Texas Instruments | ±12-V Input, Next-Generation, Reinforced Isolated Amplifier for Voltage Sensing | Application notes | Texas Instruments ±12-V Input, Next-Generation, Reinforced Isolated Amplifier for Voltage Sensing Application notes

Texas Instruments ±12-V Input, Next-Generation, Reinforced Isolated Amplifier for Voltage Sensing Application notes
±12-V Input, Next-Generation, Reinforced Isolated
Amplifier for Voltage Sensing
Introduction
Table 1. Isolation Ratings
In high-voltage industrial applications in order to
determine power and energy, both high-side voltage
and current have to be measured. The voltage can be
measured using a resistor divider circuit followed by an
isolated amplifier. Texas Instruments offers a wide
variety of basic and reinforced isolated amplifiers
optimized for voltage and current sensing.
The ISO224, next generation ISO12x, is a highprecision reinforced isolated amplifier designed for
isolated voltage sensing of ±10-V signals which are
widely used in high-voltage industrial applications. The
device features a very high input resistance, ideal for
voltage sensing applications, and offers improved
isolation ratings, higher performance, and simplified
system-level design and diagnostics.
Typical applications include but not limited to:
• Analog Input Modules
• AC Analog Input Modules
• Compact Relays
• Rail Transport
• Inverter and Motor Control
Figure 1 shows ISO224 implementation in power line
monitoring.
Parameter
ISO124
ISO224
Isolation Working Voltage (max) (VRMS)
per DIN VDE V 0884-11
not specified
1500
Isolation Transient Overvoltage (max)
(VPEAK)
2100
7071
Surge Isolation Voltage (max) (VPEAK)
4000
12800
CMTI (typ) (kV/µs)
not specified
80
Higher Performance with the ISO224
The ISO224 is offered in 2 grades of performance and
enables more stable and accurate measurements over
extended industrial temperature range that allow
engineers to design high-precision systems and
overcome current performance limitations.
The ISO224 features:
• More accurate measurements with lower offset and
gain error
• Lower impact of signal source impedance on
overall gain error with higher input resistance of 1
MΩ (min)
• Higher temperature stability with lower offset and
gain error drift over a wider temperature range
• Faster system response for broader use range with
wider output bandwidth
Table 2. Electrical Parameters
Figure 1. AC Voltage Sensing with the ISO224
Parameter
ISO124
ISO224A
ISO224B
Input Resistance (typ) (MΩ)
0.2
1.25
1.25
Input Offset (max) (mV)
±50
±50
±5
Input Offset Drift (max) (µV/°C)
±200 (typ)
±60
±15
±0.3
Gain Error (max) (%)
±0.5
±1
Gain Error Drift (max) (ppm/°C)
±10 (typ)
±60
±35
Output BW (typ) (kHz)
50
185
275
Temperature Range (°C)
-25 to 85
-55 to 125
-55 to 125
ISO224 Improved Isolation Ratings
With TI’s Capacitive Isolation Technology that enables
higher working voltages and the longest insulation
barrier lifetimes, engineers can now design more
robust and reliable systems. The ISO224 is fullycertified per DIN VDE V 0884-11 and UL1577, can
withstand an isolation working voltage breakdown of
1500 VRMS, and provides reinforced galvanic isolation
of 7071 kVpeak. The device also features high CMTI
of 80 kV/µs (typ) to maintain safe operation and
ensure data integrity in the presence of high common
mode transients.
SBAA311 – September 2018
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ISO224 System-Level Improvement
The ISO224 operates of a single supply on the highside, features an integrated voltage detection, an
reduces the board space.
The ISO224 offers:
•
•
Simplified design of isolated power supply and
reduced system size and cost due to unipolar highside supply VDD1
Simplified system-level diagnostics with the ISO224
±12-V Input, Next-Generation, Reinforced Isolated Amplifier for Voltage
Sensing
Copyright © 2018, Texas Instruments Incorporated
1
www.ti.com
•
•
fail-safe mode, integrated voltage detection feature,
that activates when the high-side supply VDD1 is
missing
Reduced board space due to fully-differential
output structure that supports direct connectivity to
an ADCs with 5 V input
Reduced board space as a result of 60%+ smaller
package
Table 3. Operating Conditions and Package
Information
Parameter
ISO124
ISO224
Power Supply
Bipolar
Unipolar
VDD1 (V)
±15
4.5-18 (LDO)
VDD2 (V)
±15
4.5-5.5
Input Voltage Range (V)
±10 / (FSR: ±12.5)
±12 (FSR: ±12.3)
Fail Safe Mode
No
Yes
Output
Single-ended
Differential
±10
±4
Output Voltage Range (V)
Package
2
17.9 mm × 7.5 mm
(PDIP-16)
20.01 mm × 6.61 mm
(SOIC-28)
5.85 mm x 7.50 mm
(SOIC-8)
Conclusion
With isolated amplifiers being a key components in
high-voltage industrial applications, it is critical to
choose the devices that not only meet the
performance requirements, but also provide the
highest reliability and support the longest lifetime in
harsh environments. The ISO224 offers designers all
of the benefits of reinforced isolation with higher
working voltages and longer lifetimes, supports more
stable and accurate measurements over extended
temperature range, and reduces the board space for
compact designs.
References
• ISO224 Fail-Safe Output Feature Application
Report
• ±12-V Voltage Sensing Circuit With an Isolated
Amplifier and Differential Input SAR ADC
Application Report
• Isolated Amplifiers Overview
• TI Precision Labs - Isolation
±12-V Input, Next-Generation, Reinforced Isolated Amplifier for Voltage
Sensing
Copyright © 2018, Texas Instruments Incorporated
SBAA311 – September 2018
Submit Documentation Feedback
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