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Texas Instruments LPC661IMX/NOPB
- Part No.:
- LPC661IMX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LPC661IMX/NOPB.pdf
- Description:
- IC OPAMP GP 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,463
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Product details
Overview
LPC661IMX/NOPB from Texas Instruments (formerly National Semiconductor) is a single, low-power CMOS operational amplifier designed for single-supply operation with rail-to-rail output swing, 55 µA supply current, 3 mV input offset voltage, and 0.11 V/µs slew rate - ideal for high-impedance sensor buffering and precision current-to-voltage conversion in battery-powered instrumentation.
For engineers reviewing the LPC661IMX/NOPB datasheet, LPC661IMX/NOPB pinout, LPC661IMX/NOPB application, or LPC661IMX/NOPB equivalent, key selection criteria include ultra-low input bias current (2 fA), input common-mode range extending to ground, guaranteed performance at 5 V and 15 V supplies, and stability with capacitive loads when compensated per application note DS011227.
Technical Context
The LPC661IMX/NOPB uses a non-conventional topology without a unity-gain output buffer; instead, the output is taken directly from the integrator stage to achieve rail-to-rail swing. This architecture incorporates dual feed-forward compensation (Cf and Cff) and a push-pull output stage capable of sourcing/sinking ≥13 mA at 5 V.
It delivers asymmetric large-signal voltage gain: ≥400 V/mV (sourcing, RL = 100 kΩ) and ≥180 V/mV (sinking, RL = 100 kΩ), with guaranteed minimum gain down to 5 kΩ loads. Stability with capacitive loads requires external series resistance (50–100 Ω) and feedback capacitance (5–10 pF), as confirmed in Figure 2 and Application Hints.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | +4.75 V to +15.5 V - supports both 5 V and 12 V single-rail systems without level-shifting. |
| Supply Current | 55 µA typical at 5 V - enables multi-year battery life in portable sensing nodes. |
| Input Offset Voltage | 3 mV max - ensures ≤3 mV error in DC-coupled transimpedance amplifiers at room temperature. |
| Input Bias Current | 2 fA typical - preserves signal integrity in picoampere-level photodiode or ion-selective electrode interfaces. |
| Slew Rate | 0.11 V/µs - limits full-power bandwidth to ~16 kHz at 10 V output swing, suitable for sub-audio precision signal conditioning. |
| Rail-to-Rail Output | Swings within 60 mV of rails at 100 kΩ load - maximizes dynamic range in 5 V ADC front-ends. |
| Input Common-Mode Range | Includes ground (−0.1 V min at 5 V supply) - allows direct interfacing to grounded sensors and reference-free signal sources. |
Pinout & Package
Package: 8-pin SOIC (Small Outline Integrated Circuit), body width 3.9 mm, JEDEC MS-012AC, RoHS-compliant / NOPB finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Inverting Input (−) | Differential input node | Accepts feedback network connection; ultra-high impedance (≥1 TΩ) minimizes loading on high-Z sources. |
| Non-Inverting Input (+) | Differential input node | Direct interface point for grounded or low-impedance reference signals; common-mode range includes GND. |
| Output | Amplified signal source | Delivers rail-to-rail swing into ≥5 kΩ loads; requires external RC compensation for >100 pF capacitive loads. |
| V− | Negative supply terminal | Connected to ground in single-supply operation; must not float or be left unconnected. |
| V+ | Positive supply terminal | Accepts 4.75–15.5 V; internal ESD protection rated to 1000 V (HBM). |
| NC | No connect | Internally unused pin; must remain unconnected per datasheet Figure 1 and ordering table. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail output swing | Enables full utilization of 5 V ADC input range without level-shifting circuitry or dual supplies. |
| 2 fA input bias current | Reduces voltage error across 1 GΩ feedback resistors to <2 µV, critical for femtoampere current measurement. |
| Specified performance at 5 kΩ load | Guarantees usable gain and linearity when driving moderate-impedance filters or ADC input networks. |
| Low distortion (0.01% THD) | Maintains signal fidelity in active filter and peak-detect applications up to 1 kHz. |
| Stable with capacitive loads (with Rx/Cf) | Supports direct connection to long PCB traces, coaxial cables, or piezoelectric sensor outputs without oscillation. |
Applications
| High-Impedance Buffer | Precision Current-to-Voltage Converter |
|---|---|
Use Scenario: Interfacing pH electrodes or glass microelectrodes with output impedances >100 MΩ in portable lab equipment. IC Role / Device Role / Timing Role: Voltage follower with guard-ring PCB layout to suppress surface leakage; maintains signal integrity without loading the sensor. Use Value: 2 fA bias current ensures <0.2 mV error across 100 MΩ source impedance, preserving measurement resolution. | Use Scenario: Converting photodiode current (10 pA–1 µA) into measurable voltage for optical smoke detectors. IC Role / Device Role / Timing Role: Transimpedance amplifier with 10 MΩ–1 GΩ feedback resistor; operates from single 5 V supply with rail-to-rail output. Use Value: Ultra-low input bias current prevents DC offset drift, enabling stable baseline over temperature and time. |
| Long-Term Integrator | Active Filter |
Use Scenario: Charge integration in radiation dosimeters or electrochemical coulometric analyzers requiring >1-hour time constants. IC Role / Device Role / Timing Role: Precision integrator using low-leakage capacitor (e.g., polypropylene) and guarded input traces. Use Value: Input bias current ≤2 fA limits integration error to <0.4 mV/hour with 1 µF capacitor, meeting IEC 61557-8 requirements. | Use Scenario: 10 Hz bandpass filtering in seismic sensor front-ends or low-frequency vibration monitors. IC Role / Device Role / Timing Role: Dual-amplifier active filter (e.g., MFB topology) with 0.01% THD and rail-to-rail swing at 10 VPP. Use Value: Low noise (42 nV/√Hz) and high CMRR (≥70 dB) reject power supply ripple and ambient EMI in battery-operated field units. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-power, rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC27L1CDR | Higher input offset (10 mV max), higher supply current (15 µA), no rail-to-rail output (swing limited to V+ −1.5 V). | Less suitable for precision DC-coupled circuits requiring full 5 V output range. | Select only if cost sensitivity outweighs offset and output swing requirements. |
| LPV521MG/NOPB | Lower supply current (320 nA), lower slew rate (0.0035 V/µs), same 2 fA bias current and rail-to-rail output. | Better for nanoampere-static systems (e.g., gas sensors), but unsuitable for >1 kHz signal conditioning. | Prefer for ultra-low-power, low-bandwidth monitoring; avoid where 0.11 V/µs slew is needed. |
Compared with TLC27L1CDR, LPC661IMX/NOPB provides 3× lower offset and true rail-to-rail output, enabling higher-accuracy single-supply designs; compared with LPV521MG/NOPB, it delivers 31× higher slew rate for faster settling in active filters and sample-and-hold circuits - making LPC661IMX/NOPB optimal for precision analog signal chains operating up to 10 kHz.
Availability
LPC661IMX/NOPB is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered sensor nodes, and industrial process monitoring requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for LPC661IMX/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments (TI) is a global semiconductor leader delivering analog and embedded processing solutions, with heritage from National Semiconductor's precision analog portfolio.
The LPC661IMX/NOPB belongs to TI's legacy low-power CMOS op amp family, engineered specifically for single-supply, high-impedance, precision DC and low-frequency AC signal conditioning in resource-constrained environments.
FAQ
What is the maximum capacitive load the LPC661IMX/NOPB can drive without oscillation?
The LPC661IMX/NOPB may oscillate with capacitive loads >100 pF in unity-gain configuration. Stable operation up to 1 nF is achievable using a 50–100 Ω series resistor at the output and a 5–10 pF feedback capacitor from inverting input to output, as validated in DS011227 Figures 2 and 4. Uncompensated loads above 200 pF risk instability.
Does the LPC661IMX/NOPB support true rail-to-rail input common-mode range?
No - the LPC661IMX/NOPB features rail-to-rail *output* swing but only extends its input common-mode range *down to ground* (−0.1 V min at 5 V supply). The upper limit is V+ − 2.3 V, so at 5 V supply, maximum valid input is 2.7 V. This makes it suitable for ground-referenced inputs but not for signals near V+.
Can the LPC661IMX/NOPB operate from a 3.3 V supply?
No - the LPC661IMX/NOPB has a minimum specified supply voltage of 4.75 V per the Operating Ratings table. At 3.3 V, key parameters including output swing, gain, and bias current are not characterized or guaranteed. For 3.3 V systems, consider TI's LPV521 or OPA333 families instead.
What is the thermal resistance θJA for the LPC661IMX/NOPB package?
The LPC661IMX/NOPB uses an 8-pin SOIC package (M08A) with a thermal resistance θJA of 165 °C/W when soldered directly to a standard PCB, as specified in the Absolute Maximum Ratings section. Derating is required above 70 °C ambient to maintain junction temperature ≤125 °C for industrial-grade operation.
Is the LPC661IMX/NOPB pin-compatible with the LPC662 dual op amp?
No - the LPC661IMX/NOPB is a single-channel device in 8-pin SOIC, while the LPC662 is a dual op amp in the same 8-pin SOIC package but with different pin mapping (e.g., shared V+ and V−, separate outputs). Pinouts are incompatible; PCB layout must be redesigned to substitute one for the other.
LPC661IMX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.11V/µs
- Gain Bandwidth Product:
- 350 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 0.002 pA
- Voltage - Input Offset:
- 1 mV
- Current - Supply:
- 58µA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 4.75 V
- Voltage - Supply Span (Max):
- 15.5 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LPC661IMX/NOPB FAQ
1.How can I place an order for LPC661IMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LPC661IMX/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LPC661IMX/NOPB reliable?
The price and inventory of LPC661IMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LPC661IMX/NOPB is usually 5 days.
3.What payment methods are accepted for LPC661IMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LPC661IMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LPC661IMX/NOPB?
LPC661IMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LPC661IMX/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LPC661IMX/NOPB?
For technical support, including LPC661IMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LPC661IMX/NOPB requirements.
6.How does Aetrix verify that LPC661IMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LPC661IMX/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LPC661IMX/NOPB meets industry standards.
7.What is the process for return or replacement of LPC661IMX/NOPB?
All LPC661IMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LPC661IMX/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LPC661IMX/NOPB part is unused and in its original packaging.
Return procedure for LPC661IMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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