SBOU024C august 2004 – july 2023 PGA309
Traditional methods for trimming nonlinear, real-world bridge sensors to a linear, useful function require additional resistors to be added around the base bridge sensor, as shown in Figure 5-10. This approach often requires special prepackaged fixtures and special laser trim or manual trim resistors. The trims are interactive with each other, which requires multiple test/trim/test/trim passes; this only allows for a finite number of trims and range for a particular bridge sensor.
The PGA309 provides a modern digital trim approach for bridge sensors, as shown in Figure 5-11. This technique allows for post-package trim of both the bridge sensor and its signal conditioning electronics. The digital trimming is simplified through the use of a computer interface and spreadsheet analysis computation tools. A near-infinite number of trim cycles can be performed with finer resolution, wider range, and less interaction between trimmed parameters than the traditional trim method. Packaging shifts are eliminated.