 to 6, R15 and
R17 = 49.9Ω, C9 and C13 = 0Ω, and R5, R6, R16, and R21 = open. A waveform generator is connected to the
power-down input of the EVM with a 50Ω coaxial cable at J8. The differential output at J3 and J4 is connected
with 50Ω coaxial cables to an oscilloscope to measure the outputs. J1 is left disconnected so that the output is
driven to the V_OCM voltage when the device is active, and discharged through the resistive load on the output
when disabled. Both outputs are the same and only one is shown.
Differential Z-out
The standard EVM is used with R15 and R17 = 24.9Ω, and R16 = open. A network analyzer is connected to the
output of the EVM at J3 with 50Ω coaxial cable, both inputs are terminated with a 50Ω load, and a
high-impedance differential probe is used for the measurement. The analyzer is set to measure the forward
transfer function (s21). The analyzer with probe input is calibrated across the open resistor pads of R16 and the
signal is measured at the output pins of the device. The output impedance is calculated using the known resistor
values and the attenuation caused by R15 and R17.
Output Balance Error
The standard EVM is used with R15 and R17 = 100Ω, and R16 = 0Ω. A network analyzer is connected to the
input of the EVM with 50Ω coaxial cable, the output is left open, and a high-impedance differential probe is used
for the measurement. The analyzer is set to measure the forward transfer function (s21). The analyzer with probe
input is calibrated at the input pins of the device and the signal is measured from the shorted pads of R16 to
ground.
Common-Mode Rejection
The standard EVM is used with T1 removed and jumpers place across terminals 3 to 4, 1 to 6, and 1 to 3. A
network analyzer is connected to the input and output of the EVM with 50Ω coaxial cable and set to measure the
forward transfer function (s21).
V_OCM Frequency Response
The standard EVM is used with T2 removed and jumpers across terminals 3 to 4 and 1 to 6; R10, R15, and
R17 = 49.9Ω; C3 and C4 = 0Ω; and R9, R16, and R21 = open. A network analyzer is connected to the V_OCM
input of the EVM at J7 and output of the EVM with 50Ω coaxial cable, and set to measure the forward transfer
function (s21). The input signal frequency is swept with the signal level set for 200mV. Each output at J3 and J4
is measured as single-ended, and because both are the same, only one output is shown.
V_OCM Slew Rate and Pulse Response
The standard EVM is used with T2 removed and jumpers across terminals 3 to 4 and 1 to 6; R10, R15, and
R17 = 49.9Ω; C9 and C13 = 0Ω; and C3, C4, R9, R16, and R21 = open. A waveform generator is connected to
the V_OCM input of the EVM at J7 with 50Ω coaxial cable. The differential output at J3 and J4 is connected with
50Ω coaxial cable to an oscilloscope to measure the outputs. J1 is left disconnected so that the output is driven
to the V_OCM voltage. Both outputs are the same, so only one is shown.
Input/Output Voltage Noise, Settling Time, and Power-Supply Rejection
These parameters are taken from simulation.
Copyright © 2010–2012, Texas Instruments Incorporated
Product Folder Link(s): THS770006
Submit Documentation Feedback
17