Data Sheet AD7400 Isolated Sigma-Delta Modulator FEATURES ► ► ► ► ► ► ► ► ► ► ► GENERAL DESCRIPTION 10 MHz clock rate Second-order modulator 16 bits no missing codes ±2 LSB INL typical at 16 bits 3.5 µV/°C maximum offset drift On-board digital isolator On-board reference Low power operation: 18 mA maximum at 5.25 V −40°C to +105°C operating range 16-lead SOIC package Safety and regulatory approvals ► UL 1577 ► VISO = 5000 V rms for 1 minute ► IEC / CSA 62368-1 ► IEC / CSA 61010-1 ► DIN EN IEC 60747-17 (VDE 0884-17) ► VIORM = 645 V peak The AD7400 is a second-order, sigma-delta (Σ-Δ) modulator that converts an analog input signal to a high speed, 1-bit data stream with on-chip digital isolation based on Analog Devices, Inc. iCoupler® technology. The AD7400 operates from a 5 V power supply and accepts a differential input signal of ±200 mV (±320 mV full scale). The analog input is continuously sampled by the analog modulator, eliminating the need for external sample-and-hold circuitry. The input information is contained in the output stream as a density of ones with a data rate of 10 MHz. The original information can be reconstructed with an appropriate digital filter. The serial I/O can use a 5 V or a 3 V supply (VDD2). The serial interface is digitally isolated. High speed CMOS, combined with monolithic air core transformer technology, means the on-chip isolation provides outstanding performance characteristics superior to alternatives such as optocoupler devices. The part contains an on-chip reference. The AD7400 is offered in a 16-lead SOIC and has an operating temperature range of −40°C to +105°C. An external clock version, AD7401, is also available. APPLICATIONS AC motor controls ► Data acquisition systems ► A/D + opto-isolator replacements FUNCTIONAL BLOCK DIAGRAM Rev. I DOCUMENT FEEDBACK TECHNICAL SUPPORT Information furnished by Analog Devices is believed to be accurate and reliable "as is". However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered tr

Data Sheet

Data Sheet SPECIFICATIONS VDD1 = 4.5 V to 5.25 V, VDD2 = 3 V to 5.5 V, VIN+ = −200 mV to +200 mV, and VIN− = 0 V (single-ended); TA = TMIN to TMAX, fMCLK = 10 MHz, tested with Sinc3 filter, 256 decimation rate, as defined by Verilog code, unless otherwise noted. Temperature range is −40°C to +85°C. Table 1. Y Version1, 2 Parameter STATIC PERFORMANCE Resolution Integral Nonlinearity3 Differential Nonlinearity3 Offset Error3 ±50 Offset Drift vs. Temperature Offset Drift vs. VDD1 Gain Error3 Gain Error Drift vs. Temperature Gain Error Drift vs. VDD1 ANALOG INPUT Input Voltage Range Dynamic Input...

Data Sheet SPECIFICATIONS TIMING SPECIFICATIONS VDD1 = 4.5 V to 5.25 V, VDD2 = 3 V to 5.5 V, TA = TMAX to TMIN, unless otherwise noted. Sample tested during initial release to ensure compliance. Table 2. Parameter Limit at TMIN, TMAX Main clock output frequency Main clock output frequency Data access time after MCLK rising edge Data hold time after MCLK rising edge Main clock low time Main clock high time Mark space ratio for clock output is 40/60 to 60/40. Measured with the load circuit of Figure 2 and defined as the time required for the output to cross 0.8 V or 2.0 V. Figure 2. Load Circuit...

Data Sheet SPECIFICATIONS REGULATORY INFORMATION The AD7400 certification approvals are listed in Table 4. Table 4. Regulatory Information Regulatory Agency Standard Certification/Approval 1577 Single protection, 5000 V rms isolation voltage1 IEC / CSA 62368-1 Basic insulation, 780 V rms Reinforced insulation, 390 V rms IEC / CSA 61010-1 Basic Insulation, 600 V rms Overvoltage category III Reinforced insulation, 300 V rms In accordance with UL 1577, each AD7400 is proof tested by applying an insulation test voltage ≥ 6000 V rms for 1 second (current leakage detection limit = 15 µA). In accordance...

Data Sheet SPECIFICATIONS Table 5. (Continued) Description Case Temperature Side 1 Current Side 2 Current INSULATION RESISTANCE AT TS, VIO = 500 V Figure 4. Thermal Derating Curve, Dependence of Safety-Limiting Values with Case Temperature per DIN EN IEC 60747-17 (VDE 0884-17)

Data Sheet ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. All voltages are relative to their respective ground. Table 6. Parameter VDD1 to GND1 VDD2 to GND2 Analog Input Voltage to GND1 Output Voltage to GND2 Input Current to Any Pin Except Supplies1 Operating Temperature Range Storage Temperature Range Junction Temperature SOIC Package θJA Thermal Impedance θJC Thermal Impedance Resistance (Input-to-Output), RI-O Capacitance (Input-to-Output), CI-O2 Pb-Free Temperature, Soldering Reflow ESD ESD CAUTION ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards...

Data Sheet PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 5. Pin Configuration Table 7. Pin Function Descriptions Pin No. Supply Voltage. 4.5 V to 5.25 V. This is the supply voltage for the isolated side of the AD7400 and is relative to GND1. Positive Analog Input. Specified range of ±200 mV. Negative Analog Input. Normally connected to GND1. No Connect. Supply Voltage. 4.5 V to 5.25 V. This is the supply voltage for the isolated side of the AD7400 and is relative to GND1. No Connect (NC). If desired, Pin 7 may be allowed to float. It should not be tied to ground. The AD7400 will operate...

Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS TA = 25°C, using a 20 kHz brick wall filter, unless otherwise noted. Figure 6. PSRR vs. Supply Ripple Frequency Without Supply Decoupling (1 MHz Filter Used) Figure 7. SINAD vs. Analog Input Frequency for Various Supply Voltages Figure 10. Typical DNL, ±200 mV Range (Using Sinc3 Filter, 256 Decimation Rate) Figure 8. Typical FFT, ±200 mV Range (Using Sinc3 Filter, 256 Decimation Rate) Figure 11. Typical INL, ±200 mV Range (Using Sinc3 Filter, 256 Decimation Rate)