Do these 3 things before closing this tab:
1Fix the driver behind crashes, sound loss and screen glitches2Clear out junk files and repair common Windows errors3Scan for outdated or missing drivers - takes under a minuteA switched-capacitor filter’s corner or center frequency is tied to its switching clock by a ratio set by the particular device. Because the circuit is sampled, input energy above half the clock frequency can alias into lower frequencies. If that energy could interfere with the signal you want to keep, filter it in the analog path before it reaches the switched-capacitor stage. The right clock, input filter, and external components depend on the selected IC and the signal spectrum—not on one universal rule.
How does the clock rate set a switched-capacitor filter’s frequency?
A switched-capacitor circuit repeatedly charges and transfers charge between capacitors. The switching action emulates frequency-dependent behavior, so the filter’s characteristic frequency tracks the clock rather than being fixed only by an external resistor-capacitor time constant. The relationship is proportional, but the ratio is part-specific: for a device with a 50:1 clock-to-cutoff ratio, the clock frequency is 50 times the cutoff frequency.
As an Amazon Associate I earn from qualifying purchases.
That makes the clock an adjustment input as well as a design constraint. Changing it moves the filter’s characteristic frequency; changing the clock by a given percentage changes that frequency by the same percentage, assuming the device remains within its operating limits. TI describes switched-capacitor center or cutoff frequency as proportional to clock frequency and notes that the relationship can make a wide tuning range possible without changing external circuitry. The available tuning range and permitted clock values still depend on the part. TI’s filter introduction explains the general relationship.
Translate a target cutoff using the selected part’s ratio
First find the clock-to-corner ratio in the datasheet, then calculate the clock needed for the target frequency. For a 50:1 device, a 1 kHz cutoff corresponds to a 50 kHz clock. That arithmetic illustrates the ratio; it is not a recommendation that every filter use 50:1. TI lists that ratio for the TLC04, a fourth-order Butterworth low-pass filter. Its product information gives a cutoff range of 0.1 Hz to 30 kHz under the listed supply conditions. Check the full datasheet for the allowable clock range and other operating conditions before treating any calculated clock as valid. TLC04 product information
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Clock accuracy matters too. Since the filter corner follows the clock, a clock frequency error or drift produces a corresponding error or drift in the filter’s characteristic frequency. If the application depends on a particular cutoff, include clock stability and the device’s specified limits in the design decision rather than choosing a clock solely from nominal arithmetic.
Why can input frequencies above half the clock cause aliasing?
A switched-capacitor filter is a sampled-data system: it observes and processes the input through periodic switching. In sampled systems, distinct higher-frequency components can appear at lower frequencies after sampling. The half-clock boundary is the relevant Nyquist frequency for this discussion. TI warns that input content higher than one-half the clock frequency can alias in a switched-capacitor filter. TI’s filter introduction
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
The practical risk is not simply that an input contains any energy above that boundary. The key question is where the aliased component lands and whether it overlaps the wanted band. If it does, the filter receives an in-band-looking component that cannot be distinguished from genuine signal content there. The original higher-frequency source is no longer recoverable from that result by ordinary downstream filtering. Analog Devices explains that anti-alias filtering must happen in the analog signal path before the sampling operation. Analog Devices’ anti-aliasing article
Free tools Windows power users keep installed
One-click scans. No signup required.
This is why a filter’s nominal passband alone does not answer whether the input is safe. A low-pass filter may reject frequencies in its stopband, but out-of-band input energy can already have folded into the band of interest during the switched-capacitor stage. Consider the full spectrum the source can produce, including interference or harmonics, not just the intended signal band.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
When should an analog anti-alias filter go before the IC?
Use an analog prefilter when the input can contain out-of-band energy that could alias into a frequency range you need to preserve or measure. The prefilter reduces that energy before the switched-capacitor circuit samples it. The required amount of reduction depends on the unwanted signal levels, where their aliases would land, and how much interference the application can tolerate. The manufacturer sources establish the need for pre-sampling analog filtering but do not prescribe one universal corner frequency or attenuation target.
Decide from the signal spectrum, not from a default RC value
- Define the wanted band. Record the frequencies the application must pass and any transition region where attenuation can begin without harming the signal.
- Identify possible out-of-band energy. Include what the source, sensor, preceding circuitry, and operating environment can place at the filter input.
- Check where that energy could alias. Compare potential input frequencies with the clock and determine whether their sampled aliases could fall in the wanted band.
- Set the prefilter requirement. Choose enough analog attenuation at the problematic frequencies while preserving the useful signal and respecting the filter IC’s input requirements.
- Verify the complete response. Evaluate the prefilter and switched-capacitor stage together; the prefilter’s response does not disappear just because the IC has its own passband.
What an RC low-pass can—and cannot—do
A resistor-capacitor low-pass is one possible analog prefilter. Its corner and attenuation must suit both the unwanted spectrum and the wanted passband. A corner set too low can attenuate useful signal; setting it higher preserves more of the desired band but reduces rejection nearer the passband. The choice is therefore a system trade-off, not a universal component recipe.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
In particular, an added low-pass can be a poor fit ahead of a high-pass or notch function if it cuts frequencies the application needs to retain. TI calls out this trade-off for switched-capacitor high-pass and notch applications. A prefilter should be judged against the intended response of the whole signal chain, rather than treated as a harmless accessory. TI’s filter introduction
What external components does a switched-capacitor filter need?
There is no class-wide answer. Some devices or operating conditions may need only a clock for the relevant filtering function; others require supporting capacitors or have other application-circuit requirements. Read the selected part’s datasheet and application guidance for the exact response, frequency range, supply, clock, and external-component conditions. Do not carry component assumptions from one switched-capacitor IC to another.
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Two examples show why the datasheet matters
- LTC1064-1: Analog Devices Design Note 16 says no external components are required for cutoff frequencies up to 20 kHz in the described use. Above 20 kHz, two small capacitors are required to maintain passband flatness. The note’s example of an eighth-order Cauer low-pass uses a 4 MHz clock for a 40 kHz cutoff. These are historical, device-specific circuit details, not specifications for switched-capacitor filters generally. Analog Devices Design Note 16
- TLC04: TI describes this part as a fourth-order Butterworth low-pass with a 50:1 clock-to-cutoff ratio and lists a 0.1 Hz to 30 kHz cutoff range under the stated supply conditions. Those figures describe that device; confirm its pin connections, clock limits, supplies, input and output constraints, and any external components in the full datasheet. TI TLC04 product information
The examples are not interchangeable design recipes: they describe different parts and applications. Lifecycle, inventory, and current alternatives are not established by these technical references, so the figures should not be read as a statement about present availability.
What clock-related artifacts should you check?
The idealized picture of a smooth filter response does not capture every clock-related effect. Analog Devices’ filter primer discusses clock-rate steps or spikes at the output and deviations from an ideal continuous-time model, with effects depending on the design. The closer a filter pole is to the clock frequency, the more relevant nonideal response can become, but the actual behavior must be assessed for the specific device. Analog Devices’ filter primer
ADI application note AN40 illustrates clock feedthrough, sidebands around the clock, and an input harmonic appearing as an alias for the LTC1064-1. Those examples establish effects worth checking; they do not establish a fixed artifact level for every part or circuit. Inspect the selected device’s specifications and consider whether clock-related energy falls within the system’s measurement or signal bandwidth. ADI AN40
Recommended Free Tools
How to choose a device and clock together
Start with the response and interference problem, then shortlist devices and clock settings that can meet it. A nominal cutoff by itself is not enough: the selected clock affects the characteristic frequency and the aliasing boundary, while any prefilter affects the wanted signal as well as unwanted content.
- Wanted response: Establish the passband, transition width, and whether the required function is low-pass, high-pass, notch, or another response.
- Device ratio and clock range: Use the part’s stated clock-to-corner ratio and permitted clock range to see whether it can reach the target frequency.
- Clock quality: Account for clock stability and frequency error when the filter corner must remain accurate.
- Out-of-band inputs: Identify signals above half the clock that could alias into the band of interest, and decide whether prefiltering can reduce them without damaging the wanted response.
- Nonideal behavior: Check the relevant specifications and application guidance for ripple, feedthrough, noise, distortion, supplies, and input/output constraints.
- External parts: Follow the exact device’s application circuit for component values and operating conditions; examples from another IC do not establish what this one needs.
Manufacturer documents provide device-specific ratios and examples, not a single optimum ratio, RC corner, or universal component list. Where the datasheet does not make a system trade-off for you, the decision depends on the actual source spectrum and the response your application must preserve.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
