LMP7701MF/NOPB

Manufacturer Part NumberLMP7701MF/NOPB
DescriptionIC OP AMP PREC 12V RRIO SOT23-5
ManufacturerNational Semiconductor
SeriesLMP®
LMP7701MF/NOPB datasheet
 


Specifications of LMP7701MF/NOPB

Amplifier TypeGeneral PurposeNumber Of Circuits1
Output TypeRail-to-RailSlew Rate1.1 V/µs
Gain Bandwidth Product2.5MHzCurrent - Input Bias0.2pA
Voltage - Input Offset37µVCurrent - Supply790µA
Current - Output / Channel86mAVoltage - Supply, Single/dual (±)2.7 V ~ 12 V, ±1.35 V ~ 6 V
Operating Temperature-40°C ~ 125°CMounting TypeSurface Mount
Package / CaseSOT-23-5, SC-74A, SOT-25Number Of Channels1
Voltage Gain Db130 dBCommon Mode Rejection Ratio (min)88 dB
Input Voltage Range (max)12 VInput Voltage Range (min)2.7 V
Input Offset Voltage0.2 mV at 5 VOutput Current (typ)42 mA
Operating Supply Voltage3 V, 5 V, 9 VSupply Current1 mA at 5 V
Maximum Operating Temperature+ 125 CMounting StyleSMD/SMT
Minimum Operating Temperature- 40 CLead Free Status / RoHS StatusLead free / RoHS Compliant
-3db Bandwidth-Other namesLMP7701MF
LMP7701MFTR
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PRECISION CURRENT SOURCE
The LMP7701/LMP7702/LMP7704 can each be used as a
precision current source in many different applications. Figure
6 shows a typical precision current source. This circuit imple-
ments a precision voltage controlled current source. Amplifier
A1 is a differential amplifier that uses the voltage drop across
R
as the feedback signal. Amplifier A2 is a buffer that elimi-
S
nates the error current from the load side of the R
that would flow in the feedback resistor if it were connected
to the load side of the R
resistor. In general, the circuit is
S
stable as long as the closed loop bandwidth of amplifier A2 is
greater then the closed loop bandwidth of amplifier A1. Note
that if A1 and A2 are the same type of amplifiers, then the
feedback around A1 will reduce its bandwidth compared to
A2.
FIGURE 6. Precision Current Source
The equation for output current can be derived as follows:
Solving for the current I results in the following equation:
LOW INPUT VOLTAGE NOISE
The LMP7701/LMP7702/LMP7704 have the very low input
voltage noise of 9 nV/
. This input voltage noise can be
further reduced by placing N amplifiers in parallel as shown
in Figure 7. The total voltage noise on the output of this circuit
is divided by the square root of the number of amplifiers used
in this parallel combination. This is because each individual
amplifier acts as an independent noise source, and the aver-
age noise of independent sources is the quadrature sum of
the independent sources divided by the number of sources.
For N identical amplifiers, this means:
resistor
S
Figure 7 shows a schematic of this input voltage noise reduc-
tion circuit. Typical resistor values are:
= 10Ω, R
R
= 1 kΩ, and R
G
F
20127305
FIGURE 7. Noise Reduction Circuit
17
= 1 kΩ.
O
20127356
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