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
High frequency instrumentation Data acquisition
Data acquisition
ZXFV302
ISSUE 4 - NOVEMBER 2002
1
4:1 HIGH SPEED MULTIPLEXER
Part Number
Container
Increment
ZXFV302N16TA
Reel 7
500
ZXFV302N16TC
Reel 13
2500
Ordering information
3
1
2
4
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
1 5
1 6
Z X F V 3 0 2
IN 1
0 V
0 V
0 V
O U T
IN 2
IN3
IN 4
V +
V -
0 V
E N
N C
A 1
A 0
N C
Connection Diagram
Fig.1:Typical Application for 8 channel CCTV
ABSOLUTE MAXIMUM RATINGS
Supply voltage V
CC
-0.5V to +6V
Supply voltage V
EE
-6V to +0.5V
Analog inputs to ground
V
EE
-0.5V to V
CC
+0.5V
Digital inputs to ground
-0.5V to V
CC
+0.5V
Outputs to ground*
V
EE
-0.5V to VCC +0.5V
Output current, max continous
40mA
Operating Ambient Temperature Range
-40 C to 85 C Storage -65 C to 150 C
Operating Junction temperature T
JMAX
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.
ZXFV302
ISSUE 4 - NOVEMBER 2002
2
PARAMETER
CONDITIONS
TEST
MIN
TYP
MAX
UNIT
Supply Voltage V+
4.75
5
5.25
V
Supply Voltage V-
-5.25
-5
-4.75
V
Positive supply current
P
13
17
21
mA
Negative supply current
P
9
13
18
mA
Voltage gain DC
P
0.99
1.000
1.01
V/V
Input Common mode Voltage
P
3
V
Input resistance
P
45
k
Output offset Voltage
All channels held at 0V
P
-10
+11
+30
mV
Input bias current
Active channels held at 0V
P
-25
-11
+5
A
Output Voltage swing
P
3
V
Output drive current
P
40
mA
Output resistance
C
1
Output resistance
Disabled (EN low)
P
1.5
3
4.5
M
Positive PSRR
P
40
54
dB
Negative PSRR
P
30
51
dB
Small signal bandwidth
1
C
300
MHz
Slew rate, 25% to 75%
2V pk-pk
C
450
V/ s
Logic input HIGH V
Hmin
C
2
V
Logic input LOW V
Lmax
C
0.8
V
Logic input current I
INHIGH
logic input voltage = 5V
C
5
pA
Logic input current I
INLOW
logic input voltage = 0V
C
-70
A
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
ZXFV302
ISSUE 4 - NOVEMBER 2002
3
A1
A0
EN
OUT
X
X
0
Hi Z
0
0
1
IN 1
0
1
1
IN 2
1
0
1
IN 3
1
1
1
IN 4
Truth table for selection of input channel
Notes: The `select' waveform represents a change in the the 2 bit control word A0 and A1.
t
HIGH
is equivalent to t
LOW
but , applies for a positive going transition of OUT.
Fig.2: TIMING DIAGRAM
PARAMETER
CONDITIONS
TEST
MIN
TYP
MAX
UNIT
t
ON
Vout =
2V, see timing diagram
C
35
ns
t
OFF
Vout =
2V, see timing diagram
C
10
ns
t
LOW
Vout =
2V, see timing diagram
C
50
ns
t
HIGH
Vout =
2V, see timing diagram
C
40
ns
Cross-talk, all hostile
1
10MHz, 0dBm in
C
75
dB
Differential Gain
C
0.01
%
Differential Phase
C
0.04
deg
Switching transients,
magnitude
All channels held at 0V
C
50
mV
Switching transients,
duration
All channels held at 0V
C
25
ns
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
Notes:
1. Bandwidth and cross talk measured using Zetex Evaluation Circuit Board detailed later in this datasheet.
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
f i l t e r i n g . A d o u b l e - s i d e d o r m u l t i - l a y e r P C B
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.
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:
ZXFV302
ISSUE 4 - NOVEMBER 2002
5
QTY CCT-REF
VALUE
DESCRIPTION
Resistors, surface mount
4
R1,R2,R3,R4
51R
0805
4
R5,R6,R7,R8
22k
0805
1
R9
120R
0805
1
R10
62R
0805
1
R11
10R
0805
5
R12 to R16
47k
0805
Capacitors, surface mount
6
100nF
25V ceramic 0805
X7R
2
1nF
50V ceramic 0805
NPO
2
10 F
16V Tant Elec size
C
Integrated Circuits
1
U1
Zetex ZXF 301N16
or ZXFV302N16
Miscellaneous
5
BNC Socket, PCB
straight flange,
e.g. Tyco
B35N14H999X99
1
3-way PCB screw
terminal block IMO
20.501/3SB
1
SW1
DIL switch, 8 way
10
TP1 to TP10
PCB test terminal,
red, W.Hughes
100-107
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