LMP7721MA/NOPB - 3fA Input Bias Precision Op Amp | TI
MPN: LMP7721MA/NOPB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.25 | $6.25 |
| 10 | $5.62 | $56.20 |
| 100 | $4.99 | $499.00 |
| 500 | $4.37 | $2,185.00 |
| 1,000 | $3.75 | $3,750.00 |
Drop-in alternatives for LMP7721MA/NOPB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LMP7721MAX/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LMP7721MA
✅ Drop-In📋 Reference alternative (not in catalog)
AD8627ARZ
✅ Drop-In✓ In Stock
$2.82 / Unit
View Datasheet →LMP7721MA/NOPB
✅ Drop-In✓ In Stock
$3.75 / Unit
View Datasheet →LMP7721MA/NOPB Maximum Ratings & Electrical Characteristics
| Amplifier Type | General Purpose |
| Number of Circuits | 1 |
| Input Bias Current | 3 fA (typ), ±20 fA max at 25°C |
| Input Offset Voltage | 26 µV (typ) |
| Gain Bandwidth Product | 17 MHz |
| Slew Rate | 12.8 V/µs |
| Supply Voltage Range | 1.8 V to 5.5 V |
| Output Type | Rail-to-Rail |
| Input Voltage Noise | 7.5 nV/√Hz |
| Supply Current (Quiescent) | 1.3 mA (typ) |
| Shutdown Supply Current | 40 µA |
| Operating Temperature Range | -40°C to +125°C |
| Package / Case | 8-SOIC (0.154", 3.90mm Width) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
LMP7721MA/NOPB Pin Configuration
| Pin 1 | NC — No connect |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | NC — No connect |
| Pin 6 | OUT — Output |
| Pin 7 | V+ — Positive supply |
| Pin 8 | SD — Shutdown (active low) |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
LMP7721MA/NOPB is suitable for 6 applications: Electrochemical Sensors, Photodiode Amplifiers, Medical Instrumentation, High-Impedance Buffer, Battery-Powered Instruments, Sensor Interface Circuits.
Electrochemical Sensors
The LMP7721MA/NOPB is ideal for electrochemical cell amplifiers due to its ultra-low input bias current of 3 fA, which minimizes loading on high-impedance electrodes. Its low noise of 7.5 nV/√Hz ensures accurate measurement of small currents in pH, gas, and ion-selective sensors. The wide supply range and rail-to-rail output allow direct interface with ADCs. In a typical potentiostat circuit, the op amp maintains the cell potential while measuring the resulting current, and the LMP7721's femtoampere bias ensures negligible error. The device's shutdown mode helps conserve power in portable sensor systems.
Recommended
Photodiode Amplifiers
The LMP7721MA/NOPB excels in photodiode amplifier applications where the input bias current directly affects measurement accuracy. With only 3 fA of bias current, it introduces negligible error when amplifying the tiny currents from photodiodes, which are typically in the nanoampere to microampere range. The 17 MHz gain bandwidth product supports high-speed optical communication and LIDAR systems. The low input voltage noise of 7.5 nV/√Hz ensures a high signal-to-noise ratio. The unique pinout with isolated inputs allows for effective guard ring layout, reducing PCB leakage. This makes the LMP7721 ideal for precision light measurement in medical, industrial, and scientific instruments.
Recommended
Medical Instrumentation
In medical devices such as glucose monitors and blood gas analyzers, the LMP7721MA/NOPB provides the ultra-low input bias current required to measure tiny currents from electrochemical sensors. Its low noise and high accuracy ensure reliable patient monitoring. The device operates from a 1.8V to 5.5V supply, making it suitable for battery-powered portable medical devices. The extended temperature range of -40°C to +125°C ensures operation in clinical environments. The shutdown mode reduces power consumption to 40 µA, extending battery life. The LMP7721's small 8-SOIC package allows for compact PCB designs, which is critical for wearable and implantable devices.
Recommended
High-Impedance Buffer
The LMP7721MA/NOPB is an excellent choice for buffering high-impedance sources such as pH electrodes, piezoelectric sensors, and capacitive sensors. Its input bias current of 3 fA and input impedance of 10^13 Ω ensure that the source is not loaded, preserving signal integrity. The rail-to-rail output allows the buffer to drive ADCs or other loads over the full supply range. The 17 MHz bandwidth ensures fast settling for dynamic signals. The device's low offset voltage of 26 µV minimizes DC errors. In applications where the source impedance is in the gigaohm range, the LMP7721's femtoampere bias current is essential to avoid voltage drops across the source resistance.
Recommended
Battery-Powered Instruments
The LMP7721MA/NOPB is designed for low-power, battery-operated instruments. It operates from a supply voltage as low as 1.8V, allowing direct operation from a single lithium-ion cell. The quiescent current is only 1.3 mA, and the shutdown mode reduces this to 40 µA, significantly extending battery life in duty-cycled applications. The wide supply range accommodates battery voltage variations. The device's precision specifications ensure accurate measurements in portable analytical instruments, such as handheld pH meters and gas detectors. The small 8-SOIC package and surface-mount design enable compact, lightweight products.
Recommended
Sensor Interface Circuits
The LMP7721MA/NOPB is a versatile choice for sensor interface circuits, including temperature sensors, strain gauges, and capacitive sensors. Its ultra-low input bias current minimizes errors when interfacing with high-impedance sensors. The low offset voltage and low noise ensure accurate signal conditioning. The rail-to-rail output allows direct connection to ADCs without additional level shifting. The device's wide supply range and low power consumption make it suitable for distributed sensor networks. In a typical bridge amplifier configuration, the LMP7721 provides the precision needed for accurate measurements. The unique pinout facilitates guard ring design to reduce leakage currents.
Recommended
Recommended Products Summary
Engineering reference data for LMP7721MA/NOPB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LMP7721MAX/NOPB | LMP7721MA | ADA4530-1ARMZ | AD8627ARZ |
|---|---|---|---|---|---|
| Package | 8-SOIC | 8-SOIC | 8-SOIC | 8-MSOP | 8-SOIC |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Input Bias Current | 3 fA | 3 fA | 3 fA | 20 fA | 1 pA |
| Gain Bandwidth Product | 17 MHz | 17 MHz | 17 MHz | 4.5 MHz | 5 MHz |
| Supply Voltage Range | 1.8V to 5.5V | 1.8V to 5.5V | 1.8V to 5.5V | 4.5V to 16V | 5V to 26V |
| Input Offset Voltage | 26 µV | 26 µV | 26 µV | 4 µV | 50 µV |
| Slew Rate | 12.8 V/µs | 12.8 V/µs | 12.8 V/µs | 1.4 V/µs | 5 V/µs |
| Shutdown Supply Current | 40 µA | 40 µA | 40 µA | 1 µA | 1 µA |
Key Differentiators
- Lowest input bias current in industry (vs AD8627ARZ)
- Higher bandwidth (vs ADA4530-1ARMZ)
- Wider supply voltage range (vs AD8627ARZ)
Design Notes
To achieve femtoampere-level input bias current, PCB layout is critical. Use guard rings around the input pins (pins 2 and 3) connected to a low-impedance node at the same potential as the inputs. This prevents surface leakage currents from reaching the input pins. Also, minimize the use of solder flux and clean the board thoroughly after assembly, as ionic contamination can create leakage paths.
The LMP7721 operates from 1.8V to 5.5V. For best performance, use a low-noise power supply and bypass each supply pin with a 0.1 µF ceramic capacitor placed close to the device. If the supply is noisy, consider adding a ferrite bead in series. The shutdown pin (pin 8) can be used to reduce supply current to 40 µA, but ensure it is not left floating; tie it to V+ for normal operation.
Do not exceed the absolute maximum supply voltage of 6V. Also, avoid connecting the input pins to voltages outside the supply rails, as this can damage the device. The unique pinout isolates inputs from output and supply pins, but still ensure that traces to the inputs are kept short and shielded from noise sources. For high-impedance sources, use a Teflon or PTFE PCB material to reduce leakage.
Compliance Information
RoHS compliant per TI product page. Not AEC-Q100 qualified. Lead-free per NOPB designation.
