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ISO122
SBOS160A – NOVEMBER 1993 – REVISED JANUARY 2015
ISO122 Precision Lowest-Cost Isolation Amplifier
1 Features
3 Description
•
•
•
•
•
•
•
•
The ISO122 is a precision isolation amplifier
incorporating a novel duty cycle modulationdemodulation technique. The signal is transmitted
digitally across a 2-pF differential capacitive barrier.
With digital modulation the barrier characteristics do
not affect signal integrity, thus resulting in excellent
reliability and good high-frequency transient immunity
across the barrier. Both barrier capacitors are
imbedded in the plastic body of the package.
1
100% Tested for High-Voltage Breakdown
Rated 1500 Vrms
High IMR: 140 dB at 60 Hz
Bipolar Operation: VO = ±10 V
16-Pin Plastic DIP and 28-Lead SOIC
Ease of Use: Fixed Unity Gain Configuration
0.020% Maximum Nonlinearity
±4.5-V to ±18-V Supply Range
2 Applications
•
•
•
•
•
•
Industrial Process Control:
– Transducer Isolator, Isolator for
Thermocouples, RTDs, Pressure Bridges, and
Flow Meters, 4-mA to 20-mA Loop Isolation
Ground Loop Elimination
Motor and SCR Control
Power Monitoring
PC-Based Data Acquisition
Test Equipment
The ISO122 is easy to use. No external components
are required for operation. The key specifications are
0.020% maximum nonlinearity, 50-kHz signal
bandwidth, and 200-V/°C VOS drift. A power supply
range of 4.5 V to 18 V and quiescent currents of 5
mA on VS1 and ±5.5 mA on VS2 make the ISO122
ideal for a wide range of applications.
The ISO122 is available in 16-pin plastic DIP and
28-lead plastic surface-mount packages.
Device Information(1)
PART NUMBER
ISO122
PACKAGE
BODY SIZE (NOM)
PDIP (16)
17.90 mm × 7.50 mm
SOIC (28)
20.01 mm × 6.61 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
4 Simplified Schematic
VIN
VOUT
–VS2
Gnd
+VS2
–VS1
Gnd
+VS1
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
ISO122
SBOS160A – NOVEMBER 1993 – REVISED JANUARY 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Simplified Schematic.............................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
1
2
3
4
7.1
7.2
7.3
7.4
7.5
7.6
4
4
4
4
5
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Typical Characteristics ..............................................
Detailed Description .............................................. 8
8.1 Overview ................................................................... 8
8.2 Functional Block Diagram ......................................... 8
8.3 Feature Description................................................... 8
8.4 Device Functional Modes.......................................... 9
9
Application and Implementation .......................... 9
9.1 Application Information.............................................. 9
9.2 Typical Application ................................................. 10
10 Power Supply Recommendations ..................... 17
10.1 Signal and Supply Connections ............................ 17
11 Layout................................................................... 18
11.1 Layout Guidelines ................................................. 18
11.2 Layout Example .................................................... 18
12 Device and Documentation Support ................. 19
12.1 Trademarks ........................................................... 19
12.2 Electrostatic Discharge Caution ............................ 19
12.3 Glossary ................................................................ 19
13 Mechanical, Packaging, and Orderable
Information ........................................................... 19
5 Revision History
Changes from Original (November1993) to Revision A
•
2
Page
Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional
Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device
and Documentation Support section, and Mechanical, Packaging, and Orderable Information section ............................... 1
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6 Pin Configuration and Functions
16 Pins PDIP
NVF Package
Top View
28 Pins SOIC
DVA Package
Top View
+VS1
1
16
Gnd 1
+VS1
1
28
Gnd 1
–VS1
2
15
VIN
–VS1
2
27
VIN
VOUT
7
10
–VS2
VOUT
13
16
–VS2
Gnd 2
8
9
+VS2
Gnd 2
14
15
+VS2
Pin Functions
PIN
NAME
I/O
DESCRIPTION
PDIP
SOIC
GND
8
14
-
Low-side ground reference
GND
16
28
-
High-side ground reference
VIN
15
27
I
High-side analog input
VOUT
7
13
O
Low-side analog output
+VS1
1
1
-
High-side positive analog supply
-VS1
2
2
-
High-side negative analog supply
+VS2
9
15
-
Low-side positive analog supply
-VS2
10
16
-
Low-side negative analog supply
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7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
MIN
Supply voltage
MAX
UNIT
±18
V
VIN
100
V
Continuous isolation voltage
1500
Vrms
Junction temperature
150
°C
Output short to common
Continuous
Storage temperature, Tstg
(1)
–40
125
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
7.2 ESD Ratings
VALUE
V(ESD)
(1)
(2)
Electrostatic discharge
Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1)
±1000
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±500
UNIT
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
TA
NOM
MAX
–25
85
+VS1
15
-VS1
–15
+VS2
15
-VS2
–15
VIN
±10
UNIT
°C
7.4 Thermal Information
ISO122
THERMAL METRIC
(1)
NVF (PDIP)
DVA (SOIC)
16 PINS
28 PINS
RθJA
Junction-to-ambient thermal resistance
51.0
79.8
RθJC(top)
Junction-to-case (top) thermal resistance
32.4
32.9
RθJB
Junction-to-board thermal resistance
29.5
42.2
ψJT
Junction-to-top characterization parameter
10.4
6.6
ψJB
Junction-to-board characterization parameter
29.0
40.9
(1)
4
UNIT
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
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7.5 Electrical Characteristics
At TA = +25°C , VS1 = VS2 = ±15 V, and RL = 2 kΩ, unless otherwise noted.
PARAMETER
TEST
CONDITIONS
ISO122P/U
MIN
TYP
ISO122JP/JU
MAX
MIN
TYP
MAX
UNIT
ISOLATION
Voltage rated continuous ac 60Hz
100% Test (1)
1s, 5pc PD
Isolation Mode Rejection
60Hz
1500
1500
Vac
2400
2400
Vac
Barrier Impedance
Leakage Current at 60Hz
VISO = 240Vrms
140
140
1014 || 2
1014 || 2
0.18
dB
Ω || pF
0.5
0.18
0.5
µArms
±0.50
±0.05
±0.50
%FSR
±0.016 ±0.020
±0.025
±0.050
±20
±50
GAIN
Nominal Gain
1
VO = ±10V
Gain Error
±0.05
Gain vs Temperature
1
±10
Nonlinearity (2)
V/V
±10
ppm/°C
%FSR
INPUT OFFSET VOLTAGE
Initial Offset
±20
vs Temperature
vs Supply
±50
±200
±200
±2
±2
Noise
mV
µV/°C
mV/V
4
µV/√Hz
INPUT
Voltage Range
±10
Resistance
±12.5
±10
200
±12.5
V
200
kΩ
OUTPUT
Voltage Range
Current Drive
±10
±12.5
±10
±12.5
±5
±15
±5
±15
mA
0.1
0.1
µF
20
20
mVp-p
50
50
kHz
Capacitive Load Drive
Ripple Voltage
(3)
V
FREQUENCY RESPONSE
Small-Signal Bandwidth
Slew Rate
Settling Time 0.10%
Settling Time 0.01%
VO = ±10V
Overload Recovery Time
2
2
V/µs
50
50
µs
350
350
µs
150
150
µs
POWER SUPPLIES
Rated Voltage
Voltage Range
VS1
VS2
±15
±4.5
Quiescent Current
±15
±18
±4.5
V
±18
±5
±7
±5
±7
±5.5
±7
±5.5
±7
V
mA
TEMPERATURE RANGE
θJA
θJC
(1)
(2)
(3)
Specification
–25
85
–25
85
°C
Operating
–25
85
–25
85
°C
Storage
–40
125
–40
125
°C
Thermal Resistance
100
100
°C/W
65
65
°C/W
Tested at 1.6 X rated, fail on 5pC partial discharge.
Nonlinearity is the peak deviation of the output voltage from the best-fit straight line. It is expressed as the ratio of deviation to FSR.
Ripple frequency is at carrier frequency (500kHz).
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7.6 Typical Characteristics
At TA = +25°C, and VS = ±15 V, unless otherwise noted.
+10
Output Voltage (V)
Output Voltage (V)
+10
0
–10
0
500
0
–10
0
1000
50
Time (µs)
f = 2kHz
f = 20kHz
Figure 1. Sine Response
Figure 2. Sine Response
+10
Output Voltage (V)
+10
Output Voltage (V)
100
Time (µs)
0
–10
0
500
0
–10
50
0
1000
100
Time (µs)
Time (µs)
Figure 3. Step Response
Figure 4. Step Response
160
Max DC Rating
140
1k
120
IMR (dB)
Peak Isolation Voltage
2.1k
Degraded
Performance
100
100
80
Typical
Performance
60
0
40
100
1k
10k
100k
1M
10M
100M
1
Frequency (Hz)
100
1k
10k
100k
1M
Frequency (Hz)
Figure 5. Isolation Voltage vs Frequency
6
10
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Figure 6. IMR vs Frequency
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Typical Characteristics (continued)
At TA = +25°C, and VS = ±15 V, unless otherwise noted.
60
54
100mA
Leakage Current (rms)
PSRR (dB)
10mA
40
+VS1 , +VS2
–VS1 , –VS2
20
1mA
1500Vrms
100mA
10mA
240Vrms
1mA
0.1mA
0
1
10
100
1k
10k
100k
1
1M
10
100
10k
100k
1M
Figure 8. Isolation Leakage Current vs Frequency
VOUT/VIN
100kHz
Freq
Out
0
250
–10
200
–20
150
–30
100
–40
50
0
500kHz
1MHz
Frequency Out
Figure 7. PSRR vs Frequency
V OUT / VIN dBm
1k
Frequency (Hz)
Frequency (Hz)
1.5MHz
Input Frequency
NOTE: Shaded area shows aliasing frequencies that cannot be removed by a
low-pass filter at the output.
Figure 9. Signal Response to Inputs Greater than 250 kHz
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8 Detailed Description
8.1 Overview
The ISO122 isolation amplifier uses an input and an output section galvanically isolated by matched 1-pF
isolating capacitors built into the plastic package. The input is duty-cycle modulated and transmitted digitally
across the barrier. The output section receives the modulated signal, converts it back to an analog voltage and
removes the ripple component inherent in the demodulation. Input and output sections are fabricated, then laser
trimmed for exceptional circuitry matching common to the input and output sections. The sections are then
mounted on opposite ends of the package with the isolating capacitors mounted between the two sections. The
ISO122 contains 250 transistors.
8.1.1 Modulator
An input amplifier (A1, Functional Block Diagram) integrates the difference between the input current (VIN/200
kΩ) and a switched ±100-mA current source. This current source is implemented by a switchable 200-mA source
and a fixed 100-µA current sink. To understand the basic operation of the modulator, assume that VIN = 0 V. The
integrator will ramp in one direction until the comparator threshold is exceeded. The comparator and sense amp
will force the current source to switch; the resultant signal is a triangular waveform with a 50% duty cycle. The
internal oscillator forces the current source to switch at 500 kHz. The resultant capacitor drive is a
complementary duty-cycle modulation square wave.
8.1.2 Demodulator
The sense amplifier detects the signal transitions across the capacitive barrier and drives a switched current
source into integrator A2. The output stage balances the duty-cycle modulated current against the feedback
current through the 200 kW feedback resistor, resulting in an average value at the VOUT pin equal to VIN. The
sample and hold amplifiers in the output feedback loop serve to remove undesired ripple voltages inherent in the
demodulation process.
8.2 Functional Block Diagram
Isolation Barrier
200µA
200µA
Sense
150pF
200kW
VIN
1pF
1pF
1pF
1pF
Sense
150pF
100µA
200kW
100µA
VOUT
–
–
||
+
A1
A2
S/H
G=1
Osc
+VS1 Gnd 1 –VS1
+VS2
+
S/H
G=6
Gnd 2 –VS2
8.3 Feature Description
8.3.1 Isolation Amplifier
The ISO122 is a precision analog isolation amplifier. The input signal is transmitted digitally across a high-voltage
differential capacitive barrier. With digital modulation the barrier characteristics do affect signal integrity, resulting
in excellent reliability and high-frequency transient immunity.
8
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8.4 Device Functional Modes
The ISO122 does not have any additional functional modes.
9 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
9.1.1 Carrier Frequency Considerations
The ISO122 amplifier transmits the signal across the isolation barrier by a 500kHz duty cycle modulation
technique. For input signals having frequencies below 250 kHz, this system works like any linear amplifier. But
for frequencies above 250 kHz, the behavior is similar to that of a sampling amplifier. The signal response to
inputs greater than 250 kHz performance curve shows this behavior graphically; at input frequencies above
250 kHz the device generates an output signal component of reduced magnitude at a frequency below 250 kHz.
This is the aliasing effect of sampling at frequencies less than two times the signal frequency (the Nyquist
frequency). At the carrier frequency and its harmonics, both the frequency and amplitude of the aliasing go to
zero.
9.1.2 Isolation Mode Voltage Induced Errors
IMV can induce errors at the output as indicated by the plots of IMV vs Frequency. It should be noted that if the
IMV frequency exceeds 250 kHz, the output also will display spurious outputs (aliasing), in a manner similar to
that for VIN > 250 kHz and the amplifier response will be identical to that shown in the Signal Response to Inputs
Greater Than 250-kHz performance curve. This occurs because IMV-induced errors behave like input-referred
error signals. To predict the total error, divide the isolation voltage by the IMR shown in the IMR vs Frequency
curve and compute the amplifier response to this input-referred error signal from the data given in the Signal
Response to Inputs Greater than 250-kHz performance curve. For example, if a 800-kHz 1000-Vrms IMR is
present, then a total of [(–60 dB) + (–30 dB)] x (1000 V) = 32-mV error signal at 200 kHz plus a 1 V, 800-kHz
error signal will be present at the output.
9.1.3 High IMV dV/dt Errors
As the IMV frequency increases and the dV/dt exceeds 1000 Vµs, the sense amp may start to false trigger, and
the output will display spurious errors. The common-mode current being sent across the barrier by the high slew
rate is the cause of the false triggering of the sense amplifier. Lowering the power-supply voltages below ±15 V
may decrease the dV/dt to 500 V/µs for typical performance.
9.1.4 High Voltage Testing
Texas Instruments has adopted a partial discharge test criterion that conforms to the German VDE0884
Optocoupler Standards. This method requires the measurement of minute current pulses (< 5 pC) while applying
2400-Vrms, 60-Hz high-voltage stress across every ISO122 isolation barrier. No partial discharge may be
initiated to pass this test. This criterion confirms transient overvoltage (1.6 × 1500 Vrms) protection without
damage to the ISO122. Lifetest results verify the absence of failure under continuous rated voltage and
maximum temperature.
This new test method represents the “state of the art” for nondestructive high–voltage reliability testing. It is
based on the effects of nonuniform fields that exist in heterogeneous dielectric material during barrier
degradation. In the case of void nonuniformities, electric field stress begins to ionize the void region before
bridging the entire high-voltage barrier. The transient conduction of charge during and after the ionization can be
detected externally as a burst of 0.01–0.1 ms current pulses that repeat on each AC voltage cycle. The minimum
AC barrier voltage that initiates partial discharge is defined as the “inception voltage.” Decreasing the barrier
voltage to a lower level is required before partial discharge ceases and is defined as the “extinction voltage.” The
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Application Information (continued)
package insulation processes have been characterized and developed to yield an inception voltage in excess of
2400 Vrms so that transient overvoltages below this level will not damage the ISO122. The extinction voltage is
above 1500 Vrms so that even overvoltage induced partial discharge will cease once the barrier voltage is
reduced to the 1500 Vrms (rated) level. Older high-voltage test methods relied on applying a large enough
overvoltage (above rating) to break down marginal parts, but not so high as to damage good ones. Our new
partial discharge testing gives us more confidence in barrier reliability than breakdown/no breakdown criteria.
9.2 Typical Application
9.2.1 Output Filter
C2
1000pF
+VS1
+VS2
1
VIN
15
In
9
7
ISO
122
8
16
Gnd
R1
R2
4.75kW
9.76kW
A1
OPA602
10
C1
220pF
–VS2
Gnd2
2
VOUT = VIN
Gnd1
–VS1
Figure 10. ISO122 With Output Filter for Improved Ripple
9.2.1.1 Design Requirements
The ISO122 isolation amplifiers (ISO amps) have a small (10 to 20 mVp-p typical) residual demodulator ripple at
the output. A simple filter can be added to eliminate the output ripple without decreasing the 50-kHz signal
bandwidth of the ISO amp.
9.2.1.2 Detailed Design Procedure
The ISO122 is designed to have a 50-kHz single-pole (Butterworth) signal response. By cascading the ISO amp
with a simple 50-kHz, Q = 1, two-pole, low-pass filter, the overall signal response becomes three-pole
Butterworth. The result is a maximally flat 50-kHz magnitude response and the output ripple reduced below the
noise level. Figure 10 shows the complete circuit. The two-pole filter is a unity-gain Sallen-Key type consisting of
A1, R1, R2, C1, and C2. The values shown give Q = 1 and f–3-dB bandwidth = 50 kHz. Because the op amp is
connected as a unity-gain follower, gain and gain accuracy of the ISO amp are unaffected. Using a precision op
amp such as the OPA602 also preserves the DC accuracy of the ISO amp.
10
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Typical Application (continued)
9.2.1.3 Application Curves
+3
0
Gain (dB)
–3
1
–9
2
–15
–21
–27
2k
5k
10k
20k
50k
Frequency (Hz)
100k
200k
1) Standard ISO122 has 50kHz single-pole (Butterworth) response.
2) ISO122 with cascaded 50kHz, Q = 1, two-pole, low-pass
filter has three-pole Butterworth response.
Figure 11. Gain vs. Frequency
Figure 12. Standard ISO122 (Approximately 20-mVp-p
Output Ripple)
Figure 13. Filtered ISO122 (No Visible Output Ripple)
Figure 14. Step Response of Standard ISO122
Figure 15. Step Response of ISO122 With Added Twopole
Output Filter
Figure 16. Large-signal, 10 kHz Sine-wave Response of
ISO122 With and Without Output Filter
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Typical Application (continued)
9.2.2 Battery Monitor
Figure 17 provides a means to monitor the cell voltage on a 600-V battery stack by using the battery as a power
source for the isolated voltage.
This Section Repeated 49 Times.
ISO122P
10kW
1
e1 = 12V
+V
9
10kW
15
V = e1
2
7
8
10
e2 = 12V
2
–V
Multiplexer
16
Control
Section
Charge/Discharge
Control
ISO122P
e49=12V
1
15
+V
9
7
e50=12V
2
25kW
+V
–V
7
4
25kW
5
8
10kW
10
2
10kW
25kW
–V
+
3
25kW
16
–
INA105
6
V = e50
2
1
(Derives Input Power from the Battery.)
Figure 17. Battery Monitor for a 600-V Battery Power System
12
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Typical Application (continued)
9.2.3 Programmable Gain Amplifier
In applications where variable gain configurations are required, a programmable gain amplifier like the PGA102
can be used with the ISO122. Figure 18 uses an ISO150 to provide gain pin selection options to the PGA102.
A0
A1
ISO150
+15V –15V
+15V –15V
1
2
1
VIN
6
2
7 PGA
8 102
45
3
9
10
15 15
7
VOUT
8
ISO122P
16
Figure 18. Programmable-Gain Isolation Channel With Gains of 1, 10, and 100
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Typical Application (continued)
9.2.4 Thermocouple Amplifier
For isolated temperature measurements, Figure 19 provides an application solution using the INA101 feeding the
input stage of the ISO122. The table provides suggested resistor values based on the type of thermistor used in
the application.
+15V
2
10.0V
6
REF
102
Thermocouple
4
R4
+15V –15V
R1
27kW
Isothermal
Block with
1N4148 (1)
1MW
+15V –15V
+15V
1
12
RG
R2
2
2
4 +In
5
INA101
10
11 –In
1
R5
50W
R6
10
15
14
7
VOUT
8
13
16
3
R3
100W
ISO122P
9
–15V
100
Zero Adj
ISA
TYPE
E
Ground Loop Through Conduit
J
NOTE: (1) –2.1mV/°C at 2.00µA.
K
T
MATERIAL
SEEBACK
COEFFICIENT
(µV/°C)
R2
(R3 = 100W)
R4
(R5 + R6 = 100W)
58.5
3.48kW
56.2kW
50.2
4.12kW
64.9kW
39.4
5.23kW
80.6kW
38.0
5.49kW
84.5kW
Chromel
Constantan
Iron
Constantan
Chromel
Alumel
Copper
Constantan
Figure 19. Thermocouple Amplifier With Ground Loop Elimination,
Cold Junction Compensation, and Up-scale Burn-out.
14
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Typical Application (continued)
9.2.5 Isolated 4- to 20-mA Instrument Loop
For isolated temperature measurements in a 4- to 20-mA loop, Figure 20 provides a solution using the XTR101
and RCV420. A high-performance PT100 resistance temperature detector (RTD) provides the user with an
isolated 0- to 5-V representation of the isolated temperature measurement.
1mA
1mA
10
8
5
RS
XTR101
4-20mA
0.01µF
11
3
+VS =15V
on PWS740
6
4
R1 = 100W
7
3
16
1
14
2 RCV420
5, 13
10
4
RTD
(PT100)
ISO122P
15
+V
15
9
7
8
11
R2 = 2.5kW
10
12
VOUT
0V-5V
2
16
–V
2mA
Gnd
–VS = –15V
on PWS740
Figure 20. Isolated 4- to 200-mA Instrument Loop. (RTD shown.)
9.2.6 Single-Supply Operation of the ISO122P Isolation Amplifier
The circuit shown in Figure 21 uses a 5.1-V Zener diode to generate the negative supply for an ISO122 from a
single supply on the high-voltage side of the isolation amplifier. The input measuring range will be dependent on
the applied voltage as noted in the accompanying table.
VS1 (+15V)
VS
(V)
INPUT RANGE
(V)(1)
20+
15
12
–2 to +10
–2 to +5
–2 to +2
7
INA105
Difference Amp
2
5
R1
10kW
6
Signal Source
VIN
+
RS
R4
R3
3
+VS2 (+15V)
R2
15 In
RC
GND
16
4
9
ISO
ISO
122P
122
122P
(1)
1
1
Reference
IN4689
5.1V
NOTE: (1) Select to match RS .
7
8
VOUT = VIN
10
2
–VS1
Com 2
–VS2 (–15V)
NOTE: Since the amplifier is unity gain, the input
range is also the output range. The output can go to
–2V since the output section of the ISO amp operates
from dual supplies.
For additional information see SBOA004.
Figure 21. Single-Supply Operation of the ISO122P Isolation Amplifier
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Typical Application (continued)
9.2.7 Input-Side Powered ISO Amp
The user side of the ISO122 can be powered from the high-voltage side using an isolated DC-DC converter as
shown in Figure 22.
1
2
4
5
6
HPR117
–15V, 20mA
VIN
Input
GND
+15V, 20mA
15
10
9
GND VIN
16
V–
V+
INPUT
SECTION
V+
V–
1
2
Auxiliary
Isolated
Power
Output
OUTPUT
SECTION
ISO122P
V
O
7
GND
8
+15V
Output
GND
–15V
VO
Figure 22. Input-Side Powered ISO Amp
9.2.8 Powered ISO Amp With Three-Port Isolation
Figure 23 shows an application solution that provides isolated power to both the user and high-voltage sides of
the ISO122 amplifier.
+15V
GND
1
2
5
4
5
6
HPR117
HPR117
6
4
2
1
VIN
–15V, 20mA
Input
GND
+15V, 20mA
15
10
9
GND VIN
16
V–
V+
INPUT
SECTION
Auxiliary
Isolated
Power
Output
V+
V–
1
2
ISO122P
Auxiliary
Isolated
Power
Output
OUTPUT
SECTION
V
O
7
GND
8
+15V, 20mA
Output
GND
–15V, 20mA
VO
Figure 23. Powered ISO Amp With Three-Port Isolation
16
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10 Power Supply Recommendations
10.1 Signal and Supply Connections
Each power-supply pin should be bypassed with 1-µF tantalum capacitors located as close to the amplifier as
possible. The internal frequency of the modulator/demodulator is set at 500 kHz by an internal oscillator.
Therefore, if it is desired to minimize any feedthrough noise (beat frequencies) from a DC-DC converter, use a π
filter on the supplies (see Figure 24). The ISO122 output has a 500-kHz ripple of 20 mV, which can be removed
with a simple 2-pole low-pass filter with a 100-kHz cutoff using a low-cost op amp (see Figure 10).
The input to the modulator is a current (set by the 200-kΩ integrator input resistor) that makes it possible to have
an input voltage greater than the input supplies, as long as the output supply is at least ±15 V. It is therefore
possible, when using an unregulated DC-DC converter, to minimize PSR related output errors with ±5-V voltage
regulators on the isolated side and still get the full ±10V input and output swing.
Isolation Barrier
VIN
VOUT
–VS2
Gnd
Gnd
+VS2
+VS1
–
VS1
–VS1
1µF
1µF
–VS2
1µF
1µF
Figure 24. Basic Signal and Power Connections
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11 Layout
11.1 Layout Guidelines
To maintain the isolation barrier of the device, the distance between the high-side ground (pin 16 or 28) and the
low-side ground (pin 8 or 14) should be kept at maximum; that is, the entire area underneath the device should
be kept free of any conducting materials.
11.2 Layout Example
Top View
1 µF
SMD
0603
1 µF
1
+VS1
GND
VIN
-VS1
SMD
0603
ISOLATION
BOUNDARY
ISOLATION
BOUNDARY
ISO122
1 µF
VOUT
-VS2
GND
+VS2
SMD
0603
LEGEND
TOP layer:
copper pour & traces
1 µF
GND
SMD
0603
via to ground plane
Figure 25. Typical Layout
18
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SBOS160A – NOVEMBER 1993 – REVISED JANUARY 2015
12 Device and Documentation Support
12.1 Trademarks
All trademarks are the property of their respective owners.
12.2 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
12.3 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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19
PACKAGE OPTION ADDENDUM
www.ti.com
20-Aug-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
ISO122JP
ACTIVE
PDIP
NVF
8
25
RoHS &
Non-Green
NIPDAU
N / A for Pkg Type
-25 to 85
ISO122JP
ISO122JPE4
ACTIVE
PDIP
NVF
8
25
RoHS &
Non-Green
NIPDAU
N / A for Pkg Type
-25 to 85
ISO122JP
ISO122JU
ACTIVE
SOIC
DVA
8
20
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-25 to 85
ISO
122JU
ISO122JU/1K
ACTIVE
SOIC
DVA
8
1000
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-25 to 85
ISO
122JU
ISO122JUE4
ACTIVE
SOIC
DVA
8
20
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-25 to 85
ISO
122JU
ISO122P
ACTIVE
PDIP
NVF
8
25
RoHS &
Non-Green
NIPDAU
N / A for Pkg Type
-25 to 85
ISO122P
ISO122PE4
ACTIVE
PDIP
NVF
8
25
RoHS &
Non-Green
NIPDAU
N / A for Pkg Type
-25 to 85
ISO122P
ISO122U
ACTIVE
SOIC
DVA
8
20
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-25 to 85
ISO
122U
ISO122U/1K
ACTIVE
SOIC
DVA
8
1000
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-25 to 85
ISO
122U
ISO122UE4
ACTIVE
SOIC
DVA
8
20
RoHS & Green
NIPDAU
Level-3-260C-168 HR
-25 to 85
ISO
122U
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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