SLOS318E − MAY 2000 − REVISED JANUARY 2004 features key applications D High Performance D D D D D Single-Ended To Differential Conversion − 150 MHz −3 dB Bandwidth (VCC = ± 15 V) D Differential ADC Driver − 51 V/µs Slew Rate D Differential Antialiasing − −100 dB Third Harmonic Distortion at D Differential Transmitter And Receiver 250 kHz D Output Level Shifter Low Noise − 1.3 nV/√Hz Input-Referred Noise Differential-Input/Differential-Output THS4130 THS4131 − Balanced Outputs Reject Common-Mode D, DGN, OR DGK PACKAGE D, DGN, OR DGK PACKAGE Noise (TOP VIEW) (TOP VIEW) − Reduced Second Harmonic Distortion VIN− VIN+ VIN− VIN+ 1 8 1 8 Due to Differential Output VOCM PD VOCM NC 2 7 2 7 Wide Power Supply Range VCC− VCC+ VCC− VCC+ 3 6 3 6 − VCC = 5 V Single Supply to ± 15 V Dual VOUT+ VOUT− VOUT+ VOUT− 4 5 4 5 Supply ICC(SD) = 860 µA in Shutdown Mode (THS4130) HIGH-SPEED DIFFERENTIAL I/O FAMILY description The THS413x is one in a family of fully-differential input/differential output devices fabricated using Texas Instruments’ state-of-the-art BiComI complementary bipolar process. The THS413x is made of a true fully-differential signal path from input to output. This design leads to an excellent common-mode noise rejection and improved total harmonic distortion. DEVICE DESCRIPTION THS412x 100 MHz, 43 V/µs, 3.7 nV/√Hz THS414x 160 MHz, 450 V/µs, 6.5 nV/√Hz THS415x 180 MHz, 850 V/µs, 9 nV/√Hz typical A/D application circuit VDD 5V VIN VOCM + − − AVDD DVDD AIN + AIN AVSS Vref DIGITAL OUTPUT −5 V NUMBER OF CHANNELS THS4130 1 X THS4131 1 − SHUTDOWN TOTAL HARMONIC DISTORTION vs FREQUENCY −20 THD − Total Harmonic Distortion − dB RELATED DEVICES DEVICE −30 VOUT = 2 VPP −40 −50 −60 VCC = 5 V to ± 5 V −70 −80 VCC = ± 15 V −90 −100 100k 1M f − Frequency − Hz 10M Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright 2001 − 2004, Texas Instruments Incorporated !"# $ %&'# "$ (&)*%"# +"#', +&%#$ %! # $('%%"#$ (' #-' #'!$ '."$ $#&!'#$ $#"+"+ /""#0, +&%# (%'$$1 +'$ # '%'$$"*0 %*&+' #'$#1 "** (""!'#'$, POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 SLOS318E − MAY 2000 − REVISED JANUARY 2004 AVAILABLE OPTIONS PACKAGED DEVICES TA MSOP PowerPAD SMALL OUTLINE (D) 0°C to 70°C −40°C to 85°C EVALUATION MODULES MSOP (DGN) SYMBOL (DGK) THS4130CD THS4130CDGN AOB THS4130CDGK SYMBOL ATP THS4130EVM THS4131CD THS4131CDGN AOD THS4131CDGK ATQ THS4131EVM THS4130ID THS4130IDGN AOC THS4130IDGK ASO − THS4131ID THS4131IDGN AOE THS4131IDGK ASP − absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage, VCC− to VCC+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 33 V Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± VCC Output current, IO (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 mA Differential input voltage, VID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 6 V Continuous total power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table Maximum junction temperature, TJ (see Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C Maximum junction temperature, continuous operation, long term reliability, TJ (see Note 3) . . . . . . . . 125°C Operating free-air temperature, TA:C suffix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C I suffix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −40°C to 85°C Storage temperature, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C Lead temperature 1,6 mm (1/16 Inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C ESD ratings: HBM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2500 V CDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1500 V MM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 V † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. NOTE 1: The THS413x may incorporate a PowerPad on the underside of the chip. This acts as a heatsink and must be connected to a thermally dissipative plane for proper power dissipation. Failure to do so may result in exceeding the maximum junction temperature which could permanently damage the device. See TI technical brief SLMA002 and SLMA004 for more information about utilizing the PowerPad thermally enhanced package. NOTE 2: The absolute maximum temperature under any condition is limited by the constraints of the silicon process. NOTE 3: The maximum junction temperature for continuous operation is limited by package constraints. Operation above this temperature may result in reduced reliability and/or lifetime of the device. DISSIPATION RATING TABLE POWER RATING§ PACKAGE θJA ‡ (°C/W) θJC (°C/W) D 97.5 38.3 TA = 25°C 1.02 W TA = 85°C 410 mW DGN 58.4 4.7 1.71 W 685 mW DGK 260 54.2 385 mW 154 mW ‡ This data was taken using the JEDEC standard High−K test PCB. § Power rating is determined with a junction temperature of 125°C. This is the point where distortion starts to substantially increase. Thermal management of the final PCB should strive to keep the junction temperature at or below 125°C for best performance and long term reliability. recommended operating conditions MIN Dual supply Supply voltage, VCC+ to VCC− Single supply C suffix Operating free-air temperature, TA I suffix PowerPAD is a trademark of Texas Instruments. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 TYP MAX ± 2.5 ± 15 5 30 0 70 −40 85 UNIT V °C SLOS318E − MAY 2000 − REVISED JANUARY 2004 electrical characteristics, VCC = ±5 V, RL = 800 Ω, TA = 25°C (unless otherwise noted)† dynamic performance PARAMETER TEST CONDITIONS Small signal bandwidth (− 3 dB), Single ended input, differential output, VI = 63 mVPP BW Small signal bandwidth (− 3 dB), Single ended input, differential output, VI = 63 mVPP SR ts Slew rate (see Note 2) MIN Gain = 1, Rf = 390 Ω Gain = 1, Rf = 390 Ω 125 VCC = ± 15 VCC = 5 Gain = 1, Rf = 390 Ω Gain = 2, Rf = 750 Ω 150 VCC = ± 5 VCC = ± 15 Gain = 2, Rf = 750 Ω Gain = 2, Rf = 750 Ω 85 UNIT MHz 80 90 Step voltage = 2 V, Gain = 1 Settling time to 0.01% MAX 135 Gain = 1 Settling time to 0.1% TYP VCC = 5 VCC = ± 5 52 V/µs 78 ns 213 ns † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. NOTE 4: Slew rate is measured from an output level range of 25% to 75%. distortion performance PARAMETER TEST CONDITIONS VCC = 5 Total harmonic distortion, Differential input, differential output, Gain = 1, Rf = 390 Ω, RL = 800 Ω, VO = 2 VPP VCC = ±5 VCC = ±15 THD VCC = ±5 VO = 4 VPP VCC = ±15 Spurious free dynamic range (SFDR), Differential input, differential output, Gain = 1, Rf = 390 Ω,, RL = 800 Ω, f = 250 kHz VO = 2 Vpp VO = 4 Vpp MIN TYP f = 250 kHz −95 f = 1 MHz −81 f = 250 kHz −96 f = 1 MHz −80 f = 250 kHz −97 f = 1 MHz −80 f = 250 kHz −91 f = 1 MHz −75 f = 250 kHz −91 f = 1 MHz −75 VCC = ± 2.5 VCC = ± 5 97 VCC = ± 15 VCC = ± 5 99 95 Third intermodulation distortion VI(PP) = 4 V, F1 = 3 MHz, VCC = ± 15 G = 1, F2 = 3.5 MHz Third order intercept VI(PP) = 4 V, F1 = 3 MHz, G = 1, F2 = 3.5 MHz MAX UNIT dBc 98 dB 93 −53 dBc 41.5 dB † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 SLOS318E − MAY 2000 − REVISED JANUARY 2004 electrical characteristics, VCC = ±5 V, RL = 800 Ω, TA = 25°C (unless otherwise noted) (continued)† noise performance PARAMETER TEST CONDITIONS MIN TYP Vn Input voltage noise f = 10 kHz In Input current noise f = 10 kHz † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. MAX UNIT 1.3 nV/√Hz 1 pA/√Hz dc performance PARAMETER TEST CONDITIONS Open loop gain IIB IOS TYP 71 MAX dB 69 0.2 0.2 Input offset voltage drift TA = 25°C TA = full range Input bias current TA = full range 2 6 100 500 Common mode input offset voltage, referred to VOCM Input offset current 2 3 mV 3.5 µV/°C 4.5 TA = full range Offset drift UNIT 78 TA = 25°C TA = full range Input offset voltage V(OS) MIN TA = 25°C TA = full range 2 µA nA nA/°C † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. input characteristics PARAMETER CMRR Common-mode rejection ratio VICR Common-mode input voltage range RI Input resistance CI Input capacitance, closed loop TEST CONDITIONS MIN TA = full range TYP MAX UNIT 80 95 dB −3.77 to 4.3 −4 to 4.5 V Measured into each input terminal ro Output resistance Open loop † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. 34 MΩ 4 pF 41 Ω output characteristics PARAMETER Output voltage swing IO Output current TEST CONDITIONS TYP 0.9 to 4.1 VCC = 5 V VCC = ± 5 V TA = 25°C TA = full range ± 3.7 VCC = ± 15 V TA = 25°C TA = full range ± 10.5 VCC = 5 V, RL = 7 Ω TA = 25°C TA = full range 25 VCC = ± 5 V, RL = 7 Ω TA = 25°C TA = full range 30 VCC = ± 15 V, RL = 7 Ω TA = 25°C TA = full range 60 † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. 4 MIN 1.2 to 3.8 TA = 25°C TA = full range POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 MAX UNIT 1.3 to 3.7 ±4 ± 3.6 V ± 12.4 ± 10.2 45 20 55 mA 28 50 85 SLOS318E − MAY 2000 − REVISED JANUARY 2004 electrical characteristics, VCC = ±5 V, RL = 800 Ω, TA = 25°C (unless otherwise noted) (continued)† power supply PARAMETER TEST CONDITIONS MIN Single supply VCC Supply voltage range ICC Quiescent current Split supply VCC = ± 15 V ICC(SD) Quiescent current (shutdown) (THS4130 only) PSRR Power supply rejection ratio (dc) VPD = −5 V ±2 ± 16.5 12.3 TA = full range † The full range temperature is 0°C to 70°C for the C suffix, and −40°C to 85°C for the I suffix. UNIT V 15 16 TA = 25°C TA = 25°C TA = full range TA = 25°C MAX 33 TA = 25°C TA = full range VCC = ± 5 V TYP 4 mA 14 0.86 1.4 1.5 73 70 mA 98 dB TYPICAL CHARACTERISTICS Table of Graphs FIGURE Small signal frequency response CMMR 1, 2 Small signal frequency response (various supplies) 3 Small signal frequency response (various CF) 4 Small signal frequency response (various CL) 5 Large signal transient response (differential in/single out) 6 Large signal frequency response 7 Common mode rejection ratio ICC Supply current IIB Input bias current vs Frequency 8 vs Free-air temperature 9 vs Free-air temperature (shutdown state) 10 vs Free-air temperature Settling time PSRR Power supply rejection ratio vs Frequency (differential out) Large signal transient response THD 11 12 13 14 Total harmonic distortion Second harmonic distortion Third harmonic distortion vs Frequency 15 vs Frequency 16, 17 vs Output voltage 18, 19 vs Frequency 20, 21 vs Output voltage 22, 23 Vn In Voltage noise vs Frequency 24 Current noise vs Frequency 25 V(OS) VO Input offset voltage vs Common-mode output voltage 26 Output voltage vs Differential load resistance 27 zo Output impedance vs Frequency 28 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS SMALL SIGNAL FREQUENCY RESPONSE SMALL SIGNAL FREQUENCY RESPONSE 25 Output −dB 15 2 1 Gain = 5_Rf = 2 kΩ Rf = 620 Ω Gain = 1, RL = 800 Ω, VCC = ± 5 V, VI = 63 mVPP 0 Output − dB 20 3 RL = 800 Ω, VCC = ± 5 V, VI = 63 mVPP Gain = 10_Rf = 4 kΩ 10 Gain = 2_Rf = 750 Ω 5 −1 Rf = 390 Ω −2 −3 −4 Gain = 1_Rf = 390 Ω 0 −5 −5 −6 −7 −10 100 k 1M 10 M 100 M f − Frequency − Hz −8 100 k 1G 1M Figure 1 10 M 100 M f − Frequency − Hz Figure 2 SMALL SIGNAL FREQUENCY RESPONSE (VARIOUS SUPPLIES) SMALL SIGNAL FREQUENCY RESPONSE (VARIOUS CF) 2 3 VCC= ± 15 1 2 CF = 0 pF 1 0 0 VCC= 5 −1 Output − dB Output − dB −1 −2 −3 −4 −7 −2 −3 −6 Gain = 1, RL = 800 Ω, Rf = 390 Ω, VI = 63 mVPP −8 100 k 1M −7 −8 −9 10 M 100 M f − Frequency − Hz 1G −10 100 k Figure 3 6 CF = 1 pF −4 −5 −5 −6 1G 1M 10 M 100 M f − Frequency − Hz Figure 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1G SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS SMALL SIGNAL FREQUENCY RESPONSE (VARIOUS CL) LARGE SIGNAL TRANSIENT RESPONSE (DIFFERENTIAL IN/SINGLE OUT) 5 3 2 Output − dB 1 1 Gain = 1, RL = 800 Ω, VCC = ± 5 V, VI = 63 mVPP, Rf = 390 Ω CL = 10 pF Large Signal Transient Response − V 4 −0 CL = 0 pF −1 −2 −3 −4 −5 −6 VO+ 0.5 0 VO− −0.5 0.5 0 VI (Diff) −0.5 −7 −8 100 k 1M 10 M 100 M f − Frequency − Hz −1 1G 0 0.1 0.2 0.6 COMMON MODE REJECTION RATIO vs FREQUENCY LARGE SIGNAL FREQUENCY RESPONSE −50 CMRR − Common Mode Rejection Ratio − dB 5 VCC = ± 15 V 0 −5 Output − dB 0.5 Figure 6 Figure 5 −10 VCC = ± 5 V −15 −20 0.4 0.3 t − Time − µs Gain = 1 Rf = 390 Ω, RL = 800 Ω, CF = 0 pF, VI = 0.2 VRMS −25 100 k 1M VCC = 5 V 10 M 100 M 1G −55 Rf = 1 kΩ, VCC = ± 5 V −60 −65 −70 −75 −80 −85 −90 −95 −100 100 k f − Frequency − Hz Figure 7 1M 10 M f − Frequency − Hz 100 M Figure 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS SUPPLY CURRENT vs FREE-AIR TEMPERATURE (SHUTDOWN STATE) SUPPLY CURRENT vs FREE-AIR TEMPERATURE 15 940 14.5 920 VCC = ± 15 V I CC − Supply Current − µ A I CC − Supply Current − mA 14 13.5 13 12.5 VCC = ± 5 V 12 11.5 900 880 860 840 11 820 10.5 10 −40 −20 0 20 40 60 80 800 −50 −25 0 25 50 75 100 TA − Free-Air Temperature (Shutdown State) − °C 100 TA − Free-Air Temperature − °C Figure 9 Figure 10 SETTLING TIME 2.4 2.04 2.35 2.02 VO − Output Voltage − V IIB− Input Bias Current − µ A INPUT BIAS CURRENT vs FREE-AIR TEMPERATURE 2.3 IIB+ 2.25 2.2 2.15 2 RF = 510 Ω CF = 1 pF, VCC = 5 V VO = 4 VPP RL = 800 Ω 1.98 1.96 1.94 IIB− 2.1 2.05 −50 1.92 −25 0 25 50 75 TA − Free-Air Temperature − °C 100 1.9 0 Figure 11 8 25 50 75 100 t − Time − ns Figure 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 125 150 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS POWER SUPPLY REJECTION RATIO vs FREQUENCY (DIFFERENTIAL OUT) LARGE SIGNAL TRANSIENT RESPONSE 2.5 1.5 −60 −70 VO+ 2 VO − Output Voltage − V −50 Gain = 1, Rf = 330 Ω, RL = 400 Ω VCC = 5 V −80 VCC = − 5 V G = 1, Rf = 390 Ω, RL = 800 Ω, CF = 0 pF, CL = 10 pF, VI_Peak = 2 V, VCC = ± 15 V TA = 25°C 1 5 0 −5 −1 −1.5 −90 −2 −100 10 k VO− −2.5 100 k 1M 10 M f − Frequency (Differential Out) − Hz 100 M 0 40 80 120 160 200 t − Time − nS Figure 13 Figure 14 TOTAL HARMONIC DISTORTION vs FREQUENCY −20 THD − Total Harmonic Distortion − dB PSRR − Power Supply Rejection Ratio − dB −40 −30 VOUT = 2 VPP −40 −50 −60 VCC = 5 V to ± 5 V −70 −80 VCC = ± 15 V −90 −100 100k 1M f − Frequency − Hz 10M Figure 15 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS SECOND HARMONIC DISTORTION vs FREQUENCY SECOND HARMONIC DISTORTION vs FREQUENCY −30 −30 Second Harmonic Distortion − dBc −40 Single Ended Input Differential Output Second Harmonic Distortion − dBc VO = 2 VPP, RL = 800 Ω, Rf = 390 Ω, G=1 −50 −60 VCC = 5 V −70 −80 −90 −40 −50 VCC = ± 5 V −60 −70 −80 VCC = ± 15 V −90 −100 −100 VCC = ± 15V, ± 5V −110 100 k 1M f − Frequency − Hz −110 100 k 10 M 1M f − Frequency − Hz SECOND HARMONIC DISTORTION vs OUTPUT VOLTAGE SECOND HARMONIC DISTORTION vs OUTPUT VOLTAGE −88 −92 Second Harmonic Distortion − dBc −96 VCC = ±15 V VCC = ± 5 V −90 Second Harmonic Distortion − dBc f = 250 KHz RL = 800 Ω, Rf = 390 Ω, G=1 −94 VCC = 5 V −98 VCC = ± 15 V −100 −102 −104 Single Ended Input Differential Output −92 −94 VCC = ± 5 V −96 −98 VCC = 5 V −100 −102 Single Ended Input Differential Output −104 −106 0 1 2 3 4 5 VO − Output Voltage − V 6 7 0 1 Figure 18 10 10 M Figure 17 Figure 16 −106 Single Ended Input Differential Output VO = 4 VPP, RL = 800 Ω, Rf = 390 Ω, G=1 2 3 4 5 VO − Output Voltage − V Figure 19 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 f = 500 KHz RL = 800 Ω, Rf = 390 Ω, G=1 6 7 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS THIRD HARMONIC DISTORTION vs FREQUENCY THIRD HARMONIC DISTORTION vs FREQUENCY −30 −50 −60 VCC = ± 15 V −70 −80 −90 −100 1M f − Frequency − Hz −50 −60 Single Ended Input Differential Output −70 VCC = ± 15 V −80 VCC = ± 5 V −90 VCC = 5 V −100 Single Ended Input Differential Output −110 100 k VO = 2 VPP, RL = 800 Ω, Rf = 390 Ω, Gain = 1 −40 VCC = ± 5 V Third Harmonic Distortion − dBc −40 Third Harmonic Distortion − dBc −30 VO = 4 VPP RL = 800 Ω, Rf = 390 Ω, G=1 −110 100 k 10 M 1M f − Frequency − Hz Figure 20 Figure 21 THIRD HARMONIC DISTORTION vs OUTPUT VOLTAGE THIRD HARMONIC DISTORTION vs OUTPUT VOLTAGE −88 −88 VCC = ± 15 V −92 −94 VCC = ± 5 V −96 VCC = 5 V −98 f = 500 KHz RL = 800 Ω, Rf = 390 Ω, G=1 −100 −102 −104 −106 1 2 3 4 5 6 −92 7 VCC = ± 5 V −94 −96 VCC = 5 V −98 VCC = ± 15 V −100 −102 −104 Single Ended Input Differential Output 0 f = 250 KHz RL = 800 Ω, Rf = 390 Ω, G=1 −90 Third Harmonic Distortion − dBc −90 Third Harmonic Distortion − dBc 10 M −106 Single Ended Input Differential Output 0 1 VO − Output Voltage − V 2 3 4 5 VO − Output Voltage − V 6 7 Figure 23 Figure 22 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS VOLTAGE NOISE vs FREQUENCY Vn − Voltage Noise − nV/ Hz 10 1 10 100 1k 10 k 100 k f − Frequency − Hz Figure 24 CURRENT NOISE vs FREQUENCY INPUT OFFSET VOLTAGE vs COMMON-MODE OUTPUT VOLTAGE 7E−12 1000 V(OS) − Input Offset Voltage − µ V I n − Current Noise − pA/ Hz 6E−12 5E−12 4E−12 3E−12 2E−12 1E−12 0 800 Rf = 1 k, RL = 800 Ω, G=1 600 400 200 VCC = ± 5 V 0 VCC = ± 15 V −200 −400 1 10 100 1k f − Frequency − Hz 10 k 100 k −600 −12 −9 −6 −3 0 3 6 9 VOCM − Common-Mode Output Voltage − V Figure 25 12 VCC = ± 2.5 V Figure 26 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 12 SLOS318E − MAY 2000 − REVISED JANUARY 2004 TYPICAL CHARACTERISTICS OUTPUT VOLTAGE vs DIFFERENTIAL LOAD RESISTANCE OUTPUT IMPEDANCE vs FREQUENCY 15 100 Rf = 1 k G=2 5 VOUT+ VCC = ± 5 V VOUT− VCC = ± 5 V 0 −5 −10 VCC = ± 5 V VOUT+ zo − Output impedance − Ω VO − Output Voltage − V 10 VCC = ± 15 V VOUT− 10 1 VCC = ± 15 V −15 100 1000 10 k RL − Differential Load Resistance − Ω 100 k 0.1 100 k 1M 10 M 100 M 1G f − Frequency − Hz Figure 27 Figure 28 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 SLOS318E − MAY 2000 − REVISED JANUARY 2004 APPLICATION INFORMATION resistor matching Resistor matching is important in fully differential amplifiers. The balance of the output on the reference voltage depends on matched ratios of the resistor. CMRR, PSRR, and cancellation of the second harmonic distortion will diminish if resistor mismatch occurs. Therefore, it is recommended to use 1% tolerance resistors or better to keep the performance optimized. VOCM sets the dc level of the output signals. If no voltage is applied to the VOCM pin, it will be set to the midrail voltage internally defined as: ǒVCC Ǔ ) ǒ ) V CC– Ǔ 2 In the differential mode, the VOCM on the two outputs cancel each other. Therefore, the output in the differential mode is the same as the input in the gain of 1. VOCM has a high bandwidth capability up to the typical operation range of the amplifier. For the prevention of noise going through the device, use a 0.1 µF capacitor on the VOCM pin as a bypass capacitor. The following graph shows the simplified diagram of the THS413x. VCC+ Output Buffer VIN− x1 VOUT+ C VIN+ Vcm Error Amplifier + _ C x1 Output Buffer VCC+ 30 kΩ 30 kΩ VCC− VCC− VOCM Figure 29. THS413x Simplified Diagram 14 R POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 R VOUT− SLOS318E − MAY 2000 − REVISED JANUARY 2004 APPLICATION INFORMATION data converters Data converters are one of the most popular applications for the fully differential amplifiers. The following schematic shows a typical configuration of a fully differential amplifier attached to a differential ADC. VDD VCC 5V VIN + − AVDD AIN1 − + AIN2 AVSS VOCM 0.1 µF DVDD Vref −5 V VCC− Figure 30. Fully Differential Amplifier Attached to a Differential ADC Fully differential amplifiers can operate with a single supply. VOCM defaults to the midrail voltage, VCC/2. The differential output may be fed into a data converter. This method eliminates the use of a transformer in the circuit. If the ADC has a reference voltage output (Vref), then it is recommended to connect it directly to the VOCM of the amplifier using a bypass capacitor for stability. For proper operation, the input common-mode voltage to the input terminal of the amplifier should not exceed the common-mode input voltage range. VDD VCC 5V VIN + − AVDD AIN1 − + AIN2 AVSS VOCM 0.1 µF DVDD Vref Figure 31. Fully Differential Amplifier Using a Single Supply POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 SLOS318E − MAY 2000 − REVISED JANUARY 2004 APPLICATION INFORMATION data converters (continued) Some single supply applications may require the input voltage to exceed the common-mode input voltage range. In such cases, the following circuit configuration is suggested to bring the common-mode input voltage within the specifications of the amplifier. VDD VCC VCC RPU Rg VIN 0.1 µF Rf 5V VP V OCM Rg VOUT + − − + VOUT RPU VCC AVDD DVDD AIN1 THS1206 AIN2 Vref AVSS Rf Figure 32. Circuit With Improved Common-Mode Input Voltage The following equation is used to calculate RPU: R PU + V –V P CC 1 1 V –V ) V –V IN P RG P RF OUT ǒ Ǔ ǒ Ǔ driving a capacitive load Driving capacitive loads with high performance amplifiers is not a problem as long as certain precautions are taken. The first is to realize that the THS413x has been internally compensated to maximize its bandwidth and slew rate performance. When the amplifier is compensated in this manner, capacitive loading directly on the output will decrease the device’s phase margin leading to high frequency ringing or oscillations. Therefore, for capacitive loads of greater than 10 pF, it is recommended that a resistor be placed in series with the output of the amplifier, as shown in Figure 33. A minimum value of 20 Ω should work well for most applications. For example, in 50-Ω transmission systems, setting the series resistor value to 50 Ω both isolates any capacitance loading and provides the proper line impedance matching at the source end. 390 Ω 20 Ω 390 Ω Output THS413x 20 Ω 390 Ω Output 390 Ω Figure 33. Driving a Capacitive Load 16 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SLOS318E − MAY 2000 − REVISED JANUARY 2004 APPLICATION INFORMATION Active antialias filtering For signal conditioning in ADC applications, it is important to limit the input frequency to the ADC. Low-pass filters can prevent the aliasing of the high frequency noise with the frequency of operation. The following figure presents a method by which the noise may be filtered in the THS413x. R2 C1 VCC R4 + R1 − VIN− + VIN+ R(t) THS413x − + C2 Vs C3 R3 VIN+ R1 THS1050 VIN− VOCM VOCM R3 C3 VIC R4 VCC− + C1 R2 Figure 34. Antialias Filtering The transfer function for this filter circuit is: ȡ ȣȡ Rt ȣ 2R4 ) Rt K ȧ ȧ xȧ H (f) + d ȧ f 2 1 jf ȧ 1 ) j2πfR4RtC3ȧ 2R4 ) Rt Ȥ Ȣ–ǒFSF x fcǓ ) Q FSF x fc ) 1Ȥ Ȣ FSF x fc + Where K + R2 R1 Ǹ2 x R2R3C1C2 1 and Q + Ǹ R3C1 ) R2C1 ) KR3C1 2π 2 x R2R3C1C2 K sets the pass band gain, fc is the cutoff frequency for the filter, FSF is a frequency scaling factor, and Q is the quality factor. FSF + ǸRe 2 ) |Im| 2 and Q + ǸRe 2 ) |Im| 2 2Re where Re is the real part, and Im is the imaginary part of the complex pole pair. Setting R2 = R, R3 = mR, C1 = C, and C2 = nC results in: FSF x fc + Ǹ2 x mn 1 and Q + Ǹ 1 ) m(1 ) K) 2πRC 2 x mn Start by determining the ratios, m and n, required for the gain and Q of the filter type being designed, then select C and calculate R for the desired fc. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 17 SLOS318E − MAY 2000 − REVISED JANUARY 2004 PRINCIPLES OF OPERATION theory of operation The THS413x is a fully differential amplifier. Differential amplifiers are typically differential in/single out, whereas fully differential amplifiers are differential in/differential out. THS413x Fully differential Amplifier VCC+ Differential Amplifier Rf R(g) _ VIN+ + R(g) _ VIN− + Rf VO+ + _ VO− VOCM VCC− Figure 35. Differential Amplifier Versus a Fully Differential Amplifier To understand the THS413x fully differential amplifiers, the definition for the pinouts of the amplifier are provided. Input voltage definition V Output voltage definition V Transfer function V ǒ + V ID Ǔ – ǒVI–Ǔ I) ǒ OD + V OD + V Output common mode voltage V OC Differential Structure Rejects Coupled Noise at The Input VIN− VIN+ Differential Structure Rejects Coupled Noise at The Power Supply Ǔ – ǒVO–Ǔ O) ID V IC V + OC ǒVI)Ǔ ) ǒVI–Ǔ 2 + ǒVO)Ǔ ) 2 x Aǒ Ǔ f + V OCM Differential Structure Rejects Coupled Noise at The Output VCC+ _ + VO+ + _ VO− VOCM VCC− Figure 36. Definition of the Fully Differential Amplifier 18 ǒVO–Ǔ POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SLOS318E − MAY 2000 − REVISED JANUARY 2004 PRINCIPLES OF OPERATION theory of operation (continued) The following schematics depict the differences between the operation of the THS413x, fully differential amplifier, in two different modes. Fully differential amplifiers can work with differential input or can be implemented as single in/differential out. Rf R(g) VIN− VCC+ VO+ −+ Vs +− VIN+ VO− VOCM R(g) VCC− Rf Note: For proper operation, maintain symmetry by setting Rf1 = Rf2 = Rf and R(g)1 = R(g)2 = R(g) ⇒ A = Rf/R(g) Figure 37. Amplifying Differential Signals Rf VIN− R(g) VIN+ Vs VCC+ RECOMMENDED RESISTOR VALUES −+ VO+ +− VO− VOCM R(g) GAIN R(g) Ω Rf Ω 1 2 5 10 390 374 402 402 390 750 2010 4020 VCC− Rf Figure 38. Single In With Differential Out If each output is measured independently, each output is one-half of the input signal when gain is 1. The following equations express the transfer function for each output: V O + 1 V 2 I The second output is equal and opposite in sign: V O + –1 V 2 I POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 19 SLOS318E − MAY 2000 − REVISED JANUARY 2004 PRINCIPLES OF OPERATION theory of operation (continued) Fully differential amplifiers may be viewed as two inverting amplifiers. In this case, the equation of an inverting amplifier holds true for gain calculations. One advantage of fully differential amplifiers is that they offer twice as much dynamic range compared to single-ended amplifiers. For example, a 1-VPP ADC can only support an input signal of 1 VPP. If the output of the amplifier is 2 VPP, then it will not be practical to feed a 2-VPP signal into the targeted ADC. Using a fully differential amplifier enables the user to break down the output into two 1-VPP signals with opposite signs and feed them into the differential input nodes of the ADC. In practice, the designer has been able to feed a 2-V peak-to-peak signal into a 1-V differential ADC with the help of a fully differential amplifier. The final result indicates twice as much dynamic range. Figure 39 illustrates the increase in dynamic range. The gain factor should be considered in this scenario. The THS413x fully differential amplifier offers an improved CMRR and PSRR due to its symmetrical input and output. Furthermore, second harmonic distortion is improved. Second harmonics tend to cancel because of the symmetrical output. a VOD= 1−0 = 1 VCC+ VIN− VIN+ +1 _ + + _ VO+ 0 VO− +1 0 VOCM VCC− VOD = 0−1 = −1 b Figure 39. Fully Differential Amplifier With Two 1-VPP Signals Similar to the standard inverting amplifier configuration, input impedance of a fully differential amplifier is selected by the input resistor, R(g). If input impedance is a constraint in design, the designer may choose to implement the differential amplifier as an instrumentation amplifier. This configuration improves the input impedance of the fully differential amplifier. The following schematic depicts the general format of instrumentation amplifiers. The general transfer function for this circuit is: V ǒ Ǔ R OD f 1 ) 2R2 + R R1 V –V (g) IN1 IN2 THS4012 VIN1 R(g) + _ Rf R2 _ R1 THS413x + R2 _ VIN2 + THS4012 R(g) Rf Figure 40. Instrumentation Amplifier 20 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SLOS318E − MAY 2000 − REVISED JANUARY 2004 PRINCIPLES OF OPERATION circuit layout considerations To achieve the levels of high frequency performance of the THS413x, follow proper printed-circuit board high frequency design techniques. A general set of guidelines is given below. In addition, a THS413x evaluation board is available to use as a guide for layout or for evaluating the device performance. D Ground planes—It is highly recommended that a ground plane be used on the board to provide all components with a low inductive ground connection. However, in the areas of the amplifier inputs and output, the ground plane can be removed to minimize the stray capacitance. D Proper power supply decoupling—Use a 6.8-µF tantalum capacitor in parallel with a 0.1-µF ceramic capacitor on each supply terminal. It may be possible to share the tantalum among several amplifiers depending on the application, but a 0.1-µF ceramic capacitor should always be used on the supply terminal of every amplifier. In addition, the 0.1-µF capacitor should be placed as close as possible to the supply terminal. As this distance increases, the inductance in the connecting trace makes the capacitor less effective. The designer should strive for distances of less than 0.1 inches between the device power terminals and the ceramic capacitors. D Sockets—Sockets are not recommended for high-speed operational amplifiers. The additional lead inductance in the socket pins will often lead to stability problems. Surface-mount packages soldered directly to the printed-circuit board is the best implementation. D Short trace runs/compact part placements—Optimum high frequency performance is achieved when stray series inductance has been minimized. To realize this, the circuit layout should be made as compact as possible, thereby minimizing the length of all trace runs. Particular attention should be paid to the inverting input of the amplifier. Its length should be kept as short as possible. This will help to minimize stray capacitance at the input of the amplifier. D Surface-mount passive components—Using surface-mount passive components is recommended for high frequency amplifier circuits for several reasons. First, because of the extremely low lead inductance of surface-mount components, the problem with stray series inductance is greatly reduced. Second, the small size of surface-mount components naturally leads to a more compact layout thereby minimizing both stray inductance and capacitance. If leaded components are used, it is recommended that the lead lengths be kept as short as possible. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 21 SLOS318E − MAY 2000 − REVISED JANUARY 2004 PRINCIPLES OF OPERATION power-down mode The power-down mode is used when power saving is required. The power-down terminal (PD) found on the THS413x is an active low terminal. If it is left as a no-connect terminal, the device will always stay on due to an internal 50 kΩ resistor to VCC. The threshold voltage for this terminal is approximately 1.4 V above VCC−. This means that if the PD terminal is 1.4 V above VCC −, the device is active. If the PD terminal is less than 1.4 V above VCC −, the device is off. For example, if VCC − = −5 V, then the device is on when PD reaches −3.6 V, (−5 V + 1.4 V = −3.6 V). By the same calculation, the device is off below −3.6 V. It is recommended to pull the terminal to VCC − in order to turn the device off. The following graph shows the simplified version of the power-down circuit. While in the power-down state, the amplifier goes into a high impedance state. The amplifier output impedance is typically greater than 1 MΩ in the power-down state. VCC 50 kΩ To Internal Bias Circuitry Control PD VCC− Figure 41. Simplified Power-Down Circuit Due to the similarity of the standard inverting amplifier configuration, the output impedance appears to be very low while in the power-down state. This is because the feedback resistor (Rf) and the gain resistor (R(g)) are still connected to the circuit. Therefore, a current path is allowed between the input of the amplifier and the output of the amplifier. An example of the closed loop output impedance is shown in Figure 42. OUTPUT IMPEDANCE (IN POWER DOWN) vs FREQUENCY Output Impedance − Ω 2200 VCC = ±5 V G=1 Rf = 1 kΩ PD = VCC− 1200 200 100 k 1M 10 M 100 M f − Frequency − Hz Figure 42 22 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1G SLOS318E − MAY 2000 − REVISED JANUARY 2004 PRINCIPLES OF OPERATION general PowerPAD design considerations The THS413x is available packaged in a thermally-enhanced DGN package, which is a member of the PowerPAD family of packages. This package is constructed using a downset leadframe upon which the die is mounted [see Figure 43(a) and Figure 43(b)]. This arrangement results in the lead frame being exposed as a thermal pad on the underside of the package [see Figure 43(c)]. Because this thermal pad has direct thermal contact with the die, excellent thermal performance can be achieved by providing a good thermal path away from the thermal pad. The PowerPAD package allows for both assembly and thermal management in one manufacturing operation. During the surface-mount solder operation (when the leads are being soldered), the thermal pad can also be soldered to a copper area underneath the package. Through the use of thermal paths within this copper area, heat can be conducted away from the package into either a ground plane or other heat dissipating device. The PowerPAD package represents a breakthrough in combining the small area and ease of assembly of the surface mount with the, heretofore, awkward mechanical methods of heatsinking. More complete details of the PowerPAD installation process and thermal management techniques can be found in the Texas Instruments Technical Brief, PowerPAD Thermally Enhanced Package (SLMA002). This document can be found at the TI web site (www.ti.com) by searching on the key word PowerPAD. The document can also be ordered through your local TI sales office. Refer to literature number SLMA002 when ordering. DIE Side View (a) Thermal Pad DIE End View (b) Bottom View (c) NOTE A: The thermal pad is electrically isolated from all terminals in the package. Figure 43. Views of Thermally Enhanced DGN Package POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 23 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. 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