Video Instrumentation Amplifiers Features General Description # Fully differential inputs and feedback Ð Differential input range of g 2V Ð Common-mode range of g 12V Ð High CMRR at 4 MHz of 70 dB Ð Stable at gains of 1, 2 # Calibrated and clean input clipping # 4430Ð80 MHz @ G e 1 # 4431Ð160 MHz GBWP # 380V/ms slew rate # 0.02% or § differential gain or phase # Operates on g 5 to g 15V supplies with no AC degradation The EL4430 and 4431 are video instrumentation amplifiers which are ideal for line receivers, differential-to-single-ended converters, transducer interfacing, and any situation where a differential signal must be extracted from a background of common-mode noise or DC offset. Applications # # # # # Line receivers ‘‘Loop-through’’ interface Level translation Magnetic head pre-amplification Differential-to-single-ended conversion EL4430C/EL4431C EL4430C/EL4431C These devices have two differential signal inputs and two differential feedback terminals. The FB terminal connects to the amplifier output, or a divided version of it to increase circuit gain, and the REF terminal is connected to the output ground or offset reference. The EL4430 is compensated to be stable at a gain of 1 or more, and the EL4431 for a gain of 2 or more. The amplifiers have an operational temperature of b 40§ C to a 85§ C and are packaged in plastic 8-pin DIP and SO-8. The EL4430 and EL4431 are fabricated with Elantec’s proprietary complementary bipolar process which gives excellent signal symmetry and is free from latchup. Connection Diagram Ordering Information Part No. Temp. Range Package OutlineÝ EL4430CN b 40§ C to a 85§ C 8-pin P-DIP MDP0031 MDP0027 EL4430CS b 40§ C to a 85§ C 8-lead SO EL4431CN b 40§ C to a 85§ C 8-pin P-DIP MDP0031 MDP0027 EL4431CS b 40§ C to a 85§ C 8-lead SO 4430 – 1 January 1996 Rev. D Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a ‘‘controlled document’’. Current revisions, if any, to these specifications are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation. © 1996 Elantec, Inc. EL4430C/EL4431C Video Instrumentation Amplifiers Absolute Maximum Ratings (TA e 25§ C) Positive Supply Voltage V a to Vb Supply Voltage Voltage at any Input or Feedback Difference between Pairs of Inputs or Feedback Current into any Input, or Feedback Pin Va VS VIN DVIN IIN IOUT PD TA TS 16.5V 33V V a to Vb Continuous Output Current Maximum Power Dissipation Operating Temperature Range Storage Temperature Range 30 mA See Curves b 40§ C to a 85§ C b 60§ C to a 150§ C 6V 4 mA Important Note: All parameters having Min/Max specifications are guaranteed. The Test Level column indicates the specific device testing actually performed during production and Quality inspection. Elantec performs most electrical tests using modern high-speed automatic test equipment, specifically the LTX77 Series system. Unless otherwise noted, all tests are pulsed tests, therefore TJ e TC e TA. Test Level I II Test Procedure 100% production tested and QA sample tested per QA test plan QCX0002. 100% production tested at TA e 25§ C and QA sample tested at TA e 25§ C , TMAX and TMIN per QA test plan QCX0002. QA sample tested per QA test plan QCX0002. Parameter is guaranteed (but not tested) by Design and Characterization Data. Parameter is typical value at TA e 25§ C for information purposes only. III IV V Open-Loop DC Electrical Characteristics Power supplies at g 5V, TA e 25§ . For the EL4431, Parameter Description VDIFF Differential input voltage - Clipping (VCM e 0) 0.1% nonlinearity VCM Common-mode range (VDIFF e 0) EL4430/31 Test Level Units 2.3 I V 1.8 V V g2 g 3.0 g 12 g 13.0 I I V V Min Typ 2.0 EL4430/31 VS e g 5V VS e g 15V VOS Input offset voltage 2 8 I mV IB Input bias current (IN a , INb, REF, and FB terminals) 12 20 I mA IOS Input offset current between IN a and INb and between REF and FB 0.2 2 I mA RIN Input resistance CMRR Common-mode rejection ratio PSRR Power supply rejection ratio EL4430/31 EG Gain error, excluding feedback resistors EL4430/31 VO Output voltage swing EL4430, VS e g 5V VS e g 15V EL4431, VS e g 5V VS e g 15V ISC Output short-circuit current IS Supply current, VS e g 15V EL4430/31 Max EL4430/31 100 230 I kX 70 90 I dB 60 V dB I % I I I I V V V V b 1.5 b 0.2 g2 g 2.8 g 12 g 12.8 g 2.5 g 3.0 g 12.5 g 13.0 40 90 13.5 2 a 0.5 16 I mA I mA TD is 3.5in RF e RG e 500X. EL4430C/EL4431C Video Instrumentation Amplifiers Parameter Description Min Typ Max Test Level Units BW, b3 dB b 3 dB small-signal bandwidth EL4430 EL4431 82 80 V V MHz MHz BW, g 0.1 dB 0.1 dB flatness bandwidth EL4430 EL4431 20 14 V V MHz MHz Peaking Frequency response peaking EL4430 EL4431 0.6 1.0 V V dB dB SR Slew rate, VOUT between b2V and a 2V All 380 V V/ms VN Input-referred noise voltage density EL4430/31 26 V nV/rt-Hz dG Differential gain error, Voffset between b 0.7V and a 0.7V EL4430 EL4431, RL e 150X 0.02 0.04 V V % % di Differential gain error, Voffset between b 0.7V and a 0.7V EL4430 EL4431, RL e 150X 0.02 0.08 V V (§ ) (§ ) TS Settling time, to 0.1% from a 4V step EL4430 48 V ns Test Circuit Typical Performance Curves EL4430 and EL4431 Common-Mode Rejection Ratio vs Frequency 4430 – 3 4430 – 4 3 TD is 2.5in Closed-Loop AC Electrical Characteristics Power supplies at g 12V, TA e 25§ C, RL e 500X for the EL4430, RL e 150X for the EL4431, CL e 15 pF. For the EL4431, RF e RG e 500X. EL4430C/EL4431C Video Instrumentation Amplifiers Typical Performance Curves Ð Contd. EL4430 Frequency Response vs Gain EL4430 Frequency Response for Various RL, CL VS e g 5V 4430 – 5 EL4431 Frequency Response vs Gain 4430 – 6 EL4431 Frequency Response for Various RL, CL VS e g 5V 4430 – 9 4430 – 8 4 EL4430 Frequency Response for Various RL, CL VS e g 15V 4430 – 7 EL4431 Frequency Response for Various RL, CL VS e g 15V 4430 – 10 EL4430C/EL4431C Video Instrumentation Amplifiers Typical Performance Curves Ð Contd. EL4430 Differential Gain and Phase vs Input Offset Voltage for VS e g 5V EL4430 Differential Gain and Phase vs Input Offset Voltage for VS e g 12V 4430 – 14 EL4431 Differential Gain and Phase vs Input Offset Voltage for VS e g 5V EL4430 Differential Gain and Phase Error vs RL 4430 – 15 EL4431 Differential Gain and Phase vs Input Offset Voltage for VS e g 12V 4430 – 16 EL4431 Differential Gain and Phase Error vs RL 4430 – 18 4430 – 17 EL4430 Nonlinearity vs Input Signal Span 4430 – 19 EL4431 Nonlinearity vs Input Signal Span 4430 – 20 4430 – 21 5 EL4430C/EL4431C Video Instrumentation Amplifiers Typical Performance Curves Ð Contd. EL4430 b 3 dB Bandwidth and Peaking vs Supply Voltage for AV e a 1 EL4430 b 3 dB Bandwidth and Peaking vs Die Temperature for AV e a 1 4430 – 23 EL4431 b 3 dB Bandwidth and Peaking vs Supply Voltage 4430 – 24 EL4431 b 3 dB Bandwidth and Peaking vs Die Temperature for AV e a 2 4430 – 26 4430 – 27 6 EL4430 Gain, b 3 dB Bandwidth and Peaking vs Load Resistance for AV e a 1 4430 – 25 EL4431 Gain, b 3 dB Bandwidth and Peaking vs Load Resistance for AV e a 2 4430 – 28 EL4430C/EL4431C Video Instrumentation Amplifiers Typical Performance Curves Ð Contd. Slew Rate vs Supply Voltage Slew Rate vs Die Temperature 4430 – 32 Common Mode Input Range vs Supply Voltage 4430 – 33 Offset Voltage vs Die Temperature 4430 – 35 Supply Current vs Supply Voltage Input Voltage and Current Noise vs Frequency 4430 – 34 Bias Current vs Die Temperature 4430 – 36 Supply Current vs Die Temperature 4430 – 38 4430 – 39 7 4430 – 37 Power Dissipation vs Ambient Temperature 4430 – 40 EL4430C/EL4431C Video Instrumentation Amplifiers stray capacitance should be at least 200 MHz; typical strays of 3 pF thus require a feedback impedance of 270X or less. Two 510X resistors are acceptable for a gain of 2; 300X and 2700X make a good gain-of-10 divider. Alternatively, a small capacitor across RF can be used to create more of a frequency-compensated divider. The value of the capacitor should scale with the parasitic capacitance at the FB terminal input. It is also practical to place small capacitors across both the feedback resistors (whose values maintain the desired gain) to swamp out parasitics. For instance, two 10 pF capacitors (for a gain of 2) across equal divider resistors will dominate parasitic effects and allow a higher divider resistance. Applications Information The EL4430 and EL4431 are designed to convert a fully differential input to a single-ended output. It has two sets of inputs; one which is connected to the signal and does not respond to its common-mode level, and another which is used to complete a feedback loop with the output. Here is a typical connection: Input Connections The input transistors can be driven from resistive and capacitive sources, but are capable of oscillation when presented with an inductive input. It takes about 80nH of series inductance to make the inputs actually oscillate, equivalent to 4× of unshielded wiring or about 6× of unterminated input transmission line. The oscillation has a characteristic frequency of 500 MHz. Often, placing one’s finger (via a metal probe) or an oscilloscope probe on the input will kill the oscillation. Normal high-frequency construction obviates any such problems, where the input source is reasonably close to the input. If this is not possible, one can insert series resistors of approximately 51X to de-Q the inputs. 4430 – 2 The gain of the feedback divider is H. The transfer function of the part is VOUT e AO c ((VIN a ) b (VIN b ) a (VREF b VFB)). VFB is connected to VOUT through a feedback network, so VFB e H c VOUT. AO is the openloop gain of the amplifier, and is about 600 for the EL4430 and EL4431. The large value of AO drives (VIN a ) b (VIN b ) a (VREF b VFB) x 0. Rearranging and substituting for VFB Signal Amplitudes Signal input common-mode voltage must be between (V b ) a 3V and (V a ) b 3V to ensure linearity. Additionally, the differential voltage on any input stage must be limited to g 6V to prevent damage. The differential signal range is g 2V in the EL4430 and EL4431. The input range is substantially constant with temperature. VOUT e ((VIN a ) b (VIN b ) a VREF )/H. Thus, the output is equal to the difference of the VIN’s and offset by VREF, all gained up by the feedback divider ratio. The input impedance of the FB terminal (equal to RIN of the input terminals) is in parallel with an RG, and raises circuit gain slightly. The Ground Pin The ground pin draws only 6mA maximum DC current, and may be biased anywhere between (V b ) a 2.5V and (V a ) b 3.5V. The ground pin is connected to the IC’s substrate and frequency compensation components. It serves as a shield within the IC and enhances CMRR over frequency, and if connected to a potential other than ground, it must be bypassed. The EL4430 is stable for a gain of 1 (a direct connection between VOUT and FB) or more and the EL4431 for gains of 2 or more. It is important to keep the feedback divider’s impedance at the FB terminal low so that stray capacitance does not diminish the loop’s phase margin. The pole caused by the parallel of resistors RF and RG and 8 EL4430C/EL4431C Video Instrumentation Amplifiers Applications Information Ð Contd. The maximum dissipation a package can offer is Power Supplies PD, max e (TJ, max b TA max)/iJA where TJ, max is the maximum die junction temperature, 150§ C for reliability, less to retain optimum electrical performance. TA, max is the ambient temperature, 70§ C for commercial and 85§ C for industrial range. iJA is the thermal resistance of the mounted package, obtained from datasheet dissipation curves. The instrumentation amplifiers work well on any supplies from g 3V to g 15. The supplies may be of different voltages as long as the requirements of the Gnd pin are observed ( see the Ground Pin section for a discussion). The supplies should be bypassed close to the device with short leads. 4.7mF tantalum capacitors are very good, and no smaller bypasses need be placed in parallel. Capacitors as low as 0.01mF can be used if small load currents flow. The more difficult case is the SO-8 package. With a maximum die temperature of 150§ C and a maximum ambient temperature of 85§ C, the 65§ C temperature rise and package thermal resistance of 170§ C/W gives a dissipation of 382 mW at 85§ C. This allows a maximum supply voltage of g 8.5V for the EL4431 operated in our example. If an % ), EL4430 were driving a light load (RPAR it could operate on g 15V supplies at a 70§ C maximum ambient. Single-polarity supplies, such as a 12V with a 5V can be used, where the ground pin is connected to a 5V and V- to ground. The inputs and outputs will have to have their levels shifted above ground to accommodate the lack of negative supply. x The dissipation of the amplifiers increases with power supply voltage, and this must be compatible with the package chosen. This is a close estimate for the dissipation of a circuit: Output Loading The output stage of the instrumentation amplifiers is very powerful. It typically can source 80 mA and sink 120 mA. Of course, this is too much current to sustain and the part will eventually be destroyed by excessive dissipation or by metal traces on the die opening. The metal traces are completely reliable while delivering the 30 mA continuous output given in the Absolute Maximum Ratings table in this datasheet, or higher purely transient currents. PD e 2 c VS c IS, max a (VS b VO) c VO/RPAR where IS, max is the maximum supply current VS is the g supply voltage (assumed equal) VO is the output voltage RPAR is the parallel of all resistors loading the output Gain or gain accuracy degrades only 10% from no load to 100X load. Heavy resistive loading will degrade frequency response and video distortion for loads k 100X For instance, the EL4431 draws a maximum of 16 mA and we might require a 2V peak output into 150X and a 270X a 270X feedback divider. The RPAR is 117X. The dissipation with g 5V supplies is 201 mW. The maximum supply voltage that the device can run on for a given PD and the other parameter is Capacitive loads will cause peaking in the frequency response. If capacitive loads must be driven, a small-valued series resistor can be used to isolate it (12X to 51X should suffice). A 22X series resistor will limit peaking to 2.5 dB with even a 220 pF load. VS, max e (PD a VO2/RPAR)/ (2IS a VO/RPAR) 9 EL4430C/EL4431C Video Instrumentation Amplifiers Macromodel This is a Pspice-compatible macromodel of the EL4430 video instrumentation amplifier assembled as a subcircuit. The pins are numbered sequentially as the subcircuit interface nodes. T1 is a transmission line which provides a good emulation of the more complicated real device. This model correctly displays the characteristics of input clipping, frequency response, CMRR both AC and DC, output clipping, output sensitivity to capacitive loads, gain accuracy, slewrate limiting, input bias current and impedance. The macromodel does not exhibit proper results with respect to supply current, supply sensitivities, offsets, output current limit, differential gain or phase, nor temperature. Connections: IN a VIN b l Vb l l Va l l l VFB l l l l VREF l l l l l l l l l l l .SUBCKT EL4430/EL 3 4 *** *** EL4430 macromodel *** *** ****** i1 7 10 .00103 i2 7 11 .00103 i3 7 12 .00105 i4 7 13 .00105 v1 7 14 3 v2 7 15 3 v3 19 2 3 ****** c1 11 1 .03p c2 12 1 .03p c3 18 1 2.1p c4 16 17 0.6p ****** r1 10 11 2000 r2 12 13 2000 r3 10 1 30e6 r4 16 2 1000 r5 17 2 1000 r6 18 1 1.27e6 r7 23 21 20 r8 21 8 100 ****** 11 21 8 50n ****** d1 11 14 diode d2 12 14 diode d3 18 15 diode d4 19 18 diode .model diode d(tt e 120n) ****** q1 16 3 10 1 pnp q2 17 4 11 1 pnp q3 16 5 12 1 pnp q4 17 6 13 1 pnp .model pnp pnp (bf e 90 va e 44 tr e 50n) ****** g1 18 1 17 16 .0005 e1 20 1 1 18 1.0 t1 22 1 20 1 z0 e 50 td e 1.5n r1t1 22 1 50 e2 23 1 22 1 1.0 ****** .ENDS l l l 2 l l l 7 l l l l l l 6 5 VOUT l l 8 GND l 1 TD is 7.0in * * * * * * * * * * * * 10 EL4430C/EL4431C Video Instrumentation Amplifiers EL4430C/EL4431C Macromodel Ð Contd. 4430 – 41 11 EL4430C/EL4431C EL4430C/EL4431C Video Instrumentation Amplifiers General Disclaimer Specifications contained in this data sheet are in effect as of the publication date shown. Elantec, Inc. reserves the right to make changes in the circuitry or specifications contained herein at any time without notice. Elantec, Inc. assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement. January 1996 Rev. D WARNING Ð Life Support Policy Elantec, Inc. products are not authorized for and should not be used within Life Support Systems without the specific written consent of Elantec, Inc. Life Support systems are equipment intended to support or sustain life and whose failure to perform when properly used in accordance with instructions provided can be reasonably expected to result in significant personal injury or death. Users contemplating application of Elantec, Inc. products in Life Support Systems are requested to contact Elantec, Inc. factory headquarters to establish suitable terms & conditions for these applications. Elantec, Inc.’s warranty is limited to replacement of defective components and does not cover injury to persons or property or other consequential damages. Elantec, Inc. 1996 Tarob Court Milpitas, CA 95035 Telephone: (408) 945-1323 (800) 333-6314 Fax: (408) 945-9305 European Office: 44-71-482-4596 12 Printed in U.S.A.