AD536A

Features:

True RMS-to-DC Conversion
Laser-Trimmed to High Accuracy
0.2% Max Error (AD536AK)
0.5% Max Error (AD536AJ)
Wide Response Capability:
Computes RMS of AC and DC Signals
450 kHz Bandwidth: V rms > 100 mV
2 MHz Bandwidth: V rms > 1 V
Signal Crest Factor of 7 for 1% Error
dB Output with 60 dB Range
Low Power: 1.2 mA Quiescent Current
Single or Dual Supply Operation
Monolithic Integrated Circuit
55 to +125 Operation (AD536AS)




Pinout








Specifications

Supply Voltage
Dual Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V
Single Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +36 V
Internal Power Dissipation² . . . . . . . . . . . . . . . . . . 500 mW
Maximum Input Voltage . . . . . . . . . . . . . . . . . . . ±25 V Peak
Buffer Maximum Input Voltage . . . . . . . . . . . . . . . . . . . .±V_S
Maximum Input Voltage . . . . . . . . . . . . . . . . . . .±25 V Peak
Storage Temperature Range . . . . . . . . . 55°C to +150
Operating Temperature Range
AD536AJ/K . . . . . . . . . . . . . . . . . . . . . . . . ... 0 to +70
AD536AS . . . . . . . . . . . . . . . . . . . . . . . ..55 to +125
Lead Temperature Range
(Soldering 60 sec) . . . . . . . . . . . . . . . . . . . . . . . . . .+300
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1000 V






Description

The AD536A is a complete monolithic integrated circuit which performs true rms-to-dc conversion. It offers performance which is comparable or superior to that of hybrid or modular units costing much more. The AD536A directly computes the true rms value of any complex input waveform containing ac and dc components. It has a crest factor compensation scheme which allows measurements with 1% error at crest factors up to 7. The wide bandwidth of the device extends the measurement capability to 300 kHz with 3 dB error for signal levels above 100 mV.

An important feature of the AD536A not previously available in rms converters is an auxiliary dB output. The logarithm of the rms output signal is brought out to a separate pin to allow the dB conversion, with a useful dynamic range of 60 dB. Using an externally supplied reference current, the 0 dB level can be conveniently set by the user to correspond to any input level from 0.1 to 2 volts rms.

The AD536A is laser trimmed at the wafer level for input and output offset, positive and negative waveform symmetry (dc reversal error), and full-scale accuracy at 7 V rms. As a result, no external trims are required to achieve the rated unit accuracy.

There is full protection for both inputs and outputs. The input circuitry can take overload voltages well beyond the supply levels. Loss of supply voltage with inputs connected will not cause unit failure. The output is short-circuit protected.

The AD536A is available in two accuracy grades (J, K) for commercial temperature range (0°C to +70°C) applications, and one grade (S) rated for the 55°C to +125°C extended range. The AD536AK offers a maximum total error of ±2 mV ±0.2% of reading, and the AD536AJ and AD536AS have maximum errors of ±5 mV ±0.5% of reading. All three versions are available in either a hermetically sealed 14-lead DIP or 10-pin TO-100 metal can. The AD536AS is also available in a 20-leadless hermetically sealed ceramic chip carrier.