Japanese electronics company Rohm has developed a compact 1.8 to 5V, rail-to-rail CMOS op amp for amplifying signals from sensors such as temperature, pressure and flow rate in small IoT devices and smartphones.

The size of IoT devices continues to decrease, requiring smaller components. To amplify small signals accurately as needed in high precision sensing, op amps must improve low input offset voltage and noise performance while continuing to shrink the form factor.

The TLR377GYZ op amp balances miniaturisation with high accuracy, which has been difficult to achieve with conventional op amps, by evolving proprietary circuit design, process and packaging technologies cultivated over many years.

Input offset voltage and noise generation degrade amplification accuracy and can be suppressed by increasing the size of the built-in transistors, but at the expense of miniaturisation. In response, Rohm developed proprietary circuits that achieve a maximum offset voltage as low as 1mV without increasing the size of the transistors. In addition, proprietary process technology reduces flicker noise, while low noise is achieved with an input equivalent noise voltage density of 12nV/√Hz by optimising the resistive components at the element level.

Furthermore, the product (www.rohm.com/products/amplifiers-and-linear/operational-amplifiers/high-performance/input-output-rail-to-rail-low-offset-voltage/tlr377gyz-product) adopts a WLCSP (wafer level chip scale package) with a ball pitch of 0.3mm using original packaging technology. This reduces size by approximately 69% compared with conventional products and 46% over existing compact products.

A shut down function required by mobile devices is built in, reducing power consumption during standby mode.

The IC-mounted conversion board that can replace SSOP6 packages is also offered to support replacement considerations and initial evaluation. Both the product and conversion board are available for purchase through online distributors. In addition, a Spice model – called Rohm Real Model – is available on the firm’s web site (www.rohm.com) for verification simulations.

Real Models are high accuracy Spice models that use original model-based technology to reproduce the electrical and temperature characteristics of the actual IC, resulting in a perfect match between the IC and simulation values. This ensures reliable verification, contributing to more efficient application development, for example by preventing rework after prototyping.

Rohm has more than 23,300 employees. It has manufacturing plants in Japan, Germany, Korea, Malaysia, Thailand, Philippines and China.