ISL54233IRTZ-T7A Datasheet, PDF (9/18 Pages) Intersil Corporation – Wideband Differential 3:1 Multiplexer

ISL54233
POWER
The power supply connected at V_DD (pin 11) provides power to
the ISL54233 part. Its voltage should be kept in the range of
2.7V to 4.6V. In a typical application, V_DD will be in the range of
2.7V to 4.3V and will be connected to the battery or LDO of the
MP3 player or cellphone.
A 0.01µF or 0.1µF decoupling capacitor should be connected
from the V_DD pin to ground to filter out any power supply noise
from entering the part. The capacitor should be located as close
to the V_DD pin as possible.
LOGIC CONTROL
The state of the ISL54233 device is determined by the voltage at
the C1 pin (pin 9) and the C0 pin (pin 10). Refer to the “Truth
Table” on page 2.
The C1 pin and C0 pin are internally pulled low through 4MΩ
resistors to ground and can be tri-stated or left floating.
The C1 pin and C0 pin can be driven with a voltage that is higher
than the V_DD supply voltage. They can be driven up to 5.25V with
the V_DD supply in the range of 2.7V to 4.6V. Driving the logic
higher than the supply rail will cause the logic current to
increase. With V_DD = 2.7V and V_LOGIC = 5.25V, I_LOGIC current is
approximately 5.5µA.
Logic Control Voltage Levels
With V_DD in the range of 2.7V to 3.6V the logic levels are: C1,
C0 = Logic “0” (Low) when ≤ 0.5V or Floating. C1, C0 = Logic “1”
(High) when ≥ 1.4V.
ALL SWITCHES OFF Mode
If the C1 pin = Logic “0” and C0 pin = Logic “0” the part will be in
the ALL SWITCHES OFF mode. In this mode, the 3D- and 3D+
data switches, the 2D- and 2D+ data switches, and the 1D- and
1D+ data switches will be OFF (high impedance).
The COM pins can accommodate signals that swing below
ground by as much as -2V. This allows an audio CODEC to be
connected to the COM pins when the device is in the all off state.
USB/DV 1 Mode
If the C1 pin = Logic “0” and C0 pin = Logic “1” the part will go
into USB/DV1 mode. The 1D- and 1D+ switches are ON and the
2D- and 2D+ switches and 3D- and 3D+ will be OFF (high
impedance).
USB/DV 2 Mode
If the C1 = Logic “1” and C0 pin = Logic “0” the part will be in the
USB/DV2 mode. The 2D- and 2D+ switches will be ON and the
1D- and 1D+ switches and the 3D- and 3D+ will be OFF (high
impedance).
USB/DV 3 Mode
If the C1 pin = Logic “1” and C0 pin = Logic “1” the part will be in
the USB/DV3 mode. The 3D- and 3D+ switches are ON, and the
1D- and 1D+ switches and 2D- and 2D+ switches will be OFF
(high impedance).
Printed Circuit Board Design for High
Frequency Performance
In 50Ω systems, the ISL54233 has a -3dB bandwidth of 1.6GHz
(see Figure 19).
To achieve this high bandwidth requires careful design and layout
of the PCB board. Signal traces must be designed to minimize
reflections and reduce parasitic resistance, inductance and
capacitance that degrade the frequency response performance.
Figure 9 shows a picture of the engineering board used to
measure the frequency response of the ISL54233 part. The
board was specifically design for taking high frequency
bandwidth measurements. The board was made with special
materials and was carefully layed out using RF board techniques
to maximize it for high frequency operation.
The next section, “Board Layout Guidelines”, will provide a list of
the PCB board requirements needed to get the maximum
bandwidth from the ISL54233 part when tested with a 50Ω
Network Analyzer.
FIGURE 9. RF HIGH FREQUENCY BOARD
9
FN7918.0
December 21, 2011