CMC7106 Datasheet, PDF (10/11 Pages) California Micro Devices Corp – CMC7106 Low Power Operational Amplifier, RRIO, with Shutdown, SOT23-6

CALIFORNIA MICRO DEVICES
CMC7106
Application Benefits
The CMC7106 is very similar to the CAMD CMC7101AY,
an improved version of the industry standard ‘7101’ op
amp. The CMC7106 has the additional benefit of reducing
power consumption to almost nothing (<5microWatts @
5V) when the amplifier is not being used.
Packaging
Most of the benefits of the CMC7106 are due to the use of
a SOT package. The industry has readily adopted the SOT23-
5 footprint, and this similar version has six pins. This leads
to smaller finished products.
PC CARDS (PCMCIA type III cards) require low profile components.
At 0.056 inches (1.43 mm), the CMC7106 is ideal.
Signal Integrity
As products become smaller, the natural space used to
isolate circuits is lost. Signals can interact or pick up noise
in these designs. By using a physically smaller amplifier
package, the CMC7106 can be placed closer to the signal
source, reducing noise pickup and it’s small size makes it a
simple buffer.
Rail-to-Rail Input and Output allow the amplifier to operate
from lower supplies and also maintain signal level swings
under large signal amplitude conditions.
Simplified Board Layout
Board layout is helped in a couple of ways due to the
small size. Op Amps can be placed where amps are
needed, shortening signal paths and PCB traces subject
to noise pick up. Compared to a dual or quad device,
two or four strategically placed SOT Amps reduce cross-
talk and avoid long traces.
Lower Power Supply Current Drain
The CAMD CMC7106 is similar to the CAMD CMC7101AY,
which has lower power supply drain than other SOT Amps.
The CMC7106 lower supply current means longer operation
in battery operated products, and even further savings in a
‘shutdown’ to idle mode.
Higher Output Drive
The CAMD CMC7106 has higher output current than other
SOT Amps. It can be used as a driver in addition to use as
a signal level amplifier.
Rail-To-Rail Input Swing
When the amplifier is used as a buffer, the input of the
amplifier follows the input signal and if this is large
compared to the available supply voltage, it is important
that the Op Amp has a wide CMVR (Common Mode Voltage
Range). RRIO Op Amps have a CMVR equal to (or greater
than) the supplies and this allows large signal swings
without clipping or distortion.
Shutdown Operation
Compared to a typical SOT Amp, an additional pin,
Shutdown, is used to control the ‘idle’ mode of the
amplifier. It allows the amplifier to be placed in a very low
power consumption mode, effectively reducing the current
to less than 5 µW (at 5V supply).
To use the shutdown pin, a logic level signal is connected
to the shutdown pin, which is configured as a digital input
(Logic “1” turns the amplifier on). This makes the input
directly compatible with common logic family parts. If the
shutdown feature is not desired, the pin should be shorted
to V+ (pin 4).
Turn On and Turn Off (Shutdown) Characteristics
The turn off delay, t_OFF, is defined as the time between the
Shutdown signal crossing and the disable threshold (typically
V+ - 1 volt) and the time for the amplifier’s output to
come within 10% of its final value. It is largely governed
by a propagation delay within the CMC7106 of a few
hundred nanoseconds followed by an exponential decay
determined by the load resistance in parallel with the load
capacitance.
The turn on delay, t_ON, is defined as the time between the
Shutdown signal crossing the threshold and the time the
output reaches to within 10% of its final value. It exhibits
a larger propagation delay through the amplifier which
increases as V+ decreases (see the typical Performance
Characteristics). The delay is followed by output slewing
to the final value.
The delay time for V+ equal to 5 volts is about 4 µS, and
since the slew rate is 1V/µS, a five volt signal requires about
10 µS to reach its final value. With V+ equal to 3 volts,
however, the propagation delay increases to 20 µS yielding
a total turn-on time of 24 µS for a 3 volt signal.
©1999 California Micro Devices Corp. All rights reserved.
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10/99