ANALOG DEVICES FEATURES Low Cost Synchronized Design for Single and Multi-Channel Applications Low Nonlinearity: 0.05% max, 288K Low Gain Drift: 0.01%/C max, 288K Small Size: 1 x 1 x 0.56 (288J/K) Adjustable Gain, 1 to 1000V/V; Single Resistor APPLICATIONS Transient Voltage Protection in Data Acquisition System Ground Loop Elimination in Industrial & Process Control Off-Ground Signal Measurements 10 Bit Accurate Process Signal Isolator GENERAL DESCRIPTION Model 288 is a low cost, compact isolation amplifier offering 10 bit accuracy (model 288K) in a unique transformer isolated, synchronized design that is optimized for multi-channel indus- trial instrumentation and control applications. This new design features guaranteed low nonlinearity, 0.05% max, model 288K; 0.1% max, model 288J, guaranteed low gain drift, 10Oppm/C max, model 288K; 300ppm/C max, model 288]. The input stage of moclel 288 is a low drift, 5uV/C max, model 288K, bipolar op amp offering gain adjustment from 1V/V to 1000V/V with a single external resistor. Front-end protection combined with high CMV (850V dc, continuous operation) and high CMR (92cB min @ 60Hz) performance facilitate accurate low level measurements in the presence of noisy elec- trical equipment such as motors and power busses. Model 288 requires external modulator and demodulator drive signals. Two compatible drive modules, models 947 and 948, are available for driving up to eight model 288J/K isolation amplifiers. Model 947, see Figure 2, offers eight isolated mod- ular drive outputs, providing 850V de channel-to-channel in- put isolation, as well as 850V dc input-to-output isolation. Model 948, see Figure 3, affords the same 850V dc input-to- output isolation for 1 to 8 model 288J/K isolation amplifiers with a common input ground reference (see Figure 4). Multiple 947 and 948 drive modules may be synchronized in systern application of more than 8 channels. WHERE TO USE MODEL 288 Using modulation techniques with reliable transformer isola- tion, model 288 will interrupt ground loops, leakage paths, and high voltage transients to +850V pk, providing dc to 2.5kHz (-3dB) response. In low level multi-channel data acquisition systems, process monitoring and computer inter- face systems, model 288 offers complete galvanic isolation as well as protection against damage from transients and fault voltages. Low Cost, High Accuracy, Synchronized Isolation Amplifier . eevee 3 CHANNEL ISOLATED DATA ACQUISITION SYSTEM DEMOD IN DEMODULATOR DRIVE FROM 947 OR 948 FROM 947 DC to 3.5kHz IDEmoD] oy BIPOLAR INPUT AMPLIFIER gain - 1 - TOOK? (aviv To 1900v/v) Figure 1. Block Diagram - Model 288 DEMOD DRIVE QUTPUT FOR 1TO 8 ISO AMPS -{5 } ) +BUF IN ype OUT +PWR IN ry 100kHz REGULATOR osciLLaTon [7] DRIVER PWR COM T I J (16) 2) MOD MODULATOR SYNC IN. DRIVE avng ws | DRIVE FOR SYNC OUT f woo 8 ISO AMPS ) Osc TRIM MOD Figure 2. Block Diagram Model 947 Driver ISOLATION AMPLIFIERS 153 SPECIFICATIONS (typical @ +25C and Vs = +15V de unless otherwise noted, see note 1) Model 288K GAIN (NON-INVERTING) Range (50k Load) Gain Formula Deviation from Formula vs. Temperature (0 to +70C)? vs. Time Nonlinearity? +5V Output (G = 1 to 1000V/V) INPUT VOLTAGE RATINGS Linear Differential Range, G = 1V/V Safe Differential Input Voltage Continuous Pulse, 10ms Duration, 1 Pulse/sec CMV, Inputs to Ourputs ac, 60Hz, One Minute Duration Continuous Operation CMR, Inputs to Outputs, 60Hz, Rg Stk Balanced Source Impedance 1kQ Source Impedance Imbalance Leakage Current, Inputs to Outputs 10.01%/C typ, 0.03%,"C max 40.05% typ, 40.1% max 1 to 1000V/V Gain = 1 + 100kQ/Rj(k&2) 4% 0,0035%/C typ, 0.01%/C max +4:),001%/1000 hours +0.02% typ, 0,05% max +5V min 240V rms max +400V pk max 750V rms +850V pk max 1)0dB 92dB min @ 115V ac, 60Hz 5 OvA rms max OFFSET VOLTAGE, REFERRED TO INPUT Initial, @ +25C (Adjustable to zero) Gain = 500V/V Gain = 1 to 1000V/V vs. Temperature (0 ta +70C) Gain = 500V/V Gain = 1V/V Gain = 1 to 1000V/V vs. Supply Voltage INPUT BIAS CURRENT Initial, @ +25C 0.5mV typ, #lmV ma +(1.0 + 50/G)mV max t5uV/C typ, 10nV/C max 250uV/C typ, 500n7/C max +10 + 500/G)uV PC mux +(20+ oe) +25nA max +0.1mV typ, +0.5mV max (0.5 + 30/G)mV max 42uVPC typ, +5uV/C max +1002 V/C typ, t300NV/C max +(5 + 300/G)uV/C max uVIV vs, Temperature (0 to +70C) +),1nAPC INPUT IMPEDANCE Differential 19 Q170pF Overload 2390k2 Common Mode 138 QI30pF INPUT NOISE Voltage, Gain = 5O0V/V O.01Hz to 10Hz 24V pk-pk 10Hz to 1kHz 2.5uV rms Current 0.01Hz to 10Hz SpA pk-pk FREQUENCY RESPONSE Small Signal Bandwidth, -3dB Gain = 00V/V 3.5kHz Gain = 1V/V L.5kHy Full Power Response, 10V pk-pk Output Gain = 500V/V 2.0kHz Gain = 1V/V 1.SkHz RATED OUTPUT Voltage, 50kQ Load +5V min Output Impedance 1kQ Output Ripple, 1MHz Bandwidth amV pk-pk POWER SUPPLY* Voltage, Rated Performance -15Vde Voltage Range, Operating 413.5V de to +24V de Current, Quiescent, Model 947 425mA Current, Quiescent, Model 948 ~15mA TEMPERATURE RANGE Rated Performance Storage C to +70C -55C to +85C PACKAGE SIZE 1 x 1.5" x 0.56 NOTES: ' Specifications apply using either model 947 or model 948 mod/dem ad drive. 2 Gain temperature drift is specified as a percentage of output signal level. >Gain nonlinearity is specified as a percentage of output signal span. Power supply voltage ratings refer to models 947 or 948 mod/demod modules. Specifications subject to change without notice. 154 ISOLATION AMPLIFIERS OUTLINE DI MENSIONS Dimensions shown in inches and (mm). pp 15 138.10} | 0.56 288 (142) 388) 6.20 190.25 DIA (5 TO 6.4) 3 INPUT COM OUTPUT | {cri 0.11254) MATING SOCKET: AC1055 4 MOD IN BOTTOM VIEW WEIGHT. 20 Grams eo i302 1 062 948 6.7 a||s 04 (1.02) DIA Uf. | 0.20 TO 0.25 (8 TO 6.4) 1 +12V OUT $444 2 +PWR IN 3 PWRCOM +4 DEMOD OUT SYNC OUT OSC TRIM BCITTOM VIEW WEIGHT: 40 Grams -| [cro 112.54) MATING SOCKET AC 1057 ~~ 24 161 =| 947 6 (95.2) 0.02 0.20 TO0. (0.5) DIA Sroed *12V OUT 3 +BUFIN 4 25 MOD | 24 com + 23 MOD COM BOTTOM VIEW WEIGHT. 50 Grams SYNC IN 8 18 (45.7) -| fae-caww 0.3 (2.54) MATING SOCKET - AC1056, +12V OUTPUT 4g) DEMOD DRIVE OUTPL [ | [ FOR 173 8 ISO AMPS i 1ooKH MODULATOR ORIVE REGULATOR} OSCILLATOR pe] DRIVER OUTPUT FOR 8 1SO AMPS, l it J (9) Guaro Figure 3. Block Diagram ~- Model 948 Driver Tr 7 * 7) move. 948 ORIVER | CAN HANDLE FROM 948 pO" i 1TO.8 MODEL 288J/K ISOLATION AMPLIFIERS GAIN 288. con, Figure 4. Application of Models 288/948 in Multi-Channel Data Isolation (Note Common Signal Data Reference at Input)