Comlinear CLC427 Dual Voltage Feedback Amplifier for Single Supply Operation General Description Features The Comlinear CLC427 is a dual wideband voltage-feedback operational amplifier that is uniquely designed to provide high performance from a single power supply. This CLC427 provides near rail-to-rail operation and the common-mode input range includes the negative rail. Each of the CLC427’s amplifiers offers plenty of headroom for single-supply applications as evidenced by its 4.3Vpp output voltage from a single 5V supply. ■ Fabricated with a high-speed complementary bipolar process, the CLC427 delivers a wide 94MHz unity-gain bandwidth, 7.5ns rise/fall time and 150V/µs slew rate. For single supply applications such as video distribution or desktop multimedia, the CLC427 offers low 0.35%, 0.55° differential gain and phase errors. ■ ■ ■ ■ ■ ■ Applications ■ ■ ■ ■ ■ ■ With its traditional voltage-feedback architecture and high-speed performance, the CLC427 is the perfect choice for composite signal conditioning circuit functions such as active filters, integrators, differentiators, simple gain blocks and buffering. ■ Video ADC driver Desktop multimedia Single supply cable driver Instrumentation Video cards Wireless IF amplifiers Telecommunications Frequency Response vs. Vout Av = +2V/V Magnitude (1dB/div) Each of the CLC427’s amplifiers provides high signal fidelity with -74/-94dBc 2nd/3rd harmonics (1Vpp, 1MHz, RL=150Ω). Combining this high fidelity performance with CLC427’s quick 46ns settling time to 0.1% makes it an excellent choice for ADC buffering. Single +5V supply Input includes VEE 94MHz unity-gain bandwidth -74/-94dBc HD2/HD3 60mA output current 7.5ns rise/fall time (1Vpp) 46ns settling time to 0.1% 1Vpp 2Vpp 4Vpp 1 10 Comlinear CLC427 Dual Voltage Feedback Amplifier for Single Supply Operation February 1996 100 Frequency (MHz) Single Supply Response Typical Application VCC Single +5V Supply operation 0.1µF 6.8µF + + 1/2 CLC427 - Vo Output Voltage (V) 4 +5V Vin 5 VEE 3 2 1 0 Time (100ns/div) 150Ω 50Ω Pinout 250Ω DIP & SOIC 250Ω VCC Vinv1 Vo2 Vnon-inv1 NOTE: Vin = 0.15V to 2.3V © 1996 National Semiconductor Corporation Vo1 VEE Vinv2 Vnon-inv2 Printed in the U.S.A. Electrical Characteristics PARAMETERS (Vs = +5V1, Vcm = +2.5V, Av = +2, Rf = 250W, RL = 150W to GND; unless specified) CONDITIONS CLC427AJ TYP 25° GUARANTEED MIN/MAX 25° 0° to +70° -40° to +85° FREQUENCY DOMAIN RESPONSE -3dB bandwidth Vo < 1.0Vpp -3dB bandwidth Vo < 3.0Vpp -3dB bandwidth AV = +1V/V Vo < 1.0Vpp rolloff <10MHz peaking DC to 200MHz linear phase deviation <15MHz differential gain NTSC, RL=150Ω differential phase NTSC, RL=150Ω 48 26 94 0.1 0 0.3 0.35 0.55 32 16 28 14 27 11 0.5 0.5 0.6 0.7 2 0.7 0.7 0.8 – – TIME DOMAIN RESPONSE rise and fall time settling time to 0.1% overshoot slew rate AV = +2 7.5 46 5 150 13 70 13 90 74 62 94 75 1V step 1V step 1V step 2V step DISTORTION AND NOISE RESPONSE 1Vpp, 1MHz 2nd harmonic distortion 1Vpp, 5MHz 3rd harmonic distortion 1Vpp, 1MHz 1Vpp, 5MHz equivalent input noise voltage >1MHz current >1MHz crosstalk, input referred 10MHz STATIC DC PERFORMANCE input offset voltage average drift input bias current average drift input offset current average drift power supply rejection ratio common-mode rejection ratio supply current (per amplifier) DC DC no load MISCELLANEOUS PERFORMANCE input capacitance input resistance output impedance @DC input voltage range, high input voltage range, low output voltage range, high RL = 150Ω output voltage range, low RL = 150Ω output voltage range, high no load output voltage range, low no load output current source output current sink supply voltage, maximum supply voltage, minimum UNITS NOTES B 0.8 0.8 0.9 – – MHz MHz MHz dB dB deg % deg 14 – – 83 16 – – 65 ns ns % V/µs – 55 – 65 – 52 – 63 – 52 – 62 -dBc -dBc -dBc -dBc 10 4 65 12.5 5 59 13.6 5.5 59 14 5.7 59 nV/√Hz pA/√Hz -dB 2 4 17 80 0.2 10 82 82 7 7 – 30 – 5 – 65 55 8.5 8 22 36 145 6 22 64 53 8.5 10 35 45 175 7.5 27 60 50 8.5 mV µV/˚C µA nA/˚C µA nA/˚C dB dB mA 1 700 0.07 3.7 0 4.5 0.35 4.8 0.45 60 36 2 500 0.15 3.45 0 4.35 0.5 4.6 0.65 50 20 7 4 2 450 0.24 3.25 0 4.3 0.5 4.55 0.7 40 16 7 4 2 360 0.7 3.15 0 4.2 0.55 4.45 0.75 34 10 7 4 pF kΩ Ω V V V V V V mA mA V V B B 2 2 B B A A B A 1 1 transistor count = 124 Absolute Maximum Ratings supply voltage (Vs) Iout is short circuit protected to ground common-mode input voltage maximum junction temperature storage temperature range lead temperature (soldering 10 sec) differential input voltage ESD tolerance (Note 3) Notes A) J-level: spec is 100% tested at 25°C, sample tested at 85°C. B) J-level: spec is sample tested at 25°C. 1) Vs = VCC – VEE. 2) Tested with RL tied to +2.5V. 3) Human body model, 1.5kΩ in series with 100pF. +7V VEE to VCC +175˚C -65˚C to +150˚C +260˚C ±2V 2000V 2 Typical Performance Characteristics (Vs = +5V1, Vcm = +2.5V, Av = +2, Rf =250 W, Inverting Frequency Response Non-Inverting Frequency Response RL = 150W to GND; unless specified) Frequency Response vs. RL 225 0 Av = 10 -45 Av = 2 -90 Av = 4 -135 10 Av = -1 Av = -10 Av = -1 Av = -5 90 45 0 -225 -45 1 100 10 1 100 1k -40 60 40 20 -80 0 -100 -20 0.001 100 -120 0.01 0.1 -80 3rd RL = 1kΩ 3rd RL = 150Ω 1 10 100 Frequency (MHz) 3rd Harmonic Distortion vs. Vout -30 RL = 150Ω -40 10MHz -50 5MHz -40 2MHz -60 -70 1MHz -80 0.1MHz -50 Distortion (dBc) Distortion (dBc) 2nd RL = 1kΩ -60 Phase RL = 150Ω -60 10MHz 5MHz -60 2MHz -70 -80 1MHz -90 0.1MHz -90 -100 0.1 -20 Gain -30 -90 0 Frequency (MHz) 2nd RL = 150Ω 100 80 2nd Harmonic Distortion vs. Vout -50 -70 10 Open Loop Gain & Phase 10 Frequency (MHz) Harmonic Distortion vs. Frequency -135 100 CL = 10pF Rs = 249Ω 250Ω 250Ω 10 -90 Frequency (MHz) Rs CL Vo = 1Vpp Vo = 1Vpp -45 RL = 150Ω -225 CL = 1000pF Rs = 22Ω 1/2 CLC427 0 RL = 75Ω 0 100 CL = 100pF Rs = 54.9Ω Magnitude (1dB/div) Vo = 2Vpp 45 -180 Frequency Response vs. CL Vo = 4Vpp 135 90 RL = 75Ω RL = 1kΩ Frequency (MHz) Vo = 0.25Vpp 180 Phase (deg) Magnitude (1dB/div) 135 -180 Frequency Response vs. Vout Distortion (dBc) 180 Av = -2 Av = -10 Frequency (MHz) 1 Av = -2 Open Loop Gain (dB) 1 Magnitude (1dB/div) Av = 10 Av = -5 RL = 1kΩ RL = 150Ω Phase (deg) Av = 1 Vo = 0.25Vpp Phase (deg) Phase (deg) Magnitude (1dB/div) Av = 1 Rf = 0 Av = 2 Av = 4 Vo = 0.25Vpp Magnitude (1dB/div) Vo = 0.25Vpp 1 -100 0 10 1 2 3 4 0 Output Amplitude (Vpp) Frequency (MHz) Small Signal Pulse Response 1 2 3 4 Output Amplitude (Vpp) Large Signal Pulse Response Equivalent Input Noise 100 Voltage Noise (nV/Hz) Output Voltage (0.5V/div) Time (20ns/div) Voltage = 9.5nV/√Hz 10 Current = 3.2pA/√Hz 1 0.001 Time (20ns/div) 10 Current Noise (pA/Hz) Output Voltage (0.05V/div) 100 1 0.01 1 0.1 10 Frequency (MHz) Differential Gain and Phase (3.58MHz) IB, VIO, vs. Temperature -10 1.7 PSRR, CMRR & Linear Rout vs. Frequency 2.5 2.5 25 100 -12 VIO -16 0.9 -18 0.7 -20 Gain (%) 1.1 IB (µA) IB Phase Neg Sync 1.5 1.5 1 1 Gain Neg Sync 0.5 0.5 Phase (deg) -14 1.3 VIO (mV) 2 2 80 20 CMRR 15 60 PSRR 40 10 5 20 Rout -22 0.5 -40 -20 0 20 40 Temperature (°C) 60 80 0 0 1 2 3 Number of 150Ω Loads 3 4 0 0.001 0 0.01 0.1 Frequency (MHz) 1 10 Output Resistance (Ω) 1.5 PSRR, CMRR (dB) RL tied to +2.5V CLC427 OPERATIONS Description The CLC427 contains two single supply voltage-feedback amplifiers. The CLC427 is a dual version of the CLC423 with the following features: +5V 6.8µF + 3(5) • Operates from a single +5V supply • Maintains near rail-to-rail performance • Includes the negative rail (0V) in the Common Mode Input Range (CMIR) • Offers low -74/-94dBc 2nd and 3rd harmonic distortion • Provides BW > 20MHz and 1MHz distortion < -50dBc at Vo = 4Vpp Rb 2(6) + 0.1µF 1/2 CLC427 - Rg Vin 8 4 Vo 1(7) Rf Rt R Vo =− f Vin Rg Select R t to yield desired Rin = R t || R g Figure 2: Inverting Configuration Single Supply Operation (VCC = +5V, VEE = GND) The CLC427 is designed to operate from 0 and 5V supplies. The specifications given in the Electrical Characteristics table are measured with a common mode voltage (Vcm) of 2.5V. Vcm is the voltage around which the inputs are applied and the output voltages are specified. Single Supply Operation for Inputs that go below 0V Figures 3 and 4 show possible non-inverting and inverting configurations for input signals that go below ground. The input is AC coupled to prevent the need for level shifting the input signal at the source. The resistive voltage divider biases the non-inverting input to VCC ÷ 2 = 2.5V. Operating from a single +5V supply, the CMIR of the CLC427 is typically 0V to +3.7V. The typical output range with RL = 150Ω is +0.35V to +4.5V. +5V 6.8µF + For simple single supply operation, it is recommended that input signal levels remain above ground. For input signals that drop below ground, AC coupling and level shifting the signal are possible remedies. For input signals that remain above ground, no adjustments need to be made. The non-inverting and inverting configurations for both input conditions are illustrated in the following 2 sections. Vin R Cc 3(5) 2.5V R Standard Single Supply Operation Figures 1 and 2 show the recommended non-inverting and inverting configurations for purely positive input signals. 1/2 CLC427 - 4 1(7) Rf 1 R , where: Rin = 2πRinC c 2 R gC >> RC c R >> Rsource Figure 3: AC Coupled Non-inverting Configuration +5V +5V 6.8µF 6.8µF + + 2.5V Vin 3(5) Rt 2(6) + 8 4 R 3(5) 0.1µF 1/2 CLC427 - Vo Rg C R Vo = Vin 1+ f + 2.5 Rg low frequency cutoff = 2(6) 0.1µF 8 + 1(7) Vo Vin Cc Rg 2(6) + 8 0.1µF 1/2 CLC427 - 4 1(7) Vo Rf R Rf R Vo = Vin − f + 2.5 Rg Rg R Vo = 1+ f Vin Rg low frequency cutoff = 1 2πR gC c Figure 4: AC Coupled Inverting Configuration Figure 1: Non-inverting Configuration 4 Load Termination Since the CLC427 design has been optimized for Single Supply Operation, it is more capable of sourcing rather than sinking current. For optimum performance, the load should be tied to VEE. When the load is tied to VEE, the output always sources current. -40 Crosstalk (dB) -50 Output Overdrive Recovery When the output range of an amplifier is exceeded, time is required for the amplifier to recover from this overdriven condition. Figure 5 illustrates the overload recovery of the CLC427 when the output is overdriven. An input was applied in an attempt to drive the output to twice the supply rails, VCC - VEE = 10V, but the output limits. An inverting gain topology was used, see Figure 2. As indicated, the CLC427 recovers within 25ns on the rising edge and within 10ns on the falling edge. -80 -100 1 10 100 Frequency (MHz) Channel A Channel B Output Channel B (20mV/div) Output Channel A (1V/div) Figure 7: Input Referred Crosstalk vs. Frequency Output Voltage (2V/div) Input Voltage (4V/div) -70 -90 Input Output -60 Time (50ns/div) Figure 8: Pulsed crosstalk Time (50ns/div) Driving Cables and Capacitive Loads When driving cables, double termination is used to prevent reflections. For capacitive load applications, a small series resistor at the output of the CLC427 will improve stability. The Frequency Response vs. Capacitive Load plot, in the typical performance section, gives the recommended series resistance value for optimum flatness at various capacitive loads. Figure 5: Overdrive Recovery Channel Matching Channel matching and crosstalk rejection are largely dependent on board layout. The layout of Comlinear’s dual amplifier evaluation boards are designed to produce optimum channel matching and isolation. Channel matching for the CLC427 is shown in Figure 6. Power Dissipation The power dissipation of an amplifier can be described in two conditions: Magnitude (0.5dB/div) Vout = 0.25Vpp • Quiescent Power Dissipation PQ (No Load Condition) Channel A Channel B • Total Power Dissipation PT (with Load Condition) The following steps can be taken to determine the power consumption for each CLC427 amplifier: 1 1. Determine the quiescent power PQ = ICC (VCC – VEE) 2. Determine the RMS power at the output stage PO = (VCC – Vload) (Iload) 3. Determine the total RMS power PT = PQ + PO 10 Frequency (MHz) Figure 6: Channel Matching The CLC427’s channel-to-channel isolation is better than -70dB for video frequencies of 4MHz. Input referred crosstalk vs frequency is illustrated in Figure 7. Pulsed crosstalk is shown in Figure 8. Add the total RMS powers for both channels to determine the power dissipated by the dual. 5 The maximum power that the package can dissipate at a given temperature is illustrated in the Power Derating curves in the Typical Performance section. The power derating curve for any package can be derived by utilizing the following equation: +5V 6.8µF + 5.1kΩ 3(5) (175° − Tamb ) 5.1kΩ θ JA Vin where: Tamb = Ambient temperature (°C) θJA = Thermal resistance, from junction to ambient, for a given package (°C/W) R2 = R1 = Layout Considerations A proper printed circuit layout is essential for achieving high frequency performance. Comlinear provides evaluation boards for the CLC427 (730038 - DIP, 730036-SOIC) and suggests their use as a guide for high frequency layout and as an aid for device testing and characterization. 2(6) R1 C 50Ω 390pF Q π fr c fr = resonant frequency R2 A = 2Q 2 4Q 2 + 8 0.1µF 1/2 CLC427 - 4 1(7) Vo R2 3.16kΩ C 390pF A = mid− band gain Figure 9: Bandpass Filter Topology 40 30.6dB 940kHz Magnitude (dB) 30 General layout and supply bypassing play major roles in high frequency performance. Follow the steps below as a basis for high frequency layout: 1. Include 6.8µF tantalum and 0.1µF ceramic capacitors on both supplies. 2. Place the 6.8µF capacitors within 0.75 inches of the power pins. 3. Place the 0.1µF capacitors within 0.1 inches of the power pins. 4. Remove the ground plane under and around the part, especially near the input and output pins to reduce parasitic capacitance. 5. Minimize all trace lengths to reduce series inductances. 20 10 0 -10 1 10 Frequency (MHz) Figure 10: Bandpass Response Distribution Amplifier Figure 11 illustrates a distribution amplifier. The topology utilizes the dual amplifier package. The input is AC coupled and the non-inverting terminals of both amplifiers are biased at 2.5V. Additional information is included in the evaluation board literature. +5V 6.8µF + Applications Circuits Vin Typical Application Circuit The typical application shown on the front page illustrates the near rail-to-rail performance of the CLC427. CC Ro Multiple Feedback Bandpass Filter Figure 9 illustrates a bandpass filter and design equations. The circuit operates from a single supply of +5V. The voltage divider biases the non-inverting input to 2.5V. The input is AC coupled to prevent the need for level shifting the input signal at the source. Use the design equations to determine R1 and R2 based on the desired Q and center frequency. R 3(5) R 2(6) + 8 0.1µF 1/2 CLC427 - 1(7) Ro Zo Rf Vo1 Ro Rg C 3(5) 2(6) + 1/2 CLC427 - 4 1(7) Ro Zo Rf Rg C This example illustrates a bandpass filter with Q = 4 and center frequency fc = 1MHz. Figure 10 indicates the filter response. Figure 11: Distribution Amplifier 6 Vo2 Ro Ordering Information DC Coupled Single-to-Differential Converter A DC coupled single-to-differential converter is illustrated in Figure 12. Model CLC427AJP CLC427AJE +5V Temperature Range Description -40˚C to +85˚C -40˚C to +85˚C 8-pin PDIP 8-pin SOIC 6.8µF + Vin 3(5) Rt 2(6) + 8 Package Thermal Resistance Package Plastic (AJP) Surface Mount (AJE) 0.1µF 1/2 CLC427 1(7) VH (Av = +1V/V) - 250Ω 2kΩ 3(5) 3kΩ 2(6) Vo + 1/2 CLC427 - 4 1(7) VL (Av = -1V/V) 250Ω Vo = VH – V L Vo = 2Vin Figure 12: Single-to-Differential Converter 7 qJC qJA 75˚/W 90˚/W 90˚/W 115˚/W Comlinear CLC427, Dual Voltage Feedback Amplifier for Single Supply Operation Customer Design Applications Support National Semiconductor is committed to design excellence. For sales, literature and technical support, call the National Semiconductor Customer Response Group at 1-800-272-9959 or fax 1-800-737-7018. Life Support Policy National’s products are not authorized for use as critical components in life support devices or systems without the express written approval of the president of National Semiconductor Corporation. As used herein: 1. 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National Semiconductor Japan Ltd. 1111 West Bardin Road Arlington, TX 76017 Tel: 1(800) 272-9959 Fax: 1(800) 737-7018 Fax: (+49) 0-180-530 85 86 E-mail: [email protected] Deutsch Tel: (+49) 0-180-530 85 85 English Tel: (+49) 0-180-532 78 32 Francais Tel: (+49) 0-180-532 93 58 Italiano Tel: (+49) 0-180-534 16 80 13th Floor, Straight Block Ocean Centre, 5 Canton Road Tsimshatsui, Kowloon Hong Kong Tel: (852) 2737-1600 Fax: (852) 2736-9960 Tel: 81-043-299-2309 Fax: 81-043-299-2408 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. © 1996 National Semiconductor Corporation 8 Lit #150427-001