RTKA-BDGSTKEV2Z 2. Design Considerations
R12UZ0045EU0200 Rev.2.00 Page 6 of 14
Jul.9.19
2. Design Considerations
2.1 ISL28134
The ISL28134 is an ideal choice for the input amplifier for a strain gauge design. The ISL28134 uses
auto-correction circuitry to provide ultra low offset voltage (2.5μV) and low offset temperature drift (15nV/°C). The
very low 1/f noise corner (<0.1Hz) and low input noise voltage (8nV/√Hz at 100Hz) of the amplifier makes the
ISL28134 ideal for low frequency precision applications requiring very high gain and low noise. Other key features
of the ISL28134 are the wide gain bandwidth and rail-to-rail input/output swing.
2.2 ISL26102 24-Bit ADC
The ISL26102 is a complete analog front-end with dual differential multiplexed inputs for high resolution
measurements. The ISL26102 features a third order modulator providing up to 21.4-bit noise-free performance
(10Sps). The 24-bit delta-sigma analog-to-digital converter includes a very low-noise amplifier with programmable
gain. Although this application demonstration uses an input buffer amplifier (ISL28134), the high input impedance
of the ISL26102 allows direct connection of sensors such as load cell bridges to ensure the specified
measurement accuracy without a buffer amplifier.
To initiate a correct power-up reset, diode D1, resistor R3 and capacitor C8 implement a simple RC delay to
ensure the PDWN transitions from low to high after both power supplies have settled to specified levels.
2.3 ISL21010 (3.3V) Voltage Reference
The ISL21010CFH333 is a precision 3.3V, low dropout micropower band-gap voltage reference, which provides a
±0.2% accurate reference. The ISL21010 provides up to 25mA output current sourcing with low 150mV dropout
voltage. The low supply current and low dropout voltage combined with high accuracy make the ISL21010 ideal
for precision low powered applications.
2.4 ISL21010 (4.096V) Voltage Reference
The ISL21010CFH341 is a precision 4.096V, low dropout micropower band-gap voltage reference, which
provides a ±0.2% accurate reference. The ISL21010 provides up to 25mA output current sourcing with low
150mV dropout voltage. The low supply current and low dropout voltage combined with high accuracy make the
ISL21010 ideal for precision low powered applications.
2.5 ISL22316 DCP
The ISL22316 is a low noise, low power I2C™ bus, 128 tap DCP. The DCP can be used as a three-terminal
potentiometer or as a two-terminal variable resistor in a wide variety of applications including control, parameter
adjustments, and signal processing.
2.6 ISL43840 Low-Voltage, Dual 4-to-1 Multiplexer
The ISL43840 is a precision, bidirectional, analog switch configured as a dual 4-channel
multiplexer/demultiplexer. In this design, the mux is configured as a differential mux. The mux is designed to
operate from a single +2V to +12V supply or from a ±2V to ±6V supply. The ISL43840 has low charge injection
with 1pC (maximum) at VS = ±5V.
