ZHCSL30B June 2009 – March 2020 PGA280
PRODUCTION DATA.
The PGA280 is a universal high-voltage instrumentation amplifier with digital gain control. This device offers excellent dc precision and long-term stability using modern chopper technology with internal filters that minimize chopper-related noise. The input gain extends from ⅛ V/V (attenuation) to 128 V/V in binary steps. The output stage offers a gain multiplying factor of 1 V/V and 1⅜ V/V for optimal gain adjustment. The output stage connects to the low-voltage (5 V or 3 V) supply. .
A signal multiplexer provides two differential inputs. Several signal switches allow signal diagnosis of wire break, input disconnect, single-ended (versus differential), and shorted inputs.
The supply voltage of up to ±18 V offers a wide common-mode range with high input impedance; therefore, large common-mode noise signals and offsets can be suppressed.
A pair of high-speed current buffers can be activated to avoid inrush currents during fast signal transients, such as those generated from switching the signal multiplexers. This feature minimizes discharge errors in passive signal input filters in front of the multiplexer.
The fully differential signal output matches the inputs of modern high-resolution and high-accuracy analog-to-digital converters (ADCs), including delta-sigma (ΔΣ) as well as successive-approximation response (SAR) converters. The supply voltage for the output stage is normally connected together with the converter supply, thus preventing signal overloads from the high-voltage analog supply.
Internal error detection in the input and output stage provides individual information about the signal condition. Integrating ADCs may hide momentary overloads. Together with the input switch matrix, extensive signal and error diagnosis is made possible.
The serial peripheral interface (SPI) provides write and read access to internal registers. These registers control gain, the current buffer, input switches, and the general-purpose input/output (GPIO) or special function pins, as well as configuration and diagnostics.
The GPIO port controls the multiplexer (MUX) and switches and indicates internal conditions. The GPIO port can also be individually configured for output or input. A special CS mode for the GPIO extends the communication to other external SPI devices, such as data converters or shift registers. This special function is intended for SPI communication via a minimum number of isolation couplers. Additional proof for communication integrity is provided by an optional checksum byte following each communication block.