Philips Semiconductors Linear Products Product specification LVDT signal conditioner NE/SA/SE5521 DESCRIPTION PIN CONFIGURATIONS The NE/SA/SE5521 is a signal conditioning circuit for use with Linear Variable Differential Transformers (LVDTs) and Rotary Variable Differential Transformers (RVDTs). The chip includes a low distortion, amplitude-stable sine wave oscillator with programmable frequency to drive the primary of the LVDT/RVDT, a synchronous demodulator to convert the LVDT/RVDT output amplitude and phase to position information, and an output amplifier to provide amplification and filtering of the demodulated signal. F, N Packages AMP OUT 1 18 V+ +IN 2 17 C T –IN 3 16 V REF LVDT IN 4 15 FEEDBACK DEMOD OUT 5 14 OSC SYNC 6 13 OSC GND 7 FEATURES • Low distortion • Single supply 5V to 20V, or dual supply ±2.5V to ±10V • Oscillator frequency 1kHz to 20kHz • Capable of ratiometric operation • Low power consumption (182mV typ) 12 V REF/2 N.C. 8 11 R T N.C. 9 10 N.C. TOP VIEW D1 Package AMP OUT 1 16 V+ +IN 2 15 CT –IN 3 14 V REF APPLICATIONS • LVDT signal conditioning • RVDT signal conditioning • LPDT signal conditioning • Bridge circuits LVDT IN 4 13 FEEDBACK DEMOD OUT 5 12 OSC SYNC 6 11 OSC GND 7 10 VREF/2 N.C. 8 9 RT TOP VIEW NOTE: 1. SOL — released in large SO package only. ORDERING INFORMATION TEMPERATURE RANGE ORDER CODE DWG # 18-Pin Plastic Dual In-Line Package (DIP) DESCRIPTION 0 to +70°C NE5521N 0407A 16-Pin Small Outline Large (SOL) Package 0 to +70°C NE5521D 0171B 18-Pin Plastic Dual In-Line Package (DIP) –40 to +85°C SA5521N 0407A 18-Pin Ceramic Dual In-Line Package (CERDIP) –55 to +125°C SE5521F 0583A 16-Pin Ceramic Dual In-Line Package (CERDIP) –40 to +85°C SA5521D 0582B ABSOLUTE MAXIMUM RATINGS SYMBOL RATING UNIT Supply voltage +20 V Split supply voltage ±10 V TA Operating temperature range NE5521 SA5521 SE5521 0 to 70 –40 to +85 –55 to +125 °C °C °C TSTG Storage temperature range –65 to +125 °C PD Power dissipation1 910 mW VCC PARAMETER NOTES: 1. For derating, see typical power dissipation versus load curves (Figure 1). August 31, 1994 901 853-0043 13721 Philips Semiconductors Linear Products Product specification LVDT signal conditioner NE/SA/SE5521 BLOCK DIAGRAM VREF 16 15 FEEDBACK 10k 10k 17 OSC CT RT SINE CONV – – + + 11 14 10k V+ 13 18 +IN AMP OUT 3 VREF/2 7 AUX AMP – 2 OSC 12 10k –IN OSC 4 + SYNCHRONOUS DEMODULATOR 1 6 GND/V– LVDT IN SYNC 5 DOMOD OUT NOTE: Pin numbers are for F, N packages. PIN DEFINITIONS FOR D, F AND N PACKAGES PIN NO. SYMBOL DEFINITION D F, N 1 1 Amp Out 2 2 +IN Auxiliary Amplifier non-inverting input. 3 3 –IN Auxiliary Amplifier inverting input. 4 4 LVDT IN 5 5 DEMOD OUT Pulsating DC output from the Synchronous Demodulator output. This voltage should be filtered before use. 6 6 SYNC Synchronizing input for the Synchronizing Demodulator. This input should be connected to the OSC or OSC output. Sync is referenced to VREF/2. 7 7 GND Device return. Should be connected to system ground or to the negative supply. 8 8 NC No internal connection. -- 9 NC No internal connection. -- 10 NC No internal connection. 9 11 RT A temperature stable 18kΩ resistor should be connected between this pin and Pin 7. 10 12 VREF/2 11 13 OSC Oscillator sine wave output that is 180° out of phase with the OSC signal. The LVDT/RVDT primary is usually connected between OSC and OSC pins. 12 14 OSC Oscillator sine wave output. The LVDT/RVDT primaries are usually connected between OSC and OSC pins. 13 15 FEEDBACK 14 16 VREF Reference voltage input for the oscillator and sine converter. This voltage MUST be stable and must not exceed +V supply voltage. 15 17 CT Oscillator frequency-determining capacitor. The capacitor connected between this pin and ground should be a temperature-stable type. 16 18 +V Positive supply connection. August 31, 1994 Auxiliary Amplifier Out. Input to Synchronous Demodulator from the LVDT/RVDT secondary. A high impedance source of one half the potential applied to VREF. The LVDT/RVDT secondary return should be to this point. A bypass capacitor with low impedance at the oscillator frequency should also be connected between this pin and ground. Usually connected to the OSC output for unity gain, a resistor between this pin and OSC, and one between this pin and ground can provide for a change in the oscillator output pin amplitudes. 902 Philips Semiconductors Linear Products Product specification LVDT signal conditioner NE/SA/SE5521 DC ELECTRICAL CHARACTERISTICS V+ = VREF = 10V, TA = 0 to 70°C for NE5521, TA = –55 to +125°C for SE5521, TA = –40 to 85°C for SA5521, Frequency = 1kHz, unless otherwise noted. SYMBOL PARAMETER TEST CONDITIONS NE5521 Min SA/SE5521 Typ Max Min Typ Max UNIT VCC Supply current 12.9 20 12.9 18 mA IREF Reference current 5.3 8 5.3 8 mA VREF Reference voltage range V+ V 182 280 182 260 mW PD 5 Power dissipation V+ 5 Oscillator Section Oscillator output THD RL = 10kΩ V REF 8.8 V REF 8.8 1.5 VRMS Sine wave distortion No load 1.5 Initial amplitude error TA = 25°C 0.4 ±3 0.4 ±3 % 0.005 0.01 0.005 0.01 %/°C ±0.9 ±5 ±0.9 ±5 Tempco of amplitude Init. accuracy of oscillator freq. TA = 25°C Temperature coeff. of frequency1 0.05 Voltage coeff. of frequency 2.5 Min OSC (OSC) Load2 300 170 300 % % 0.05 %/°C 3.3 %/V(VREF) 170 Ω Demodulator Section ∈r Linearity error ±0.05 5VP-P input Maximum demodulator input VOS TCVOS IBIAS Demodulator offset voltage Demodulator offset voltage drift Demodulator input current –600 VR/2 accuracy ±0.1 ±0.05 V REF 2 ±1.4 ±5 V REF 2 ±1.4 ±5 mV 5 25 5 25 µV/5C –234 –500 ±0.1 ±1 ±0.5 ±5 ±0.1 %FS VP-P –234 nA ±0.1 ±1 % ±0.5 ±5 mV Auxiliary Output Amplifier VOS Input offset voltage IBIAS Input bias current IOS Input offset current AV Gain SR Slew rate GBW Unity gain bandwidth product –600 –210 10 100 –500 50 385 10 100 1.3 AV = 1 1.6 Output voltage swing RL = 10kΩ Output short circuit current to ground or to VCC TA = 25°C 7 8.2 42 7 100 –210 nA 50 nA 385 V/mV 1.3 V/µs 1.6 MHz 8.2 V 42 100 mA NOTES: 1. This is temperature coefficient of frequency for the device only. It is assumed that CT and RT are fixed in value and CT leakage is fixed over the operating temperature range. 2. Minimum load impedance for which distortion is guaranteed to be less than 5%. August 31, 1994 903 Philips Semiconductors Linear Products Product specification LVDT signal conditioner NE/SA/SE5521 DEFINITION OF TERMS Oscillator Output RMS value of the AC voltage at the oscillator output pin. This output is referenced to VREF/2 and is a function of VREF. Sine Wave Distortion The Total Harmonic Distortion (THD) of the oscillator output with no load. This is not a critical specification in LVDT/RVDT systems. This figure could be 15% or more without affecting system performance. Initial Amplitude Error A measure of the interchangeability of NE/SA/SE5521 parts, not a characteristic of any one part. It is the degree to which the oscillator output of a number of NE/SA/SE5521 samples will vary from the median of that sample. Initial Accuracy of Oscillator Frequency Another measure of the interchangeability of individual NE/SA/SE5521 parts. This is the degree to which the oscillator frequency of a number of NE/SA/SE5521 samples will vary from the median of that sample with a given timing capacitor. Tempco of Oscillator Amplitude A measure of how the oscillator amplitude varies with ambient temperature as that temperature deviates from a 25°C ambient. Tempco of Oscillator Frequency A measure of how the oscillator frequency varies with ambient temperature as that temperature deviates from a 25°C ambient. Voltage Coefficient of Oscillator Frequency The degree to which the oscillator frequency will vary as the reference voltage (VREF) deviates from +10V. Min OSC (OSC) Load Minimum load impedance for which distortion is guaranteed to be less than 5%. Linearity Error The degree to which the DC output of the demodulator/amplifier combination matches a change in the AC signal at the demodulator input. It is measured as the worst case nonlinearity from a straight line drawn between positive and negative fullscale end points. Maximum Demodulator Input The maximum signal that can be applied to the demodulator input without exceeding the specified linearity error. APPLICATION INFORMATION OSC frequency V REF 1.3V V REF (R T 1.5k) C T DEVICE POWER DISSIPATION (mW) 2000 PDMAX (N PACKAGE) 1000 AT TA = 70°C, TJ(MAX) = +150°C 800 PDMAX (SO PACKAGE) AT TA = +85°C, TJ(MAX) = +150°C 700 600 VREF = V+ = 20V 500 PDMAX (F PACKAGE) AT TA = +125°C, TJ(MAX) = +165°C 400 PDMAX (F PACKAGE) AT TA = +125°C, TJ(MAX) = +150°C 15V 300 10V 200 5V 100 0.2 0.4 0.6 0.8 1 2 3 OSC–OSC LOAD (kΩ) Figure 1. Device Power Dissipation vs OSC – OSC Load at +25°C August 31, 1994 904 Philips Semiconductors Linear Products Product specification LVDT signal conditioner NE/SA/SE5521 16 16 14 8 ICC 12 I(mA) ∆fOSC (%) 0 10 8 –8 6 –16 5 8 10 12 14 16 18 4 –55 20 VCC = VREF (V) I(mA) ICC IREF 5 0 5 10 15 20 25 VCC = VREF (V) Figure 3. IREF and ICC vs Voltage (TA = +25°C) August 31, 1994 0 25 70 85 125 Figure 4. IREF and ICC vs Temperature (VREF = VCC = 10V) 20 10 –40 TA (°C) Figure 2. Oscillator Frequency Variation With Voltage (Normalized to VREF = VCC = 10V) TA = +25°C 15 IREF 905