Introduction

As the core component of signal chains, operational amplifiers (OPA) directly determine the measurement upper limit of systems. In automotive electronics and medical equipment applications, there is an urgent demand for precision OPAs with ultra-low offset voltage and low noise characteristics. This paper analyzes the technical features and application value of the CBM8628/CBM8629/CBM8630 series of OPAs.

Status and development trend of operational amplifier technology

In high-end fields such as industrial control, automotive electronics, and medical instrumentation, precision operational amplifiers serve as core signal processing components, with their performance directly determining system measurement accuracy and stability. As market demand for miniaturized, low-power, and highly reliable equipment surges, the limitations of traditional operational amplifiers in key metrics like input offset voltage, temperature drift, and noise control have become increasingly apparent—— For instance, conventional devices typically exhibit offset voltages exceeding 10μV and temperature drift over 0.1μV/℃, making them inadequate for high-precision applications such as thermocouple signal amplification and biomedical detection.

1、Product overview

CBM8628/CBM8629/CBM8630 are high-precision self-calibrating operational amplifiers from Corebai, featuring cutting-edge chopper stabilization technology that delivers ultra-low offset voltage and drift characteristics. These devices specialize in "precision signal amplification with broad application compatibility", catering to demanding fields like automotive, medical, and industrial sectors requiring exceptional signal accuracy. Positioned as a strategic "domestic substitution for imported alternatives", this series matches international precision operational amplifiers in performance while offering cost-effectiveness and flexible packaging options. It stands as an optimal high-performance solution for mid-to-high-end precision amplification applications.

2、Core technical characteristics and performance advantages

The core competitiveness of this series comes from the coordinated optimization of "precision, noise and reliability" in three dimensions. The key technical parameters and advantages are as follows:

Amplifier characteristics specification sheet

1、Precision core: low offset performance driven by chopper stabilization technology

The circuit employs a chopping stabilization (self-stabilized zero) design that dynamically eliminates input offset voltage and temperature drift through periodic switching of the input signal and compensation capacitor. With typical input offset voltage as low as 1μV (maximum 5μV) and offset drift as low as 0.002μV/℃ (maximum 0.02μV/℃), it significantly outperforms conventional operational amplifiers (typically with offsets ≥10μV and drifts ≥0.1μV/℃). This capability enables direct amplification of "micro-volt-level weak signals" from thermocouples, pressure sensors, and similar devices. Maintaining measurement stability across a wide temperature range from-40℃ to 125℃, it is particularly suitable for extreme environments such as automotive engine compartments and industrial high-temperature equipment.

2、Low noise and high anti-interference capability

The noise performance directly determines the amplification quality of weak signals: This series features low-frequency noise as low as 0.5μVp-p at 0.1Hz-10Hz and voltage noise density of 22nV/√Hz at 1kHz, effectively preventing interference in scenarios requiring physiological signal amplification (e.g., electrocardiogram) and optical power detection. Additionally, with a 130dB common-mode rejection ratio (CMRR) and 115dB power supply rejection ratio (PSRR), it effectively resists electromagnetic interference (EMI) and power fluctuations in industrial environments, thereby enhancing signal acquisition reliability.

3、Flexible power supply and output design

Supports 2.7V-5V single or ±1.35V-±2.5Vdual power supply configurations, compatible with battery-powered portable devices (e.g., handheld medical monitors) and industrial fixed equipment. Both input and output support "rail-to-rail" functionality, delivering an output voltage range close to the power rail (with high-level outputs ≥4.95V at 5V supply). This maximizes dynamic range and minimizes signal clipping distortion.

4、Low power consumption and high reliability

The static current of each amplifier is only 0.85mA (maximum 1.1mA), and the multi-channel model (CBM8629/8630) has more obvious power consumption advantage after integration; 5kV HBM electrostatic protection (ESD) and 300℃ pin soldering temperature tolerance improve the reliability in assembly and use.

3、Model differentiation and package selection

4、 application scenarios

Automotive electronics

In automotive sensor systems, signals from pressure sensors (e.g., fuel pressure, brake pressure) and temperature sensors are often weak and susceptible to interference from engine compartment heat and power supply fluctuations. This product series features a wide operating temperature range (-40℃ to +125℃), low offset voltage drift, and high common-mode rejection ratio, enabling precise signal amplification to ensure reliable data acquisition by the ECU (Electronic Control Unit). The single-channel CBM8628's compact package design meets the miniaturization requirements of automotive electronics.

Medical instrumentation

Medical devices require exceptionally stringent signal precision—— for instance, equipment such as electrocardiographs and blood glucose analyzers must capture micro-volt-level bioelectrical signals or trace chemical signals. This series features low noise (0.5μVp-p) and minimal input bias current (maximum 100pA), effectively preventing signal distortion while ensuring measurement accuracy. The dual-channel CBM8629 processor handles two signals simultaneously, enhancing system integration efficiency and meeting the high-reliability, precision-driven design standards of medical equipment.

Industry and sensing

In industrial pressure detection and thermocouple temperature measurement, millivolt-level signals from pressure sensors and microvolt-level temperature differential signals from thermocouples require high-precision amplification. The CBM8630's four-channel design supports simultaneous adaptation to multiple sensor channels, reducing system complexity. Its rail-to-rail input/output characteristics fully utilize the power supply's dynamic range, enhancing signal acquisition accuracy. Additionally, in optoelectronic diode amplifiers and precision current detection scenarios, the product's low input offset and high gain characteristics effectively convert photoelectric current signals and detect minute current variations, meeting the precise control requirements of industrial automation.