LHE7904, LHE7906, LHE7908, and LHE7909 (LHE790X) are multi-channel synchronous sampling 24 bit Δ - ∑ analog-to-digital converters (ADCs) series, with built-in programmable gain amplifiers (PGA), internal references, and oscillators. LHE790X includes all the functions typically required for medical electrocardiography (ECG) and electroencephalography (EEG) applications. With high integration and excellent performance, LHE790X is capable of developing scalable medical instrument systems with significantly reduced size, significantly reduced power consumption, and overall cost. Each channel of LHE790X has a flexible input multiplexer (MUX) that can independently connect to internally generated signals for testing, temperature, and lead disconnection detection. In addition, any configuration of the input channel can be selected to generate the Right Leg Drive (RLD) output signal. The LHE790X has a working data rate of up to 64kSPS and integrates hardware pacing detection algorithms. Lead disconnection detection can be achieved inside the device through pull-up/pull-down resistors or excitation current sources. Three integrated amplifiers are used to generate the Wilson Center Terminal (WCT) and Goldberg Center Terminal (GCT) required for standard 12 lead ECG. Multiple LHE790X devices can be connected in series using a daisy chain configuration in high channel count systems. The packaging options include miniature 8mm × 8mm, 64 solder ball BGA, and LQFP-64 packaging. The commercial grade rated temperature range of LHE790X BGA version is 0 ° C to 70 ° C. The industrial grade rated temperature range is -40 ° C to+85 ° C. The following are its product features and application scenarios:



1. Product features



8 low-noise programmable gain amplifiers (PGA) and 8 high-resolution analog-to-digital converters (ADC) (LHE7908)



Low power consumption: 0.73mW per channel



Ultra low power consumption mode: 0.4mW per channel



Input induced noise: 2.3 μ VPP (150Hz bandwidth (BW), G=6)



Input bias current: 500pA



Data rate: 250SPS to 64kSPS



Common mode rejection ratio (CMRR): -120dB



Programmable gain: 1, 2, 3, 4, 6, 8, 12 or 24



Support systems that meet AAMI EC11, EC13, IEC60601-1, IEC60601-2-27, and IEC60601-2-51 standards



Unipolar or Bipolar Power Supply:



AVDD=2.7V to 5.25V



- DVDD=1.65V to 5.25V



Built in right leg driver amplifier, lead disconnection detection, Wilson center terminal, pacing detection, test signal



Enhance the function of DC lead detachment and impedance detection of AC lead detachment



Integrated hardware pacing detection algorithm



Built in oscillator and reference/crystal oscillator driver interface



SPI compatible serial port



2. Application scenarios



Medical instruments (electrocardiogram (ECG), electromyography (EMG), and electroencephalography (EEG)):



Patient monitoring; Dynamic electrocardiogram, events, stress, and vital signs,



Including ECG AED、 Telemedicine, Bispectral Index (BIS), Induced Audio Potential (EAP), Sleep Monitor.



3. Encapsulation and compatibility



BGA64 and LQFP64 are packaged for easy PCB layout.



Compatible with ADS1294 as a substitute for TI ADS1296、ADS1298、ADS1299， Suitable for domestic substitution needs.