App note: Silicon Labs’ TS3004 VS. the CMOS 555 – Determining lowest supply current for battery-powered applications

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Good read on this app note from Silicon Labs comparing their low power but obsolete timer. Link here (PDF)

The 555 timer is the workhorse of ICs, with close to a billion of them manufactured every year. Introduced in 1972, the 555 is still in widespread use because of its ease of use, reasonable price, and good stability. It can be found in a wide variety of applications for oscillation, timing and pulse generation. But what if you need a timer IC for ultralong life, low-frequency battery-powered/portable applications where a low supply current is a requirement? Is the CMOS555 timer your best option?

App note: Single-cell regulated Q-pump draws low quiescent current

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Q-pump an alternative to inductor charge pump boost regulator for low power and sleepy microcontroller from Silicon Labs. Link here (PDF)

In the switch-mode power supply world, capacitor-based charge pumps (or Q-pumps) generally aren’t useful for heavy lifting, but work well in niche micropower applications where space is at a premium. They work best in applications where the output voltage is an integer multiple of the input voltage, which are operating points that result in peak efficiency. However, they can also shine when powered from a variable input like a battery, particularly when quiescent battery drain is more important than heavy-load efficiency. This might be the case when powering a microcontroller that spends most of its life sleeping.

App note: Hand soldering tutorial for fine pitch QFP devices

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No SMD tools removal and soldering of QFP packages tutorial from Silicon labs. Link here (PDF)

This document is intended to help designers create their initial prototype systems using Silicon Lab’s TQFP and LQFP devices where surface mount assembly equipment is not readily available. This application note assumes that the reader has at least basic hand soldering skills for through-hole soldering. The example presented will be the removal, cleanup and replacement of a TQFP with 48 leads and 0.5 mm lead pitch.

App note: Replacing traditional optocouplers with Si87xx digital isolators

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Digital isolator from Silicon Labs app note shows pin compatible plus high performance replacment of incumbent optoisolators, link here (PDF)

Opto-couplers are a decades-old technology widely used for signal isolation, typically providing safety isolation, signal level shifting, and ground loop mitigation. They are commonly used in a wide range of end applications, including data communication circuits, switch mode power systems, measurement and test systems, and isolated data acquisition systems. Optocouplers have several weaknesses, including parametric instability with temperature and device aging, significant internal parasitic couplings, long propagation delay times, narrow operating temperature ranges, and relatively low reliability.

Today’s advanced CMOS signal isolation products offer better timing performance, higher reliability, and lower power consumption compared to optocouplers and are capturing sockets traditionally held by optocouplers. However, converting to CMOS isolation devices has, most often, required circuit changes and PCB modifications that cost money and create design risks, until now.

App note: Introduction to gapped clocks and PLLs

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App note from Silicon Labs on the introduction of gapped clocks, how they can be used in network timing, and their impact upon phase locked loop (PLL) technology. Link here (PDF)

Gapped clocks are periodic clock signals of a single clock frequency that have clock pulses removed from their stream. Well-formed gapped clocks do not have reduced width pulses (known as runt pulses). Rather, each individual clock pulse is either completely present or completely absent.

App note: A simple alternative to analog isolation amplifiers

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A linear isolation amplifier from Silicon Labs app note. Link here (PDF)

Analog circuits sometimes require linear (analog) signal isolation for safety, signal level shifting, and/or ground loop elimination. Linear signal isolation is typically difficult to implement, costly, and often exhibits mediocre performance. While the design community thirsts for a flexible and inexpensive linear isolator solution, it is the analog isolation amplifier (ISOamp) that most often captures the socket.

App note: High-speed lithium-ion battery charger

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C8051F300 implementation of Li-Ion battery charger from Silicon Labs. Link here (PDF)

Driven by the need for untethered mobility and ease of use, many systems rely on rechargeable batteries as their primary power source. The battery charger is typically implemented using a fixedfunction IC to control the charging current/voltage profile.

The C8051F300 family provides a flexible alternative to fixed-function linear battery chargers. This note discusses how to use the C8051F300 device in Li-Ion battery charger applications. The Li-Ion charging algorithms can be easily adapted to other battery chemistries.

App note: Sub-1 V current sensing with the TS1001, A 0.8 V, 0.6 µA OP-AMP

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Another TS1001 op-amp application from Silicon Labs on sensing nano currents. Link here (PDF)

Current-sense amplifiers can monitor battery or solar cell currents, and are useful to estimate power capacity and remaining life. However, if the battery or solar source is a single cell, it’s difficult to find a low voltage solution that works below 1V and draws just microamps. A new class of nanopower analog ICs, namely the TS1001 0.8 V/0.6 µA op amp, makes a sub-1 V supply current sense amplifier possible. This discrete circuit operates from as low as 0.8 V and draws 860 nA at no load while providing a 0–500 mV output for measured currents of 0–100 mA, though the scale can be adjusted by changing the values of a few resistors. With its extremely low power, the circuit can simply remain “always on,” providing a continuously monitored, averaged indication of current which can subsequently be read periodically by a microcontroller, without causing too much current drain in the battery.

App note: A microwatt charge pump boosts 1 V to 1.8 V at 90% efficiency, providing “Always On” standby power for microcontrollers

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Interesting app note from Silicon Labs on high efficiency charge pump utilizing their nanopower TS1001 op amp. Link here (PDF)

Boosting the output voltage of common alkaline button-cells to at least 1.8 V needed by microcontrollers provides an “always on” standby power source sufficient for low-power oscillator interrupt/sleep state operation. Two ultralow power op amps are used in a charge pump configuration to double an input voltage, creating an output voltage of approximately 2x the input voltage. Output currents up to 100 µA are available at 90% efficiency; even load currents as low as 10 µA achieve 80% efficiency, beating commercially available charge pump ICs and inductorbased boost regulators.