Datasheet

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LMV951
SNOSAI3C –OCTOBER 2006–REVISED APRIL 2013 www.ti.com
APPLICATION INFORMATION
CIRCUIT DESCRIPTION AND ADVANTAGE OF THE LMV951
The LMV951 utilizes an internal voltage generator which allows for rail to rail input and output operation from 1 to
3V supplies. An internal switching frequency between 10 MHz and 15 MHz is used for generating the internal
voltages.
The bipolar input stage provides rail to rail input operation with no input bias current phase reversal and a
constant input offset voltage over the entire input common mode range.
The CMOS output stage provides a gain that is virtually independent of resistive loads and an output drive
current in excess of 35 mA at 1V. A further benefit of the output stage is that the LMV951 is stable in positive
unity gain at capacitive loads in excess of 1000 pF.
BATTERY OPERATED SYSTEMS
The maximum operating voltage is 3V and the operating characteristics are ensured down to 1V which makes
the LMV951 an excellent choice for battery operated systems using one or two NiCd or NiMH cells. The LMV951
is also functional at 0.9V making it an appropriate choice for a single cell alkaline battery.
SHUTDOWN CAPABILITY
While in shutdown mode, the LMV951 typically consumes less than 50 nA of supply current making it ideal for
power conscious applications. Full functionality is restored within 3 μs of enable.
SMALL SIZE
The small footprint of the LMV951 package is ideal for high density board systems. By using the small 6-Pin
SOT23 package, the amplifier can be placed closer to the signal source, reducing noise pickup and increasing
signal integrity.
POWER SUPPLY BYPASSING
As in any high performance IC, proper power supply bypassing is necessary for optimizing the performance of
the LMV951. The internal voltage generator needs proper bypassing for optimum operation. A surface mount
ceramic .01 µF capacitor must be located as close as possible to the V
+
and V
−
pins (pins 2 and 6). This
capacitor needs to have low ESR and a self resonant frequency above 15 MHz. A small tantalum or electrolytic
capacitor with a value between 1 µF and 10 µF also needs to be located close to the LMV951.
DRIVING CAPACITIVE LOAD
The unity gain follower is the most sensitive op amp configuration to capacitive loading; the LMV951 can drive up
to 10,000 pF in this configuration without oscillation. If the application requires a phase margin greater than those
shown in the datasheet graphs, a snubber network is recommended. The snubber offers the advantage of
reducing the output signal ringing while maintaining the output swing which ensures a wider dynamic range; this
is especially important at lower supply voltages.
Figure 48. Snubber Network to Improve Phase Margin
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