ZXFV302
4:1 HIGH SPEED MULTIPLEXER
DEVICE DESCRIPTION
The ZXFV302 is a 4:1 high speed analog switch
designed for use as a buffered video multiplexer and
other high-speed applications.
It features low different gain and phase distortion. The
high speed high output current capability provides 75
cable drive for use in high performance video
applications.
The input channel is selected by means of two logic
lines using an internal decoder. An output enable line
allows expansion to eight channels using two devices
ZXFV302 as shown in the example application figure 1.
An alternative device, ZXFV301 provides the same
functionality and pin-out as the ZXFV302 but with four
separate logic lines controlling the switch channels
directly.
FEATURES AND BENEFITS
•
3dB Bandwidth 300MHz
•
Slew rate 450V/ s
•
Differential gain 0.01%
•
Differential phase 0.04
•
Output current 40mA
•
Stable up to 100pF load
•
5 Volt supply
•
Supply current 17mA
•
16 pin SO package
APPLICATIONS
•
Video routing and switching
•
CCTV switching
•
Video distribution selection
•
RGB multiplexing
Connection Diagram
•
High frequency instrumentation Data acquisition
•
Data acquisition
IN 1
0V
IN 2
0V
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V+
OUT
0V
EN
A0
A1
NC
NC
IN3
0V
IN 4
V-
ZXFV302
Ordering information
Part Number
ZXFV302N16TA
ZXFV302N16TC
Container
Reel 7″
Reel 13″
Increment
500
2500
Fig.1:Typical Application for 8 channel CCTV
ISSUE 4 - NOVEMBER 2002
1
ZXFV302
ABSOLUTE MAXIMUM RATINGS
Supply voltage V
CC
Supply voltage V
EE
Analog inputs to ground
Digital inputs to ground
Outputs to ground*
Output current, max continous
Operating Ambient Temperature Range
Operating Junction temperature T
JMAX
-0.5V to +6V
-6V to +0.5V
V
EE
-0.5V to V
CC
+0.5V
-0.5V to V
CC
+0.5V
V
EE
-0.5V to VCC +0.5V
40mA
-40 C to 85 C Storage -65 C to 150 C
150 C**
**The thermal resistance from the semiconductor die to ambient is typically 120 C/W when the SO16 package is
mounted on a PCB in free air. The power dissipation of the device when loaded must be designed to keep the
device junction temperature below T
JMAX
.
*During power-up and power-down, these voltage ratings require an appropriate sequence of applying and
removing signals and power supplies.
ELECTRICAL CHARACTERISTICS
5V power supplies, T
amb
= 25 C unless otherwise stated. R
L
= 150 , C
L
= 10pF
Characteristics apply to channel selected, and EN input HIGH unless otherwise stated
Test level:
P = 100% production test
C = characterised only
CONDITIONS
TEST
MIN
4.75
-5.25
P
P
P
P
P
All channels held at 0V
Active channels held at 0V
P
P
P
P
C
Disabled (EN low)
P
P
P
C
2V pk-pk
C
C
C
logic input voltage = 5V
logic input voltage = 0V
C
C
0.8
5
-70
1.5
40
30
3
54
51
300
450
2
40
1
4.5
M
dB
dB
MHz
V/ s
V
V
pA
A
-10
-25
13
9
0.99
TYP
5
-5
17
13
1.000
3
45
+11
-11
3
+30
+5
MAX
5.25
-4.75
21
18
1.01
UNIT
V
V
mA
mA
V/V
V
k
mV
A
V
mA
PARAMETER
Supply Voltage V+
Supply Voltage V-
Positive supply current
Negative supply current
Voltage gain DC
Input Common mode Voltage
Input resistance
Output offset Voltage
Input bias current
Output Voltage swing
Output drive current
Output resistance
Output resistance
Positive PSRR
Negative PSRR
Small signal bandwidth
1
Slew rate, 25% to 75%
Logic input HIGH V
Hmin
Logic input LOW V
Lmax
Logic input current I
INHIGH
Logic input current I
INLOW
ISSUE 4 - NOVEMBER 2002
2
ZXFV302
APPLICATIONS INFORMATION
Introduction
A typical circuit application is outlined in Figure 1,
above, where two devices are combined to provide
8-to-1 multiplexing. A more detailed basic application
circuit for 4 dc-coupled channels is given in Figure 3,
and an AC coupled circuit for 8 channels is shown in
Figure 4. These circuits are suitable for 75
transmission line connections at both the input and the
output and are useful for distribution of wide-band
signals such as video via cables. The 75 reverse
terminating resistor at the output gives the correct
matching condition to a terminated video cable. The
amplifier load is then 150 .
The wide bandwidth of this device necessitates some
care in the layout of the printed circuit. Partly for this
reason, an Evaluation Circuit board is available and is
described in a later paragraph. A continuous ground
plane is required under the device and its signal
connection paths, to provide the shortest possible
ground return paths for signals and power supply
filtering. A double-sided or multi-layer PCB
construction is required, with plated-through via holes
providing closely spaced low-inductance connections
from some components to the continuous ground
plane (some of these holes are not visible in the figures
for the Evaluation Circuit Board – artworks and NC drill
output can be provided if required).
For the power supply filtering, low inductance surface
mount capacitors are normally required. It has been
found that very good RF decoupling is provided on
each supply using a 1000 pF NPO size 0805 ceramic
surface mount capacitor, closest to the device pin, with
an adjacent 0.1 F X7R capacitor. Other configurations
are possible and it may be found that a single 0.01 F or
0.1 F X7R capacitor, size 0805 or smaller, on each
supply gives good results. However this should be
supported by larger decoupling capacitors elsewhere
on the printed circuit board. Values of 1 to 10 F are
recommended, particularly where the voltage
regulators are located more than a few inches from the
device. These larger capacitors are recommended to
be solid tantalum electrolytic or ceramic types.
Evaluation Circuit
An evaluation circuit is available, constructed on a
double-side printed circuit board. The circuit is suitable
for both the ZXFV301 and ZXFV302 and either device
may be fitted. Figures 5 and 6 show the circuit diagram,
and the layout of components and copper. A parts list
is provided below. This layout serves as a useful
example for many applications, showing the practical
implementation of the advice given above in the
Introduction.
1
10
SW1
TP1 to TP10
BNC connector sockets allow connection to test
instruments via 50 cables. The output circuit includes
a resistor matching circuit to present a load of 150 to
the device and simultaneously provide 50 output
impedance. The attenuation of this matching circuit is
15.45 dB. As the device has unity voltage gain, the
overall loss when loaded by 75 is also 15.45 dB.
EVALUATION CIRCUIT PARTS LIST:
QTY CCT-REF
VALUE
DESCRIPTION
Resistors, surface mount
4
4
1
1
1
5
R1,R2,R3,R4
R5,R6,R7,R8
R9
R10
R11
R12 to R16
51R
22k
120R
62R
10R
47k
0805
0805
0805
0805
0805
0805
Capacitors, surface mount
6
2
2
Integrated Circuits
1
U1
Zetex ZXF 301N16
or ZXFV302N16
100nF
1nF
10 F
25V ceramic 0805
X7R
50V ceramic 0805
NPO
16V Tant Elec size
C
Miscellaneous
5
BNC Socket, PCB
straight flange,
e.g. Tyco
B35N14H999X99
3-way PCB screw
terminal block IMO
20.501/3SB
DIL switch, 8 way
PCB test terminal,
red, W.Hughes
100-107
1
ISSUE 4 - NOVEMBER 2002
5
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