Additional Information - Linear Technology LT6411 Quick Start Manual

LT6411 HIGH-SPEED ADC DRIVER COMBO BOARD
Figure 3. DC1057 Input Network, see Table 2 and text for configuration options

ADDITIONAL INFORMATION

Although the DC1057 demo board is ready to use,
it has additional flexibility built in for various types
of input networks, filtering configurations, and sin-
gle-ended or differential inputs. Below is some in-
formation about configuring DC1057 to meet the
specific needs of any application.
APPLYING INPUT SIGNALS
The input network consists of various components
designed to allow either single-ended or differential
inputs, transformer-coupled or DC-coupled. Table
2 and Figure 4 show some possible input configu-
rations, and which components to install. Linear
Technology's ADC driver families are generally
characterized and designed for both single-ended
and differential input drive, but for optimal per-
formance differential input drive (or transformer-
coupled drive) is recommended. By default, trans-
former drive is used on DC1057 so that only a sin-
gle-ended input is needed. See the LT6411 data-
sheet for more comprehensive information on pos-
sible configurations.
Table 2: DC1057 Input Configuration Guide
CONFIGURATION COMPONENTS NECESSARY
Single-Ended In- Install 0Ω jumper at R16 or R6.
put
Install transformer T1. Install 25Ω at R7
Transformer Drive and R13 for impedance matching.
Gain = +2 Establish DC bias by using R37 and R38
or R2/R3 and R17/R18.
(default, not
shown) Tie feedback resistors to AC ground
through 0.1µF at C5 and C9 (or replace
with 0Ω resistors if using dual sup-
plies).
Single-Ended In- Install 0Ω jumper at R16. Install R6 for
put impedance matching.
Remove T1, C5, C9. Install 0Ω at R5, R10,
Single-Ended
Drive R39, R42.
Install 0.1µF at C33, C34. Establish DC
Gain = +2
bias with R17, R18 resistors.
(Figure 4a)
Install 0Ω at R5, R10.
3