The MCP6001, MCP6002, and MCP6004 devices,
which offer rail-to-rail input/output and have 90-degree phase margin
into a 60-picofarad (pf), 10-kilo-ohm
(kohm) load, are said to offer exceptional stability in a low-cost operational
amplifier. "This means that the amplifier still maintains low power
use and can drive capacitive loads without oscillating," explains
Art Eck, product marketing manager for Microchip's Analog and Interface
Products Division. "Although it is possible to find very stable
operational amplifiers, stability in combination with a low-voltage and
amplifier is hard to beat."
typical power usage of 180 microwatts (¬ĶW), the new family
of 1-MHz operational amplifiers from Microchip are reportedly ideal
for use in sensors, instrumentation devices, consumer products,
battery-operated applications, and devices powered by a single
communication loop such as phones, security, and building safety
According to Mr. Eck, stability is a
big issue for design engineers. "It
is hard to predict in a design when instability will be reached and how
that point will shift with typical component and manufacturing variations," he
explains. "For this reason, cost increase may be incurred by delays
due to solving this issue, yield loss due to unwanted oscillations, and
added components to stabilize the amplifier."
The amplifiers are
also said to reduce supply voltage demand. "Careful
use of the Standard Microchip Technology Inc. CMOS process has allowed
the development of operational amplifiers that can be fully integrated
into PICmicro(R) [field-programmable RISC microcontrollers]. This has
required innovative use of available solid-state devices in order to
standard wafer fabrication flow and still achieve proper analog performance.
In the case of low-voltage performance, the addition of a mask was used
to strategically create devices that would be capable of maintaining
applicable behavior even under low supply voltage conditions," Mr.
Eck tells APPLIANCE.
This, he says, is important because many products
are being pushed to
two dry cells (two AAA, AA, C, or D cells) in order to lower product
end user cost. "The near dead cell point, 90-percent used, for a
dry cell is 0.9 V. Two dry cells placed in series and almost completely
will result in a 1.8-V supply," Mr. Eck says. "These amplifiers
will operate from two new cells at 3.2 V down to 1.8 V, without a need
for voltage increasing techniques that add cost."
According to Mr.
Eck, this new family of 1-MHz operational amplifiers is expected to
find its way into most appliance applications where an embedded
control system has been introduced. For now, however, the added benefit
of low-voltage operation makes the devices popular in battery-power
or battery-backed-up systems, he says. Applications include real-time
systems that must continue when the power goes out, security and safety
systems, portable equipment, wireless devices, wearable products, and
remote control products.