COS620BRZ Instrumentation Amp: ECG/EEG and Industrial Sensor Front Ends
ECG/EEG front ends, pressure transmitters, and bridge sensors all face the same challenge: millivolt-level differential signals plus strong common-mode interference. A single-ended op amp rarely delivers high CMRR, low offset, and wide supply range at once. That is where an instrumentation amplifier belongs.
COSINE COS620BRZ is a precision instrumentation amplifier in SOP-8. The datasheet lists about 50µV max offset (COS620BRZ grade), 0.2µV/°C typical drift, 1.5MHz GBW, and roughly ±2.25V to ±18V supplies (also usable in many single-supply 4.5V–36V designs). Gain is set by one external resistor from 1 to 10,000. If you are evaluating TI INA129 or ADI AD620, COS620BRZ is a solid second-source / alternative candidate.
ECG/EEG and industrial sensors: why an in-amp?
1. Medical / vital-sign monitoring: EEG, ECG, infusion pumps, NIBP—signals are tiny and easily corrupted by mains and environment. COS620 amplifies the electrode differential pair, uses high CMRR to reject interference, and keeps bias current/noise low for signal integrity.
2. Precision sensing and DAQ: pressure transmitters, high-accuracy scales, strain gauges—boost millivolt bridge outputs into the ADC range while rejecting field common-mode noise.
3. Test & measurement front ends: DMMs, scope front ends, precision current measurement that still need low drift across a wide supply.
4. Automotive and industrial control: cluster, motor position feedback, automation boards with larger supply swing.
Selection checklist
| Item | COS620 datasheet highlights | Why it matters |
|---|---|---|
| Gain | G = 1 + 49.4kΩ/RG, about 1–10000 | One resistor matches sensor full scale |
| Offset / drift | COS620BRZ: 50µV max; 0.2µV/°C typ. drift | DC error and temperature stability |
| Input bias | IB max about 2nA | Better for higher-impedance electrodes/sensors |
| CMRR | About 125dB (datasheet conditions) | Key for ECG and industrial common-mode rejection |
| Supply / Iq | ±2.25V–±18V; Iq about 1.0mA | Covers common industrial dual supplies |
| Package | COS620BRZ SOP-8 (MSOP8/DIP8 also available) | Simplifies cross-check vs mainstream in-amps |
For selection reference only. Confirm with the latest datasheet, order grade, and board validation before production.
Alternative note: COS620BRZ vs INA129 / AD620
Mapped alternatives in the JARWEY catalog:
- INA129UA / INA129U (Texas Instruments)
- AD620ARZ / AD620ARZ-REEL7 (Analog Devices)
All three are resistor-programmable precision instrumentation amplifiers used in medical front ends, bridge sensing, and DAQ. Evaluate in this order: package/pinout and RG/REF connections; gain equation; offset/drift/bias vs error budget; CMRR and noise at target gain; supply coverage (±5/±12/±15V); then lead time/cost with a pilot lot.
“Alternative” is not a no-test swap—especially for medical and metrology designs.
Quick fit check
Differential weak signal? Prefer an in-amp for ECG/bridges.
Strong common mode (mains / ground shift)? You need high CMRR.
Wide industrial supplies? COS620’s range helps.
For 1.8V–5.5V battery systems that need micro-power zero-drift, use COS8552SR instead.
Datasheet and product page
View COS620BRZ instrumentation amplifier details and datasheet
For samples, cross-reference, or volume supply across Southeast Asia, request via the product page or contact JARWEY support.
Summary
An instrumentation amplifier is the standard choice for ECG/EEG and industrial sensor front ends. COSINE COS620BRZ offers low offset/drift, high CMRR, and wide supplies for medical, bridge sensing, test, and industrial control—and can be evaluated against INA129 / AD620 as a second-source path. Align package, gain equation, error budget, and CMRR before design-in.
Related Articles