Datasheet AD215 (Analog Devices) - 5

AD215 FB 4 AD215 UNCOMMITTED INPUT OP AMP SIGNAL IN– 3 R R 38 OUT HI IN+ 1 LOW-PASS MODULATOR DEMODULATOR FILTER 150kHz IN COM 2 OUTPUT T1 BUFFER 36 TRIM 33k
Ω
0.01µF 37 OUT LO POWER +V 6 42 +15V ISO IN ISOLATED 430kHz DC POWER 44 –15VIN SUPPLY OSCILLATOR –VISO 5 43 PWR RTN T2
Figure 1. Functional Block Diagram
PIN CONFIGURATIONS INSIDE THE AD215
The AD215 is a fully self-contained analog signal and power isolation solution. It employs a double-balanced amplitude
1 3 5 37 43 BOTTOM VIEW OF
modulation technique to perform transformer coupling of sig-
2 4 6 36 38 42 44 FOOTPRINT
nals ranging in frequency from true dc values to those having frequencies of 120 kHz or less. To generate the power supplies used for the isolated front-end
AD215 PIN DESIGNATIONS
circuitry, an internal clock oscillator drives the primary winding of the integral dc/dc power supply’s transformer, T2. The
Pin Designation Function
resultant voltage developed across the secondary winding is 1 IN+ Noninverting Input then rectified and filtered for use as the isolated power supply. 2 IN COM Input Common This built-in isolated dc/dc converter provides sufficient power 3 IN– Inverting Input for both the internal isolated circuit elements of the AD215 as 4 FB Amplifier Feedback well as any ancillary components supplied by the user. It saves 5 –VISO OUT Isolated –15 V dc Power Supply onboard space and component cost where additional amplifica- 6 +VISO OUT Isolated +15 V dc Power Supply tion or signal conditioning is required. 36 TRIM Output Offset Trim Adjust After an input signal is amplified by the uncommitted op amp, 37 OUT LO Output Low it is modulated at a carrier frequency of approximately 430 kHz 38 OUT HI Output High and applied across the primary winding of the signal isolation 42 +15 VIN +15 V dc Power transformer T1. 43 PWR RTN ±15 V dc Power Supply Common 44 –15 V The resultant signal induced on the secondary winding of the IN –15 V dc Power transformer is then demodulated and filtered using a low-pass Bessel response filter set at a frequency of 150 kHz. The func-
ORDERING GUIDE
tion of the filter reconstructs the original signal as it appears on the input.
Model Temperature Range VCMV Nonlinearity*
The signal transformer design and construction allow non- AD215AY –40°C to +85°C 750 0.01% linearity to be independent of both the specified temperature AD215BY –40°C to +85°C 1500 0.005% and gain ranges. *Typical @ +25°C, G = 1 V/V. After complete reconstruction, the signal is subjected to an off- set trim stage and final output buffer. The trim circuit allows the designer flexibility to adjust for any offset as desired. –4– REV. 0