May 30, 2008 LMH6518 825 MHz, Digital Controlled, Variable Gain Amplifier General Description Features The LMH6518 is a digitally controlled variable gain amplifier whose total gain can be varied from −1.16 dB to 38.84 dB for a 40 dB range in 2 dB steps. The −3 dB bandwidth is 825 MHz at all gains. Gain accuracy at each setting is typically 0.1 dB. When used in conjunction with a National Semiconductor Gsample/second (Gsps) ADC with adjustable full scale (FS) range, the LMH6518 gain adjustment will accommodate full scale input signals from 6.8 mVPP to 920 mVPP. The LMH6518 gain is programmed via a SPI-1 serial bus. A signal path combined gain resolution of 8.5 mdB can be achieved when the LMH6518’s gain and the Gsps ADC’s FS input are both manipulated. Propagation Delay variation across gain settings is typically 100 ps. 2nd/3rd order harmonic distortion is −50/−53 dBc at 100 MHz. Inputs and outputs are dc-coupled. The outputs are differential with individual Common Mode (CM) voltage control (for Main and Auxiliary outputs) and have a selectable bandwidth limiting circuitry (common to both Main & Auxiliary) of 20, 100, 200, 350, 650 MHz, 750 MHz or full bandwidth. The Auxiliary output (“OUT PA” and “OUT NA”) follows the Main output and is intended for use in Oscilloscope trigger function circuitry but may have other uses in other applications. ■ Gain range ■ Gain step size ■ Combined gain resolution with ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 40 dB 2 dB 8.5 mdB Gsample/second ADC’s Min gain Max gain −3 dB BW Rise/fall time Recovery time Propagation delay variation HD2 @ 100 MHz HD3 @ 100 MHz Input-referred noise (max gain) Power consumption −1.16 dB 38.84 dB 825 MHz 500 ps 5 ns 100 ps −50 dBc −53 dBc 0.93 nV/√Hz 1.1W Applications ■ Oscilloscope programmable gain amplifier ■ Differential ADC drivers ■ High frequency single ended input to differential conversion ■ Precision gain control applications ■ Medical applications ■ RF/ IF applications Functional Block Diagram 30068801 LMH™ is a trademark of National Semiconductor Corporation. © 2008 National Semiconductor Corporation 300688 www.national.com LMH6518 825 MHz, Digital Controlled, Variable Gain Amplifier PRELIMINARY LMH6518 Operating Ratings Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance Human Body Model Machine Model Supply Voltage VCC (5V nominal) VDD (3.3V nominal) (Note 1) Supply Voltage VCC = 5V (±5%) VDD = 3.3V (±5%) −40°C to 85°C Temperature Range Thermal Properties 2000V 200V Junction-to-Ambient Thermal Resistance (θJA), LLP TBD TBD 45°C/W 150°C max Junction Temperature Electrical Characteristics Unless otherwise specified, all limits are guaranteed for TA = 25°C, Input CM = 2.5V, VCM = 1.2V, VCM AUX = 1.2V, VCC = 5V, VDD = 3.3V, RL = 100Ω differential, VOUT = 0.7 VPP differential, Main and Auxiliary Output Specifications, full bandwidth setting, gain = 18.84 dB (Preamp HG, 0 dB ladder attenuation), Full Power setting (Note 3). Boldface limits apply at the temperature extremes. Symbol Parameter Condition Min Typ 750 825 Max Units Dynamic Performance LSBW −3 dB Bandwidth All Gains Peaking Peaking All Gains 0.5 dB GF_0.1dB ±0.1 dB Gain Flatness All Gains 200 MHz GF_1dB ±1 dB Gain Flatness All Gains 600 MHz TRS Rise Time 500 TBD TRL Fall Time 500 TBD OS Overshoot Main Output 7 ts_long Long Term Settling time Main Output, ±0.5% 10 ts_short Short Term Settling time Main Output, ±0.05% 14 t_recover_1 Recovery Time (Note 2) Preamp HG, 0 dB Ladder ΔVIN = 12 mVPP 5 t_recover_2 Preamp HG, 20 dB Ladder ΔVIN = 120 mVPP TBD t_recover_3 Preamp LG, 0 dB Ladder ΔVIN = 120 mVPP TBD t_recover_4 Preamp LG, 20 dB Ladder ΔVIN = 1.2 VPP TBD 1.6 ns Gain Varied 100 ps Max Gain, 10 MHz 0.93 Preamp LG and 0 dB Ladder Attenuation, 10 MHz 4.3 Preamp LG and 0 dB Ladder Attenuation, 100 Hz to 400 MHz 940 μV Max Gain, 100 Hz to 400 MHz 2.2 mV Preamp LG and 0 dB Ladder Attenuation, RS = 50Ω each Input 13.5 Max Gain, RS = 50Ω each Input 3.8 PD Propagation Delay PD_var Propagation Delay Variation MHz ps % ns ns Noise, Distortion, and RF Specifications en_1 Input Noise Spectral Density en_2 eno_1 RMS Output Noise eno_2 NF_1 Noise Figure NF_2 HD2/ HD3_1 2nd/ 3rd Harmonic Distortion dB Main Output, 100 MHz, All Gains −50/ −53 HD2/ HD3_2 Auxiliary Output, 100 MHz, All Gains −48/ −50 HD2/ HD3_3 Main Output, 250 MHz, All Gains −44/ −50 Auxiliary Output, 250 MHz, All Gains −42/ −42 HD2/ HD3_4 IMD3 www.national.com Intermodulation Distortion f = 250 MHz, Main output 2 nV/ −65 dBc dBc OIP3_1 Parameter Intermodulation Intercept OIP3_2 P_1dB_main −1 dB Compression P_1dB_aux Condition Min Main Output, 250 MHz Typ Max 26 Auxiliary Output, 250 MHz TBD Main Output, 250 MHz TBD Auxiliary Output, 250 MHz TBD Units dBm dBm Gain Parameters AV_MAX Max Gain Up to 50 MHz AV_MIN Min Gain Gain_step Gain Step Size Up to 50 MHz Gain Step Size with ADC See (Note 1) ADC FS Adjusted Gain_Range Gain Range TC_AV Gain Temp Coefficient 0 to 40°C Gain_ACC Absolute Gain Accuracy Up to 50 MHz 37.84 38.84 39.84 dB −2.16 −1.16 −0.16 dB 1.8 2 2.2 dB 8.5 39 TBD mdB 40 41 dB −1 ±10 mdB/°C 0.1 TBD dB Matching Specifications Gain_match Gain Matching Main/Auxiliary All Gains ±0.1 dB BW_match −3 dB Bandwidth Matching Main/ Auxiliary All Gains 5 % RT_match Rise Time Matching Main/ Auxiliary All Gains 5 % PD_match Propagation Delay Matching Main/ Auxiliary All Gains TBD ps VIN_MAX Maximum Differential Input voltage Min Gain CMVR Common Mode Voltage Range Zin_diff Differential Input Impedance All Gains 150||1.5 Zin_CM CM Input impedance Preamp HG 420||1.7 Preamp LG 900||1.7 Analog I/O FSOUT1 Full Scale Voltage Swing FSOUT2 IOUT_1 Maximum Output Current TBD 0.8 TBD 2V to 3V Main Output, THD < −40 dBc @ 100 MHz 770 800 Auxiliary Output TBD 700 V KΩ || pF mVPP Main Output, Sourcing TBD IOUT_2 Auxiliary Output, Sourcing TBD IOUT_3 Main Output, Sinking TBD IOUT_4 VPP TBD Auxiliary Output, Sinking mA TBD Zout_diff Differential Output Impedance TBD VOOS Output Offset Voltage All Gain Settings TBD ±50 mV TCVOOS Output Offset Voltage Drift 0 to 40°C 500 TBD µV/°C VOCM Output CM voltage range VOS_CM Output CM offset voltage TC_VOS_CM CM Offset Voltage Temp Coefficient TBD BAL_Error_DC Output Gain Balance Error -70 0.95 BAL_Error_AC 100 1.45 V 15 TBD mV BAL_Error_AC_ Output Phase Balance Error Phase f = 750 MHz, (VOUT+ - VOUT−) Phase ±0.8 PSRR1 Preamp HG −80 Preamp LG −70 PSRR2 PSRR_CM CM Power Supply Rejection CMRR CM Rejection Ratio 2V < CMVR < 3V , DC (see definition) 3 Ohms 1.2 -45 Output Referred Differential Power Supply Rejection TBD mV/°C dB deg dB TBD dB TBD dB www.national.com LMH6518 Symbol LMH6518 Symbol Parameter Condition Min Typ Max VCM_I VCM Input Bias Current 1 TBD VCM_AUX_I VCM_AUX Input Bias Current 1 TBD 3.3 3.6 Units nA Digital I/O & Timing Logic Input/Output Levels I_in Input Bias Current TBD nA CLK_max Maximum SCLK Rate TBD KHz 3.0 V Power Requirements IS1 Supply Current VCC 210 TBD IS1_off VCC Aux off 150 TBD IS2 VDD 160 TBD PO_FP Power Consumption PO_AUX_off Full Power 1.1 Aux off 0.75 mA μA W Bandwidth Limiting Filter Specifications Filter 20 MHz Parameter Pass Band Tolerance Condition −3 dB Bandwidth Pass Band Tolerance (Gain Varied) 100 MHz Stop Band Attenuation at 40 MHz Pass Band Tolerance −3 dB Bandwidth Stop Band Attenuation at 200 MHz Pass Band Tolerance −3 dB Bandwidth Stop Band Attenuation at 400 MHz −6.5 Pass Band Tolerance −3 dB Bandwidth ±10 ±25 Stop Band Attenuation at 750 MHz −8 Pass Band Tolerance −3 dB Bandwidth ±10 Pass Band Tolerance (Gain Varied) 750 MHz ±25 Stop Band Attenuation at 1 GHz −9 Pass Band Tolerance −3 dB Bandwidth ±10 Pass Band Tolerance (Gain Varied) Stop Band Attenuation www.national.com −7 −0, +20 TBD Pass Band Tolerance (Gain Varied) 650 MHz −7 −0, +20 TBD Pass Band Tolerance (Gain Varied) 350 MHz Typ −0, +20 TBD Pass Band Tolerance (Gain Varied) 200 MHz Min ±25 at TBD TBD 4 Max Units % dB % dB % dB % dB % dB % dB LMH6518 Definition of Terms and Specifications 1. CMRR (dB) Differential Gain – CM Gain (from input to output). 2. CM Common Mode 3. ΔVO_CM Variation in output common mode voltage (VO_CM). 4. ΔVOUT Change in differential output voltage (Corrected for DC offset (Voos)). 5. Voos DC offset voltage. Differential output voltage measured with inputs shorted together to VCC/2. 6. ΔVIN (V) Differential voltage across device inputs. 7. Balance Error. Measure of the output swing balance of “out P” and “out N”, as reflected on the output common mode voltage (VO_CM), relative to the differential output swing (VOUT). Calculated as output common mode voltage change (ΔVO_CM) divided by the output differential voltage change (ΔVOUT, which is nominally around 700 mVPP). 8. Out P Positive Main Output 9. Out N Negative Main Output 10. Out PA Positive Auxiliary Output 11. Out NA Negative Auxiliary Output 12. PSRR Differential output change (ΔVOUT) with respect to VCC voltage change (ΔVCC) with nominal differential output. 13. PSRR_CM Output common mode voltage change (ΔVO_CM) with respect to VCC voltage change 14. HG Preamp High Gain 15. LG Preamp Low Gain 16. Ladder Ladder Attenuator setting (0-20 dB 17. Min Gain Gain = −1.16 dB 18. Max Gain Gain = 38.84 dB (ΔVCC). Note 1: Gain Step Size with ADC: With the National Semiconductor GigaSample/second ADC Full Scale (FS) adjustment (512 steps from 0.56V to 0.84V), the worst case gain step size would be: Note 2: “Recovery time” is the slower of the Main and Auxiliary outputs. Measured values correspond to time it takes to return to zero. Note 3: ”Full Power” setting is with Auxiliary output turned on. 5 www.national.com LMH6518 Pin Out Pin Out Function P1 = Out PA Auxiliary positive output P2 = Out NA Auxiliary negative output P3 = VCC (5V) Analog power supply P4 = VCC (5V) Analog power supply P5 = Gnd Ground, electrically connected to the LLP heat sink P6 = Input P Positive Input P7 = Input N Negative Input P8 = Gnd Ground, electrically connected to the LLP heat sink P9 = CS SPI interface, Chip Select, Active low P10 = SDIO SPI interface, Serial Data Input/Output P11 = SCLK SPI interface, Clock P12 = VDD (3.3V) Digital power supply P13 = VCM Input from ADC to control main output CM P14 = Out N Main positive output P15 = Out P Main negative output P16 = VCM_AUX Input from ADC to control auxiliary output CM www.national.com 6 LMH6518 Physical Dimensions inches (millimeters) unless otherwise noted 16-Pin Package NS Package Number SQA16A 7 www.national.com LMH6518 825 MHz, Digital Controlled, Variable Gain Amplifier Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS, IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS DOCUMENT. TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS. EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness. National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. Copyright© 2008 National Semiconductor Corporation For the most current product information visit us at www.national.com National Semiconductor Americas Technical Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Technical Support Center Email: [email protected] German Tel: +49 (0) 180 5010 771 English Tel: +44 (0) 870 850 4288 National Semiconductor Asia Pacific Technical Support Center Email: [email protected] National Semiconductor Japan Technical Support Center Email: [email protected]