feature

0.1dB Gain Flatness to 90MHz@2Vpp

0.02%/0.05 differential gain/phase error

500MHz large signal - 3dB bandwidth when G=2

2200V/m slew rate

75mA output current (easy to drive two video loads)

70dB channel-to-channel isolation

13mA current supply

3.5mA current supply in disabled mode

2.5mA current supply in shutdown mode

fully specified in

Lead-free SOIC-14 and TSSOP-14 packages

application

Video Switches and Routers

Multiple HDTV switching inputs

Picture-in-picture video switch

Multi-channel ADC driver

illustrate

The FHP3194 is a 4:1 analog multiplexer designed for high-speed video applications. The output amplifier is a high-speed current feedback amplifier that provides stellar 500MHz-3dB bandwidth for large signal performance with a 90MHz 0.1dB bandwidth. The gain of the output amplifier is selectable by two external resistors (Rf and Rg), allowing further design flexibility. 2Vpp bandwidth performance and 2200V/ms slew rate exceed high-definition television (HDTV) and other multimedia applications. The output amplifier provides enough output current to drive multiple video loads. Two address bits (A0 and A1) are used to select the four inputs. The FHP3194 provides better than 70dB of channel isolation. FHP3194 provides shutdown and disable functions. During shutdown, the FHP3194 consumes only 2.5mA or current supply. In disable mode, only the output amplifier is disabled, reducing output glitches and allowing for multiple expansions.

Functional block diagram

Absolute Maximum Ratings

"Absolute Maximum Ratings" are values at which the safety of the device cannot be guaranteed. This device should not operate within these limitations. Parameter values defined in the Electrical Characteristics table are not guaranteed at absolute maximum ratings. The "Recommended Operating Conditions" table defines these conditions for actual equipment operation.

Electrical Characteristics at ±5V

TA=25°C, Vs=±5V, Rf=475Ω, RL=150Ω, G=2; unless otherwise noted.

notes:

1. 100% tested at 25°C

Electrical Characteristics at ±5V (continued)

TA=25°C, Vs=±5V, Rf=475Ω, RL=150Ω, G=2 unless otherwise specified.

Note:

100% tested at 25°C

Sd and in pins are grounded. In1 and in3=+0.5v, in2 and in4=-0.5v, see truth table to properly set A0 and A1 based on the channels driven. Switching time is switching

Time from 50% of A0 or A1 input value (+2.5v) to the time which the switched channel is at 90% (+99%) of its final value.

Typical performance characteristics

TA=25°C, Vs=±5V, Rf=475Ω, RL=150Ω, G=2, unless otherwise specified

application information

circuit diagram

application information

General Instructions

The FHP3194 4:1 multiplexer has a positive input feedback amplifier with four analog switches driving high speed current. It is designed so that only one channel is open at a time. Ground unused input signals. The figure shows the FHP3194 in 6dB (G=2) and 0dB (G=1) configurations. Rf and Rg select the output of the FHP3194 to be a current feedback amplifier. The gain of this amplifier is set by two external resistors: front right and rear right. The frequency response and bandwidth of the closed-loop current feedback amplifier are highly dependent on the RF value. For both gains, use Rf=475Ω. For other gains, see RF vs. Gain Graphs in Figures. Generally speaking, lower RF peak frequency response and increase bandwidth, while higher RF will reduce bandwidth and reduce frequency response. Unity gain (G=1) requires a feedback resistor with a recommended value of 1.5kΩ. The A0, A1 level A0 and A1 logic pins are TTL/CMOS compatible and are used to select which output the four inputs are connected to. See the truth table on page 2 for more information. If both pins are left floating. EN, standard deviation FHP3194 provides shutdown and disable functions. The EN (enable) pin is active low. During disable mode (EN=1), only the output amplifier is disabled, reducing output glitches and allowing multiplexer expansion. When the EN pin is left floating, the FHP3194 is enabled or grounded. The SD (Shutdown) pin is active high.

During shutdown (SD=1), FHP3194 only consumes 2.5mA of current. When the SD pin is left, the FHP3194 is enabled to float or run aground. Supply Voltage The FHP3194 operates from a single supply of 5V to a dual supply of 12V or ±2.5V to ±6.0V for low supply voltage operation, ensuring that the common mode input voltage range (CMIR) or output voltage range (Vo) is not exceeded. Exceeding the CMIR or Vo range will put the FHP3194 into overdrive. For example the typical CMIR of the FHP3194 is ±3.1V on ±5V supplies, which means 1.9V of headroom is required per supply. With a single 5V supply, the CMIR becomes 1.9V to 3.1V The same theory applies to the VOUT range. Driving Video The FHP3194 is designed to drive high-speed video. 90MHz 0.1dB bandwidth, 2Vpp output, 0.02./0.05% differential gain/phase and ±75mA output current closure FHP3194 is suitable for driving standard definition, high definition or PC graphics video. Single 5V Power Drive Video The FHP3194 drives video signals from a 5V power supply only when G=1. At higher gains, the range of CMIR and Vo is not suitable for delivering video without clipping the signal.

Driving capacitive loads

The frequency response versus CL plot in the figure illustrates the response of the FHP3194. The resistance (Rs) at the output of the small series amplifier, as shown in the graph, improves stability and settling performance. The value in the Rupee frequency response vs. CL plot peaks by choosing a maximum bandwidth of less than 1dB. For maximum flatness, use a larger RS.

Power consumption

The maximum allowable internal power dissipation is directly related to the maximum junction temperature. Device failure may occur if the maximum junction temperature exceeds 150°C for extended periods of time. The FHP3194 is short circuit protected; however, this may not guarantee that the maximum junction temperature (150±C) is not exceeded under all conditions. RMS power dissipation can be calculated using the following formula: Power dissipation = Yes*(Vs+-Vs-)+(Vs+-Vo(RMS))*IOUT(RMS) where is the supply current, Vs+ is the positive supply pin voltage, and Vs- is the negative Supply pin voltage, Vo(RMS) is the RMS output voltage, IOUT(RMS) is the RMS output current delivered to the load. Follow the maximum power derating

overdrive recovery

For amplifiers, when the output and/or input range is exceeded. The resuscitation time is based on how much the input or output is overspeed and out of range. The FHP3194 typically goes out of overdrive in less than 75 nanoseconds. Diagram showing the overdriving state.

Layout Considerations

General floorplan and supply bypass performance at high frequencies. Fairchild has evaluations for use as a high frequency layout and as an aid for device testing and characterization. Follow these guidelines as a basis for a high frequency layout: Include 6.8µF and 0.1µF ceramic capacitors. Place 6.8µF capacitors at the power pins. Place 0.1µF capacitors on the power pins. Remove ground planes under and around parts, especially near input and output pins and under RF and Rg to reduce parasitic capacitance. Minimize all trace lengths to reduce series inductance. For a current feedback amplifier, from inverting the input (pin 12) to ground or inverting the output (pin 13) increases the peaking of the AC response. For best performance, place Rf and Rg as close to FHP3194 as possible. Small size surface mount resistors are recommended. Avoid using vias near devices; vias add unwanted via inductance. If traces larger than 1 inch are required, use stripline or microstrip technology with a characteristic impedance of 50Ω or 75Ω, properly terminated with impedance matching components on both ends. Testing and layout of these devices: