EL4390C EL4390C Triple 80 MHz Video Amplifier with DC Restore Features General Description # 80 MHz b 3 dB bandwidth for gains of 1 to 10 # 800 V/ms slew rate # 15 MHz bandwidth flat to 0.1 dB # Excellent differential gain and phase # TTL/CMOS compatible DC restore function # Available in 16 lead P-DIP, 16 lead SOL The EL4390C is three wideband current-mode feedback amplifiers optimized for video performance, each with a DC restore amplifier. The DC restore function is activated by a common TTL/CMOS compatible control signal while each channel has a separate restore reference. Applications # RGB drivers requiring DC restoration # RGB multiplexers requiring DC restoration # RGB building blocks # Video gain blocks requiring DC restoration # Sync and color burst processing Each amplifier can drive a load of 150X at video signal levels. The EL4390C operates on supplies as low as g 4V up to g 15V. Being a current-mode feedback design, the bandwidth stays relatively constant at approximately 80MHz over the g 1 to g 10 gain range. The EL4390C has been optimized for use with 1300X feedback resistors. Connection Diagram Ordering Information Part No. Temp. Range Package Outline Ý EL4390CN b 40§ C to a 85§ C 16-Pin P-DIP MDP0031 EL4390CM b 40§ C to a 85§ C 16-Lead SOL MDP0027 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. © 1994 Elantec, Inc. November 1994, Rev A 4390 – 1 EL4390C Triple 80 MHz Video Amplifier with DC Restore Absolute Maximum Ratings (TA e 25§ C) Voltage between VS a and VSb Voltage at VS a Voltage at VSb Voltage between VIN a and VINb Current into VIN a and VINb Internal Power Dissipation Operating Ambient Temp. Range Operating Junction Temperature Storage Temperature Range a 33V a 18V b18V g 6V See Curves b 40§ C to a 85§ C 150§ C b 65§ C to a 150§ C 5mA 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 III IV V 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. Open Loop DC Electrical Characteristics Supplies at g 15V, Load e 1KX Parameter Description Temp Min Typ Max Test Level Units Amplifier Section (not restored) VOS Input Offset Voltage a 25§ C 2 15 II mV IB a IIN a Input Bias Current a 25§ C 0.2 5 II mA IBb IINb Input Bias Current a 25§ C 10 65 ROL Transimpedance (Note 1) a 25§ C RINb INb Resistance a 25§ C CMRR Common-Mode Rejection Ratio (Note 2) a 25§ C PSRR Power Supply Rejection Ratio (Note 4) a 25§ C VO Output Voltage Swing; RL e 1kX ISC ISY II mA 220 II kX 50 V X 50 56 II dB 50 70 II dB a 25§ C g 12 g 13 II V Short-Circuit Current a 25§ C 45 70 100 II mA Supply Current (Quiescent) a 25§ C 10 20 32 II mA 100 VOS, COMP Composite Input Offset Voltage (Note 3) a 25§ C 8 35 II mV IB a , R Restore IN a Input Bias Current a 25§ C 0.2 5 II mA IOUT Restoring Current Available a 25§ C 2 4 II mA PSRR Power Supply Rejection Ratio (Note 4) a 25§ C 50 70 II dB GOUT Conductance a 25§ C 8 V mA/V ISY, RES Supply Current, Restoring a 25§ C VIL, RES RES Logic Low Threshold a 25§ C RES Logic High Threshold a 25§ C VIH, RES 2 10 1.4 23 37 II mA 1.0 1.4 II V II V 1.8 TD is 4.1in Restoring Section EL4390C Triple 80 MHz Video Amplifier with DC Restore Parameter Typ Max Test Level Units a 25§ C 2 10 II mA a 25§ C 0.5 3 II mA Description Temp IIL, RES RES Input Current, Logic Low IIH, RES RES Input Current, Logic High Min Restoring Section Note Note Note Note TD is 0.9in Open Loop DC Electrical Characteristics Supplies at g 15V, Load e 1KX Ð Contd. 1: For current feedback amplifiers, AVOL e ROL/RINb. 2: VCM e g 10V for VS e g 15V. 3: Measured from VCL to amplifier output, while restoring. 4: VOS is measured at VS e g 4.5V and VS e g 16V, both supplies are changed simultaneously. Closed Loop AC Electrical Characteristics Supplies at g 15V, Load e 150X and 15 pF, TA e 25§ C (See note 7 re: test fixture) Parameter Description Min Typ Max Test Level Units SR Slew Rate (Note 5) 800 V V/ms SR Slew Rate w/ g 5V Supplies (Note 5) 550 V V/ms BW Bandwidth, b3dB, AV e 1 g 5V Supplies, b 3dB 95 72 V V MHz MHz BW Bandwidth, b0.1 dB g 5V Supplies, b 0.1dB 20 14 V V MHz MHz dG Differential Gain at 3.58 MHz at g 5V Supplies (Note 6) 0.02 0.02 V V % % di Differential Phase at 3.58 MHz at g 5V Supplies (Note 6) 0.03 0.06 V V (§ ) (§ ) Restoring Section TRE Time to Enable Restore 35 V ns TRD Time to Disable Restore 35 V ns Note 5: SR is measured at 20% to 80% of 4V pk-pk square wave, with AV e 5, RF e 820X, RG e 200X. Note 6: DC offset from b0.714V to a 0.714V, AC amplitude is 286m Vp-p, equivalent to 40 ire. Note 7: Test fixture was designed to minimize capacitance at the INb input. A ‘‘good’’ fixture should have less than 2 pF of stray capacitance to ground at this very sensitive pin. See application notes for further details. 3 TD is 2.7in Amplifier Section EL4390C Triple 80 MHz Video Amplifier with DC Restore Table 1. Charge Storage Capacitor Value vs. Droop and Charging Rates Cap Value (nF) Droop in 60mS (mV) Charge in 2mS (mV) Charge in 4mS (mV) 10 30 400 800 22 13.6 182 364 47 6.4 85 170 100 3.0 40 80 220 1.36 18 36 These numbers represent the worst case bias current, and the worst case charging current. Note that to get the full (2mA a ) charging current, the clamp input must have l 250mV of error voltage. Note that the magnitude of the bias current will decrease as temperature increases. The basic droop formula is : V (droop) e IB a c (Line time b Charge time) / capacitor value and the basic charging formula is: V (charge) e IOUT c Charge time / capacitor value Where IOUT is: IOUT e (Clamp voltage b IN a voltage) / 120 4 EL4390C Triple 80 MHz Video Amplifier with DC Restore Typical Performance Curves Gain Flatness for Various RF VS e g 15V, AV e 0 dB Gain Flatness for Various RF VS e g 5V, AV e 0 dB Gain Flatness for Various RF and RG Values VS e g 15V, AV e 6 dB 4390 – 3 4390 – 2 4390 – 4 Gain Flatness for Various RF and RG Values VS e g 5V, AV e 6 dB Phase Shift for AV e 2, RF e RG e 1300X Phase Shift for AV e 2, RF e RG e 1000X at VS e g 5V and VS e g 15V 4390 – 5 4390 – 7 4390 – 6 Gain Flatness VS e g 15V, AV e 14 dB, RF/RG as Shown Gain Flatness VS e g 5V, AV e 14 dB, RF/RG as Shown 4390 – 8 Phase Shift for AV e 5 dB, RF e 820X, RG e 200X, VS e g 5V 4390 – 9 5 4390 – 10 EL4390C Triple 80 MHz Video Amplifier with DC Restore Typical Performance Curves Ð Contd. Gain Flatness VS e g 5V, AV e 20 dB, RF/RG as Shown Gain Flatness VS e g 5V, AV e 26 dB, RF e 680X, RG e 36X 4390 – 11 Differential Gain at VS e g 15V 4390 – 12 4390 – 17 Differential Phase at VS e g 15V Differential Gain at VS e g 5V Differential Phase at VS e g 5V 4390 – 19 4390 – 18 4390 – 20 Frequency Response for Various CLOAD, VS e g 15V, RF e RG e 1300X Frequency Response for Various CLOAD, VS e g 5V, RF e RG e 1300X Crosstalk, Channel R and B to Channel G, VS e g 5V, RF e 1300X 4390 – 13 4390 – 14 6 4390 – 15 EL4390C Triple 80 MHz Video Amplifier with DC Restore Typical Performance Curves Ð Contd. Crosstalk, Channel R and G to Channel B, VS e g 5V, RF e 1300X IN a Input Impedance during HOLD, VS e g 5V IN a Input Impedance during SAMPLE, VS e g 5V 4390 – 21 4390 – 22 4390 – 16 Phase Shift at IN a Pin during Restore, RS e 75X and 150X, VS e g 5V IOUT Restoring vs Clamp, Voltage at VS e g 5V Pulse Response with AV e 2, RF e RG e 1300X at VS e g 5V 4390 – 24 4390 – 25 4390 – 23 Output during DC-Restoration, Showing DC Droop RF e RG e 1300X, VS e g 5V Output during DC-Restoration, RF e RG e 1300X, VS e g 5V 4390 – 27 4390 – 26 7 Pulse Response with AV e 5, RF e 820X and RG e 200X at VS e g 15V 4390 – 28 EL4390C Triple 80 MHz Video Amplifier with DC Restore Typical Performance Curves Ð Contd. Maximum Power Dissipation vs Ambient TemperatureÐ 16-Pin PDIP Maximum Power Dissipation vs Ambient TemperatureÐ 16-Pin SOL 4390 – 29 4390 – 30 4390 – 31 Simplified Schematic of One Channel of EL4390 8 EL4390C Triple 80 MHz Video Amplifier with DC Restore In normal circuit operation, the picture content will also cause a slow change in voltage across the capacitor, so at every back porch time period, these error terms can be corrected. Applications Information Circuit Operation Each channel of the EL4390 contains a current feedback amplifier and a TTL/CMOS compatible clamp circuit. The current that the clamp can source or sink into the non-inverting input is approximately: I e (VCLAMP b VIN a ) / 120 When a signal source is being switched, eg. from two different surveillance cameras, it is recommended to synchronize the switching with the vertical blanking period, and to drive the HOLD pin (pin 6) low, during these lines. This will ensure that the system has been completely restored, regardless of the average intensity of the two pictures. So, when the non-inverting input is at the same voltage as the clamp reference, no current will flow, and hence no charge is added to the capacitor. When there is a difference in voltage, current will flow, in an attempt to cancel the error AT THE NON-INVERTING input. The amplifier’s offset voltage and (IB b c RF) DC errors are not cancelled with this loop. It is purely a method of adding a controlled DC offset to the signal. Application Hints Figures 1 & 2 shows a three channel DC-restoring system, suitable for R-G-B or Y-U-V component video, or three synchronous composite signals. Figure 1 shows the amplifiers configured for noninverting gain, and Figure 2 shows the amplifiers configured for inverting gains. Note that since the DC-restoring function is accomplished by clamping the amplifier’s non-inverting input, during the back porch period, any signal on the non-inverting input will be distorted. For this reason, it is recommended to use the inverting configuration for composite video, since this avoids the color burst being altered during the clamp time period. As well as the offset voltage error, which goes up with gain, and the IB b c RF error which drops with gain, there is also the IB a error term. Since the amplifier is capacitively coupled, this small current is slowly integrated and shows up as a very slow ramp voltage. Table below shows the output voltage drift in 60mS for various values of coupling capacitor, all assuming the very worst IB a current. Table 1. Charge Storage Capacitor Value vs. Droop and Charging Rates Cap Value (nF) Droop in 60mS (mV) Charge in 2mS (mV) Charge in 4mS (mV) 10 30 400 800 22 13.6 182 364 47 6.4 85 170 100 3.0 40 80 220 1.36 18 36 Since all three amplifiers are monolithic, they run at the same temperature, and will have very similar input bias currents. This can be used to advantage, in situations where the droop voltage needs to be compensated, since a single trim circuit can be used for all three channels. A 560KX or similar value resistor helps to isolate each signal. See Figure 2. The advantage of compensating for the droop voltage, is that a smaller capacitor can be used, which allows a larger level restoration within one line. See Table 1 for values of capacitor and charge/droop rates. 9 EL4390C Triple 80 MHz Video Amplifier with DC Restore Applications Information Ð Contd. 4390 – 32 Figure 1 10 EL4390C Triple 80 MHz Video Amplifier with DC Restore Applications Information Ð Contd. 4390 – 33 Figure 2 11 EL4390C Triple 80 MHz Video Amplifier with DC Restore Applications Information Ð Contd. 4390 – 34 Figure 3 12 EL4390C Triple 80 MHz Video Amplifier with DC Restore Since there are three amplifiers all in one package, and each amplifier can sink or source typically more than 70mA, some care is needed to avoid excessive die temperatures. Sustained, DC currents, of over 30mA, are not recommended, due to the limited current handling capability of the metal traces inside the IC. Also, the short circuit protection can be tripped with currents as low as 45mA, which is seen as excessive distortion in the output waveform. As a quick rule of thumb, both the SOL and DIP 16 pin packages can dissipate about 1.4 watts at 25§ C, and with g 15V supplies and a worst case quiescent current of 32mA, yields 0.96 watts, before any load is driven. Applications Information Ð Contd. In Figure 3, one of the three channels is used, together with a low-offset op-amp, to automatically trim the bias current of the other two channels. The two remaining channels are shown in the non-inverting configuration, but could equally well be set to provide inverting gains. Two DC-restored channels are typically needed in fader applications. See the EL4094 and EL4095 for suitable, monolithic video faders. Layout and Dissipation Considerations As with all high frequency circuits, the supplies should be bypassed with a 0.1mF ceramic capacitor very close to the supply pins, and a 4.7mF tantalum capacitor fairly close, to handle the high current surges. While a ground plane is recommended, the amplifier will work well with a ‘‘star’’ grounding scheme. The pin 3 ground is only used for the internal bias generator and the reference for the TTL compatible ‘‘HOLD’’ input. Dissipation of the EL4390 can be reduced by lowering the supply voltage. Although some performance is degraded at lower supplies, as seen in the characteristic curves, it is often found to be a useful compromise. The bandwidth can be recovered, by reducing the value of RF, and RG as appropriate. As with all current feedback capacitors, all stray capacitance to the inverting inputs should be kept as low as possible, to avoid unwanted peaking at the output. This is especially true if the value of Rf has already been reduced to raise the bandwidth of the part, while tolerating some peaking. In this situation, additional capacitance on the inverting input can lead to an unstable amplifier. 13 EL4390C Triple 80 MHz Video Amplifier with DC Restore 14 EL4390C Triple 80 MHz Video Amplifier with DC Restore 15 EL4390C EL4390C Triple 80 MHz Video Amplifier with DC Restore 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. November 1994, Rev A 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 16 Printed in U.S.A.