It’s no secret that MLC capacitors are in short supply. Manufacturers and distributors are quoting between 20 and 50+ week lead times depending on device type, and some predict this situation will continue well into 2020.
Whatever the reasons for this shortage (mostly a variation on an all-too-familiar theme of poor forecasting and deferred capex), designers and supply chain managers are stuck with three grim options to ensure supply:
- Expand their AVL list
- Assess an alternative C/V value
- Evaluate a different family of device
In this article we expand on the third option, and present you with every series of aluminum polymer capacitors currently in production by the world’s leading manufacturers.
Some manufacturers (e.g. Panasonic) are touting these devices as possible alternatives in this period of severe MLCC shortage. Of course, their suitability as replacements can only be ascertained on a case-by-case basis, and we make no recommendations either way, but merely present this complete range of possible alternatives.
The characteristics of aluminum polymer capacitors
Aluminum polymer capacitors are high ripple current. low ESR devices that do not exhibit the “dry-out” behaviour of traditional wet aluminum electrolytic capacitors.
Their higher capacitance ratings also offer potential cost and space savings, as a single device can replace multiple MLCCs.
However, compared to an MLCC, they possess a very restricted operating voltage range, typically in the range of 2.5Vdc to 35Vdc, with some higher voltage ratings available in a few selected series only e.g. 50Vdc, 80Vdc, 100Vdc and 125 Vdc (the Nichicon PCV series).
The other area where they suffer in comparison with MLCCs is upper operating temperature range. Standard upper operating temperature range is +85°C or +105°C, with currently only 16 series in production rated to operate at +125°C. This is well below the temperature ranges attainable in MLCC (and some tantalum) technologies, where operating ranges up to +250°C and above can be achieved. This makes aluminum polymer capacitors completely unsuitable for high temperature industrial and down hole applications.
These caveats aside, if your target specs fall within the ranges below, an aluminum polymer capacitor may be worth investigating:
- 2.5Vdc – 35Vdc typical, up to 125Vdc max.
- 2.2µF – 2,700µF (max.)
- -40°C – +85°C/105°C typical, 125°C max.