m21328g Mindspeed Technologies, m21328g Datasheet - Page 8

• Manufacturer Part Number: m21328g
• Description: M21328 Hd/sd And 2xhd-sdi Cable Driver
• Manufacturer: Mindspeed Technologies

1.2.2
The M21328 output buffer is an open collector buffer that is designed for a return loss of 15 dB at SD and HD rates
and 10 dB at 2xHD rates, using standard through-hole BNC connectors as typically employed in broadcast video
equipment. A typical output matching circuit is shown in
on many factors such as the value and type of components used, PCB layout, PCB trace lengths, and type of PCB
di-electric, therefore, the recommendations in the figure below should be used as starting guidelines only. Different
output matching network topologies and different component values will result in different ORL performance.
The M21328 has SD-SDI and HD-SDI rise/fall times that are typically faster than the legacy cable driver devices
but within the relevant SMPTE specification for additional margin in most designs. The faster output slew rate
results in a more open eye. The actual maximum output of the part depends on the applied IC voltage as well as
the external termination voltage for the load termination. The limitations are discussed in
Figure 1-3.
21328-DSH-001-D
Typical Output Matching/Back-termination Circuit
High-speed Outputs
M21328
AV
DD
SDO
SDO
I
DD
Mindspeed Proprietary and Confidential
Mindspeed Technologies
75Ω
75Ω
I TERM
4.7 nH
4.7 nH
Figure
75Ω
75Ω
AV
1-3. The Output Return Loss (ORL) is dependent
DDTERM
4.7 uF
4.7 uF
®
BNC
BNC
10 nF
Functional Description
Section
1.1.
3