Fully Differential SD Video Filter Amplifier with Output Short-to-Battery Protection
The ADA4433-1 is a fully integrated video reconstruction filters that combine overvoltage protection (short-to-battery [STB] protection) and short-to-ground protection [STG] on the outputs, with excellent video specifications and low power consumption. The combination of STB protection and robust ESD tolerance allows the ADA4433-1 to provide superior protection in the hostile automotive environment.
The ADA4433-1 is a fully differential video filter that can be used as a differential input to differential output or a single-ended input to differential output. It is capable of driving twisted pair or coaxial cable with minimal line attenuation. Differential signal processing reduces the effects of ground noise that can plague ground referenced systems. The ADA4433-1 is ideal for differential signal processing (gain and filtering) throughout the signal chain, easily simplifying the conversion between single-ended and differential components.
The short-to-battery protection integrated into the ADA4433-1 protects against both dc and transient overvoltage events, caused by an accidental shorts to a battery voltage up to 18 V. Analog Devices, Inc., short-to-battery protection eliminates the need for large output coupling capacitors and other complicated circuits used to protect standard video amplifiers; saving space and cost.
The ADA4433-1 features a high-order filter with −3 dB cutoff frequency response at 10 MHz and 45 dB of rejection at 27 MHz. The ADA4433-1 features an internally fixed gain of 2 V/V. This makes the ADA4433-1 ideal for SD video applications, including NTSC and PAL.
The ADA4433-1 operates on single supplies as low as 2.7 V and as high as 3.6 V while providing the dynamic range required by the most demanding video systems.
The ADA4433-1 is offered in an 8-lead 3 mm × 3 mm LFCSP package and is rated for operation over the wide automotive temperature range of −40°C to +125°C.
- Automotive rearview cameras
- Automotive video electronic control units (ECUs)
- Surveillance video systems
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
The ADA4433-1BCP-EBZ evaluation board makes it easy for designers to quickly observe the performance of the ADA4433-1 video filter in real-world applications. Input signals are applied through the SMA jacks (+IN, −IN), and outputs are taken from SMA jacks (+OUT, −OUT). Power is applied through the red +VS test point. Ground the black GND test point. The ADA4433-1 operates on a single-supply voltage ranging from 2.6 V to 3.6 V, and draws approximately 14 mA.
The evaluation board is configured with an input termination resistor (R1) of 75 Ω. Chose this resistor to provide the correct termination or load for the input signal source. For example, current-mode video digital-to-analog converter (DAC) outputs that require a 300 Ω load resistance. In this case, replace R1 with a 300 Ω resistor.
The ADA4433-1 inputs can be driven by either a balanced or an unbalanced source. For unbalanced signals, bias the unused input (−IN) to approximately 0.5 V. For a 3.3 V supply, this can be achieved by using the on-board voltage divider by setting R2 = 1.33 kΩ and R3 = 7.5 kΩ. Populate the decoupling capacitor (C3) with 0.1 μF to help eliminate noise. By default, the ADA4433-1BCP-EBZ is configured for single-ended input operation where the input signal is applied to SMA (+IN). For a balanced input configuration, R4 provides placement for the differential termination resistor.
The ADA4433-1BCP-EBZ evaluation board is configured to drive a back terminated 150 Ω differential load. Series back-termination resistors (37.5 Ω each) are installed on both outputs. These can be changed to match the actual differential load impedance.
The ADA4433-1 can be powered down (disabled) by grounding the green ENA test point at the top left of the evaluation board. On the evaluation board, this pin is pulled up to +VS through the 4.7 kÙ resistor (R7).
In normal operation, the short-to-battery output flag (STB) is held at a logic low. During a short-to-battery fault condition (where a voltage ranging from 5 V to 18 V is applied to either or both outputs), the STB output voltage is driven to a logic high state. The STB yellow test point (lower left side of the evaluation board) can be used to monitor the short-to-battery output flag function.
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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.