EC5741|Super Low Power,CMOS,Rail-To-Rail OP Amp


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Super Low Power, CMOS,

Rail-to-Rail Operational Amplifier

EC5741

 

 

 

General Description

 

The ​​ EC5741 ​​ series ​​ amplifiers ​​ are ​​ single ​​ supply, ​​ low ​​ power ​​ CMOS ​​ dual ​​ operational ​​ amplifier, ​​ these ​​ amplifiers offer ​​ bandwidth ​​ of ​​ 9KHz, ​​ rail-to-rail ​​ inputs ​​ and ​​ outputs, ​​ and ​​ single-supply ​​ operation ​​ from ​​ 1.4V ​​ to ​​ 5.5V. ​​ Low quiescent ​​ supply current ​​ of ​​ 1μA and very low input ​​ bias ​​ current ​​ of ​​ 1pA make the devices ​​ an ideal choice for ​​ low offset, ​​ low ​​ power ​​ consumption ​​ and ​​ high ​​ impedance applications ​​ such ​​ as ​​ smoke ​​ detectors, ​​ photodiode amplifiers, and other sensors.

The EC5741 is available in SOP-8 and ​​ SOT23-5 ​​ packages. The ​​ extended ​​ temperature range ​​ of ​​ -40oC ​​ to ​​ +85oC over all supply voltages offers additional design flexibility.

Features

 

Single-Supply Operation from +1.4V ~ +5.5V

Rail-to-Rail Input / Output

Gain-Bandwidth Product: 9kHz

Low Input Bias Current: 1pA

● ​​ Low Offset Voltage:1mV

​​ Quiescent Current: 400nA

​​ Available in Space-Saving Package:

SOT23-5 and SOP8 Packages

 

 

 

 

Applications

 

 

Portable Equipment

Mobile Communications

Smoke Detector

● Sensor Interface

Medical Instrumentation

Battery-Powered Instruments

Handheld Test Equipment

 

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Pin Assignments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Figure 1. Pin Assignment Diagram (SOT23-5 and SOP8 Package)

 

 

 

 

Super Low Power, CMOS,

Rail-to-Rail Operational Amplifier

EC5741

 

 

Ordering Information

 ​​ ​​​​ EC5741NN XX ​​ X

 

​​ B2SOT23-5L

​​ M1SOP-8L

 

 

​​ 

 

 

 

 

 

 

 

 

 

 

 

Part Number

Package

Marking

Marking Information

EC5741NNB2R

SOT23-5L

741YW

1. Y:Year code(D=2013;E=2014;F=2015…)

2. W:Week Code( The big character of A~Z ​​ is for the week of 1~26, and small a~z is for the week of 27~52.

EC5741NNM1R

SOP-8L

​​ EC5741

LLLLL

YYWWT

1. LLLLL:Last five Number of Lot No

2. YY:Year Code

3. WW:Week Code

4. T:Internal Tracking Code

 

 

Application Information

 

Size

EC5741 series op amps are unity-gain stable and suitable for a wide range of general-purpose applications. The small footprints of the EC5741 series packages save space on printed circuit boards and enable the design of smaller electronic products.

 

Power Supply Bypassing and Board Layout

EC5741 series operates from a single 1.4V to 5.5V supply or dual ±0.7V to ±2.75V supplies. For best performance, a 0.1μF ceramic capacitor should be placed close to the VDD pin in single supply operation. For dual supply operation, both VDD and VSS supplies should be bypassed to ground with separate 0.1μFceramic capacitors.

 

​​ Low Supply Current

​​ The low supply current (1.4μA) of EC5741 series will help to maximize battery life. They are ideal for battery powered Systems

 

 

 

 

 

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Operating Voltage

​​ EC5741 series operate under wide input supply voltage (1.4V to 5.5V). In addition, all temperature specifications apply from ​​ -40℃ to +125℃. Most behavior remains unchanged throughout the full operating voltage range. These guarantees ensure ​​ operation throughout the single Li-Ion battery lifetime.

 

Rail-to-Rail Input

The input common-mode range of EC5741 series extends 100mV beyond the supply rails (VSS-0.1V to VDD+0.1V). This is achieved by using complementary input stage. For normal operation, inputs should be limited to this range.

 

Rail-to-Rail Output

Rail-to-Rail output swing provides maximum possible dynamic range at the output. This is particularly important when operating in low supply voltages. The output voltage of EC5741 series can typically swing to less than 10mV from supply rail in light resistive loads (>100kΩ), and 60mV of supply rail in moderate resistive loads (10kΩ).

 

Capacitive Load Tolerance

The EC5741 series can directly drive 250pF capacitive load in unity-gain without oscillation. Increasing the gain enhances the amplifier’s ability to drive greater capacitive loads. In unity-gain configurations, the capacitive load drive can be improved by inserting an isolation resistor RISO in series with the capacitive load, as shown in Figure 2.

 

 

 

 

 

 

 

 

 

Figure 2. Indirectly Driving a Capacitive Load Using Isolation Resistor

 

The bigger the RISO resistor value, the more stable VOUT will be. However, if there is a resistive load RL in parallel with the capacitive load, a voltage divider (proportional to RISO/RL) is formed, this will result in a gain error.

 

The circuit in Figure 3 is an improvement to the one in Figure 2. RF provides the DC accuracy by feed-forward the VIN to RL. CF and RISO serve to counteract the loss of phase margin by feeding the high frequency component of the output signal back to the amplifier’s inverting input, thereby preserving the phase margin in the overall feedback loop. Capacitive drive can be increased by increasing the value of CF. This in turn will slow down the pulse response.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3. Indirectly Driving a Capacitive Load with DC Accuracy

 

Differential amplifier

The differential amplifier allows the subtraction of two input voltages or cancellation of a signal common the two inputs. It is useful as a computational amplifier in making a differential to single-end conversion or in rejecting a common mode signal. Figure 4. shown the differential amplifier using EC5741.

 

 

 

 

 

 

 

 

 

 

 ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​ ​​​​ Figure 4. Differential Amplifier

 

 

 

 

 

​​ If the resistor ratios are equal (i.e. R1=R3 and R2=R4), then

 

 

 

 

Instrumentation Amplifier

The input impedance of the previous differential amplifier is set by the resistors R1, R2, R3, and R4. To maintain the high input impedance, one can use a voltage follower in front of each input as shown in the following two instrumentation amplifiers.

 

 

 

 

 

 

 

 

Three-Op-Amp Instrumentation Amplifier

The three EC5741 can be used to build a three-op-amp instrumentation amplifier as shown in Figure 5.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 5. Three-Op-Amp Instrumentation Amplifier

 

The amplifier in Figure 5 is a high input impedance differential amplifier with gain of R2/R1. The two differential voltage followers assure the high input impedance of the amplifier.

 

 

 

 

​​ Two-Op-Amp Instrumentation Amplifier

​​ EC5741 can also be used to make a high input impedance two-op-amp instrumentation amplifier as shown in ​​ 

​​ Figure 6.

 

 

 

 

 

 

 

 

 

 

 

 

Figure 6. Two-Op-Amp Instrumentation Amplifier

 

 

 

​​ Where R1=R3 and R2=R4. If all resistors are equal, then Vo=2(VIP-VIN)

 

 

​​ Single-Supply Inverting Amplifier

​​ The inverting amplifier is shown in Figure 7. The capacitor C1 is used to block the DC signal going into the AC

​​ signal ​​ source VIN. The value of R1 and C1 set the cut-off frequency to ƒC=1/(2πR1C1). The DC gain is defined

​​ by VOUT=-(R2/R1)VIN

 

 

 

 

 

 

 

 

 

 

 

 

Figure 7. Single Supply Inverting Amplifier

 

 

​​ Low Pass Active Filter

The low pass active filter is shown in Figure 8. The DC gain is defined by –R2/R1. The filter has

a -20dB/decade roll-off after its corner frequency ƒC=1/(2πR3C1).

 

 

 

 

 

 

 

 

 

 

 

 

Figure 8. Low Pass Active Filter

 

 

Sallen-Key 2nd Order Active Low-Pass Filter

EC5741 can be used to form a 2nd order Sallen-Key active low-pass filter as shown in Figure 9. The transfer function from VIN to VOUT is given by

 

 

 

 

 

Where the DC gain is defined by ALP=1+R3/R4, and the corner frequency is given by

 

 

 

 

 

The pole quality factor is given by

 

 

 

Let R1=R2=R and C1=C2=C, the corner frequency and the pole quality factor can be simplified as below

 

 

 

And Q=2-R3/R4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 9. Sanllen-Key 2nd Order Active Low-Pass Filter

 

 

Sallen-Key 2nd Order high-Pass Active Filter

The 2 nd order Sallen-key high-pass filter can be built by simply interchanging those frequency selective components R1, R2, C1,and C2 as shown in Figure 10.

 

 

 

 

 

 

 

 

 

 

 

 

Figure 10. Sanllen-Key 2nd Order Active High-Pass Filter

 

 

 

 

 

 

 

 

 

 

 

 

 

Electrical Characteristics

 

Absolute Maximum Ratings

 

Condition

Min

Max

Power Supply Voltage (VDD to VSS)

-0.5V

+7V

Analog Input Voltage (IN+ or IN-)

Vss-0.5V

VDD+0.5V

PDB Input Voltage

Vss-0.5V

+7V

Operating Temperature Range

-40°C

+85°C

Junction Temperature

+150°C

Storage Temperature Range

-65°C

+150°C

Lead Temperature (soldering, 10sec)

+300°C

Package Thermal Resistance (TA=+25°C)

MSOP-8, θJA

210°C

SOP8, θJA

130°C

 

Note: Stress greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions outside those indicated in the operational sections of this specification are not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Electrical Characteristics

(VDD = +5V, VSS = 0V, VCM = VDD/2, VOUT = VDD/2, RL=100K tied to VDD/2, SHDNB = VDD, TA = -40°C to

+85°C, unless otherwise noted. Typical values are at TA =+25°C.) (Notes 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNIS

Supply-Voltage Range

VDD

Guaranteed by the PSRR test

1.4

 

5.5

V

Quiescent Supply Current

(per Amplifier)

IQ

VDD = 5V

 

1.0

2.0

μA

Shutdown Mode (PDB = VSS)

 

 ​​ ​​ ​​ ​​ ​​ ​​​​ 0.1

 

uA

Input Offset Voltage

Vos

 

 

1

±5

mV

Input Offset Voltage

Tempco

ΔVos/ΔT

 

 

0.5

 

uV/ ℃

Input Bias Current

IB

(Note 2)

 

1

 

pA

Input Offset Current

Ios

(Note 2)

 

1

 

pA

Input Common-Mode

Voltage Range

VCM

 

-0.1

 

 

 

VDD+0.1

 

V

Common-Mode    Rejection

Ratio

CMRR

VDD=5.5 Vss-0.1V ≦VCM ≦VDD+0.1V

60

 

70

 

 

dB

Vss≤VCM≤5V

65

80

 

Power-Supply Rejection

Ratio

PSRR

VDD = +1.8V to +5.5V

65

80

 

dB

Open-Loop Voltage Gain

AV

VDD=5V, RL=50k,

0.1V≤VO≤4.9V

 

90

 

dB

VDD=1.4V, RL=50k,

0.1V≤VO≤4.9V

 

80

 

dB

Output Voltage Swing

VOUT

|VIN+-VIN-| ≧10mV     VDD-VOH

 

6

 

mV

RL = 100kΩ to VDD/2   VOL-Vss

 

 

6

 

|VIN+-VIN| ≧10mV    VDD-VOH

 

40

 

RL = 50k to VDD/2         VOL-Vss

 

40

 

Output Short-Circuit

Current

ISC

Sinking or Sourcing

 

±3

 

mA

Gain Bandwidth Product

GBW

Av = +1V/V

 

9

 

KHz

Slew Rate

SR

Av = +1V/V

 

4.5

 

V/ms

Settling Time

ts

To 0.1%, VOUT = 2V step

Av = +1V/V

 

650

 

us

Input Voltage Noise

Density

en

VDD=5V, f = 1kHz

VDD=1.4V = 1kHz

 

 

150

150

 

 

nV/VHz

Note 1:  ​​​​ All devices are 100% production tested at TA = 25℃; all specifications over the automotive

temperature range is guaranteed by design, not production tested.

Note 2:  ​​​​ Parameter is guaranteed by design.

 

 

Typical characteristics

TA =+25℃,VDD = +5V, Vss = 0V, VCM = VDD/2 , VOUT = VDD/2, RL=100K tied to VDD/2, CL=60pF,unless otherwise noted.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Package Information

 

SOT23-5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SOP8