Manufacturer Part Numberacpl-c78a
DescriptionMiniature Isolation Amplifers
ManufacturerAvago Technologies
acpl-c78a datasheet
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 1/17

Download datasheet (518Kb)Embed
Miniature Isolation Amplifiers
Data Sheet
The ACPL-C78A/C780/C784 isolation amplifier family was
designed for current sensing in electronic motor drives. In
a typical implementation, motor currents flow through an
external resistor and the resulting analog voltage drop is
sensed by the ACPL-C78A/C780/C784. A differential output
voltage is created on the other side of the ACPL-C78A/
C780/C784 optical isolation barrier. This differential output
voltage is proportional to the motor current and can be
converted to a single-ended signal by using an op-amp
as shown in the recommended application circuit. Since
common-mode voltage swings of several hundred volts
in tens of nanoseconds are common in modern switching
inverter motor drives, the ACPL-C78A/C780/C784 was
designed to ignore very high common-mode transient
slew rates (of at least 10 kV/μs).
The high CMR capability of the ACPL-C78A/C780/C784
isolation amplifier provides the precision and stability
needed to accurately monitor motor current in high noise
motor control environments, providing for smoother
control (less “torque ripple”) in various types of motor
control applications.
The product can also be used for general analog signal
isolation applications requiring high accuracy, stability,
and linearity under similarly severe noise conditions. For
general applications, we recommend the ACPL-C780 (gain
tolerance of ±3%) and the ACPL-C784 (gain tolerance of
±5%). For precision applications Avago Technologies offers
the ACPL-C78A with part-to-part gain tolerance of ±1%.
The ACPL-C78A/C780/C784 utilizes sigma-delta (∑-∆) an-
alog-to-digital converter technology, chopper stabilized
amplifiers, and a fully differential circuit topology.
Together, these features deliver unequaled isolation-
mode noise rejection, as well as excellent offset and gain
accuracy and stability over time and temperature. This
performance is delivered in a compact, auto-insertable,
Stretched SO-8 (SSO-8) package that meets worldwide
regulatory safety standards.
CAUTION: It is advised that normal static precautions be taken in handling and assembly
of this component to prevent damage and/or degradation which may be induced by ESD.
• 15 kV/μs Common-Mode Rejection at V
• Compact, Auto-Insertable Stretched SO-8 Package
• 0.00025 V/V/°C Gain Drift vs. Temperature
• 0.3 mV Input Offset Voltage
• 100 kHz Bandwidth
• 0.004% Nonlinearity
• Worldwide Safety Approval: UL 1577 (5000 Vrms/1 min.),
CSA and IEC/EN/DIN EN 60747-5-2
• Advanced Sigma-Delta (∑-∆) A/D Converter Technology
• Fully Differential Amplifier
• Motor Phase and Rail Current Sensing
• Inverter Current Sensing
• Switched Mode Power Supply Signal Isolation
• General Purpose Current Sensing and Monitoring
• General Purpose Analog Signal Isolation
Functional Diagram
NOTE: A 0.1 μF bypass capacitor must be connected between pins 1 and
4 and between pins 5 and 8.
= 1000 V

acpl-c78a Summary of contents

  • Page 1

    ... ACPL-C78A/C780/C784. A differential output voltage is created on the other side of the ACPL-C78A/ C780/C784 optical isolation barrier. This differential output voltage is proportional to the motor current and can be converted to a single-ended signal by using an op-amp as shown in the recommended application circuit ...

  • Page 2

    ... To order, choose a part number from the part number column and combine with the desired option from the option column to form an order entry. Example: ACPL-C78A-560E to order product of Surface Mount package in Tape and Reel packaging with IEC/EN/DIN EN 60747-5-2 Safety Approval and RoHS compliance. Option datasheets are available. Contact your Avago sales representative or authorized distributor for information. ...

  • Page 3

    ... Note 1: “V” = Options comprise 060; other options are not marked Recommended Pb-Free IR Profile Recommended reflow condition as per JEDEC Standard, J-STD-020 (latest revision). Non-Halide Flux should be used. Regulatory Information The ACPL-C78A/C780/C784 is pending for approvals by the following organizations: IEC/EN/DIN EN 60747-5-2 Approved under: IEC 60747-5-2:1997 + A1:2002 EN 60747-5-2:2001 + A1:2002 DIN EN 60747-5-2 (VDE 0884 Teil 2):2003-01 ...

  • Page 4

    Insulation and Safety Related Specifications Parameter Symbol Minimum External Air Gap L(101) (External Clearance) Minimum External Tracking L(102) (External Creepage) Minimum Internal Plastic Gap (Internal Clearance) Tracking Resistance CTI (Comparative Tracking Index) Isolation Group IEC/EN/DIN EN 60747-5-2 Insulation Characteristics (Option ...

  • Page 5

    Absolute Maximum Rating Parameter Storage Temperature Ambient Operating Temperature Supply Voltages Steady-State Input Voltage Two Second Transient Input Voltage Output Voltages Lead Solder Temperature Notes: 1. Non-Halide Flux should be used. Recommended Operating Conditions Parameter Ambient Operating Temperature Supply Voltages ...

  • Page 6

    ... DD1 DD2 A Conditions. Parameter Symbol Input Offset Voltage V OS Input Offset Voltage V OS Magnitude of Input Offset |dV OS Change vs. Temperature Gain (ACPL-C78A, ±1%) G1 Gain (ACPL-C780, ±3%) G3 Gain (ACPL-C784, ±5%) G5 Magnitude of V Gain |dG/dT OUT Change vs.Temperature V Nonlinearity over NL OUT 200 ±200 mV Input Voltage ...

  • Page 7

    AC Electrical Specifications Unless otherwise noted, all typicals and figures are at the nominal operating conditions and T = 25°C; all Minimum and Maximum specifications are within the Recommended Operating DD1 DD2 ...

  • Page 8

    ... Data sheet value is the differential amplitude of the transient at the output of the ACPL-C78A/C780/C784 when a 1 Vpk-pk, 1 MHz square wave with 40 ns rise and fall times is applied to both V 16. In accordance with UL 1577, each optocoupler is proof tested by applying an insulation test voltage ≥ ...

  • Page 9

    ... IN 13.2 3 0.01 F 4 Figure 5. Gain and Nonlinearity Test Circuit. 9 0.39 0.38 0.37 0.36 0.35 0.34 0. 4.5 Figure 3. Input Offset vs. Supply DD2 8 0.1 ACPL-C78A ACPL-C780 10 K ACPL-C784 6 5 0.47 F vs. V DD1 vs. V DD2 4.75 5.0 5. SUPPLY VOLTAGE - V DD +15 V +15 V 0.1 F 0.1  – – AD624CD AD624CD GAIN = 4 GAIN = 10 0.1  ...

  • Page 10

    SUPPLY VOLTAGE - V Figure 6. Gain vs. Supply. 0.005 0.004 0.003 0.002 4.5 4.75 5 SUPPLY VOLTAGE - V DD Figure 8. Nonlinearity vs. Supply. 13 ...

  • Page 11

    ... FREQUENCY (Hz) Figure 12. Gain vs. Frequency. 5.5 4.7 3.9 3.1 2.3 1.5 -55 - TEMPERATURE - °C A Figure 14. Propagation Delay vs. Temperature. V DD1 1 0.1  ACPL-C78A ACPL-C780 ACPL-C784 3 0.01 F 4 IMPEDANCE LESS THAN 10  Figure 15. Propagation Delay Test Circuits -50 -100 -150 -200 -250 -300 100000 10 Figure 13. Phase vs. Frequency. Tpd 10 ...

  • Page 12

    ... R4 should be chosen to supply sufficient current from the existing floating supply. The voltage from the current sensing resistor (Rsense) is applied to the input of the ACPL-C78A/ C780/C784 through an RC anti-aliasing filter (R2 and C2). Although the application circuit is relatively simple, a few recommendations should be followed to ensure optimal performance ...

  • Page 13

    ... V ACPL-C78A C2 ACPL-C780 0.01 F ACPL-C784 * * * V (+5 V) DD2 V DD1 0.1  0.  ACPL-C78A ACPL-C780 ACPL-C784 GND2 GND2 DD2 C4 V OUT+ V OUT– C5 150 pF R3 10 0.1 F 0.1 F GND2 R1 – 2. TL032A 2. 0.1 F 150 pF 10 ...

  • Page 14

    ... The Kelvin connections to the resistor should be brought together under the body of the resistor and then run very close to each other to the input of the ACPL-C78A/C780/ C784; this minimizes the loop area of the connection and reduces the possibility of stray magnetic fields from inter- fering with the measured signal ...

  • Page 15

    ... Frequently asked questions about the ACPL-C78A/C780/C784 1. The basics 1.1. Why should I use the ACPL-C78A/C780/C784 for sensing current when Hall-effect sensors are available which don’t need an isolated supply voltage? Available in an auto-insertable, Stretched SO-8 package, the ACPL-C78A/C780/C784 is smaller than and has better linearity, offset vs ...

  • Page 16

    ... C (A value of at least 100 pF INPUT works well.) 2.4. How do I ensure that the ACPL-C78A/C780/C784 is not destroyed as a result of short circuit conditions which cause voltage drops across the sense resistor that exceed the ratings of the ACPL- C78A/C780/C784’s inputs? Select the sense resistor so that it will have less than 5 V drop when short circuits occur ...

  • Page 17

    ... Upgrade Working Insulation Voltage from 891 Vpeak to 1140 Vpeak footprint • Upgrade Isolation Voltage from 3750 Vrms to 5000 Vrms • Upgrade clearance and creepage • Upgrade the HCPL-7800 to ACPL-C78A for better gain accuracy • Upgrade the HCPL-7840 to ACPL-C78A/C780 for better gain Design and pin accuracy layout change, • ...