PATIENT MONITORING AND
DIAGNOSTIC EQUIPMENT SOLUTIONS
SIMPLY SMARTER™
Medical Solutions
Introduction
Purpose
• Introduce Intersil solutions for patient
monitors and medical diagnostic
equipment
Objectives
• Overview of several sub-blocks of the
patient monitor systems and various
medical diagnostic equipment
• Present Intersil feature products with
select application circuits
Content
• 16 pages
Learning time
• 30-40 minutes (estimated)
2
Patient Monitors –High Level System
3
Intersil Products
Products Highlighted
Other Intersil Products
•Op Amps
•Ambient Light Sensor/Proximity
•Data Converters
Detector
•Switches and Multiplexers
•LED Backlighting
•RS-485/422 Interfaces
•Audio Amplifiers
•Voltage references
•Digital Potentiometers (DCPs)
•Real Time Clocks
•PWM Controllers
•Integrated FET Switching Regulators
•Isolated Power
•Battery Chargers
•Voltage monitoring
4
ECG / EKG
ECG signals basics
• Typically 0.05 Hz to 150 Hz bandwidth, 1mV to 10mV pp
• Systems are EMI sensitive
Analog Frontend Requirements
•Low noise at low frequency, high impedance (low leakage)
components are required
– ISL28110 for low noise, high impedance body probe buffers
– ISL28217 for right leg drivers
•Other analog components:
– ISL54500 for lead switching
– ISL21009D for low power VREFs
•Accuracy depends on AC or DC coupling approach from
10-bit to 16-bit.
Power
•Multi output voltage solutions for powering processors or
FPGA
– ISL9440A triple output controller and single LDO controller
generates the rails for a FPGA.
– ISL80101 LDO family can reduce EMI in noise sensitive
areas.
5
Blood Pressure (NiBP)
- Non-Invasive Blood Pressure
Pressure Sensor Basics
• Strain Gauge, ROUT ≈ 5kΩ, 0-300mm Hg
Range, FSOUT= 300mV, BW = 5Hz
Analog Frontend Requirements
• Low noise and gain signal conditioning.
Low noise at low frequency, high DC
accuracy, low power vs. low noise
– ISL28217 or ISL28233 for low noise, high
voltage for gain amplification (10x to 20x)
• Active Filters. Low pass filters for cuff pressure.
Bandpass filters to capture oscillations, ISL28217
or ISL28233, use INTERSIL’S FILTER DESIGNER.
• See Intersil’s Medical Brochure for other analog
components.
http://www.intersil.com/literature/images/LC097.pdf
Power
• For portable monitors, efficiency and size
are the main focus.
– ISL9440A, ISL9104, ISL8033 are some of
the products that can power the FPGA and
also work well to generate the power to the
amplifiers in the system.
6
http://web.transim.com/iSimFilter/Pages/DesignReq.aspx
SpO2 – Pulse Oximetry
(saturation oxygen in blood)
Pulse Oximetry Basics
• Pulse Oximetry is the non-invasive measurement of
the arterial blood’s oxygen saturation.
• Detectors are needed to determine deoxygenated
vs. oxygenated blood.
Analog Frontend Requirements
• Diagnostic SpO2 typically uses JFET-input op amps,
or CMOS op amps are used to construct the
transimpedance amplifier frontends.
– The ISL28110/210 is a precision JFET-input op amp
that can be used for these applications because of its
low noise and high impedance.
Power
• The majority of these oximetry monitors are
portable and run from 1 or 2 cell Li-ion batteries.
These are rechargeable devices.
– The ISL9220A can be used in these applications to
recharge at higher efficiency with up to 2A charge
current.
– The ISL9104 fully integrated 500mA Switching
regulator can be used to generate a very compact
switching solution because of its high switching
frequency.
7
Body Temperature
Temperature Sensor Basics
• Type varies for surgical, patient-care, home care.
Typically either infrared, thermistor, or thermopile/
pyroelectric sensors.
• System consists of a small sensor voltage, then
gain and filter signal conditioning.
Analog Frontend Requirements
• Diagnostic (professional) vs. home use (ear-type)
vary. For diagnostic body temp monitors, use
precision op amps for signal conditioning.
– Intersil provides several options for high DC precision,
low temperature offset drift and lower power :
– For IR sensors: ISL28130 Low Cost, Low Power
– For Thermistor: ISL28217, ISL28207, ISL28218 for
precision
– For Pyroelectric/Thermopile: ISL28110, ISL28133,
ISL28217
Power
• Making the power solution compact with a
reduced BOM is critical.
– The low current switching regulators and multi- output
low current LDO’s are a good fit for power here.
8
ISL3232
ISL4221E
Product Specifics
SIMPLY SMARTER™
ISL28110/210: JFET-Input, Low Noise Op Amps
Feature
Low Input Bias Current:
• 2pA max @ room
• 4.5pA max @ 60°C
• 50pA max @ 85°C
Low Voltage Noise:
• 6nV/√Hz @ 1kHz
• 580 nVpp @ 0.1Hz to 10Hz
Low Current Noise:
• 9fA/√Hz @ 1kHz
Precision
• Low offset voltage: 300µV max
• Low Drift: 1µV/°C
Benefit
• High input impedance sensors
• Photodiode, amperometric,
transimpedance application
• Low noise for better accuracy
and improved SNR
(G=1, f=1kHz, 4Vpp, RL=2kΩ)
10
Low Bias Current of TIA Applications
• Precision signal conditioning
Superior AC (Dynamic) Performance
• BW = 12.5MHz
• Ideal for high performance
• Slew Rate = 23V/µs
instrumentation, DAQ
• THD = 0.00002%
Operating Voltage:
• 9 to 40V or ±4.5V to ±20V
Outstanding Noise Performance
• Wide operating voltage range
High Impedance Buffers
Precision Low Noise JFET Operational Amplifier
.
Competitive Summary
Mfg
ISIL
Comp A
Comp B
Comp C
Comp D
Max
Ibias
(pA)
2
75
50
10
50
Differential
Input
Noise
Capacitance @ 1kHz
(pf)
nV/rt Hz
8.3
6
12.5
8
4
13
8
6
1
8
Noise
.1 to
10Hz
nVp-p
580
2400
2100
1800
**
BW
(MHz)
12.5
8
8
25
5
Min SR
(V/us)
20
20
20
40
14
Max
Vos
(uV)
300
900
600
100
500
Max Is
(mA)
2.9
2.3
2.5
3
4.8
ISL28110/210
Superior Low IBIAS
and
Noise Performance
ISL28210 Input Bias Current (Max)
Ibias (pA)
10000
ISL28110/210 Input Bias Current (Max)
Medical Applications
Pulse Oximetry
ECG/EEG
In Vitro – Biochemical Analyzers
Anesthesia Equipment
Blood Flow Measurement
10x
Better
1000
100
10
1
Competitor A
Competitor B
25C
11
60C
85C
Competitor C
125C
ISL28210
300 fA
Typical
ISL28130/230/430: 1.65V to 6V Micropower Rail-Rail,
Precision Amps
Feature
Benefit
Precision
• Low offset voltage: 40µV max
• Low Offset Drift: 150nV/°C max
• DC Accuracy for 12-bit to
16-bit applications
Operating Voltage:
• Rail-Rail Input and Output
• 1.65V to 6V Single Supply
• ±0.825V to ±2.75V Dual Supply
• Lowest operating voltage vs.
competition, allows
operation at low battery
levels
Low Power
• 25µA max
• Low power consumption for
precision
Low Voltage Noise:
• 1.1 µV p-p @ 0.01 Hz to 10Hz
Lowest Operating Voltages
1.65V
ISL28130
0.825V
ISL28130
- 0.825V
• Ideal for high performance
instrumentation, DAQ
Low Cost Precision (single/dual/quad) • Ideal for medical consumer
applications
12
Ear Thermometer Temperature
ISL9440A: Triple Output PWM Controller With a Single
LDO Controller
Feature
Integration
• Three fully integrated PWM
controllers and one LDO
controller
Benefit
• Single solution to
generate three rails to
power a Processor/FPGA
• Allows user to power on
or off each rail
independent of the other
good
rails.
• Independently programmable • Facilitates ease of
voltage outputs
sequencing
Separate rail control
• Separate enable and power
Synchronous regulation
• Each switching rail is fully
synchronous
Out of Phase switching
• 0°/180°/0° Phase shift
between channels
Protection
• Integrated UV/OV/OC/OT
13
protection
• Gives a more efficient
method of delivering
power to the load
• Allows for reduction of
RMS input current and
voltage ripple so input
capacitance can be
reduced
• Provides protection
against various fault
modes
Medical Applications
ECG / EEG
Imaging systems
Patient monitoring
Dialysis machines
ISL9220: Switching Charger for 1 & 2 Cell Li-Ion Batteries
Feature
Benefit
• More efficient charging of 1 and 2 cell
• Li-ion batteries 90% + efficiency to
optimize the charging time
Switching topology
• Synchronous Buck Topology, with Integrated
Power FETs
Integration
• Integrated FET’s for a fully Synchronous &
compact solution
• Allows for a compact solution
• Fewer external components
Charging current
• Up to 2A charging current
• Allows faster charging or helps to
reduce charge time
Battery Charge Efficiency
95
VBAT =
3.6V
Efficiency (%)
90
85
VBAT =
3.0V
80
VBAT =
4.0V
75
70
14
0
0.2
0.4
0.6
0.8
1
1.2
Charge current (A)
1.4
1.6
1.8
2
2.2
ISL9305: Compact Power Management IC Reduces
Complexity
• Dual High Fsw Buck + Dual Low VIN LDO
• 3MHz fixed switching frequency
• 800 mA from the buck regulators (H version:
1500mA)
• 300mA output current from the LDOs
15
• Available in WLCSP & QFN packages
• I2C interface to set voltage, set on/off
sequence and En/Disable PFM mode
• 15mV Pk-Pk PFM ripple
• Excellent load transient response
ISL9103/4: Low Power Switching Regulator
• 2.5MHz/4.3MHz Synchronous Buck
Regulator with up to 95% efficiency
• 500mA Buck Regulator with high
switching frequency and ultrasonic
mode of operation
• Low Quiescent current of 20µA IQ in
PFM Mode
• 2.7V to 6V Vin range
• 3% Output Accuracy Over-Temperature
and Line for Fixed Output Options
• 100% Maximum Duty Cycle for Lowest
Dropout
• Discharge Output Capacitor when
Disabled
• Tiny 1.6x1.6mm Package
16
INPUT :
2.7V - 6V
ISL9104-2.5
L 1.0 uH
PHASE
VIN
C1
2.2µF
OUTPUT
2.5V/0.4A
C2
2.2µF
FB
EN
GND
Tiny 1µH inductor
Closing
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