ISL59420IUZ-T7 Intersil, ISL59420IUZ-T7 Datasheet - Page 9

• Manufacturer Part Number: ISL59420IUZ-T7
• Description: IC AMP MULTIPLEX 400MHZ 10-MSOP
• Manufacturer: Intersil

Specifications of ISL59420IUZ-T7

• Applications: 2:1 Multiplexer-Amplifier
• Number Of Circuits: 1
• -3db Bandwidth: 420MHz
• Slew Rate: 1462 V/µs
• Current - Supply: 11mA
• Current - Output / Channel: 130mA
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ISL59420IUZ-T7

Application Circuits
Application Information
General
The ISL59420 is a 2:1 mux that is ideal as a matrix element
in high performance switchers and routers. The ISL59420 is
optimized to drive 5pF in parallel with a 500Ω load. The
capacitance can be split between the PCB capacitance and
an external load capacitance. Its low input capacitance and
high input resistance provide excellent 50Ω or 75Ω
terminations.
Parasitic Effects on Frequency Performance
Capacitance at the Inverting Input
The AC performance of current-feedback amplifiers in the
non-inverting gain configuration is strongly affected by stray
capacitance at the inverting input. Stray capacitance from
the inverting input pin to the output (C
increase gain peaking and bandwidth. Large values of either
capacitance can cause oscillation. The ISL59420 has been
optimized for a 0.4pF to 0.7pF capacitance (C
Capacitance (C
achieve optimum performance the feedback network
resistor(s) must be placed as close to the device as possible.
Trace lengths greater than 1/4 inch combined with resistor
pad capacitance can result in inverting input to ground
capacitance approaching 1pF. Inverting input and output
F
) to the output should be minimized. To
V
IN
V
IN
9
50Ω
50Ω
F
), and to ground (C
0.4pF < C
FIGURE 25A. GAIN OF 1 APPLICATION CIRCUIT
FIGURE 25B. GAIN OF 2 APPLICATION CIRCUIT
0.6pF
0.4pF < C
0.6pF
453Ω
G
).
G
PC BOARD
CAPACITANCE
< 0.7pF
C
G
200Ω
+
-
G
PC BOARD
CAPACITANCE
< 0.7pF
C
453Ω
+
-
G
G
ISL59420
),
*C
1.6pF
L =
C
*C
traces should not run parallel to each other. Small size
surface mount resistors (604 or smaller) are recommended.
Capacitance at the Output
The output amplifier is optimized for capacitance to ground
(C
causes higher peaking with an increase in bandwidth. The
optimum range for most applications is ~1.0pF to ~6pF. The
optimum value can be achieved through a combination of
PC board trace capacitance (C
(C
pin capacitance is to minimize the trace length (C
next component, and include a discrete surface mount
capacitor (C
Feedback Resistor Values
The AC performance of the output amplifier is optimized with
the feedback resistor network (R
recommended in the application circuits. The amplifier
bandwidth and gain peaking are directly affected by the
value(s) of the feedback resistor(s) in unity gain and gain >1
configurations. Transient response performance can be
tailored simply by changing these resistor values. Generally,
lower values of R
peaking. This has the effect of decreasing rise/fall times and
increasing overshoot.
T
1.6pF
L =
C
C
L
OUT)
T
T
) directly on the output pin. Increased capacitance
+ C
C
T
+ C
OUT
. A good method to maintain control over the output
OUT
C
3.9pF
*C
OUT
C
C
OUT
L
T
OUT
C
3.9pF
: TRACE CAPACITANCE
: TOTAL LOAD CAPACITANCE
OUT
) directly at the output pin.
: OUTPUT CAPACITANCE
F
and R
R
L =
V
R
OUT
G
L =
500Ω
V
OUT
increase bandwidth and gain
500Ω
T
) and an external capacitor
F
, R
G
) values
September 22, 2005
T
) to the
FN7459.1