ACPL-796J Datasheet, PDF (1/16 Pages) AVAGO TECHNOLOGIES LIMITED – Optically Isolated Sigma-Delta Modulator

ACPL-796J
Optically Isolated Sigma-Delta Modulator
Data Sheet
Description
The ACPL-796J is a 1-bit, second-order sigma-delta ()
modulator converts an analog input signal into a high-
speed data stream with galvanic isolation based on optical
coupling technology. The ACPL-796J operates from a 5 V
power supply with dynamic range of 80 dB with an appro-
priate digital filter. The differential inputs of ±200 mV (full
scale ±320 mV) are ideal for direct connection to shunt
resistors or other low-level signal sources in applications
such as motor phase current measurement.
The analog input is continuously sampled by means of
sigma-delta over-sampling using external clock, coupled
across the isolation barrier, which allows synchronous
operation with any digital controller. The signal infor-
mation is contained in the modulator data, as a density
of ones with data rate up to 20 MHz, and the data are
encoded and transmitted across the isolation boundary
where they are recovered and decoded into high-speed
data stream of digital ones and zeros. The original signal
information can be reconstructed with a digital filter. The
serial interface has a wide supply range of 3 V to 5.5 V.
Combined with superior optical coupling technology,
the modulator delivers high noise margins and excellent
immunity against isolation-mode transients. With 0.5 mm
minimum distance through insulation (DTI), the ACPL-796J
provides reliable double protection and high working
insulation voltage, which is suitable for fail-safe designs.
This outstanding isolation performance is superior to
alternatives including devices based on capacitive- or
magnetic-coupling with DTI in micro-meter range. Offered
in an SO-16 package, the isolated ADC delivers the reli-
ability, small size, superior isolation and over-temperature
performance motor drive designers need to accurately
measure current at much lower price compared to tradi-
tional current transducers.
The internal clock version modulators, HCPL-7860 (DIP-8/
gull wing surface mount package) and HCPL-786J (SO-16
package), are also available.
Features
 5 MHz to 20 MHz external clock input range
 1-bit, second-order sigma-delta modulator
 16 bits resolution no missing codes (12 bits ENOB)
 74 dB minimum SNR
 3.5 V/°C maximum offset drift
 ±1% maximum gain error
 Internal reference voltage
 ±200 mV linear range with single 5 V supply
 3 V to 5.5 V wide supply range for digital interface
 –40°C to +105°C operating temperature range
 SO-16 package
 25 kV/s common-mode transient immunity
 Safety and regulatory approval:
IEC/EN/DIN EN 60747-5-5: 1414 Vpeak working
insulation voltage
UL 1577: 5000 Vrms/1min double protection rating
CSA: Component Acceptance Notice #5
Applications
 Motor phase and rail current sensing
 Power inverter current and voltage sensing
 Industrial process control
 Data acquisition systems
 General purpose current and voltage sensing
 Traditional current transducer replacements
Functional Block Diagram
V_DD1
VIN +
Σ−Δ
LED
MODULATOR/ DRIVER
DECODER
V_IN −
ENCODER
SHIELD
VDD2
MDAT
VREF
GND1
CLOCK
DETECTOR
SHIELD
LED
DRIVER
ACPL-796J
MCLKIN
GND2
Figure 1.
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. The components
featured in this datasheet are not to be used in military or aerospace applications or environments.