SILICON DESIGNS, INC.

Transcription

1 SILICON DESINS, INC. dvanced ccelerometer Solutions Low Noise: 5 μg/ Hz typical for 2g Full Scale Version High Stability -55 to +5 C Operation esponds to DC and C cceleration ±V Differential Output or 0.5V to.5v Single Ended Output +5 VDC, 5 m Power (ypical) Integrated Sensor & mplifier Internal emperature Sensor Nitrogen Damped & Hermetically Sealed Serialized for raceability Pin Compatible with Models 1210 and 1221 Low Noise High Stability nalog Surface Mount ccelerometer vailable -anges Full Scale cceleration 20 Pin LCC 20 Pin JLCC ± 2 g ± 5 g ± 10 g ± 25 g ± 50 g ± 100 g ± 200 g 1521L L L L L L L J J J J J J J-200 ohs Compliant DESCIPION he is a low-cost, integrated accelerometer for use in zero to medium frequency instrumentation applications that require extremely low noise. he 1521 was designed to support the harsh conditions of down hole drilling, and the 2g version is ideally suited for seismic applications. Each miniature, hermetically sealed package combines a micro-machined capacitive sense element and a custom integrated circuit that includes a sense amplifier and differential output stage. It is relatively insensitive to temperature changes and gradients. Each device is marked with a serial number on its bottom surface for traceability. n optional calibration test sheet (1521-S) is also available which lists the measured bias, scale factor, linearity, operating current and frequency response. PPLICIONS Seismic Monitoring Down Hole Earthquake Detection obotics Security Systems Crash esting Machine Control Vibration Monitoring Modal nalysis Vibration nalysis Instrumentation Vehicle Dynamics OPEION he produces two analog output voltages, which vary with acceleration as shown in the figure below. he outputs can be used either in differential or single ended mode. wo reference voltages, +5.0 and +2.5 volts (nominal), are required; the output scale factor is ratiometric to the +5 volt reference voltage, and both outputs at zero acceleration are nominally +2.5 volts. he sensitive axis is perpendicular to the bottom of the package, with positive acceleration defined as a force pushing on the bottom of the package. OUPU VOLE Full Scale 0 CCELEION + Full Scale 0.50 "L" SUFFIX PCKE cceleration 0.50 "J" SUFFIX PCKE cceleration [page 1] Sept 201

2 PEFOMNCE By Model: V DD =V =5.0 VDC, C =25 C. Model Input Frequency esponse Sensitivity Output Noise, Differential Max. Mechanical Number ange (Nominal, db) (Differential) 1 (MS, typical) Shock (0.1 ms) UNIS g Hz mv/g μg/(root Hz) g (peak) ± ± ± ± ± ± ± Note 1: Single ended sensitivity is half of values shown. ll Models: Unless otherwise specified V DD =V =5.0 VDC, C =25 C, Differential Mode. PMEE MIN YP MX UNIS Cross xis Sensitivity 2 % Bias Calibration Error % of Span Bias emperature Shift ( C = -55 to +125 C) (ppm of span)/ C Scale Factor Calibration Error 2, % Scale Factor emperature Shift ( C = -55 to +125 C) ppm/ C Non-Linearity (-90 to +90% of Full Scale) 2, % of span Power Supply ejection atio 25 db Output Impedance 90 Ohms Operating Voltage Volts Operating Current (I DD +I V ) m Mass: L package 0.62 grams Note 2: ighter tolerances may be available on special order. MXIMUM INS * Case Operating emperature 5-55 to +5 C Storage emperature -55 to +125 C cceleration Over-range 1000g for 0.1 ms Voltage on V DD to -0.5V to 6.5V Voltage on ny Pin (except ) to -0.5V to V DD +0.5V Voltage on to ±15V Power Dissipation 50 mw Note : Voltages on pins other than, or V DD may exceed 0.5 volt above or below the supply voltages provided the current is limited to 1 m. Note : he application of voltages higher than required to bring the output to positive full scale may cause device damage. Note 5: Limited exposure at 5 C recommended for maximum lifespan. * NOICE: Stresses greater than those listed above may cause permanent damage to the device. hese are maximum stress ratings only. Functional operation of the device at or above these conditions is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. [page 2] Sept 201

3 SINL DESCIPIONS V DD and (power): Pins (9,11,1) and (2,5,6,1,19) respectively. Power (+5 Volts DC) and ground. and (output): Pins 12 and respectively. nalog output voltages proportional to acceleration. he voltage increases ( decreases) with positive acceleration; at zero acceleration both outputs are nominally equal to the +2.5 volt reference. he device experiences positive (+1g) acceleration with its lid facing up in the earth s gravitational field. Either output can be used individually or the two outputs can be used differentially but differential mode is recommended for both lowest noise and highest accuracy operation. Voltages can be measured ratiometrically to V for good accuracy without requiring a precision reference voltage (See plot). (input): Pin. Deflection Voltage. Normally left open. test input that applies an electrostatic force to the sense element, simulating a positive acceleration. he nominal voltage at this pin is ½ V DD. voltages higher than required to bring the output to positive full scale may cause device damage. V (input): Pin. Voltage eference. ie directly to V DD for ratiometric measurements or to a +5V reference for better absolute accuracy. 0.1μF bypass capacitor is recommended at this pin. 2.5 Volt (input): Pin. Voltage eference. ie to a resistive voltage divider from +5 volts or to a +2.5 volt reference voltage. I (output): Pin. emperature dependent current source. (May be tied to V DD ; see full description on page 5) ECOMMENDED CONNECIONS V (gnd) VDD V 0.1 uf (gnd) ES INPU (OPIONL) 0.01uF 1521x-xxx I OUPU (POSIIVE) OUPU (NEIVE) EMPEUE DEPENDEN CUEN SOUCE (gnd) 5 (gnd) 6 7 I 9 OP VIEW VDD (vdd) (vdd) he reference input (pin ) may be driven from either a precision voltage source or by the capacitively bypassed resistive divider shown above. DEFLECION VOLE () ES INPU: his test input applies an electrostatic force to the sense element, simulating a positive acceleration. It has a nominal input impedance of 2 kω and a nominal open circuit voltage of ½ V DD. For best accuracy during normal operation, this input should be left unconnected or connected to a voltage source equal to ½ of the V DD supply. he change in differential output voltage ( - ) is proportional to the square of the difference between the voltage applied to the input (V ) and ½ V DD. Only positive shifts in the output voltage may be generated by applying voltage to the input. When voltage is applied to the input, it should be applied gradually. he application of voltages greater than required to bring the output to positive full scale may cause device damage. he proportionality constant (k) varies for each device and is not characterized. ( ) 1 k V V 2 DD 2 [page ] Sept 201

4 ESD and LCH-UP CONSIDEIONS: he model 1521 accelerometer is a CMOS device subject to damage from large electrostatic discharges. Diode protection is provided on the inputs and outputs but care should be exercised during handling to assure that the device is placed only on a grounded conductive surface. Individuals and tools should be grounded before coming in contact with the device. Do not insert the model 1521 into (or remove it from) a powered socket. INENL EMPEUE SENSIN he model 1521 accelerometer contains a temperature dependent current source that is output on pin. his signal is useful for measuring the internal temperature of the accelerometer so that any previously characterized bias and scale factor temperature dependence, for a particular accelerometer, can be corrected. he nominal output current at 25 C is 500 (±200) μ and the nominal sensitivity is 1.5 (±0.5) μ/ C. Fluctuations in V DD & V have little effect on the temperature reading. reduction of 0.10 V to both V DD & V will reduce the current about 1 μ, which corresponds to less than a 1 C change in reading. With a single resistor = 2K between I (pin ) and, as shown in Figure 1, the output voltage V will vary between and +1. volts from -55 to +125 C, which equates to a sensitivity of + mv/ C. V [( 500 ) + [( 1.5 )( 25) ] V = ( 1.5 ) If a greater voltage change versus temperature or lower signal source impedance is needed, the circuit uf in Figure 2 can be used. With offset voltage V = VDD V + 5 to + 15V -5V, gain resistor = 15.0K and offset resistor = I 7.2K, the output voltage V will vary between x-xxx 12 V and +0.5 Volts from -55 to +125 C, which equates to a sensitivity of -29 mv/ C..01uF FIUE 2 V -5 to -15V.01uF V = V VDD V ( 500 ) + [( 1.5 )( 25) ] V + 25 ( 500 ) + [( 1.5 )( )] = V ( 1.5 )( ) V = Figure shows the voltage compliance of the temperature dependent current source (I ) at room temperature. he voltage at pin must be kept in the 0 to +V range in order to achieve proper temperature readings. V 1521x-xxx 9 I FIUE 1 ( 1.5 ) 0.1 uf 2K V [page ] Sept 201

5 PCKE DIMENSIONS *U * "L" SUFFIX PCKE (20 PIN LEDLESS CEMIC CHIP CIE) C F *M cceleration D N L "J" SUFFIX PCKE (20 PIN LEDED CHIP CIE) P B E K EMINL 20 EMINL 1 J H DIM B C D E F H J K L * M N P * * U INCHES MILLIMEES MIN MX MIN MX YP 1.0 YP YP 2. YP BSC 1.27 BSC YP 0.6 YP YP 1.27 YP 0.00 x x YP 0.25 YP 0.0 YP 0.1 YP 0.0 YP 1.2 YP YP 0. YP 0.02 YP 0.5 YP 0.05 YP 2. YP 0.5 YP.5 YP NOES: 1. * DIMENSIONS 'M', '' & 'U' LOCE CCELEION SENSIN ELEMEN'S CENE OF MSS. 2. LID IS ELECICLLY IED O EMINL 19 ().. CONOLLIN DIMENSION: INCH.. EMINLS E PLED WIH 60 MICO-INCHES MIN OLD OVE 0 MICO-INCHES MIN NICKEL. (HIS PLIN SPECIFICION DOES NO PPLY O HE MELLIZED PIN-1 IDENIFIE MK ON HE BOOM OF HE J-LED VESION OF HE PCKE). 5. PCKE: 90% MINIMUM LUMIN (BLCK), LID: SOLDE SELED KOV. SOLDEIN ECOMMENDIONS: ohs Compliance: he model 1521 does not contain elemental lead and is ohs compliant. Pre-inning of ccelerometer Leads is ecommended: o prevent gold migration embrittlement of the solder joints, it is best to pre-tin the accelerometer leads. LCC Solder Contact Plating Information: he plating composition and thickness for the solder pads and castellations on the L suffix (LCC) package are 60 to 225 micro-inches thick of gold (u) over 0 to 50 micro-inches thick of nickel (Ni) over a minimum of 5 micro-inches thick of moly-manganese or tungsten refractory material. [page 5] Sept 201