Sigma-Delta Modulator. ACPL-7970 Datasheet
Optically Isolated Sigma-Delta Modulator
The ACPL-7970 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-7970 operates from a 5 V
power supply with dynamic range of 78 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 a means of
sigma-delta over-sampling using an on-board clock. The
signal information is contained in the modulator data, as a
density of ones with data rate of 10 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 for data and clock 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‑7970
provides reliable reinforced insulation 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 a DIP-8 package, the isolated ADC delivers the reliabil-
ity, 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 external clock version modulator ACPL-796J (SO-16
package) is also available.
• 10 MHz internal clock
• 1-bit, second-order sigma-delta modulator
• 16 bits resolution no missing codes (12 bits ENOB)
• 78 dB SNR
• 6 mV/°C maximum offset drift
• ±1% maximum gain error
• Internal reference voltage
• ±200 mV linear range with single 5 V supply (±320 mV
• 3 V to 5.5 V wide supply range for digital interface
• -40° C to +105° C operating temperature range
• 25 kV/ms common-mode transient immunity
• Safety and regulatory approvals:
– IEC/EN/DIN EN 60747-5-5: 891 Vpeak working
– UL 1577: 5000 Vrms/1min isolation voltage
– CSA: Component Acceptance Notice #5
• 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
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.
Pin Configuration and Descriptions
Figure 1. Pin configuration.
Table 1. Pin descriptions.
Supply voltage for signal input side (analog side), relative to GND1
Positive analog input, recommended input range ±200 mV
Negative analog input, recommended input range ±200 mV (normally connected to GND1)
Supply ground for signal input side
Supply ground for data/clock output side (digital side)
Modulator data output
Modulator clock output
Supply voltage for data output side, relative to GND2
Table 2. Ordering Information
ACPL-7970 is UL recognized with 5000 Vrms/1 minute rating per UL 1577.
Gull Wing Tape & Reel
50 per tube
50 per tube
1000 per reel
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.
ACPL-7970-500E to order product of Surface Mount package in Tape and Reel packaging with IEC/EN/DIN EN 60747-5-5
Safety Approval and RoHS compliance.
Option datasheets are available. Contact your Avago sales representative or authorized distributor for information.
Package Outline Drawings
Standard DIP Package
9.80 ± 0.25
(0.386 ± 0.010)
1.19 (0.047) MAX.
1.78 (0.070) MAX.
Dimensions in millimeters and (inches).
Floating lead protrusion is 0.5 mm (20 mils) max.
7.62 ± 0.25
(0.300 ± 0.010)
6.35 ± 0.25
(0.250 ± 0.010)
3.56 ± 0.13
(0.140 ± 0.005)
4.70 (0.185) MAX.
1.080 ± 0.320
(0.043 ± 0.013)
0.51 (0.020) MIN.
2.92 (0.115) MIN.
0.65 (0.025) MAX.
2.54 ± 0.25
(0.100 ± 0.010)
Note: Initial or continued variation in the color of the white mold compound is normal and does not affect device performance or reliability.