THS4271-EP DGN-8 www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 LOW NOISE, HIGH SLEW RATE, UNITY GAIN STABLE VOLTAGE FEEDBACK AMPLIFIER Check for Samples: THS4271-EP FEATURES 1 • • 23 • • • • • Unity Gain Stability Low Voltage Noise – 3 nV/√Hz High Slew Rate: 1000 V/ms Low Distortion – –92 dBc THD at 30 MHz Wide Bandwidth: 1.4 GHz Supply Voltages – +5 V, ±5 V Evaluation Module Available APPLICATIONS • • • • • High Linearity ADC Preamplifier Wireless Communication Receivers Differential to Single-Ended Conversion DAC Output Buffer Active Filtering SUPPORTS DEFENSE, AEROSPACE, AND MEDICAL APPLICATIONS • • • • • • • (1) Controlled Baseline One Assembly/Test Site One Fabrication Site Available in Military (–55°C/125°C) Temperature Range (1) Extended Product Life Cycle Extended Product-Change Notification Product Traceability Additional temperature ranges are available - contact factory THS4271 NC IN− IN+ VS− 1 8 2 7 3 6 4 5 NC VS+ VOUT NC DESCRIPTION The THS4271 is a low-noise, high slew rate, unity gain stable voltage-feedback amplifier designed to run from supply voltages as low as 5 V. The combination of low-noise, high slew rate, wide bandwidth, low distortion, and unity gain stability make the THS4271 a high performance device across multiple ac specifications. Designers using the THS4271 are rewarded with higher dynamic range over a wider frequency band without the stability concerns of decompensated amplifiers. The devices are available in SOIC, MSOP with PowerPAD™, and leadless MSOP with PowerPAD™ packages. The THS4271 may have low-level oscillation when the die temperature (also known as the junction temperature) exceeds +60°C and is not recommended for new designs. For more information, see Maximum Die Temperature to Prevent Oscillation. RELATED DEVICES DEVICE DESCRIPTION THS4211 1-GHz voltage-feedback amplifier THS4503 Wideband, fully-differential amplifier THS3202 Dual, wideband current feedback amplifier 1 2 3 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. PowerPAD is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2004–2010, Texas Instruments Incorporated THS4271-EP www.ti.com Harmonic and Intermodulation Distortion − dB SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 HARMONIC AND INTERMODULATION DISTORTION vs FREQUENCY −40 Gain = 2 Rf = 249 Ω RL = 150 Ω VO = 2 VPP VS = ±5 V −50 −60 IMD3 200 kHz Tone Spacing VO = 2 VPP Envelope −70 −80 HD2 −90 HD3 −100 1 10 f − Frequency − MHz 100 Low-Noise, Low-Distortion, Wideband Application Circuit +5 V 50 Ω Source 50 Ω + VI 49.9 Ω VO THS4271 _ -5 V 249 Ω 249 Ω NOTE: Power supply decoupling capacitors not shown This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PACKAGING/ORDERING INFORMATION (1) ORDERABLE PACKAGE AND NUMBER PLASTIC MSOP (2) PowerPAD PACKAGE PACKAGE MARKING THS4271MDGNTEP BLT THS4271MDGNREP (1) (2) 2 For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. All packages are available taped and reeled. The R suffix standard quantity is 2500 (e.g., THS4271MDGNREP). Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 ABSOLUTE MAXIMUM RATINGS Over operating free-air temperature range unless otherwise noted (1) UNIT VS Supply voltage VI Input voltage IO Output current 16.5 V ±VS 100 mA Continuous power dissipation TJ TJ TJ (2) (3) Tstg See Dissipation Ratings Table Maximum junction temperature +150°C Maximum junction temperature, continuous operation long term reliability +125°C Maximum junction temperature to prevent oscillation +60°C Storage temperature range –65°C to +150°C Lead temperature (1,6 mm (1/16 inch) from case for 10 seconds) +300°C HBM 3000 V ESD ratings CDM 1000 V MM (1) (2) (3) 100 V The absolute maximum temperature under any condition is limited by the constraints of the silicon process. Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. Long-term high-temperature storage and/or extended use at maximum recommended operating conditions may result in a reduction of overall device life. See Figure 1 for additional information on thermal derating. See Maximum Die Temperature to Prevent Oscillation section in the Application Information of this data sheet. PACKAGE DISSIPATION RATINGS (1) (2) PACKAGE qJC (°C/W) qJA (1) (°C/W) DGN (8 pin) (2) 4.7 58.4 This data was taken using the JEDEC standard High-K test PCB. The THS4271 may incorporate a PowerPAD™ on the underside of the chip. This feature acts as a heat sink 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 briefs SLMA002 and SLMA004 for more information about utilizing the PowerPAD thermally enhanced package. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 3 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com WIREBOND LIFE vs JUNCTION TEMPERATURE 1G Time-to-Fail - Hrs 100M 80°C, 74M Hrs 10M 100°C, 5.9M Hrs 1M 120°C, 490K Hrs 100K 140°C, 58K Hrs 10K 80 90 100 120 110 130 140 150 TJ - Junction Temperature - °C Figure 1. EME−G600 Estimated Wirebond Life RECOMMENDED OPERATING CONDITIONS Supply voltage (VS+ and VS–) Dual supply Single supply Input common-mode voltage range MIN MAX ±2.5 ±5 5 10 VS- + 1.4 VS+ – 1.4 UNIT V V PIN ASSIGNMENTS DGN PACKAGE (TOP VIEW) 1 8 NC ININ+ 2 7 3 6 VS- 4 5 NC VS+ VOUT NC NC - No internal connection 4 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 ELECTRICAL CHARACTERISTICS: VS = ±5 V At RF = 249 Ω, RL = 499 Ω, G = +2, unless otherwise noted. TYP PARAMETER TEST CONDITIONS +25°C OVER TEMPERATURE (1) +25°C –55°C to +125°C UNITS MIN/ TYP/ MAX AC PERFORMANCE G = 1, VO = 100 mVPP, RL = 150 Ω 1.4 GHz Typ G = –1, VO = 100 mVPP 400 MHz Typ G = 2, VO = 100 mVPP 390 MHz Typ G = 5, VO = 100 mVPP 85 MHz Typ G = 10, VO = 100 mVPP 40 MHz Typ 0.1-dB flat bandwidth G = 1, VO = 100 mVPP, RL = 150 Ω 200 MHz Typ Gain bandwidth product G > 10, f = 1 MHz 400 MHz Typ Full-power bandwidth G = –1, VO = 2 Vp 80 MHz Typ G = 1, VO = 2 V Step 950 V/ms Typ Small-signal bandwidth Slew rate G = –1, VO = 2 V Step 1000 V/ms Typ Settling time to 0.1% G = –1, VO = 4 V Step 25 ns Typ Settling time to 0.01% G = –1, VO = 4 V Step 38 ns Typ Harmonic distortion G = 1, VO = 1 VPP, f = 30 MHz RL = 150 Ω -92 dBc Typ RL = 499 Ω -80 dBc Typ RL = 150 Ω -95 dBc Typ RL = 499 Ω -95 dBc Typ RL = 150 Ω -65 dBc Typ RL = 499 Ω -70 dBc Typ RL = 150 Ω -80 dBc Typ RL = 499 Ω -90 dBc Typ Third-order intermodulation (IMD3) G = 2, VO = 2 VPP, RL = 150 Ω, f = 70 MHz -60 dBc Typ Third-order output intercept (OIP3) G = 2, VO = 2 VPP, RL = 150Ω, f = 70 MHz 35 dBm Typ Differential gain (NTSC, PAL) G = 2, RL = 150 Ω 0.007% Differential phase (NTSC, PAL) G = 2, RL = 150 Ω 0.004 ° Typ Input voltage noise f = 1 MHz 3 nV/√Hz Typ Input current noise f = 1 MHz 3 pA√Hz Typ Open-loop voltage gain (AOL) VO = ± 50 mV, RL = 499 Ω 75 65 56 dB Min Input offset voltage VCM = 0 V 5 14 ±16 mV Max Average offset voltage drift VCM = 0 V ±10 mV/°C Typ Input bias current VCM = 0 V 6 15 18 mA Max Average bias current drift VCM = 0 V ±10 nA/°C Typ Input offset current VCM = 0 V 8 mA Max Average offset current drift VCM = 0 V ±10 nA/°C Typ Min Second harmonic distortion Third harmonic distortion Harmonic distortion Second harmonic distortion Third harmonic distortion G = 2, VO = 2 VPP, f = 30 MHz Typ DC PERFORMANCE 1 6 INPUT CHARACTERISTICS Common-mode input range ±4 ±3.6 ±3.5 V Common-mode rejection ratio VCM = ± 2 V 72 67 62 dB Min Input resistance Common-mode 5 MΩ Typ (1) See application section "Maximum Die Temperature to Prevent Oscillation". Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 5 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com ELECTRICAL CHARACTERISTICS: VS = ±5 V (continued) At RF = 249 Ω, RL = 499 Ω, G = +2, unless otherwise noted. TYP PARAMETER TEST CONDITIONS +25°C Input capacitance Common-mode / differential OVER TEMPERATURE (1) +25°C –55°C to +125°C 0.4/0.8 UNITS MIN/ TYP/ MAX pF Typ OUTPUT CHARACTERISTICS Output voltage swing G = +2 ±4 ±3.75 ±3.6 V Min Output current (sourcing) RL = 10 Ω 160 120 104 mA Min Output current (sinking) RL = 10 Ω 80 60 44 mA Min Output impedance f = 1 MHz 0.1 Ω Typ POWER SUPPLY Specified operating voltage ±5 ±5 ±5 V Max Maximum quiescent current 22 24 34 mA Max Minimum quiescent current 22 20 13 mA Min Power-supply rejection (+PSRR) VS+ = 5.5 V to 4.5 V, VS– = 5 V 85 75 58 dB Min Power-supply rejection (-PSRR) VS+ = 5 V, VS– = -5.5 V to -4.5 V 75 65 57 dB Min 6 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 ELECTRICAL CHARACTERISTICS: VS = 5 V At RF = 249 Ω, RL = 499 Ω, G = +2, unless otherwise noted. TYP PARAMETER TEST CONDITIONS +25°C OVER TEMPERATURE (1) +25°C –55°C to +125°C UNITS MIN/ TYP/ MAX AC PERFORMANCE G = 1, VO = 100 mVPP, RL = 150 Ω 1.2 GHz Typ G = –1, VO = 100 mVPP 380 MHz Typ G = 2, VO = 100 mVPP 360 MHz Typ G = 5, VO = 100 mVPP 80 MHz Typ G = 10, VO = 100 mVPP 35 MHz Typ 0.1-dB flat bandwidth G = 1, VO = 100 mVPP, RL = 150 Ω 120 MHz Typ Gain bandwidth product G > 10, f = 1 MHz 350 MHz Typ Full-power bandwidth G = –1, VO = 2 Vp 60 MHz Typ G = 1, VO = 2 V Step 700 V/ms Typ Small-signal bandwidth Slew rate G = –1, VO = 2 V Step 750 V/ms Typ Settling time to 0.1% G = –1, VO = 2 V Step 18 ns Typ Settling time to 0.01% G = –1, VO = 2 V Step 66 ns Typ Harmonic distortion G = 1, VO = 1 VPP, f = 30 MHz RL = 150 Ω 75 dBc Typ RL = 499 Ω 72 dBc Typ RL = 150 Ω -70 dBc Typ RL = 499 Ω 70 dBc Typ Third-order intermodulation (IMD3) G = 2, VO = 1 VPP, RL = 150Ω, f = 70 MHz -65 dBc Typ Third-order output intercept (OIP3) G = 2, VO = 1 VPP, RL = 150Ω, f = 70 MHz 32 dBm Typ Input voltage noise f = 1 MHz 3 nV/√Hz Typ Input current noise f = 10 MHz 3 pA/√Hz Typ Open-loop voltage gain (AOL) VO = ± 50 mV, RL = 499 Ω 68 63 56 dB Min Input offset voltage VCM = VS/2 5 ±14 ±16 mV Max Average offset voltage drift VCM = VS/2 ±10 mV/°C Typ Input bias current VCM = VS/2 6 15 18 mA Max Average bias current drift VCM = VS/2 ±10 nA/°C Typ Input offset current VCM = VS/2 Average offset current drift VCM = VS/2 Second harmonic distortion Third harmonic distortion DC PERFORMANCE 1 6 8 mA Max ±10 nA/°C Typ V Min INPUT CHARACTERISTICS Common-mode input range 1/4 1.3/3.7 1.5/3.5 67 62 Common-mode rejection ratio VCM = ± 0.5 V, VO = 2.5 V 72 dB Min Input resistance Common-mode 5 MΩ Typ Input capacitance Common-mode / differential 0.4/0.8 pF Typ Output voltage swing G = +2 1.2/3.8 1.4/3.6 1.5/3.5 V Min Output current (sourcing) RL = 10 Ω 120 90 78 mA Min Output current (sinking) RL = 10 Ω 65 45 37 mA Min Output impedance f = 1 MHz 0.1 Ω Typ OUTPUT CHARACTERISTICS (1) See application section "Maximum Die Temperature to Prevent Oscillation". Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 7 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com ELECTRICAL CHARACTERISTICS: VS = 5 V (continued) At RF = 249 Ω, RL = 499 Ω, G = +2, unless otherwise noted. TYP PARAMETER TEST CONDITIONS OVER TEMPERATURE (1) UNITS MIN/ TYP/ MAX 10 V Max 34 mA Max 18 13 mA Min +25°C +25°C –55°C to +125°C Specified operating voltage 5 10 Maximum quiescent current 20 23 Minimum quiescent current 20 POWER SUPPLY Power-supply rejection (+PSRR) VS+ = 5.5 V to 4.5 V, VS– = 0 V 85 70 57 dB Min Power-supply rejection (-PSRR) VS+ = 5 V, VS– = –0.5 V to 0.5 V 75 65 56 dB Min 8 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 TYPICAL CHARACTERISTICS Table of Graphs (±5 V) FIGURE Small-signal unity gain frequency response 1 Small-signal frequency response 2 0.1-dB gain flatness frequency response 3 Large-signal frequency response 4 Slew rate vs Output voltage Harmonic distortion vs Frequency Harmonic distortion vs Output voltage swing Third-order intermodulation distortion vs Frequency 14, 16 Third-order intercept point vs Frequency 15, 17 Voltage and current noise vs Frequency 18 Differential gain vs Number of loads 19 Differential phase vs Number of loads 20 Settling time 5 6, 7, 8, 9 10, 11, 12, 13 21 Quiescent current vs Supply voltage 22 Output voltage vs Load resistance 23 Frequency response vs Capacitive load 24 Open-loop gain and phase vs Frequency 25 Open-loop gain vs Supply voltage 26 Rejection ratios vs Frequency 27 Rejection ratios vs Case temperature 28 Common-mode rejection ratio vs Input common-mode range 29 Input offset voltage vs Case temperature 30 Input bias and offset current vs Case temperature 31 Small-signal transient response 32 Large-signal transient response 33 Overdrive recovery 34 Closed-loop output impedance vs Frequency 35 Power-down quiescent current vs Supply voltage 36 Power-down output impedance vs Frequency 37 Turn-on and turn-off delay times 38 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 9 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com Table of Graphs (5 V) FIGURE Small-signal unity gain frequency response 39 Small-signal frequency response 40 0.1-dB gain flatness frequency response 41 Large-signal frequency response 42 Slew rate vs Output voltage Harmonic distortion vs Frequency 44, 45, 46, 47 Harmonic distortion vs Output voltage swing 48, 49, 50, 51 Third-order intermodulation distortion vs Frequency 52, 54 Third-order intercept point vs Frequency 53, 55 Voltage and current noise vs Frequency 56 Settling time 43 57 Quiescent current vs Supply voltage 58 Output voltage vs Load resistance 59 Frequency response vs Capacitive load 60 Open-loop gain and phase vs Frequency 61 Open-loop gain vs Case temperature 62 Rejection ratios vs Frequency 63 Rejection ratios vs Case temperature 64 Common-mode rejection ratio vs Input common-mode range 65 Input offset voltage vs Case temperature 66 Input bias and offset current vs Case temperature 67 Small-signal transient response 68 Large-signal transient response 69 Overdrive recovery 70 Closed-loop output impedance vs Frequency 71 Power-down quiescent current vs Supply voltage 72 Power-down output impedance vs Frequency 73 Turn-on and turn-off delay times 10 74 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 TYPICAL CHARACTERISTICS: ±5 V SMALL-SIGNAL UNIT GAIN FREQUENCY RESPONSE SMALL-SIGNAL FREQUENCY RESPONSE 22 2 1 0 −1 −2 0 Gain = 10 18 Small Signal Gain − dB 16 Gain = 5 14 RL = 499 Ω Rf = 249 Ω VO = 100 mVPP VS = ±5 V 12 10 8 6 Gain = 2 4 2 −3 −4 100 k 1M 10 M 1G 100 M Gain = −1 −2 −4 100 k 1M 10 G f − Frequency − Hz 10 M 100 M f − Frequency − Hz 1M 10 M 100 M −50 1000 8 6 800 Rise 600 400 Gain = −1 RL = 499 Ω Rf = 249 Ω VS = ±5 V Gain = 2 200 2 0 100 k Harmonic Distortion − dBc 10 Gain = 1 VO = 1 VPP VS = ±5 V Fall RL = 499 Ω Rf = 249 Ω VO = 1 VPP VS = ±5 V 10 M 100 M 0 1G −60 −70 HD3, RL = 499Ω HD3, RL = 150Ω −80 HD2, RL = 150Ω HD2, RL = 499Ω −90 −100 0 1M f − Frequency − Hz 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 1 VO − Output Voltage − V 10 f − Frequency − MHz Figure 5. Figure 6. Figure 7. HARMONIC DISTORTION vs FREQUENCY HARMONIC DISTORTION vs FREQUENCY HARMONIC DISTORTION vs FREQUENCY −50 −50 Harmonic Distortion − dBc Gain = 1 VO = 2 VPP VS = ±5 V HD2, RL = 150Ω HD3, RL = 499Ω −80 HD3, RL = 150Ω HD2, RL = 499Ω −100 100 Figure 8. 100 −50 Gain = 2 Rf = 249 Ω VO = 1 VPP VS = ±5 V −60 −70 HD3, RL = 499Ω HD3, RL = 150Ω −80 HD2, RL = 499Ω HD2, RL = 150Ω −90 −100 10 f − Frequency − MHz 1G f − Frequency − Hz HARMONIC DISTORTION vs FREQUENCY SR − Slew Rate − V/ µ s Large Signal Gain − dB Gain = 1 RL = 150 Ω VO = 100 mVPP VS = ±5 V SLEW RATE vs OUTPUT VOLTAGE 12 1 −0.7 LARGE-SIGNAL FREQUENCY RESPONSE 14 −90 −0.6 Figure 4. Gain = 5 −70 −0.5 Figure 3. Gain = 10 −60 −0.4 −1 100 k 1G 1200 4 −0.3 −0.9 20 16 −0.2 Figure 2. 22 18 −0.1 −0.8 0 Harmonic Distortion − dBc Small Signal Gain − dB 3 0.1 20 Gain = 1 RL = 150 Ω VO = 100 mVPP VS = ±5 V Small Signal Gain − dB 4 Harmonic Distortion − dBc 0.1-dB GAIN FLATNESS FREQUENCY RESPONSE Gain = 2 Rf = 249 Ω VO = 2 VPP VS = ±5 V HD3, RL = 499Ω −60 −70 HD2, RL = 499Ω HD3, RL = 150Ω −80 HD2, RL = 150Ω −90 −100 1 10 f − Frequency − MHz Figure 9. 100 1 10 f − Frequency − MHz Figure 10. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 100 11 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com TYPICAL CHARACTERISTICS: ±5 V (continued) HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING −50 −50 −60 Harmonic Distortion − dBc Gain = 1 f= 8 MHz VS = ±5 V HD3, RL = 150Ω −70 HD3, RL = 499Ω −80 HD2, RL = 499Ω HD2, RL = 150Ω −90 −60 Gain = 1 f= 32 MHz VS = ±5 V −70 HD2, RL = 150Ω Gain = 2 Rf = 249 Ω f = 8 MHz VS = ±5 V HD2, RL = 499Ω Harmonic Distortion − dBc −50 Harmonic Distortion − dBc HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING HD3, RL = 150Ω −80 −90 −60 HD3, RL = 499Ω −70 HD2, RL = 499Ω HD3, RL = 150Ω −80 HD2, RL = 150Ω −90 HD3, RL = 499Ω −100 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 VO − Output Voltage Swing − ±V 5 HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING THIRD-ORDER INTERMODULATION DISTORTION vs FREQUENCY THIRD-ORDER INTERMODULATION DISTORTION vs FREQUENCY Gain = 2 Rf = 249 Ω f = 32 MHz HD2, RL = 499Ω VS = ±5 V HD2, RL = 150Ω −60 −70 −80 HD3, RL = 150Ω −90 HD3, RL = 499Ω 0 1 2 3 4 VO − Output Voltage Swing − ±V 55 −40 Gain = 1 RL = 150 Ω VS = ±5 V 200 kHz Tone Spacing −50 Third-Order Output Intersept Point − dBm Third-Order Intermodulation Distortion − dBc Figure 13. −60 −70 VO = 2 VPP −80 −90 VO = 1 VPP −100 5 10 Gain = 1 RL = 150 Ω VS = ±5 V 200 kHz Tone Spacing 50 VO = 2 VPP 45 VO = 1 VPP 40 35 30 100 0 20 40 60 f − Frequency − MHz f − Frequency − MHz 80 100 Figure 14. Figure 15. Figure 16. THIRD-ORDER INTERMODULATION DISTORTION vs FREQUENCY THIRD-ORDER OUTPUT INTERCEPT POINT vs FREQUENCY VOLTAGE AND CURRENT NOISE vs FREQUENCY 50 −60 VO = 2 VPP −70 −80 VO = 1 VPP −90 −100 10 100 45 40 Gain = 2 RL = 150 Ω VS = ±5 V 200 kHz Tone Spacing VO = 1 VPP 35 30 0 20 40 60 f − Frequency − MHz f − Frequency − MHz Figure 17. Figure 18. 80 Submit Documentation Feedback 100 Hz −50 100 VO = 2 VPP Hz Gain = 2 RL = 150 Ω VS = ±5 V 200 kHz Tone Spacing Vn − Voltage Noise − nV/ −40 Third-Order Output Intersept Point − dBm Harmonic Distortion − dBc 5 Figure 12. −100 Third-Order Intermodulation Distortion − dBc 1 2 3 4 VO − Output Voltage Swing − ±V Figure 11. −50 12 −100 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 VO − Output Voltage Swing − ±V 100 Vn 10 10 In 1 100 1k 10 k 100 k 1M 10 M I n − Current Noise − pA/ −100 1 100 M f − Frequency − Hz Figure 19. Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 TYPICAL CHARACTERISTICS: ±5 V (continued) DIFFERENTIAL GAIN vs NUMBER OF LOADS DIFFERENTIAL PHASE vs NUMBER OF LOADS 0.015 Gain = 2 Rf = 1.3 kΩ VS = ±5 V 40 IRE − NTSC and Pal Worst Case ±100 IRE Ramp 0.09 ° Differential Phase − 0.020 3 NTSC 0.010 0.08 0.07 Rising Edge 2 VO − Output Voltage − V Gain = 2 Rf = 1.3 kΩ VS = ±5 V 40 IRE − NTSC and Pal Worst Case ±100 IRE Ramp 0.025 Differential Gain − % SETTLING TIME 0.10 0.030 0.06 0.05 PAL 0.04 0.03 NTSC 0.02 PAL 0.005 1 Gain = −1 RL = 499 Ω Rf = 249 Ω f= 1 MHz VS = ±5 V 0 −1 Falling Edge −2 0.01 0 0 1 2 3 4 5 6 7 0 8 −3 0 Number of Loads − 150 Ω 1 2 3 4 5 6 7 8 0 Figure 22. QUIESCENT CURRENT vs SUPPLY VOLTAGE OUTPUT VOLTAGE vs LOAD RESISTANCE FREQUENCY RESPONSE vs CAPACITIVE LOAD 25 20 TA = −40°C 15 10 5 0 VS = ±5 V TA = −40 to 85°C 3 2 Normalized Gain - dB VO − Output Voltage − V TA = 25°C 1 0 −1 −2 3 3.5 4 4.5 10 5 R(ISO) = 25 W, CL = 10 pF -1 R(ISO) = 15 W, CL = 50 pF -1.5 R(ISO) = 10 W, CL = 100 pF -2 -2.5 −5 2.5 -0.5 −3 −4 0 VS − Supply Voltage − ±V 100 1k RL − Load Resistance − Ω RL = 499 W VS = ±5 V -3 1M 10 k 10 M 100 M Capacitive Load - Hz Figure 23. Figure 24. Figure 25. OPEN-LOOP GAIN AND PHASE vs FREQUENCY OPEN-LOOP GAIN vs SUPPLY VOLTAGE REJECTION RATIOS vs FREQUENCY 0 VS = ±5 V Gain 60 80 40 80 30 100 Phase 120 Phase − ° 60 20 TA = 85°C 65 60 0 160 55 180 1G 50 1M 10 M 100 M f − Frequency − Hz Figure 26. PSRR+ 80 70 140 100 k TA = 25°C 75 10 −10 10 k TA = −40°C 40 50 VS = ±5 V 90 20 Open-Loop Gain − dB 70 100 85 Rejection Ratios − dB 80 25 0.5 5 4 Quiescent Current − mA 20 Figure 21. TA = 85°C Open-Loop Gain − dB 10 15 t − Time − ns Figure 20. 30 2 5 Number of Loads − 150 Ω 70 PSRR− 60 50 CMRR 40 30 20 10 0 2.5 3 3.5 4 4.5 Supply Voltage − ±VS Figure 27. 5 10 k 100 k 1M 10 M f − Frequency − Hz Figure 28. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 100 M 13 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com TYPICAL CHARACTERISTICS: ±5 V (continued) COMMON-MODE REJECTION RATIOS vs INPUT COMMON-MODE RANGE VS = ±5 V PSRR+ 100 Rejection Ratios − dB PSRR− 80 60 CMMR 40 20 0 −40−30−20−100 10 20 30 40 50 60 70 80 90 INPUT OFFSET VOLTAGE vs CASE TEMPERATURE 100 5 90 VOS − Input Offset Voltage − mV 120 CMRR − Common-Mode Rejection Ratio − dB REJECTION RATIOS vs FREQUENCY 80 70 60 50 40 30 20 VS = ±5 V TA = 25°C 10 0 −6 −4 Case Temperature − °C −2 0 2 4 0 −40−30−20−10 0 10 20 30 40 50 60 70 80 90 6 TC − Case Temperature − °C Figure 31. INPUT BIAS AND OFFSET CURRENT vs CASE TEMPERATURE SMALL-SIGNAL TRANSIENT RESPONSE LARGE-SIGNAL TRANSIENT RESPONSE 1.17 0.3 1.5 IOS 1.15 0.2 1 1.14 5 IIB+ 4 1.13 3 1.12 2 1.11 1 1.1 0.1 0 Gain = −1 RL = 499 Ω Rf = 249 Ω tr/tf = 300 ps VS = ±5 V −0.1 −0.2 1.09 0 −40−30−20−10 0 10 20 30 40 50 60 70 80 90 VO − Output Voltage − V 6 VO − Output Voltage − V 1.16 IIB− I OS − Input Offset Current − µ A 0.5 0 Gain = −1 RL = 499 Ω Rf = 249 Ω tr/tf = 300 ps VS = ±5 V −0.5 −1 −1.5 −0.3 0 TC − Case Temperature − °C 2 4 6 8 10 12 14 16 0 2 t − Time − ns 4 6 8 10 12 14 t − Time − ns 16 18 Figure 32. Figure 33. Figure 34. OVERDRIVE RECOVERY CLOSED-LOOP OUTPUT IMPEDANCE vs FREQUENCY POWER-DOWN QUIESCENT CURRENT vs SUPPLY VOLTAGE 6 1.5 2 1 1 0.5 0 0 −1 −0.5 −2 −1 −3 −1.5 −4 −2 −5 −2.5 −3 −6 1 t − Time − µs Figure 35. Closed-Loop Output Impedance − Ω 2 3 VI − Input Voltage − V 2.5 4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1000 3 VS = ±5 V 100 1200 Gain = 1 RL = 499 Ω PIN = −1 dBm VS = ±5 V Power-down Quiescent Current − µ A I IB − Input Bias Current − µ A 1 Figure 30. 7 Single-Ended Output Voltage − V VS = ±5 V 2 Input Common-Mode Range − V VS = ±5 V 14 VS = 5 V 3 Figure 29. 8 5 4 10 1 0.1 0.01 0.001 100 k 1M 10 M 100 M f − Frequency − Hz Figure 36. Submit Documentation Feedback 1G TA = 85°C 1000 TA = 25°C 800 TA = −40°C 600 400 200 0 2.5 3 3.5 4 4.5 5 VS − Supply Voltage − ±V Figure 37. Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 TYPICAL CHARACTERISTICS: ±5 V (continued) POWER-DOWN OUTPUT IMPEDANCE vs FREQUENCY Power-down Output Impedance − Ω 1M Gain = 1 RL = 150 Ω VIN = 1 dBm VS = ±5 V 100 k 10 k 100 1 100 k 1M 10 M 100 M f − Frequency − Hz 1G Figure 38. TYPICAL CHARACTERISTICS: 5 V SMALL-SIGNAL UNIT GAIN FREQUENCY RESPONSE SMALL-SIGNAL UNIT GAIN FREQUENCY RESPONSE 20 0 −1 −2 −3 −4 100 k 1M 0.1 Gain = 10 18 10 M 100 M 1G 16 Gain = 5 14 RL = 499 Ω Rf = 249 Ω VO = 100 mVPP VS = 5 V 12 10 8 6 Gain = 2 4 2 0 Gain = −1 −2 −4 100 k 1M 10 G f − Frequency − Hz −0.3 −0.4 −0.5 −0.6 Gain = 1 RL = 150 Ω VO = 100 mVPP VS = 5 V −0.7 −0.8 −0.9 10 M 100 M f − Frequency − Hz −1 100 k 1G 1M 10 M 100 M LARGE-SIGNAL FREQUENCY RESPONSE SLEW RATE vs FREQUENCY HARMONIC DISTORTION DISTORTION vs FREQUENCY 1000 14 12 10 SR − Slew Rate − V/ µ s 16 Gain = 1 RL = 499 Ω Rf = 249 Ω VS = 5 V 900 Gain = 5 RL = 499 Ω Rf = 249 Ω VO = 1 VPP VS = 5 V 6 Gain = 2 700 600 Fall Rise 500 400 300 200 Gain = 1 VO = 1 VPP RL = 150 Ω VS = 5 V −60 −70 −80 HD3 HD2 −90 100 2 0 100 k 800 −50 Harmonic Distortion − dBc Gain = 10 1G f − Frequency − Hz Figure 42. 18 Large Signal Gain − dB −0.2 Figure 41. 20 4 0 −0.1 Figure 40. 22 8 Small Signal Gain − dB Gain = 1 RL = 150 Ω VO = 100 mVPP VS = 5 V Small Signal Gain − dB Small Signal Gain − dB 1 0.2 22 3 2 0.1-dB GAIN FLTANESS FREQUENCY RESPONSE −100 0 1M 10 M 100 M 1G f − Frequency − Hz Figure 43. 0 0.5 1 1.5 2 VO − Output Voltage −V Figure 44. 2.5 1 10 Figure 45. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 100 f − Frequency − MHz 15 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com TYPICAL CHARACTERISTICS: 5 V (continued) HARMONIC DISTORTION vs FREQUENCY HARMONIC DISTORTION vs FREQUENCY −50 −20 −30 Harmonic Distortion − dBc Gain = 1 VO = 2 VPP RL = 150 Ω VS = 5 V −40 −50 HD3 −60 −70 HD2 −80 0 Gain = 2 Rf = 249 Ω RL = 249 Ω VO = 1 VPP VS = 5 V −60 −70 −80 HD3 −90 HD2 1 10 −100 −30 −40 −50 HD2 −60 −70 HD3 −80 100 −100 1 f − Frequency − MHz 10 f − Frequency − MHz 1 100 10 100 f − Frequency − MHz Figure 46. Figure 47. Figure 48. HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING −50 −40 Gain = 1 f= 8 MHz VS = 5 V −50 Harmonic Distortion − dBc −60 HD3, RL = 499Ω −70 HD3, RL = 150Ω −80 HD2, RL = 499Ω −90 Gain = 1 f= 32 MHz VS = 5 V HD2, RL = 150Ω −60 HD3, RL = 499Ω Harmonic Distortion − dBc −50 Harmonic Distortion − dBc −20 −90 −90 −100 Gain = 2 Rf = 249 Ω RL = 150 Ω VO = 2 VPP VS = 5 V −10 Harmonic Distortion − dBc 0 −10 Harmonic Distortion − dBc HARMONIC DISTORTION vs FREQUENCY HD3, RL = 150Ω −70 HD2, RL = 150Ω −80 HD2, RL = 499Ω Gain = 2 Rf = 249 Ω f = 8 MHz VS = 5 V −60 HD3, RL = 150Ω HD2, RL = 150Ω −70 −80 HD2, RL = 499Ω −90 −90 HD3, RL = 499Ω −100 0 0.5 1 1.5 2 −100 −100 2.5 0 VO − Output Voltage Swing − V 0.5 1 1.5 2 VO − Output Voltage Swing − V 2.5 Figure 50. Figure 51. HARMONIC DISTORTION vs OUTPUT VOLTAGE SWING THIRD-ORDER INTERMODULATION DISTORTION vs FREQUENCY THIRD-ORDER OUTPUT INTERCEPT POINT vs FREQUENCY HD3, RL = 150Ω HD2, RL = 150Ω −60 HD3, RL = 499Ω −70 HD2, RL = 499Ω −80 −90 −100 0 0.5 1 1.5 2 VO − Output Voltage Swing − V Figure 52. 2.5 45 −40 Third-Order Output Intersept Point − dBm −50 Third-Order Intermodulation Distortion − dBc Gain = 2 Rf = 249 Ω f = 32 MHz VS = 5 V −40 Harmonic Distortion − dBc 0 2.5 Figure 49. −30 16 0.5 1 1.5 2 VO − Output Voltage Swing − V Gain = 1 RL = 150 Ω VO = 1 VPP VS = 5 V 200 kHz Tone Spacing −50 −60 −70 −80 −90 −100 10 100 40 35 30 Gain = 1 RL = 150 Ω VO = 1 VPP VS = 5 V 200 kHz Tone Spacing 25 20 0 20 40 60 f − Frequency − MHz f − Frequency − MHz Figure 53. Figure 54. Submit Documentation Feedback 80 100 Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 TYPICAL CHARACTERISTICS: 5 V (continued) THIRD-ORDER OUTPUT INTERCEPT POINT vs FREQUENCY −70 −80 −90 −100 10 40 35 30 0 20 40 80 100 Hz 1k 10 k 100 k 1M 10 M 1 100 M f − Frequency − Hz f − Frequency − MHz Figure 55. Figure 56. Figure 57. SETTLING TIME QUIESCENT CURRENT vs SUPPLY VOLTAGE OUTPUT VOLTAGE vs LOAD RESISTANCE 30 1.5 2 TA = 85°C Rising Edge 1.5 25 1 0 −0.5 Falling Edge VO − Output Voltage − V Gain = −1 RL = 499 Ω Rf = 249 Ω f= 1 MHz VS = 5 V 0.5 TA = 25°C Quiescent Current − mA 20 TA = −40°C 15 10 −1 5 −1.5 0 1 VS = 5 V TA = −40 to 85°C 0.5 0 −0.5 −1 −1.5 0 2 4 6 8 10 12 14 16 18 20 22 24 −2 2 2.5 3 3.5 4 4.5 VS − Supply Voltage − ±V t − Time − ns Figure 59. Figure 60. FREQUENCY RESPONSE vs CAPACITIVE LOAD OPEN-LOOP GAIN AND PHASE vs FREQUENCY OPEN-LOOP GAIN vs CASE TEMPERATURE 80 −1 R(ISO) = 15 Ω, CL = 50 pF −1.5 R(ISO) = 10 Ω, CL = 100 pF −2 RL = 499 Ω VS = 5 V −3 10 100 Capacitive Load − MHz Figure 61. 50 60 40 80 30 100 20 Phase 120 10 140 0 160 −10 10 k 180 100 k 1M 10 M 80 TA = −40°C TA = 25°C 40 100 M 1G f − Frequency − Hz Figure 62. Open-Loop Gain − dB R(ISO) = 25 Ω, CL = 10 pF Open-Loop Gain − dB −0.5 20 Gain 60 75 70 TA = 85°C 65 60 55 50 2.5 3 3.5 4 4.5 Product Folder Link(s): THS4271-EP 5 Case Temperature − °C Figure 63. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated 10 k 85 0 VS = 5 V 70 0 1 100 1k RL − Load Resistance − Ω Figure 58. 0.5 −2.5 10 5 Phase − ° VO − Output Voltage − V 60 10 In 1 100 25 100 Vn 10 I n − Current Noise − pA/ −60 100 Hz −50 100 Gain = 2 RL = 150 Ω VO = 2 VPP VS = 5 V 200 kHz Tone Spacing Vn − Voltage Noise − nV/ Gain = 2 RL = 150 Ω VO = 2 VPP VS = 5 V 200 kHz Tone Spacing f − Frequency − MHz Frequency Response − dB VOLTAGE AND CURRENT NOISE vs FREQUENCY 45 −40 Third-Order Output Intersept Point − dBm Third-Order Intermodulation Distortion − dBc THIRD-ORDER INTERMODULATION DISTORTION vs FREQUENCY 17 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com TYPICAL CHARACTERISTICS: 5 V (continued) REJECTION RATIOS vs CASE TEMPERATURE 100 120 VS = 5 V 90 PSRR+ 70 PSRR− 60 CMRR 50 PSRR+ 100 PSRR− Rejection Ratios − dB 40 30 80 60 CMMR 40 20 20 VS = 5 V 10 0 10 k 100 k 1M 10 M f − Frequency − Hz 0 −40−30−20−100 10 20 30 40 50 60 70 80 90 100 M 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 Input Common-Mode Voltage Range − V Figure 65. Figure 66. INPUT OFFSET VOLTAGE vs CASE TEMPERATURE INPUT BIAS AND OFFSET CURRENT vs CASE TEMPERATURE SMALL-SIGNAL TRANSIENT RESPONSE 8 2 1 5 1.14 4 1.13 IIB+ 3 1.12 2 1.11 1 1.1 Figure 67. LARGE-SIGNAL TRANSIENT RESPONSE 1.5 Single-Ended Output Voltage − V Gain = −1 RL = 499 Ω Rf = 249 Ω tr/tf = 300 ps VS = 5 V −0.5 −1 0 1 2 3 4 5 6 7 8 9 10 11 t − Time − ns Figure 70. Gain = −1 RL = 499 Ω Rf = 249 Ω tr/tf = 300 ps VS = 5 V −0.1 −0.2 −0.3 0 4 6 8 10 12 14 16 t − Time − ns OVERDRIVE RECOVERY CLOSED-LOOP OUTPUT IMPEDANCE vs FREQUENCY 1000 1.5 VS = 5 V 2 1 1 0.5 0 0 −1 −0.5 −2 −1 −1.5 0 2 Figure 69. −3 −1.5 0 Figure 68. 3 0 0.1 TC − Case Temperature − °C TC − Case Temperature − °C 0.5 0.2 1.09 0 −40−30−20−10 0 10 20 30 40 50 60 70 80 90 0 −40−30−20−10 0 10 20 30 40 50 60 70 80 90 1 1.15 VO − Output Voltage − V VS = ±5 V 6 IOS 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 t − Time − µs Figure 71. Submit Documentation Feedback Closed-Loop Output Impedance − Ω VS = 5 V 3 1.16 IIB− I OS − Input Offset Current − µ A I IB − Input Bias Current − µ A 7 4 0.3 1.17 VS = 5 V VOS − Input Offset Voltage − mV VS = 5 V 90 Figure 64. 5 VO − Output Voltage − V 100 Case Temperature − °C VI − Input Voltage − V Rejection Ratios − dB 80 18 COMMON-MODE REJECTION RATIO vs INPUT COMMON-MODE RANGE CMRR − Common-Mode Rejection Ratio − dB REJECTION RATIOS vs FREQUENCY 100 Gain = 1 RL = 499 Ω VIN = 1 dBm VS = 5 V 10 1 0.1 0.01 0.001 100 k 1M 10 M 100 M 1G f − Frequency − Hz Figure 72. Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 TYPICAL CHARACTERISTICS: 5 V (continued) POWER-DOWN OUTPUT IMPEDANCE vs FREQUENCY 1M TA = 85°C 1000 TA = 25°C 800 TA = −40°C 600 400 200 0 2.5 3 3.5 4 4.5 5 VS − Supply Voltage − ±V Figure 73. 6.5 45 Input Gain = 1 RL = 150 Ω PIN = −1 dBm VS = 5 V I O− Output Current Level − mV Power-down Output Impedance − Ω Power-down Quiescent Current − µ A 1200 TURN-ON AND TURN-OFF TIME vs DELAY TIME 10 k 100 40 5 35 3.5 30 2 25 0.5 20 −1 15 10 0.5 Gain = −1 RL = 150 Ω VS = 5 V 0 1 100 k 0 10 M 100 M 1M f − Frequency − Hz 1G Figure 74. 10 20 30 40 50 60 Product Folder Link(s): THS4271-EP 70 t − Time − µs Figure 75. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated V I − Input Voltage Level − V POWER-DOWN QUIESCENT CURRENT vs SUPPLY VOLTAGE 19 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com APPLICATION INFORMATION Die Temperature = PDISS × qJA + TA MAXIMUM DIE TEMPERATURE TO PREVENT OSCILLATION The THS4271 may have low-level oscillation when the die temperature (also called junction temperature) exceeds +60°C and is not recommended for new designs. The oscillation is a result of the internal design of the bias circuit, and external configuration is not expected to mitigate or reduce the problem. This problem occurs randomly because of normal process variations and normal testing cannot identify problem units. The die temperature depends on the power dissipation and the thermal resistance of the device. Where: PDISS = (VS+– VS–) × (IQ + ILOAD) – (VOUT × ILOAD) Table 1 shows the estimated the maximum ambient temperature (TA max) in degrees Celsius for each package option of the THS4271 using the thermal dissipation rating given in the Dissipation Ratings table for a JEDEC standard High-K test PCB. For each case shown, RL = 499 Ω to ground and the quiescent current = 27 mA (the maximum over the 0°C to +70°C temperature range). The last entry for each package option (shaded cells) lists the worst-case scenario where the power supply is single-supply 10 V and ground and the output voltage is 5 V DC. space The die temperature can be approximated with the following formula: Table 1. Estimated Maximum Ambient Temperature Per Package Option PACKAGE DEVICE VS+ VS– PowerPad™ MSOP Worst Case 20 qJA 0V THS4271DGN THS4271DGNR VOUT 44.2°C 2 VPP 5V 10 V –5 V 0V 4 VPP TA max 43.5°C 58.4°C/W 42.8°C 6 VPP 42.3°C 8 VPP 41.9°C 5 DC 41.3°C Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 HIGH-SPEED OPERATIONAL AMPLIFIERS WIDEBAND, NONINVERTING OPERATION The THS4271 operational amplifier sets new performance levels, combining low distortion, high slew rates, low noise, and a unity-gain bandwidth in excess of 1 GHz. To achieve the full performance of the amplifier, careful attention must be paid to printed-circuit board (PCB) layout and component selection. The THS4271 is a unity gain stable, 1.4-GHz voltage-feedback operational amplifier, with and without power-down capability, designed to operate from a single 5-V to 15-V power supply. Applications Section Contents • Wideband, Noninverting Operation • Wideband, Inverting Gain Operation • Single-Supply Operation • Saving Power with Power-Down Functionality and Setting Threshold Levels with the Reference Pin • Power Supply Decoupling Techniques and Recommendations • Using the THS4271 as a DAC Output Buffer • Driving an ADC With the THS4271 • Active Filtering With the THS4271 • Building a Low-Noise Receiver with the THS4271 • Linearity: Definitions, Terminology, Circuit Techniques and Design Tradeoffs • An Abbreviated Analysis of Noise in Amplifiers • Driving Capacitive Loads • Printed Circuit Board Layout Techniques for Optimal Performance • Power Dissipation and Thermal Considerations • Performance vs Package Options • Evaluation Fixtures, Spice Models, and Applications Support • Additional Reference Material • Mechanical Package Drawings space Figure 76 is the noninverting gain configuration of 2 V/V used to demonstrate the typical performance curves. Most of the curves were characterized using signal sources with 50-Ω source impedance, and with measurement equipment presenting a 50-Ω load impedance. In Figure 76, the 49.9-Ω shunt resistor at the VIN terminal matches the source impedance of the test generator. The total 499-Ω load at the output, combined with the 498-Ω total feedback network load, presents the THS4271 with an effective output load of 249 Ω for the circuit of Figure 76. Voltage feedback amplifiers, unlike current feedback designs, can use a wide range of resistors values to set their gain with minimal impact on their stability and frequency response. Larger-valued resistors decrease the loading effect of the feedback network on the output of the amplifier, but this enhancement comes at the expense of additional noise and potentially lower bandwidth. Feedback resistor values between 249 Ω and 1 kΩ are recommended for most situations. 5 V +V S + 100 pF 50 Ω Source 0.1 µF 6.8 µF + VI VO THS4271 49.9 Ω _ Rf 249 Ω 499 Ω 249 Ω Rg 0.1 µF 6.8 µF space 100 pF space space −5 V + −VS Figure 76. Wideband, Noninverting Gain Configuration Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 21 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com WIDEBAND, INVERTING GAIN OPERATION Since the THS4271 is a general-purpose, wideband voltage-feedback amplifiers, several familiar operational amplifier applications circuits are available to the designer. Figure 77 shows a typical inverting configuration where the input and output impedances and noise gain from Figure 76 are retained in an inverting circuit configuration. Inverting operation is one of the more common requirements and offers several performance benefits. The inverting configuration shows improved slew rates and distortion due to the pseudo-static voltage maintained on the inverting input. 5 V +V S + 100 pF 0.1 µF 6.8 µF + RT 130 Ω CT 0.1 µF VO THS4271 _ 499 Ω 50 Ω Source VI Rg Rf 249 Ω RM 61.9 Ω 249 Ω 0.1 µF 100 pF −5 V 6.8 µF + −VS Figure 77. Wideband, Inverting Gain Configuration In the inverting configuration, some key design considerations must be noted. One is that the gain resistor (Rg) becomes part of the signal channel input impedance. If the input impedance matching is desired (which is beneficial whenever the signal is coupled through a cable, twisted pair, long PCB trace, or other transmission line conductors), Rg may be set equal to the required termination value and Rf adjusted to give the desired gain. However, care 22 must be taken when dealing with low inverting gains, as the resulting feedback resistor value can present a significant load to the amplifier output. For an inverting gain of 2, setting Rg to 49.9 Ω for input matching eliminates the need for RM but requires a 100-Ω feedback resistor. This has an advantage of the noise gain becoming equal to 2 for a 50-Ω source impedance—the same as the noninverting circuit in Figure 76. However, the amplifier output now sees the 100-Ω feedback resistor in parallel with the external load. To eliminate this excessive loading, it is preferable to increase both Rg and Rf, values, as shown in Figure 77, and then achieve the input matching impedance with a third resistor (RM) to ground. The total input impedance becomes the parallel combination of Rg and RM. The next major consideration is that the signal source impedance becomes part of the noise gain equation and hence influences the bandwidth. For example, the RM value combines in parallel with the external 50-Ω source impedance (at high frequencies), yielding an effective source impedance of 50 Ω || 61.9Ω = 27.7 Ω. This impedance is then added in series with Rg for calculating the noise gain. The result is 1.9 for Figure 77, as opposed to the 1.8 if RM is eliminated. The bandwidth is lower for the gain of –2 circuit, Figure 77 (NG = +1.9), than for the gain of +2 circuit in Figure 76. The last major consideration in inverting amplifier design is setting the bias current cancellation resistor on the noninverting input. If the resistance is set equal to the total dc resistance looking out of the inverting terminal, the output dc error, due to the input bias currents, is reduced to (input offset current) multiplied by Rf in Figure 77, the dc source impedance looking out of the inverting terminal is 249 Ω || (249Ω + 27.7 Ω) = 130 Ω. To reduce the additional high-frequency noise introduced by the resistor at the noninverting input, and power-supply feedback, RT is bypassed with a capacitor to ground. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 SINGLE-SUPPLY OPERATION 5V The THS4271 is designed to operate from a single 5-V to 15-V power supply. When operating from a single power supply, care must be taken to ensure the input signal and amplifier are biased appropriately to allow for the maximum output voltage swing. The circuits shown in Figure 78 demonstrate methods to configure an amplifier in a manner conducive for single-supply operation. + VCM THS4271 _ 50 Ω (1:4 Ω) Source 1:2 100 Ω -5 V 249 Ω 24.9 Ω ADS5422 22 pF 14-Bit, 62 Msps 22 pF +VS 100 Ω 24.9 Ω 50 Ω Source 249 Ω + VI 49.9 Ω RT THS4271 _ VO _ 499 Ω +VS 2 THS4271 Rg 249 Ω +VS 2 249 Ω Figure 79. A Linear, Low-Noise, High-Gain ADC Preamplifier Rf 249 Ω VS 50 Ω Source Rg VI 61.9 Ω +VS 2 249 Ω RT _ THS4271 + + VCM Rf VO 499 Ω +VS 2 The second circuit depicts single-ended ADC drive. While not recommended for optimum performance using converters with differential inputs, satisfactory performance can sometimes be achieved with single-ended input drive. An example circuit is shown here for reference. 50 Ω Source +5 V + VI Figure 78. DC-Coupled Single-Supply Operation 49.9 Ω RT _ -5 V APPLICATION CIRCUITS RISO 0.1 µF THS4271 16.5 Ω 68 pf 12-Bit, Rf The THS4271 can be used to drive high-performance analog-to-digital converters. Two example circuits are presented below. The first circuit uses a wideband transformer to convert a single-ended input signal into a differential signal. The differential signal is then amplified and filtered by two THS4271 amplifiers. This circuit provides low intermodulation distortion, suppressed even-order distortion, 14 dB of voltage gain, a 50-Ω input impedance, and a single-pole filter at 100 MHz. For applications without signal content at dc, this method of driving ADCs can be very useful. Where dc information content is required, the THS4500 family of fully differential amplifiers may be applicable. 249 Ω Rg ADS807 CM 53 Msps IN 1.82 kΩ Driving an Analog-to-Digital Converter With the THS4271 IN 0.1 µF 249 Ω For best performance, high-speed ADCs should be driven differentially. See the THS4500 family of devices for more information. Figure 80. Driving an ADC With a Single-Ended Input Using the THS4271 as a DAC Output Buffer Two example circuits are presented here showing the THS4271 buffering the output of a digital-to-analog converter. The first circuit performs a differential to single-ended conversion with the THS4271 configured as a difference amplifier. The difference amplifier can double as the termination mechanism for the DAC outputs as well. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 23 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com Active Filtering With the THS4271 3.3 V 3.3 V 100 Ω 249 Ω 100 Ω +5 V 249 Ω DAC5675 14-Bit, 400 MSps _ 124 Ω 49.9 Ω RF THS4271 + 249 Ω High-frequency active filtering with the THS4271 is achievable due to the amplifier high slew-rate, wide bandwidth, and voltage-feedback architecture. Several options are available for high-pass, low-pass, bandpass, and bandstop filters of varying orders. A simple two-pole low pass filter is presented here as an example, with two poles at 100 MHz. LO -5 V 249 Ω 6.8 pF 50 Ω Source 249 Ω Figure 81. Differential to Single-Ended Conversion of a High-Speed DAC Output VI 249 Ω 61.9 Ω 5V _ THS4271 For cases where a differential signaling path is desirable, a pair of THS4271 amplifiers can be used as output buffers. The circuit depicts differential drive into a mixer IF inputs, coupled with additional signal gain and filtering. + 49.9 Ω VO 33 pF −5 V Figure 83. A Two-Pole Active Filter With Two Poles Between 90 MHz and 100 MHz THS4271 + 3.3 V 3.3 V _ 100 Ω 100 Ω CF 1 nF 1 nF IF+ DAC5675 14-Bit, 400 MSps 249 Ω 100 Ω 249 Ω 249 Ω 49.9 Ω 249 Ω 49.9 Ω RF(out) IF1 nF 1 nF _ CF + THS4271 Figure 82. Differential Mixer Drive Circuit Using the DAC5675 and the THS4271 24 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 A Low-Noise Receiver With the THS4271 space A combination of two THS4271 amplifiers can create a high-speed, low-distortion, low-noise differential receiver circuit as depicted in Figure 84. With both amplifiers operating in the noninverting mode of operation, the circuit presents a high load impedance to the source. The designer has the option of controlling the impedance through termination resistors if a matched termination impedance is desired. 100 Ω VI+ + 49.9 Ω VO+ _ 249 Ω 499 Ω 100 Ω 249 Ω _ VI− 49.9 Ω + Figure 84. A High Input Impedance, Low-Noise, Differential Receiver A modification on this circuit to include a difference amplifier turns this circuit into a high-speed instrumentation amplifier, as shown in Figure 85. Equation 1 calculates the output voltage for this circuit. 100 Ω + VI- Rg2 Distortion Performance The THS4271 provides excellent distortion performance into a 150-Ω load. Relative to alternative solutions, it provides exceptional performance into lighter loads, as well as exceptional performance on a single 5-V supply. Generally, until the fundamental signal reaches very high frequency or power levels, the second harmonic dominates the total harmonic distortion with a negligible third harmonic component. Focusing then on the second harmonic, increasing the load impedance improves distortion directly. The total load includes the feedback network; in the noninverting configuration (Figure 76) this is the sum of Rf and Rg, while in the inverting configuration (Figure 77), only Rf needs to be included in parallel with the actual load. LINEARITY: DEFINITIONS, TERMINOLOGY, CIRCUIT TECHNIQUES, AND DESIGN TRADEOFFS VO− 100 Ω THEORY AND GUIDELINES Rf2 THS4271 _ The THS4271 features excellent distortion performance for monolithic operational amplifiers. This section focuses on the fundamentals of distortion, circuit techniques for reducing nonlinearity, and methods for equating distortion of operational amplifiers to desired linearity specifications in RF receiver chains. Amplifiers are generally thought of as linear devices. The output of an amplifier is a linearly-scaled version of the input signal applied to it. However, amplifier transfer functions are nonlinear. Minimizing amplifier nonlinearity is a primary design goal in many applications. Rf1 Rg1 _ 100 Ω _ Rf1 THS4271 + 49.9 Ω VO THS4271 Rg2 + 49.9 Ω Rf2 VI+ Figure 85. A High-Speed Instrumentation Amplifier ǒ Ǔ ǒ Ǔ 2R f1 ǒV i)–V i–Ǔ R f2 VO + 1 1 ) 2 Rg1 Rg2 (1) Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 25 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com Intercept points are specifications long used as key design criteria in the RF communications world as a metric for the intermodulation distortion performance of a device in the signal chain (e.g., amplifiers, mixers, etc.). Use of the intercept point, rather than strictly the intermodulation distortion, allows simpler system-level calculations. Intercept points, like noise figures, can be easily cascaded back and forth through a signal chain to determine the overall receiver chain intermodulation distortion performance. The relationship between intermodulation distortion and intercept point is depicted in Figure 86 and Figure 87. PO PO Power ∆fc = fc - f1 ∆fc = f2 - fc IMD3 = PS - PO PS fc - 3∆f f2 However, with an operational amplifier, the output does not require termination as an RF amplifier would. Because closed-loop amplifiers deliver signals to their outputs regardless of the impedance present, it is important to comprehend this when evaluating the intercept point of an operational amplifier. The THS4271 yields optimum distortion performance when loaded with 150 Ω to 1 kΩ, very similar to the input impedance of an analog-to-digital converter over its input frequency band. As a result, terminating the input of the ADC to 50Ω can actually be detrimental to systems performance. The discontinuity between open-loop, class-A amplifiers and closed-loop, class-AB amplifiers becomes apparent when comparing the intercept points of the two types of devices. Equation 2 and Equation 3 give the definition of an intercept point, relative to the intermodulation distortion. ŤIMD 3Ť OIP 3 + P O ) where 2 (2) PS f1 fc Due to the intercept point ease of use in system level calculations for receiver chains, it has become the specification of choice for guiding distortion-related design decisions. Traditionally, these systems use primarily class-A, single-ended RF amplifiers as gain blocks. These RF amplifiers are typically designed to operate in a 50-Ω environment. Giving intercept points in dBm, implies an associated impedance (50 Ω). fc + 3∆f ǒ f - Frequency - MHz ǒ Figure 86. P O + 10 log Ǔ Ǔ V 2P 2RL 0.001 NOTE: PO is the output power of a single tone, RL is the load resistance, and VP is the peak voltage for a single tone. (3) POUT (dBm) 1X NOISE ANALYSIS OIP3 PO IIP3 IMD3 3X PIN (dBm) High slew rate, unity gain stable, voltage-feedback operational amplifiers usually achieve the slew rate at the expense of a higher input noise voltage. The 3-nV/√Hz input voltage noise for the THS4271 is, however, much lower than comparable amplifiers. The input-referred voltage noise, and the two input-referred current noise terms (3 pA/√Hz), combine to give low output noise under a wide variety of operating conditions. Figure 88 shows the amplifier noise analysis model with all the noise terms included. In this model, all noise terms are taken to be noise voltage or current density terms in either nV/√Hz or pA/√Hz. PS Figure 87. 26 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 THS4271/THS4275 ENI + RS IBN ERS EO _ 4kTRS ERF Rf Rg 4kT Rg IBI 4kTRf 4kT = 1.6E-20J at 290K Figure 88. Noise Analysis Model The total output spot noise voltage can be computed as the square of all square output noise voltage contributors. Equation 4 shows the general form for the output noise voltage using the terms shown in Figure 88: EO + Ǹǒ 2 Ǔ 2 ENI 2 ) ǒIBNRSǓ ) 4kTR S NG 2 ) ǒIBIRfǓ ) 4kTRfNG (4) Dividing this expression by the noise gain [NG=(1+ Rf/Rg)] gives the equivalent input-referred spot noise voltage at the noninverting input, as shown in Equation 5: EO + Ǹ E NI 2 2 ǒ Ǔ ) 4kTR NG 2 I R ) ǒI BNRSǓ ) 4kTR S ) BI f NG f additional pole in the signal path that can decrease the phase margin. When the primary considerations are frequency response flatness, pulse response fidelity, or distortion, the simplest and most effective solution is to isolate the capacitive load from the feedback loop by inserting a series isolation resistor between the amplifier output and the capacitive load. This does not eliminate the pole from the loop response, but rather shifts it and adds a zero at a higher frequency. The additional zero acts to cancel the phase lag from the capacitive load pole, thus increasing the phase margin and improving stability. The Typical Characteristics show the recommended isolation resistor vs capacitive load and the resulting frequency response at the load. Parasitic capacitive loads greater than 2 pF can begin to degrade the performance of the THS4271. Long PCB traces, unmatched cables, and connections to multiple devices can easily cause this value to be exceeded. Always consider this effect carefully, and add the recommended series resistor as close as possible to the THS4271 output pin (see the Board Layout Guidelines section). The criterion for setting this R(ISO) resistor is a maximum bandwidth, flat frequency response at the load. For a gain of +2, the frequency response at the output pin is already slightly peaked without the capacitive load, requiring relatively high values of R(ISO) to flatten the response at the load. Increasing the noise gain also reduces the peaking. FREQUENCY RESPONSE vs CAPACITIVE LOAD (5) Driving Capacitive Loads One of the most demanding, and yet very common, load conditions for an op amp is capacitive loading. Often, the capacitive load is the input of an A/D converter, including additional external capacitance, which may be recommended to improve A/D linearity. A high-speed, high open-loop gain amplifier like the THS4271 can be very susceptible to decreased stability and closed-loop response peaking when a capacitive load is placed directly on the output pin. When the amplifier open-loop output resistance is considered, this capacitive load introduces an 0.5 0 Normalized Gain - dB Evaluation of these two equations for the circuit and component values shown in Figure 76 will give a total output spot noise voltage of 12.2 nV/√Hz and a total equivalent input spot noise voltage of 6.2 nV/√Hz. This includes the noise added by the resistors. This total input-referred spot noise voltage is not much higher than the 3-nV/√Hz specification for the amplifier voltage noise alone. -0.5 -1 -1.5 R(ISO) = 25 Ω CL = 10 pF R(ISO) = 15 Ω CL = 100 pF R(ISO) = 10 Ω CL = 50 pF -2 -2.5 -3 1M RL = 499 Ω VS =±5 V 10 M 100 M f - Frequency - Hz Figure 89. Isolation Resistor Diagram Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 27 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com BOARD LAYOUT GUIDELINES Achieving optimum performance with a high-frequency amplifier like the THS4271 requires careful attention to board layout parasitics and external component types. Recommendations that optimize performance include: 1. Minimize parasitic capacitance to any ac ground for all of the signal I/O pins. Parasitic capacitance on the output and inverting input pins can cause instability: on the noninverting input, it can react with the source impedance to cause unintentional band limiting. To reduce unwanted capacitance, a window around the signal I/O pins should be opened in all of the ground and power planes around those pins. Otherwise, ground and power planes should be unbroken elsewhere on the board. 2. Minimize the distance (< 0.25”) from the power supply pins to high frequency 0.1-mF de-coupling capacitors. At the device pins, the ground and power plane layout should not be in close proximity to the signal I/O pins. Avoid narrow power and ground traces to minimize inductance between the pins and the decoupling capacitors. The power supply connections should always be decoupled with these capacitors. Larger (2.2-mF to 6.8-mF) decoupling capacitors, effective at lower frequency, should also be used on the main supply pins. These may be placed somewhat farther from the device and may be shared among several devices in the same area of the PCB. 3. Careful selection and placement of external components preserves the high frequency performance of the THS4271. Resistors should be a very low reactance type. Surface-mount resistors work best and allow a tighter overall layout. Metal-film and carbon composition, axially-leaded resistors can also provide good high frequency performance. Again, keep their leads and PC board trace length as short as possible. Never use wire-wound type resistors in a high frequency application. Since the output pin and inverting input pin are the most sensitive to parasitic capacitance, always position the feedback and series output resistor, if any, as close as possible to the output pin. Other network components, such as noninverting input-termination resistors, should also be placed close to the package. Where double-side component mounting is allowed, place the feedback resistor directly under the package on the other side of the board between the output and inverting input pins. Even with a low parasitic capacitance shunting the external resistors, excessively high resistor values can create significant time constants that can degrade 28 performance. Good axial metal-film or surface-mount resistors have approximately 0.2 pF in shunt with the resistor. For resistor values > 2 kΩ, this parasitic capacitance can add a pole and/or a zero below 400-MHz that can effect circuit operation. Keep resistor values as low as possible, consistent with load driving considerations. A good starting point for design is to set the Rf to 249-Ω for low-gain, noninverting applications. Doing this automatically keeps the resistor noise terms low, and minimizes the effect of their parasitic capacitance. 4. Connections to other wideband devices on the board may be made with short direct traces or through onboard transmission lines. For short connections, consider the trace and the input to the next device as a lumped capacitive load. Relatively wide traces (50 mils to 100 mils) should be used, preferably with ground and power planes opened up around them. Estimate the total capacitive load and set RISO from the plot of recommended RISO vs capacitive load. Low parasitic capacitive loads (<4 pF) may not need an R(ISO), since the THS4271 is nominally compensated to operate with a 2-pF parasitic load. Higher parasitic capacitive loads without an R(ISO) are allowed as the signal gain increases (increasing the unloaded phase margin). If a long trace is required, and the 6-dB signal loss intrinsic to a doubly-terminated transmission line is acceptable, implement a matched impedance transmission line using microstrip or stripline techniques (consult an ECL design handbook for microstrip and stripline layout techniques). A 50-Ω environment is normally not necessary onboard, and in fact, a higher impedance environment improves distortion as shown in the distortion versus load plots. With a characteristic board trace impedance defined based on board material and trace dimensions, a matching series resistor into the trace from the output of the THS4271 is used as well as a terminating shunt resistor at the input of the destination device. Remember also that the terminating impedance is the parallel combination of the shunt resistor and the input impedance of the destination device: this total effective impedance should be set to match the trace impedance. If the 6-dB attenuation of a doubly terminated transmission line is unacceptable, a long trace can be series-terminated at the source end only. Treat the trace as a capacitive load in this case and set the series resistor value as shown in the plot of R(ISO) vs capacitive load. This does not preserve signal integrity or a doubly-terminated line. If the input impedance of the destination device is low, there is some signal attenuation due to the voltage divider formed by the series output into the terminating impedance. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 5. Socketing a high speed part like the THS4271 is not recommended. The additional lead length and pin-to-pin capacitance introduced by the socket can create a troublesome parasitic network which can make it almost impossible to achieve a smooth, stable frequency response. Best results are obtained by soldering the THS4271 onto the board. PowerPAD™ DESIGN CONSIDERATIONS The THS4271 is available in a thermally-enhanced PowerPAD family of packages. These packages are constructed using a downset leadframe upon which the die is mounted [see Figure 90(a) and Figure 90(b)]. This arrangement results in the lead frame being exposed as a thermal pad on the underside of the package [see Figure 90(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 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 surface mount with the heretofore awkward mechanical methods of heatsinking. DIE Side View (a) Thermal Pad DIE End View (b) Bottom View (c) Figure 90. Views of Thermally Enhanced Package Although there are many ways to properly heatsink the PowerPAD package, the following steps illustrate the recommended approach. space space space space PowerPAD PCB LAYOUT CONSIDERATIONS 1. Prepare the PCB with a top side etch pattern as shown in Figure 91. There should be etch for the leads as well as etch for the thermal pad. ÎÎÎ ÎÎÎÎÎÎ ÎÎÎ ÎÎÎ ÎÎÎ ÎÎÎ ÎÎÎÎÎÎ ÎÎÎ ÎÎÎ ÎÎÎ ÎÎÎ ÎÎÎÎÎÎ Single or Dual 68 Mils x 70 Mils (Via diameter = 13mils) Figure 91. PowerPAD PCB Etch and Via Pattern 2. Place five holes in the area of the thermal pad. The holes should be 13 mils in diameter. Keep them small so that solder wicking through the holes is not a problem during reflow. 3. Additional vias may be placed anywhere along the thermal plane outside of the thermal pad area. They help dissipate the heat generated by the THS4271 IC. These additional vias may be larger than the 13-mil diameter vias directly under the thermal pad. They can be larger because they are not in the thermal pad area to be soldered, so that wicking is not a problem. 4. Connect all holes to the internal ground plane. 5. When connecting these holes to the ground plane, do not use the typical web or spoke via connection methodology. Web connections have a high thermal resistance connection that is useful for slowing the heat transfer during soldering operations. This resistance makes the soldering of vias that have plane connections easier. In this application, however, low thermal resistance is desired for the most efficient heat transfer. Therefore, the holes under the THS4271 PowerPAD package should make their connection to the internal ground plane, with a complete connection around the entire circumference of the plated-through hole. 6. The top-side solder mask should leave the terminals of the package and the thermal pad area with its five holes exposed. The bottom-side solder mask should cover the five holes of the thermal pad area. This prevents solder from being pulled away from the thermal pad area during the reflow process. 7. Apply solder paste to the exposed thermal pad area and all of the IC terminals. 8. With these preparatory steps in place, the IC is simply placed in position and run through the solder reflow operation as any standard surface-mount component. This results in a part that is properly installed. Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 29 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com where: PD = Maximum power dissipation of THS4271 (watts) TMAX = Absolute maximum junction temperature (150°C) TA = Free-ambient temperature (°C) θJA = θJC + θCA θJC = Thermal coefficient from junction to the case θCA = Thermal coefficient from the case to ambient air (°C/W). (6) The next consideration is the package constraints. The two sources of heat within an amplifier are quiescent power and output power. The designer should never forget about the quiescent heat generated within the device, especially multi-amplifier devices. Because these devices have linear output stages (Class AB), most of the heat dissipation is at low output voltages with high output currents. The other key factor when dealing with power dissipation is how the devices are mounted on the PCB. The PowerPAD devices are extremely useful for heat dissipation. But, the device should always be soldered to a copper plane to fully use the heat dissipation properties of the PowerPAD. The SOIC package, on the other hand, is highly dependent on how it is mounted on the PCB. As more trace and copper area is placed around the device,q JA decreases and the heat dissipation capability increases. For a single package, the sum of the RMS output currents and voltages should be used to choose the proper package. THERMAL ANALYSIS The THS4271 device does not incorporate automatic thermal shutoff protection, so the designer must take care to ensure that the design does not violate the absolute maximum junction temperature of the device. Failure may result if the absolute maximum junction temperature of +150° C is exceeded. The thermal characteristics of the device are dictated by the package and the PCB. Maximum power dissipation for a given package can be calculated using the following formula. Tmax–T A P Dmax + q JA where: PDmax is the maximum power dissipation in the amplifier (W). Tmax is the absolute maximum junction temperature (°C). TA is the ambient temperature (°C). θJA = θJC + θCA θJC is the thermal coefficient from the silicon junctions to the case (°C/W). θCA is the thermal coefficient from the case to ambient air (°C/W). (7) For systems where heat dissipation is more critical, the THS4271 is offered in an 8-pin MSOP with PowerPAD. The thermal coefficient for the MSOP PowerPAD package is substantially improved over the traditional SOIC. Maximum power dissipation levels are depicted in the graph for the two packages. The data for the DGN package assumes a board layout that follows the PowerPAD layout guidelines referenced above and detailed in the PowerPAD application notes in the Additional Reference Material section at the end of the data sheet. 3.5 PD − Maximum Power Dissipation − W For a given qJA, the maximum power dissipation is shown in Figure 92 and is calculated by the Equation 6: Tmax * T A PD + q JA 8-Pin DGN Package 3 2.5 2 8-Pin D Package 1.5 1 0.5 0 −40 −20 0 20 40 60 TA − Ambient Temperature − °C 80 θJA = 170°C/W for 8-Pin SOIC (D) θJA = 58.4°C/W for 8-Pin MSOP (DGN) TJ = 150°C, No Airflow Figure 92. Maximum Power Dissipation vs Ambient Temperature When determining whether or not the device satisfies the maximum power dissipation requirement, it is important to consider not only quiescent power dissipation, but also dynamic power dissipation. Often maximum power is difficult to quantify because the signal pattern is inconsistent, but an estimate of the RMS power dissipation can provide visibility into a possible problem. 30 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 Performance vs Package Options The THS4271 is offered in different package options. However, performance may be limited due to package parasitics and lead inductance in some packages. In order to achieve maximum performance of the THS4271, Texas Instruments recommends using the leadless MSOP (DRB) or MSOP (DGN) packages, in addition to proper high-speed PCB layout. Figure 93 shows the unity gain frequency response of the THS4271 using the leadless MSOP, MSOP, and SOIC package for comparison. Using the THS4271 in a unity gain with the SOIC package may result in the device becoming unstable. In higher gain configurations, this effect is mitigated by the reduced bandwidth. As such, the SOIC is suitable for application with gains equal to or higher than +2 V/V or (–1 V/V). 20 18 _ Normalized Gain − dB 16 SOIC, Rf = 0 Ω Rf + 150 Ω 49.9 Ω 14 12 SOIC, Rf = 100 Ω The THS4271 EVM board shown in Figure 97 through Figure 100 is designed to accommodate different gain configurations. Its default component values are set to give a gain of 2. The EVM can be configured in a gain of +1; however, it is strongly not recommended. Evaluating the THS4271 in a gain of 1 using this EVM may cause the part to become unstable. The stability of the device can be controlled by adding a large resistor in the feedback path, the performance is sacrificed. Figure 94 shows the small-signal frequency response of the THS4271 with different feedback resistors in the feedback path. Figure 95 is the small frequency response of the THS4271 using the gain of 1 EVM. 17 + Rf = 50 Ω Rf 150 Ω 49.9 Ω Rf = 0 Ω Rf = 100 Ω 7 Rf = 150 Ω 5 3 1 −1 VIN = 100 mVPP VS = ±5 V −5 10M 100M f − Frequency − Hz −3 SOIC, Rf = 200 Ω 8 4 _ 13 9 10 6 15 11 Small Signal Gain − dB DESIGN TOOLS Leadless MSOP, & MSOP Rf = 0 Ω 1G 2 0 −2 −4 Figure 94. Frequency Response vs Feedback Resistor Using the EDGE #6439527 EVM VIN = 100 mVPP VS =±5 V 10 M 100 M 1G f − Frequency − Hz 4 Evaluation Fixtures, Spice Models, and Applications Support Texas Instruments is committed to providing its customers with the highest quality of applications support. To support this goal, evaluation boards have been developed for the THS4271 operational amplifier. Three evaluation boards are available: one THS4271, both are configurable for different gains, and a third for a gain of +1. These boards are easy to use, allowing for straightforward evaluation of the device. These evaluation boards can be ordered through the Texas Instruments web site, www.ti.com, or through your local Texas Instruments sales representative. Schematics for the evaluation boards are shown below. 3 Small Signal Gain − dB Figure 93. Effects of Unity Gain Frequency Response for DIfferential Packages _ + 2 150 Ω 49.9 Ω 1 0 −1 −2 −3 Gain = 1 RL = 150 Ω VO = 100 mVPP VS = ±5 V −4 100 k 1M 10 M 100 M f − Frequency − Hz 1G 10 G Figure 95. Frequency Response Using the EDGE #6443547 EVM Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 31 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com The peaking in the frequency response is due to the lead inductance in the feedback path. Each pad and trace on a PCB has an inductance associated with it, which in conjunction with the inductance associated with the package may cause peaking in the frequency response, causing the device to become unstable. In order to achieve the maximum performance of the device, PCB layout is very critical. Texas Instruments has developed an EVM for the evaluation of the THS4271 in a gain of 1. The EVM is shown in Figure 102 through Figure 105. This EVM is designed to minimize peaking in the unity gain configuration. Minimizing the inductance in the feedback path is critical for reducing the peaking of the frequency response in unity gain. The recommended maximum inductance allowed in the feedback path is 4 nH. This can be calculated by using Equation 8. L(nH) + Kȏ ln 2ȏ ) 0.223 W ) T ) 0.5 ȏ W)T ƪ R8 C8 R9 R5 Vs − Vs+ 7 8 2 _ R3 J1 Vin − U1 R6 6 J4 Vout 3 + R2 R7 4 1 Vs − J2 Vin+ J8 Power Down Ref C7 R1 R4 ƫ where: W = Width of trace in inches. ȏ = Length of the trace in inches. T = Thickness of the trace in inches. K = 5.08 for dimensions in inches, and K = 2 for dimensions in cm. (8) space Vs+ J9 Power Down J7 VS− J6 GND J5 VS+ TP1 FB1 FB2 VS− C5 C6 VS+ C1 C2 + + C3 C4 space space 32 Figure 96. THS4271 EVM Circuit Configuration Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 Figure 97. THS4271 EVM Board Layout (Top Layer) Figure 99. THS4271 EVM Board Layout (Third Layer, Power) Figure 98. THS4271 EVM Board Layout (Second Layer, Ground) Figure 100. THS4271 EVM Board Layout (Bottom Layer) Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 33 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com Vs+ 7 8 2 _ U1 R6 6 J4 Vout 3 + R7 4 1 J2 Vin+ Vs − R4 J7 VS− J6 GND J5 VS+ TP1 FB1 FB2 VS− C5 C6 VS+ C1 C2 + + C3 C4 Figure 101. THS4271 Unity Gain EVM Circuit Configuration Figure 103. THS4271 Unity Gain EVM Board Layout (Second Layer, Ground) Figure 102. THS4271 Unity Gain EVM Board Layout (Top Layer) Figure 104. THS4271 Unity Gain EVM Board Layout (Third Layer, Power) 34 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP THS4271-EP www.ti.com SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 Computer simulation of circuit performance using SPICE is often useful when analyzing the performance of analog circuits and systems. This is particularly true for video and RF amplifier circuits where parasitic capacitance and inductance can have a major effect on circuit performance. A SPICE model for the THS4271 is available through either the Texas Instruments web site (www.ti.com) or as one model on a disk from the Texas Instruments Product Information Center (1-800-548-6132). The PIC is also available for design assistance and detailed product information at this number. These models do a good job of predicting small-signal ac and transient performance under a wide variety of operating conditions. They are not intended to model the distortion characteristics of the amplifier, nor do they attempt to distinguish between the package types in their small-signal ac performance. Detailed information about what is and is not modeled is contained in the model file itself. ADDITIONAL REFERENCE MATERIALS • Figure 105. THS4271 Unity Gain EVM Board Layout • PowerPAD Made Easy, application brief (SLMA004) PowerPAD Thermally Enhanced Package, technical brief (SLMA002) Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP 35 THS4271-EP SGLS270C – DECEMBER 2004 – REVISED APRIL 2010 www.ti.com REVISION HISTORY SCOPE: Update specs to document device oscillation characteristics as the temperature exceeds 60°C. This documents the effort to reduce supply voltage range and reduce maximum junction temperature. Changes from Revision B (July 2008) to Revision C Page • Deleted THS4275-EP device ................................................................................................................................................ 1 • Deleted D-8 package graphic ............................................................................................................................................... 1 • Deleted "Power Down Functionality (THS4275)" and "Supply Voltage +12 V, +15 V" from FEATURES section ............... 1 • Added "The THS4271 may…" paragraph to describe the device ocsilation characteristics and updated "THS4271 are low noise,…" to remove information pertaining to the THS4275 device within the DESCRIPTION section .................. 1 • Deleted THS4275 devices, THS4271 D package devices and footnote (2) "Product Preview" from PACKAGING/ORDERING INFORMATION .......................................................................................................................... 2 • Added Maximum junction temperature to prevent oscillation to ABSOLUTE MAXIMUM RATINGS table .......................... 3 • Deleted D (8 pin) package information and footnote (2) due to THS4275 reference from PACKAGE DISSIPATION RATINGS section .................................................................................................................................................................. 3 • Deleted operating free air temperature specifications in RECOMMENDED OPERATING CONDITIONS table ................. 4 • Changed MAX specification vlaues in RECOMMENDED OPERATING CONDITIONS table ............................................. 4 • Deleted THS4275 device and D package designator for THS4271 device in PIN ASSIGNMENTS section ....................... 4 • Added footnote (1) "See application section…" to ELECTRICAL CHARACTERISTICS: VS = ±5 V section ....................... 5 • Deleted Power Down Characteristics (THS4275 only) specifications to ELECTRICAL CHARACTERISTICS: VS = ±5 V section ............................................................................................................................................................................... 5 • Added footnote (1) "See application section…" to ELECTRICAL CHARACTERISTICS: VS = 5 V section ......................... 7 • Deleted Power Down Characteristics (THS4275 only) specifications to ELECTRICAL CHARACTERISTICS: VS = 5 V section ............................................................................................................................................................................... 7 • Added MAXIMUM DIE TEMPERATURE TO PREVENT OSCILLATION section .............................................................. 20 • Deleted all THS4275 references from HIGH-SPEED OPERATIONAL AMPLIFIERS section ........................................... 21 • Deleted Saving Power With Power-Down Functionality… section due to THS4275 reference ......................................... 23 • Deleted POWER DOWN REFERENCE PIN OPERATION section due to THS4275 reference ........................................ 23 • Deleted POWER SUPPLY DECOUPLING TECHNIQUE AND RECOMMENDATION section due to THS4275 reference ............................................................................................................................................................................. 23 • Deleted THS4275 reference from NOISE ANALYSIS section ........................................................................................... 26 • Deleted THS4275 reference from PowerPAD™ DESIGN CONSIDERATIONS section .................................................... 29 • Deleted THS4275 reference from DESIGN TOOLS section .............................................................................................. 31 • Deleted THS4275 reference ............................................................................................................................................... 32 • Deleted THS4275 reference from Figure 97 ...................................................................................................................... 33 • Deleted THS4275 reference from Figure 98 ...................................................................................................................... 33 • Deleted THS4275 reference from Figure 99 ...................................................................................................................... 33 • Deleted THS4275 reference from Figure 100 .................................................................................................................... 33 36 Submit Documentation Feedback Copyright © 2004–2010, Texas Instruments Incorporated Product Folder Link(s): THS4271-EP PACKAGE OPTION ADDENDUM www.ti.com 3-Feb-2012 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp THS4271MDGNREP ACTIVE MSOPPowerPAD DGN 8 2500 Green (RoHS & no Sb/Br) CU NIPDAUAGLevel-1-260C-UNLIM V62/05610-01YE ACTIVE MSOPPowerPAD DGN 8 2500 Green (RoHS & no Sb/Br) CU NIPDAUAGLevel-1-260C-UNLIM (3) Samples (Requires Login) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. 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OTHER QUALIFIED VERSIONS OF THS4271-EP : • Catalog: THS4271 NOTE: Qualified Version Definitions: Addendum-Page 1 PACKAGE OPTION ADDENDUM www.ti.com 3-Feb-2012 • Catalog - TI's standard catalog product Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 17-Feb-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device THS4271MDGNREP Package Package Pins Type Drawing MSOPPower PAD DGN 8 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 12.4 Pack Materials-Page 1 5.3 B0 (mm) K0 (mm) P1 (mm) 3.4 1.4 8.0 W Pin1 (mm) Quadrant 12.0 Q1 PACKAGE MATERIALS INFORMATION www.ti.com 17-Feb-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) THS4271MDGNREP MSOP-PowerPAD DGN 8 2500 358.0 335.0 35.0 Pack Materials-Page 2 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. 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