LMP7715, LMP7716, LMP7716Q

SNOSAV0E – MARCH 2006 – REVISED MARCH 2013

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APPLICATION INFORMATION

LMP7715/LMP7716/LMP7716Q

The LMP7715/LMP7716/LMP7716Q are single and dual, low noise, low offset, rail-to-rail output precision

amplifiers with a wide gain bandwidth product of 17 MHz and low supply current. The wide bandwidth makes the

LMP7715/LMP7716/LMP7716Q ideal choices for wide-band amplification in portable applications.

The LMP7715/LMP7716/LMP7716Q are superior for sensor applications. The very low input referred voltage

noise of only 5.8 nV/

√Hz at 1 kHz and very low input referred current noise of only 10 fA/√Hz mean more signal

fidelity and higher signal-to-noise ratio.

The LMP7715/LMP7716/LMP7716Q have a supply voltage range of 1.8V to 5.5V over a wide temperature range

of 0°C to 125°C. This is optimal for low voltage commercial applications. For applications where the ambient

temperature might be less than 0°C, the LMP7715/LMP7716/LMP7716Q are fully operational at supply voltages

of 2.0V to 5.5V over the temperature range of

−40°C to 125°C.

The outputs of the LMP7715/LMP7716/LMP7716Q swing within 25 mV of either rail providing maximum dynamic

range

in

applications

requiring

low

supply

voltage.

The

input

common

mode

range

of

the

LMP7715/LMP7716/LMP7716Q extends to 300 mV below ground. This feature enables users to utilize this

device in single supply applications.

The use of a very innovative feedback topology has enhanced the current drive capability of the

LMP7715/LMP7716/LMP7716Q, resulting in sourcing currents of as much as 47 mA with a supply voltage of only

1.8V.

The LMP7715 is offered in the space saving SOT-23 package and the LMP7716/LMP7716Q is offered in an 8-

pin VSSOP. These small packages are ideal solutions for applications requiring minimum PC board footprint.

CAPACITIVE LOAD

The unity gain follower is the most sensitive configuration to capacitive loading. The combination of a capacitive

load placed directly on the output of an amplifier along with the output impedance of the amplifier creates a

phase lag which in turn reduces the phase margin of the amplifier. If phase margin is significantly reduced, the

response will be either underdamped or the amplifier will oscillate.

The LMP7715/LMP7716/LMP7716Q can directly drive capacitive loads of up to 120 pF without oscillating. To

reduced output swing and reduced output current drive.

Figure 49. Isolating Capacitive Load

INPUT CAPACITANCE

CMOS input stages inherently have low input bias current and higher input referred voltage noise. The

LMP7715/LMP7716/LMP7716Q enhance this performance by having the low input bias current of only 50 fA, as

well as, a very low input referred voltage noise of 5.8 nV/

√Hz. In order to achieve this a larger input stage has

been used. This larger input stage increases the input capacitance of the LMP7715/LMP7716/LMP7716Q.

Figure 50 shows typical input common mode capacitance of the LMP7715/LMP7716/LMP7716Q.

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