ISL59834IRZ Intersil, ISL59834IRZ Datasheet - Page 15

• Manufacturer Part Number: ISL59834IRZ
• Description: IC VIDEO FILTER CHRG PUMP 44-QFN
• Manufacturer: Intersil

Specifications of ISL59834IRZ

• Applications: Filter
• Number Of Circuits: 4
• -3db Bandwidth: 9MHz
• Current - Supply: 28mA
• Current - Output / Channel: 50mA
• Voltage - Supply, Single/dual (±): 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 44-VQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

is longer because extra time is needed for the charge pump
to settle before the amplifiers are enabled. When disabled,
the device supply current is reduced to 5µA. Power-down is
controlled by standard TTL or CMOS signal levels at the
ENABLE pins. The applied logic signal is relative to the GND
pin. Applying a signal that is less than 0.8V above GND will
disable the device. The device will be enabled when the
ENABLE signals are 2V above GND.
Output Drive Capability
The maximum output current for the ISL59834 is ±50mA.
Maximum reliability is maintained if the output current never
exceeds ±50mA, after which the electro-migration limit of the
process will be exceeded and the part will be damaged. This
limit is set by the design of the internal metal
interconnections.
Driving Capacitive Loads and Cables
The ISL59834 (internally-compensated to drive 75Ω cables)
will drive 10pF loads in parallel with 150Ω or 75Ω with less
than 1.3dB of peaking.
Power Dissipation
With the high output drive capability of the ISL59834, it is
possible to exceed the +150°C absolute maximum junction
temperature under certain load current conditions.
Therefore, it is important to calculate the maximum junction
temperature for an application to determine if load conditions
or package types need to be modified to assure operation of
the amplifier in a safe operating area.
The maximum power dissipation allowed in a package is
determined according to Equation 1:
PD
Where:
The maximum power dissipation actually produced by an IC
is the total quiescent supply current times the total power
supply voltage, plus the power in the IC due to the load, or:
for sourcing:
for sinking:
PD
PD
T
T
Θ
MAX
AMAX
MAX
MAX
JMAX
JA
= Thermal resistance of the package
=
=
=
= Maximum junction temperature
= Maximum ambient temperature
T
-------------------------------------------- -
V
V
JMAX
S
S
×
×
I
I
Θ
SMAX
SMAX
–
JA
T
AMAX
+
+
(
(
V
V
OUT
S
–
15
V
i V
OUT
–
S
i
)
)
×
×
I
---------------------
R
LOAD
V
LOAD
OUT
i
i
i
(EQ. 1)
(EQ. 2)
(EQ. 3)
ISL59834
Where:
By setting Equation 1 equal to Equation 2 and 3, we can
solve for the output current and R
avoid exceeding the maximum junction temperature.
Power Supply Bypassing and Printed Circuit
Board Layout
As with any high frequency device, a good printed circuit
board layout is necessary for optimum performance. Strip
line design techniques are recommended for the input and
output signal traces to help control the characteristic
impedance. Furthermore, the characteristic impedance of
the traces should be 75Ω. Trace lengths should be as short
as possible between the output pin and the series 75Ω
resistor. The power supply pin must be well bypassed to
reduce the risk of oscillation. For normal single supply
operation, a single 4.7µF tantalum capacitor in parallel with a
0.1µF ceramic capacitor from V
suffice.
The AC performance of this circuit depends greatly on the
care taken in designing the PC board. The following are
recommendations to achieve optimum high frequency
performance from your PC board.
• Use low inductance components, such as chip resistors
• Minimize signal trace lengths. Trace inductance and
• Match channel-to-channel analog I/O trace lengths and
• Route all signal I/O lines over continuous ground planes
• Place termination resistors in their optimum location as
V
I
V
R
I
i = Number of output channels
and chip capacitors whenever possible.
capacitance can easily limit circuit performance. Avoid
sharp corners; use rounded corners when possible. Vias
in the signal lines add inductance at high frequency and
should be avoided. PCB traces longer than 1" begin to
exhibit transmission line characteristics with signal rise/fall
times of 1ns or less. To maintain frequency performance
with longer traces, use striplines.
layout symmetry. This will minimize propagation delay
mismatches.
(i.e. no split planes or PCB gaps under these lines).
close to the device as possible.
SMAX
LOAD
S
OUT
LOAD
= Supply voltage
= Maximum output voltage of the application
= Load current
= Maximum quiescent supply current
= Load resistance tied to ground
S
and V
LOAD
values needed to
CP
to GND will
June 11, 2008
FN6268.1