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LNDAQ2
Complete Signal Acquisition,
Extraction & Fusion Analysis SoC
GENERAL DESCRIPTION
The LNDAQ2 is a complete signal interface, acquisition, extraction
and interrogation IC using the latest low power sub-threshold
instrumentation amplifiers, automatic gain control systems, high
order switched capacitor filters, and low OSR data converters.
The primary feature of the LNDAQ2 is that it represents the
lowest power solution on the market today integrating terminator,
AGC, INA, high order high and low pass filters, and precision data
converters. In fact the LNDAQ2 draws one quarter (1/4) of the
current of its nearest competitor dramatically extending battery life.
It does this by utilizing the latest technologies in subthreshold and
low power design, making obsolete many of the conventional
solutions used in competitive devices.
The LNDAQ2 includes a >90dB CMRR terminator, and a
precision INA with offsets in the uVs. The INA includes an SPI
controlled AGC capability which can gain up signals <50uV. The
LNDAQ2 can be configured in DC or AC configuration. In AC
configuration it includes a time constant accelerator to quickly
recapture the baseline if there is a saturation event.
Following the INA are a pair of switch capacitor filters. These
filters allow coefficients to be programmed through the SPI interface
th
and can implement a variety of filters including Bessel filters up to 8
order for the high pass filter (which can achieve 0.05Hz corner
th
frequencies) to 6 order low pass.
Following the filters are an analog buffer (which can be turned
off) as well as three ADCs. The first ADC is an 18 bit
ΔΣ
converter,
the second a 14 bit pipeline converter, and the final ADC is a 6 bit
flash converter. These three converters combined represent the
ΔΣ,
however, the pipeline and flash may be used independently to save
power or increase the bandwidth of sampling.
The
ΔΣ,
is a low OSR type using a cascade architecture and 5 bit
quantizer to minimize power consumption. OSR may be increased
to improve resolution or reduced to minimize power consumption.
The flash converter is a modern delay line design optimizing
silicon area & power consumption. The filters and dataconverters
work from 1.8V while the input stage allows
signals up to 3.6V to
FEATURES
Complete
signal
acquisition,
extraction,
interrogation and analysis system
Includes:
Common mode terminator (>90 dB)
LNDINA333A/B/C
LNDFILT8
LNDADC18
Interfaces (including probes) for all of:
Galvanic skin response
Skin impedance
Heart waveform extraction
Temperature sensing
Optional right led drive (two or three electrode
interface for heart rate extraction)
Operates from as little as 2.7V to 3.6V, 1.8V Vout
AC or DC mode instrumentation amplifier (INA)
th
6 & 8 order (LP/HP) programmable filters
<35uA average current
Signal Acquisition:
Automatic or Programmed Gain Control (AGC)
allows acquisition from multiple sites
Time Constant Accelerator for Quick Baseline
Recapture
Capable of Measuring signals <50uV even in a
noisy environment with noise in the same spectrum
Penetrates real world noise such as muscle noise,
lighting, electrode connect & disconnect, 60Hz
AGC allows multiple inputs from anywhere on the
body for physiological fusion applications
Three analog to digital converters (ADCs)
6 bit delay line flash ADC (<1uA typ)
Up to 14 bit pipeline ADC (<4uA typ)
Up to 18 bit low OSR ΔΣ ADC (<10uA typ – ΔΣ
includes the 6 bit and 14 bit ADCs)
Each ADC may be put to sleep to save power
Power optimization subsystem
SPI Interface (with independent enable)
be measured.
EXAMPLE APPLICATION
APPLICATIONS
Figure 1
– Example application requiring nanoPOWER technology.
Linear Dimensions Semiconductor Inc.
22620 Ricardo Rd, Cupertino CA 95014 USA
tel 312.321.1810
fax 312.321.1830
Portable heart rate equipment
Wellness patch products
Paper battery powered products (<40mAH)
Portable fitness & wellness products
Physiological fusion analysis consumer devices
Non-critical diagnostics
Low bandwidth portable electronics
Vibration sensors
LINEAR_DIMENSIONS [ LINEAR DIMENSIONS SEMICONDUCTOR ]
