THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 DEVICE DESCRIPTION THS4011/12 240-MHz Low Distortion High-Speed Amplifiers THS4021/2 350-MHz Low Noise High-Speed Amplifiers THS4081/2 175-MHz Low Power High-Speed Amplifiers 3 6 4 5 NULL VCC+ OUT NC NC – No internal connection THS4032 D AND DGN PACKAGE (TOP VIEW) 1OUT 1IN – 1IN + –VCC 1 8 2 7 3 6 4 5 VCC+ 2OUT 2IN– 2IN+ Cross-Section View Showing PowerPAD Option (DGN) 3 2 1 20 19 NC NULL THS4031 FK PACKAGE (TOP VIEW) NC 4 18 NC IN– 5 17 VCC+ NC 6 16 NC IN+ 7 15 OUT NC 8 14 NC 9 10 11 12 13 NC Related Devices 7 NC The THS4031 and THS4032 are ultralow-voltage noise, high-speed voltage feedback amplifiers that are ideal for applications requiring low voltage noise, including communication and imaging. The single-amplifier THS4031 and the dual-amplifier THS4032 offer very good ac performance with 100-MHz bandwidth, 100-V/µs slew rate, and 60-ns settling time (0.1%). The THS4031 and THS4032 are stable at gains of 2 (–1) or greater. These amplifiers have a high drive capability of 90 mA and draw only 8.5-mA supply current per channel. With total harmonic distortion (THD) of –72 dBc at f = 1 MHz, the THS4031 and THS4032 are ideally suited for applications requiring low distortion. 8 2 NC description 1 NULL D NULL IN – IN + VCC– VCC– NC D D D D THS4031 D, DGN, AND JG PACKAGE (TOP VIEW) NC D D Ultra-low 1.6 nV/√Hz Voltage Noise High Speed – 100 MHz Bandwidth (G = 2 (–1), –3 dB) – 100 V/µs Slew Rate Stable in Gains of 2 (–1) or Greater Very Low Distortion – THD = –72 dBc (f = 1 MHz, RL = 150 Ω) – THD = –90 dBc (f = 1 MHz, RL = 1 kΩ) Low 0.5 mV (Typ) Input Offset Voltage 90 mA Output Current Drive (Typical) ±5 V to ±15 V Typical Operation Available in Standard SOIC, MSOP PowerPAD, JG, or FK Package Evaluation Module Available NC D D CAUTION: The THS4031 and THS4032 provide ESD protection circuitry. However, permanent damage can still occur if this device is subjected to high-energy electrostatic discharges. Proper ESD precautions are recommended to avoid any performance degradation or loss of functionality. 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. Copyright 2000, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. On products compliant to MIL-PRF-38535, all parameters are tested unless otherwise noted. On all other products, production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 VOLTAGE NOISE AND CURRENT NOISE vs FREQUENCY 20 I n – Current Noise – pA/ Hz Vn – Voltage Noise – nV/ Hz VCC = ± 15 V AND ± 5 V TA = 25°C 10 Vn In 1 10 100 10 k 1k 100 k f – Frequency – Hz AVAILABLE OPTIONS PACKAGED DEVICES TA 0°C to 70°C –40°C 40°C to 85°C NUMBER OF CHANNELS PLASTIC SMALL OUTLINE† (D) PLASTIC MSOP† (DGN) CERAMIC DIP (JG) CHIP CARRIER (FK) EVALUATION MODULE DEVICE SYMBOL TIACM — — THS4031EVM 1 THS4031CD THS4031CDGN 2 THS4032CD THS4032CDGN TIABD — — THS4032EVM 1 THS4031ID THS4031IDGN TIACN — — — 2 THS4032ID THS4032IDGN TIABG — — — –55°C to 125°C 1 — — — THS4031MJG THS4031MFK † The D and DGN packages are available taped and reeled. Add an R suffix to the device type (i.e., THS4031CDGNR). 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 — THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 functional block diagram VCC 1IN– Null IN+ 2 3 8 – 1 1IN+ IN– 2 3 1OUT + 1 – 8 6 2IN– OUT 6 – 7 + 2IN+ 5 2OUT + 4 Figure 1. THS4031 – Single Channel –VCC Figure 2. THS4032 – Dual Channel absolute maximum ratings over operating free-air temperature (unless otherwise noted)† Supply voltage, VCC+ to VCC– . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 V Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±VCC Output current, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 mA Differential input voltage, VIO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±4 V Continuous total power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table Operating free-air temperature, TA: C-suffix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C I-suffix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to 85°C M-suffix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to 125°C Maximum junction temperature, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C Storage temperature, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to 150°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300°C Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds, JG package . . . . . . . . . . . . . . . . . . . . 300°C Case temperature for 60 seconds, FK package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C † 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. DISSIPATION RATING TABLE PACKAGE θJA (°C/W) θJC (°C/W) TA = 25°C POWER RATING D 167‡ 38.3 740 mW DGN§ 58.4 4.7 2.14 W JG 119 28 1050 mW FK 87.7 20 1375 mW ‡ This data was taken using the JEDEC standard Low-K test PCB. For the JEDEC Proposed High-K test PCB, the θJA is 95°C/W with a power rating at TA = 25°C of 1.32 W. § This data was taken using 2 oz. trace and copper pad that is soldered directly to a 3-in. × 3-in. PC. For further information, refer to Application Information section of this data sheet. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 recommended operating conditions MIN Supply voltage voltage, VCC+ CC and VCC– CC Operating free-air temperature, TA NOM MAX ±4.5 ±16 Single supply 9 32 C-suffix 0 70 Dual supply I-suffix –40 85 M-suffix –55 125 UNIT V °C electrical characteristics at TA = 25°C, VCC = ±15 V, RL = 150 Ω (unless otherwise noted) dynamic performance TEST CONDITIONS† PARAMETER BW SR Small signal bandwidth (–3 Small-signal ( 3 dB) VCC = ±15 V VCC = ±5 V Gain = –1 1 or 2 Bandwidth for 0.1 0 1 dB flatness VCC = ±15 V VCC = ±5 V Gain = –1 1 or 2 Full power bandwidth§ VO(pp) = 20 V, VO(pp) = 5 V, VCC = ±15 V VCC = ±5 V Slew rate‡ VCC = ±15 V, VCC = ±5 V, 20-V step Settling time to 0.1% 0 1% VCC = ±15 V, VCC = ±5 V, 5-V step Settling time to 0 0.01% 01% VCC = ±15 V, VCC = ±5 V, 5-V step ts 5-V step 2.5-V step 2.5-V step THS403xC, THS403xI MIN TYP MAX 100 MHz 90 50 MHz 45 1.6 RL = 1 kΩ MHz 5 100 Gain = –1 1 V/µs 80 60 Gain = –1 1 ns 45 90 Gain = –1 1 UNIT ns 80 † Full range = 0°C to 70°C for the THS403xC and –40°C to 85°C for the THS403xI. ‡ Slew rate is measured from an output level range of 25% to 75%. § Full power bandwidth = slew rate/2 πVO(Peak). noise/distortion performance THS4031 THD Total harmonic distortion Input voltage noise Input current noise RL = 150 Ω –81 RL = 1 kΩ –96 RL = 150 Ω –72 RL = 1 kΩ –90 MAX UNIT VCC = ±5 V or ±15 V, VCC = ±5 V or ±15 V, f = 10 kHz 1.6 nV/√Hz f = 10 kHz 1.2 pA/√Hz Gain = 2,, 40 IRE modulation, NTSC and PAL,, ±100 IRE ramp Differential phase error VCC = ±5 V or ±15 V, VCC = ±15 V VCC = ±5 V 0.015% VCC = ±15 V VCC = ±5 V 0.025° f = 1 MHz † Full range = 0°C to 70°C for the THS403xC and – 40°C to 85°C for the THS403xI. 4 TYP VO(pp) O( ) = 2 V,, Gain = 2 Differential gain error Channel-to-channel crosstalk (THS4032 only) MIN VCC = ±5 V or ±15 V,, f = 1 MHz, THS4032 Vn In THS403xC, THS403xI TEST CONDITIONS† PARAMETER POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 dBc 0.02% 0.03° –61 dBc THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 electrical characteristics at TA = 25°C, VCC = ±15 V, RL = 150 Ω (unless otherwise noted) (continued) dc performance THS403xC, THS403xI TEST CONDITIONS† PARAMETER VCC = ±15 V, V RL = 1 kΩ TYP 75 VO = ±10 V TA = 25°C TA = full range 45 VO = ±2.5 ±2 5 V TA = 25°C TA = full range 35 Open loop gain VCC = ±5 V V, RL = 1 kΩ MIN 40 UNIT V/mV 55 30 VOS Input offset voltage VCC = ±5 V or ±15 V TA = 25°C TA = full range 0.5 IIB Input bias current VCC = ±5 V or ±15 V TA = 25°C TA = full range 3 IOS Input offset current VCC = ±5 V or ±15 V TA = 25°C TA = full range 30 Offset voltage drift VCC = ±5 V or ±15 V VCC = ±5 V or ±15 V TA = full range TA = full range Input offset current drift MAX 2 3 6 8 250 400 mV µA nA 10 µV/°C 0.2 nA/°C † Full range = 0°C to 70°C for the THS403xC and – 40°C to 85°C for the THS403xI. input characteristics VICR Common mode input voltage range Common-mode VCC = ±15 V VCC = ±5 V VCC = ±15 V, V CMRR MIN TYP ±13.5 ±14.3 ± 3.8 ± 4.3 95 VICR = ±12 V TA = 25°C TA = full range 85 VICR = ±2 ±2.5 5V TA = 25°C TA = full range 90 Common mode rejection ratio VCC = ±5 V V, ri THS403xC, THS403xI TEST CONDITIONS† PARAMETER MAX UNIT V 80 dB 100 85 Input resistance Ci Input capacitance † Full range = 0°C to 70°C for the THS403xC and – 40°C to 85°C for the THS403xI. 2 MΩ 1.5 pF output characteristics TEST CONDITIONS† PARAMETER VO Output voltage swing VCC = ±15 V VCC = ±5 V VCC = ±15 V VCC = ±5 V IO Output current‡ VCC = ±15 V VCC = ±5 V ISC Short-circuit current‡ VCC = ±15 V THS403xC, THS403xI MIN TYP ±13 ±13.6 ±3.4 ±3.8 RL = 250 Ω ±12 ±12.9 RL = 150 Ω ±3 ±3.5 60 90 50 70 RL = 1 kΩ RL = 20 Ω 150 MAX UNIT V mA mA RO Output resistance Open loop 13 Ω † Full range = 0°C to 70°C for the THS403xC and – 40°C to 85°C for the THS403xI. ‡ Observe power dissipation ratings to keep the junction temperature below the absolute maximum rating when the output is heavily loaded or shorted. See the absolute maximum ratings section of this data sheet for more information. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 electrical characteristics at TA = 25°C, VCC = ±15 V, RL = 150 Ω (unless otherwise noted) (continued) power supply TEST CONDITIONS† PARAMETER VCC ICC PSRR Dual supply Supply voltage operating range THS403xC, THS403xI MIN ±16.5 9 33 VCC = ±15 V TA = 25°C TA = full range 8.5 VCC = ±5 V TA = 25°C TA = full range 7.5 VCC = ±5 V or ±15 V TA = 25°C TA = full range Supply current (each amplifier) MAX ±4.5 Single supply Power supply rejection ratio TYP UNIT V 10 11 mA 9 10.5 85 95 dB 80 † Full range = 0°C to 70°C for C suffix and – 40°C to 85°C for I suffix electrical characteristics at TA = full range, VCC = ±15 V, RL = 1 kΩ (unless otherwise noted) dynamic performance TEST CONDITIONS† PARAMETER VCC = ±15 V, VCC = ±15 V Unity gain bandwidth Small signal bandwidth (–3 Small-signal ( 3 dB) BW VCC = ±5 V VCC = ±15 V Bandwidth for 0.1 0 1 dB flatness VCC = ±5 V VO(pp) = 20 V, Full power bandwidth‡ SR Closed loop VO(pp) = 5 V, VCC = ±15 V Slew rate MIN 100§ VCC = ±15 V VCC = ±5 V Settling time to 0.1% 0 1% Settling time to 0 0.01% 01% VCC = ±15 V, VCC = ±5 V, 5-V step 2.5-V step 2.5-V step MAX 120 100 Gain = –1 or 2 90 MHz MHz 45 1.6 MHz 5 80§ 100 V/µs 60 Gain = –1 1 ns 45 90 Gain = –1 1 UNIT MHz 50 RL = 1 kΩ RL = 1 kΩ 5-V step TYP Gain = –1 or 2 Gain = –1 1 or 2 VCC = ±15 V, VCC = ±5 V, ts RL = 1 kΩ THS4031M ns 80 † Full range = –55°C to 125°C for the THS4031M. ‡ Full power bandwidth = slew rate/2 πVO(Peak). § This parameter is not tested. noise/distortion performance MAX UNIT –81 –96 f = 10 kHz, RL = 150 Ω 1.6 nV/√Hz VCC = ±5 V or ±15 V, TA = 25°C f = 10 kHz, RL = 150 Ω 1.2 pA/√Hz Gain = 2, 40 IRE modulation, modulation 25 C TA = 25°C NTSC and PAL, ±100 IRE ram ramp, RL = 150 Ω VCC = ±5 V or ±15 V,, f = 1 MHz, Gain = 2, VO( O(pp)) = 2 V,, TA = 25°C Vn Input voltage noise VCC = ±5 V or ±15 V, TA = 25°C In Input current noise VCC = ±15 V VCC = ±5 V VCC = ±15 V VCC = ±5 V † Full range = –55°C to 125°C for the THS4031M. 6 TYP RL = 1 kΩ Total harmonic distortion Differential phase error MIN RL = 150 Ω THD Differential gain error THS4031M TEST CONDITIONS† PARAMETER POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 0.015% 0.02% 0.025° 0.03° dBc THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 electrical characteristics at TA = full range, VCC = ±15 V, RL = 1 kΩ (unless otherwise noted) (continued) dc performance THS4031M TEST CONDITIONS† PARAMETER MIN TYP 75 VCC = ±15 V, V VO = ±10 V TA = 25°C TA = full range 45 5V VCC = ±5 V V, VO = ±2 ±2.5 TA = 25°C TA = full range 40 0.5 Open loop gain 40 UNIT V/mV 55 35 VIO Input offset voltage VCC = ±5 V or ±15 V TA = 25°C TA = full range IIB Input bias current VCC = ±5 V or ±15 V TA = 25°C TA = full range 3 IIO Input offset current VCC = ±5 V or ±15 V TA = 25°C TA = full range 30 Offset voltage drift VCC = ±5 V or ±15 V VCC = ±5 V or ±15 V TA = full range TA = full range Input offset current drift MAX 2 3 6 8 250 400 mV µA nA 10 µV/°C 0.2 nA/°C † Full range = –55°C to 125°C for the THS4031M. input characteristics VICR CMRR ri Common mode input voltage range Common-mode THS4031M TEST CONDITIONS† PARAMETER VCC = ±15 V VCC = ±5 V MIN TYP ±13.5 ±14.3 ± 3.8 ± 4.3 95 VCC = ±15 V, V VICR = ±12 V TA = 25°C TA = full range 85 VCC = ±5 V V, VICR = ±2 ±2.5 5V TA = 25°C TA = full range 90 Common mode rejection ratio MAX UNIT V 80 dB 100 85 Input resistance Ci Input capacitance † Full range = –55°C to 125°C for the THS4031M. 2 MΩ 1.5 pF output characteristics TEST CONDITIONS† PARAMETER VO Output voltage swing VCC = ±15 V VCC = ±5 V VCC = ±15 V VCC = ±5 V IO Output current‡ VCC = ±15 V VCC = ±5 V ISC Short-circuit current‡ VCC = ±15 V RL = 1 kΩ RL = 250 Ω RL = 150 Ω RL = 20 Ω THS4031M MIN TYP ±13 ±13.6 ±3.4 ±3.8 ±12 ±12.9 ±3 ±3.5 60 90 50 70 150 MAX UNIT V mA mA RO Output resistance Open loop 13 Ω † Full range = –55°C to 125°C for the THS4031M. ‡ Observe power dissipation ratings to keep the junction temperature below the absolute maximum rating when the output is heavily loaded or shorted. See the absolute maximum ratings section of this data sheet for more information. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 electrical characteristics at TA = full range, VCC = ±15 V, RL = 1 kΩ (unless otherwise noted) (continued) power supply VCC ICC PSRR THS4031M TEST CONDITIONS† PARAMETER MIN Dual supply Supply voltage operating range ±16.5 9 33 VCC = ±15 V TA = 25°C TA = full range 8.5 VCC = ±5 V TA = 25°C TA = full range 7.5 VCC = ±5 V or ±15 V TA = 25°C TA = full range Supply current (each amplifier) MAX ±4.5 Single supply Power supply rejection ratio TYP 11 9 330 Ω _ 95 dB 80 VI1 330 Ω _ VO1 + CH1 50 Ω 150 Ω VO2 150 Ω VI2 + CH2 50 Ω Figure 3. THS4032 Crosstalk Test Circuit Rg Rf Rg VI VO + 50 Ω 50 Ω POST OFFICE BOX 655303 _ VO + RL Figure 4. Step Response Test Circuit 8 Rf VI _ RL Figure 5. Step Response Test Circuit • DALLAS, TEXAS 75265 mA 10 85 PARAMETER MEASUREMENT INFORMATION 330 Ω V 10 † Full range = –55°C to 125°C for the THS4031M. 330 Ω UNIT THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS Table of Graphs FIGURE Input offset voltage distribution 6, 7 VIO IIB Input offset voltage vs Free-air temperature 8 Input bias current vs Free-air temperature 9 VO VOM Output voltage swing vs Supply voltage 10 Maximum output voltage swing vs Free-air temperature 11 IO ICC Maximum output current vs Free-air temperature 12 Supply current vs Free-air temperature 13 VIC ZO Common-mode input voltage vs Supply voltage 14 Closed-loop output impedance vs Frequency 15 Open-loop gain 16 Phase response PSRR Power-supply rejection ratio vs Frequency 17 CMRR Common-mode rejection ratio vs Frequency 18 Crosstalk vs Frequency 19 Harmonic distortion vs Frequency 20, 21 Harmonic distortion vs Peak-to-peak output voltage 22, 23 Slew rate vs Free-air temperature 24 0.1% settling time vs Output voltage step size 25 Output amplitude vs Frequency SR Small and large signal frequency response 26 – 30 31 – 34 Differential phase vs Number of 150-Ω loads 35, 36 Differential gain vs Number of 150-Ω loads 37, 38 1-V step response 39, 40 4-V step response 41 20-V step response 42 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS INPUT OFFSET VOLTAGE DISTRIBUTION INPUT OFFSET VOLTAGE DISTRIBUTION 22.5 14 250 Samples 3 Wafer Lots TA = 25°C VCC = ± 15 V Percentage of Amplifiers – % Percentage of Amplifiers – % 12 10 8 6 4 2 17.5 15 12.5 10 7.5 5 2.5 0 0 –2 –1.6 0.4 0.8 –1.2 –0.8 –0.4 0 VIO – Input Offset Voltage – mV –2 1.2 –1.6 0.4 –1.2 –0.8 –0.4 0 VIO – Input Offset Voltage – mV 0.8 1.2 Figure 7 Figure 6 INPUT OFFSET VOLTAGE vs FREE-AIR TEMPERATURE INPUT BIAS CURRENT vs FREE-AIR TEMPERATURE –0.3 3.10 3.05 –0.35 I IB – Input Bias Current – µ A V IO – Input Offset Voltage – mV 250 Samples 3 Wafer Lots TA = 25°C VCC = ± 5 V 20 VCC = ± 5 V –0.4 –0.45 VCC = ± 15 V –0.5 VCC = ± 15 V 3 2.95 2.90 2.85 VCC = ± 5 V 2.80 –0.55 2.75 –0.6 –40 –20 60 40 80 0 20 TA – Free-Air Temperature – °C 100 2.70 –40 –20 Figure 8 10 0 20 40 60 80 TA – Free-Air Temperature – °C Figure 9 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 100 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS OUTPUT VOLTAGE SWING vs SUPPLY VOLTAGE MAXIMUM OUTPUT VOLTAGE SWING vs FREE–AIR TEMPERATURE 14 14 VOM – Maximum Output Voltage Swing – ± V |VO | – Output Voltage Swing – ± V TA = 25°C 12 RL = 1 KΩ 10 RL = 150 Ω 8 6 4 13 13 7 9 11 ± VCC – Supply Voltage – ± V VCC = ± 15 V RL = 250 Ω 12.5 2 5 VCC = ± 15 V RL = 1 kΩ 13.5 12 4.5 VCC = ± 5 V RL = 1 kΩ 4 3.5 VCC = ± 5 V RL = 150 Ω 3 2.5 –40 15 –20 60 80 0 20 40 TA – Free-Air Temperature – °C Figure 10 Figure 11 MAXIMUM OUTPUT CURRENT vs FREE-AIR TEMPERATURE SUPPLY CURRENT vs FREE-AIR TEMPERATURE 110 11 Each Amplifier VCC = ± 15 V Source Current 100 10 I CC – Supply Current – mA I O – Maximum Output Current – mA RL = 20 Ω 90 80 100 VCC = ± 15 V Sink Current VCC = ± 5 V Sink Current 70 VCC = ± 5 V Source Current VCC = ± 10 V 8 VCC = ± 5 V 7 6 60 50 –40 VCC = ± 15 V 9 –20 60 80 0 20 40 TA – Free-Air Temperature – °C 100 5 –40 –20 Figure 12 0 20 60 80 40 TA – Free-Air Temperature – °C 100 Figure 13 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 11 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS COMMON-MODE INPUT VOLTAGE vs SUPPLY VOLTAGE CLOSED-LOOP OUTPUT IMPEDANCE vs FREQUENCY 15 100 Z O– Closed-Loop Output Impedance – Ω VIC– Common-Mode Input – ± V TA = 25°C 13 11 9 7 5 3 5 13 7 9 11 ± VCC – Supply Voltage – ± V Gain = 1 RF = 1 kΩ PI = + 3 dBm 10 1 0.1 + 50 Ω f – Frequency – Hz Figure 15 OPEN-LOOP GAIN AND PHASE RESPONSE 100 45° VCC = ± 15 V RL = 150 Ω 80 0° 60 –45° Phase 40 –90° 20 –135° 0 –180° –225° 10 k 100 k 1M 10 M 100 M 1 G f – Frequency – Hz Figure 16 12 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 Phase Response Open-Loop Gain – dB Gain 1k VI THS403x 1000 VO Zo = –1 VI 10 M 1M Figure 14 –20 100 1 kΩ ( 0.01 100 k 15 VO 1 kΩ – 100 M ) 500 M THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS POWER-SUPPLY REJECTION RATIO vs FREQUENCY COMMON-MODE REJECTION RATIO vs FREQUENCY 120 CMRR – Common-Mode Rejection Ratio – dB THS4032 – VCC+ 100 THS4031 – VCC+ THS4031 – VCC– 80 60 THS4032 – VCC– 40 20 VCC = ± 15 V and ± 5 V 10 100 1k 10 k 1M 100 k 10 M VCC = ± 5 V 100 VCC = ± 15 V 80 60 1 kΩ 1 kΩ 40 _ VI VO + 20 0 1 kΩ RL 150 Ω 1 kΩ 0 100 M 10 100 1k 10 k 100 k 1M f – Frequency – Hz f – Frequency – Hz Figure 17 Figure 18 10 M 100 M THS4032 CROSSTALK vs FREQUENCY 0 –10 VCC = ± 15 V PI = 0 dBm See Figure 3 –20 Crosstalk – dB PSRR – Power-Supply Rejection Ratio – dB 120 –30 –40 –50 Input = CH 2 Output = CH 1 –60 –70 Input = CH 1 Output = CH 2 –80 –90 100 k 1M 10 M 100 M 500 M f – Frequency – Hz Figure 19 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 13 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS HARMONIC DISTORTION vs FREQUENCY –40 –40 VCC = ± 15 V and ± 5 V Gain = 2 RF = 300 Ω RL = 1 kΩ VO(PP) = 2 V THS4031 and THS4032 Third Harmonics –60 –70 THS4031 Second Harmonic –80 VCC = ± 15 V and ± 5 V Gain = 2 RF = 300 Ω RL = 150 Ω VO(PP) = 2 V THS4031 Second Harmonic –50 Harmonic Distortion – dBc –50 Harmonic Distortion – dBc HARMONIC DISTORTION vs FREQUENCY THS4032 Second Harmonic –90 –100 –60 THS4032 Second Harmonic –70 –80 –90 –100 THS4031 and THS4032 Third Harmonics –110 100 k –110 100 k 10 M 1M f – Frequency – Hz Figure 20 Figure 21 HARMONIC DISTORTION vs PEAK-TO-PEAK OUTPUT VOLTAGE HARMONIC DISTORTION vs PEAK-TO-PEAK OUTPUT VOLTAGE –50 –10 THS4031 and THS4032 Third Harmonics VCC = ± 15 V Gain = 5 RF = 300 Ω RL = 150 Ω f = 1 MHz –20 –30 THS4032 Second Harmonic Harmonic Distortion – dBc Harmonic Distortion – dBc –60 –70 –80 THS4031 Second Harmonic –90 VCC = ± 15 V Gain = 5 RF = 300 Ω RL = 1 kΩ f = 1 MHz –100 0 2 4 6 8 10 12 14 16 18 VO(PP) – Peak-to-Peak Output Voltage – V –40 –50 THS4032 Second Harmonic –60 –70 –80 THS4031 Second Harmonic –90 THS4031 and THS4032 Third Harmonics –100 –110 20 –110 0 2 4 6 8 10 12 14 16 18 VO(PP) – Peak-to-Peak Output Voltage – V Figure 22 14 10 M 1M f – Frequency – Hz Figure 23 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 20 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS SLEW RATE vs FREE-AIR TEMPERATURE 0.1% SETTLING TIME vs OUTPUT VOLTAGE STEP SIZE 120 80 Gain = –1 RL = 150 Ω t s – 0.1% Settling Time – ns SR – Slew Rate – V/ µ s Vcc = ± 15 V Step = 20 V 100 Gain = –1 RF = 430 Ω 70 110 90 80 Vcc = ± 5 V Step = 4 V 70 60 60 VCC = ± 5 V 50 40 VCC = ± 15 V 30 20 10 50 –40 –20 60 80 0 20 40 TA – Free-Air Temperature – °C 0 100 4 2 3 VO – Output Voltage Step Size – V 1 Figure 24 Figure 25 OUTPUT AMPLITUDE vs FREQUENCY OUTPUT AMPLITUDE vs FREQUENCY 8 8 RF = 1 kΩ 7 6 5 Output Amplitude – dB Output Amplitude – dB 7 RF = 300 Ω RF = 100 Ω 4 3 2 1 0 5 VCC = ± 15 V Gain = 2 RL = 150 Ω VO(PP) = 0.4 V –1 100 k 1M 6 5 500 M RF = 100 Ω 3 2 0 100 M RF = 300 Ω 4 1 10 M RF = 1 kΩ VCC = ± 5 V Gain = 2 RL = 150 Ω VO(PP) = 0.4 V –1 100 k 1M 10 M f – Frequency – Hz f – Frequency – Hz Figure 26 Figure 27 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 100 M 500 M 15 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS OUTPUT AMPLITUDE vs FREQUENCY OUTPUT AMPLITUDE vs FREQUENCY 2 2 1 RF = 1 kΩ 0 –1 Output Amplitude – dB Output Amplitude – dB 1 RF = 360 Ω RF = 100 Ω –2 –3 –4 –5 –6 VCC = ± 15 V Gain = –1 RL = 150 Ω VO(PP) = 0.4 V –7 100 k RF = 1 kΩ 0 –1 RF = 360 Ω RF = 100 Ω –2 –3 –4 VCC = ± 5 V Gain = –1 RL = 150 Ω VO(PP) = 0.4 V –5 –6 1M 100 M 10 M –7 100 k 500 M 1M f – Frequency – Hz 10 M f – Frequency – Hz Figure 28 Figure 29 OUTPUT AMPLITUDE vs FREQUENCY 16 VCC = ± 15 V Output Amplitude – dB 14 12 10 VCC = ± 5 V 8 6 4 2 0 100 k Gain = 5 RF = 3.9 kΩ RL = 150 Ω VO(PP) = 0.4 V 1M 10 M 100 M f – Frequency – Hz Figure 30 16 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 500 M 100 M 500 M THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS SMALL AND LARGE SIGNAL FREQUENCY RESPONSE SMALL AND LARGE SIGNAL FREQUENCY RESPONSE 3 –3 –6 0 VO – Output Voltage Level – dBV VO – Output Voltage Level – dBV 0 3 VCC = ± 15 V Gain = 2 RF = 300 Ω RL= 150 Ω VI = 0.5 V RMS VI = 0.25 V RMS –9 –12 VI = 125 mV RMS –15 –18 VI = 62.5 mV RMS –3 –6 VI = 0.25 V RMS –9 –12 VI = 125 mV RMS –15 –18 VI = 62.5 mV RMS –21 –21 –24 100 k 1M 10 M 100 M –24 100 k 500 M 1M f – Frequency – Hz VI = 0.25 V RMS –15 18 VI = 125 mV RMS –21 –24 VI = 62.5 mV RMS –27 –30 100 k –3 –6 VO – Output Voltage Level – dBV VO – Output Voltage Level – dBV –9 –12 SMALL AND LARGE SIGNAL FREQUENCY RESPONSE VCC = ± 15 V Gain = –1 RF = 430 Ω RL = 150 Ω VI = 0.5 V RMS 500 M Figure 32 SMALL AND LARGE SIGNAL FREQUENCY RESPONSE –3 100 M 10 M f – Frequency – Hz Figure 31 –6 VCC = ± 5 V Gain = 2 RF = 300 Ω RL = 150 Ω VI = 0.5 V RMS VCC = ± 5 V Gain = –1 RF = 430 Ω RL = 150 Ω VI = 0.5 V RMS –9 –12 VI = 0.25 V RMS –15 18 VI = 125 mV RMS –21 –24 VI = 62.5 mV RMS –27 1M 10 M 100 M 500 M –30 100 k f – Frequency – Hz 1M 10 M 100 M 500 M f – Frequency – Hz Figure 33 Figure 34 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 17 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS DIFFERENTIAL PHASE vs NUMBER OF 150-Ω LOADS DIFFERENTIAL PHASE vs NUMBER OF 150-Ω LOADS 0.2° 0.25° Gain = 2 RF = 680 Ω 40 IRE-NTSC Modulation Worst Case ± 100 IRE Ramp VCC = ± 5 V 0.2° Differential Phase Differential Phase 0.15° 0.1° Gain = 2 RF = 680 Ω 40 IRE-PAL Modulation Worst Case ± 100 IRE Ramp VCC = ± 15 V 0.15° VCC = ± 5 V VCC = ± 15 V 0.1° 0.05° 0.05° 0° 1 2 3 Number of 150-Ω Loads 0° 4 1 2 3 Number of 150-Ω Loads Figure 35 Figure 36 DIFFERENTIAL GAIN vs NUMBER OF 150-Ω LOADS DIFFERENTIAL GAIN vs NUMBER OF 150-Ω LOADS 0.025° 0.03 Gain = 2 RF = 680 Ω 40 IRE-NTSC Modulation Worst Case ± 100 IRE Ramp Gain = 2 RF = 680 Ω 40 IRE-PAL Modulation Worst Case ± 100 IRE Ramp 0.02° Differential Gain – % 0.025 Differential Gain – % 4 VCC = ± 5 V VCC = ± 15 V 0.015° VCC = ± 5 V 0.02 VCC = ± 15 V 0.15 0.01° 1 3 2 Number of 150-Ω Loads 4 0.01 1 Figure 37 18 3 2 Number of 150-Ω Loads Figure 38 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 4 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 TYPICAL CHARACTERISTICS 1-V STEP RESPONSE 1-V STEP RESPONSE 0.6 0.6 VCC = ± 5 V Gain = 2 RF = 300 Ω RL = 150 Ω See Figure 4 0.4 VO – Output Voltage – V VO – Output Voltage – V 0.4 VCC = ± 15 V Gain = 2 RF = 300 Ω RL = 150 Ω See Figure 4 0.2 0 –0.2 –0.4 0.2 0 –0.2 –0.4 –0.6 –0.6 0 200 400 800 600 1000 0 200 t – Time – ns 600 800 1000 800 1000 t – Time – ns Figure 39 Figure 40 4-V STEP RESPONSE 20-V STEP RESPONSE 2.5 15 2 10 VO – Output Voltage – V 1.5 VO – Output Voltage – V 400 1 0.5 0 –0.5 VCC = ± 5 V Gain = –1 RF = 430 Ω RL = 150 Ω See Figure 5 –1 –1.5 –2 200 400 600 0 RL = 150 Ω –5 –10 –2.5 0 RL = 1 kΩ 5 VCC = ± 15 V Gain = 2 RF = 330 Ω See Figure 4 Offset For Clarity 800 1000 –15 0 200 t – Time – ns 400 600 t – Time – ns Figure 42 Figure 41 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 19 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION theory of operation The THS403x is a high-speed operational amplifier configured in a voltage feedback architecture. It is built using a 30-V, dielectrically isolated, complementary bipolar process with NPN and PNP transistors possessing fTs of several GHz. This results in an exceptionally high-performance amplifier that has a wide bandwidth, high slew rate, fast settling time, and low distortion. A simplified schematic is shown in Figure 43. (7) VCC + (6) OUT IN – (2) IN + (3) (4) VCC – NULL (1) NULL (8) Figure 43. THS4031 Simplified Schematic noise calculations and noise figure Noise can cause errors on very small signals. This is especially true when amplifying small signals. The noise model for the THS403x, shown in Figure 44, includes all of the noise sources as follows: • • • • 20 en = Amplifier internal voltage noise (nV/√Hz) IN+ = Noninverting current noise (pA/√Hz) IN– = Inverting current noise (pA/√Hz) eRx = Thermal voltage noise associated with each resistor (eRx = 4 kTRx ) POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION noise calculations and noise figure (continued) eRs RS en Noiseless + _ eni IN+ eno eRf RF eRg IN– RG Ǹǒ Ǔ Figure 44. Noise Model The total equivalent input noise density (eni) is calculated by using the following equation: e Where: + ni en 2 ǒ ) IN ) Ǔ )ǒ ǒ 2 R S IN– R ǓǓ ǒ Ǔ ø RG ) 4 kTRs ) 4 kT RF ø RG F 2 k = Boltzmann’s constant = 1.380658 × 10–23 T = Temperature in degrees Kelvin (273 +°C) RF || RG = Parallel resistance of RF and RG ǒ Ǔ To get the equivalent output noise of the amplifier, just multiply the equivalent input noise density (eni) by the overall amplifier gain (AV). e no + eni AV + e ni 1 ) RR F (Noninverting Case) G As the previous equations show, to keep noise at a minimum, small-value resistors should be used. As the closed-loop gain is increased (by reducing RG), the input noise is reduced considerably because of the parallel resistance term. This leads to the general conclusion that the most dominant noise sources are the source resistor (RS) and the internal amplifier noise voltage (en). Because noise is summed in a root-mean-squares method, noise sources smaller than 25% of the largest noise source can be effectively ignored. This advantage can greatly simplify the formula and make noise calculations much easier to calculate. For more information on noise analysis, please refer to the Noise Analysis section in Operational Amplifier Circuits Applications Report (literature number SLVA043). POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 21 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION noise calculations and noise figure (continued) This brings up another noise measurement usually preferred in RF applications, the noise figure (NF). Noise figure is a measure of noise degradation caused by the amplifier. The value of the source resistance must be defined and is typically 50 Ω in RF applications. NF + 10log ȱȧ Ȳǒ ȳȧ Ǔȴ e 2 ni 2 e Rs Because the dominant noise components are generally the source resistance and the internal amplifier noise voltage, we can approximate noise figure as: ȱȧ ȡȧǒ ȧȧ )Ȣ ȧȲ e NF + 10log 1 Ǔ )ǒ ) 2 n IN 4 kTR Ǔ ȣȧȤȳȧ 2 R S S ȧȧ ȧȴ Figure 45 shows the noise figure graph for the THS403x. NOISE FIGURE vs SOURCE RESISTANCE 16 f = 10 kHz TA = 25°C 14 Noise Figure – dB 12 10 8 6 4 2 0 10 100 1k Source Resistance – Ω 10 k Figure 45. Noise Figure vs Source Resistance 22 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION optimizing frequency response Internal frequency compensation of the THS403x was selected to provide very wide bandwidth performance and still maintain a very low noise floor. In order to meet these performance requirements, the THS403x must have a minimum gain of 2 (–1). Because everything is referred to the noninverting terminal of an operational amplifier, the noise gain in a G = –1 configuration is the same as a G = 2 configuration. One of the keys to maintaining a smooth frequency response, and hence, a stable pulse response, is to pay particular attention to the inverting terminal. Any stray capacitance at this node causes peaking in the frequency response (see Figure 46 and Figure 47). Two things can be done to help minimize this effect. The first is to simply remove any ground planes under the inverting terminal of the amplifier, including the trace that connects to this terminal. Additionally, the length of this trace should be minimized. The capacitance at this node causes a lag in the voltage being fed back due to the charging and discharging of the stray capacitance. If this lag becomes too long, the amplifier will not be able to correctly keep the noninverting terminal voltage at the same potential as the inverting terminal’s voltage. Peaking and possible oscillations will then occur if this happens. OUTPUT AMPLITUDE vs FREQUENCY 9 Output Amplitude – dB 8 7 4 VCC = ± 15 V Gain = 2 RF = 300 Ω RL = 150 Ω VO(PP) = 0.4 V Ci– = 10 pF 3 2 Output Amplitude – dB 10 OUTPUT AMPLITUDE vs FREQUENCY 6 No Ci– (Stray C Only) 5 4 3 2 300 Ω Ci– 300 Ω VI + 0 No Ci– (Stray C Only) –1 –2 –3 –4 150 Ω Ci–= 10 pF 1 VO 50 Ω 1 0 100 k _ VCC = ± 15 V Gain = –1 RF = 360 Ω RL = 150 Ω VO(PP) = 0.4 V 360 Ω 360 Ω VI 56 Ω Ci– _ VO + 150 Ω –5 1M 10 M 100 M 500 M –6 100 k 1M 10 M f – Frequency – Hz f – Frequency – Hz Figure 46 Figure 47 100 M 500 M The second precaution to help maintain a smooth frequency response is to keep the feedback resistor (Rf) and the gain resistor (Rg) values fairly low. These two resistors are effectively in parallel when looking at the ac small-signal response. This is why in Figure 30, a feedback resistor of 3.9 kΩ with a gain resistor of 1 kΩ only shows a small peaking in the frequency response. The parallel resistance is only 800 Ω. This value, in conjunction with a very small stray capacitance test PCB, forms a zero on the edge of the amplifier’s natural frequency response. To eliminate this peaking, all that needs to be done is to reduce the feedback and gain resistances. One other way to compensate for this stray capacitance is to add a small capacitor in parallel with the feedback resistor. This helps to neutralize the effects of the stray capacitance. To keep this peaking out of the operating range, the stray capacitance and resistor value’s time constant must be kept low. But, as can be seen in Figures 26 – 29, a value too low starts to reduce the bandwidth of the amplifier. Table 1 shows some recommended feedback resistors to be used with the THS403x. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 23 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION optimizing frequency response (continued) Table 1. Recommended Feedback Resistors GAIN Rf for VCC = ±15 V and ± 5 V 2 300 Ω –1 360 Ω 5 3.3 kΩ (low stray-c PCB only) unity-gain concerns THS403x was designed for extremely low noise with a minimum gain of 2 (–1). If the amplifier were to be configured for unity gain, the output would tend to oscillate because the open-loop intersection on a Bode diagram is at a –40 dB/decade slope instead of the –20 dB/decade slope required for stable operation. But, it is sometimes desirable to have a low-noise unity gain buffer. There is a way to accomplish this feat with the THS403x with some added complexity (see Figure 48). The lag compensation circuit shown in Figure 48 increases the noise gain of the amplifier without increasing the signal gain. Another way to look at this is that the open-loop gain is effectively reduced by the 1 + RF/RC gain. This reduction causes the –40 dB/decade pole to be shifted down into an open-loop gain of less than 1. The drawbacks of this circuit are the decreased frequency response, the increased noise, and the increased output offset voltage (VOO). One way to eliminate the VOO increase is to add a capacitor (CC) in series with RC, with the added requirement that the time constant of CC and RC be set low enough for the Bode plot intersection to be at a –20 dB/decade slope. Typically, a 1 + RF /RC gain of 2 to 3 yields a smooth frequency response for the THS403x. If CC is used, it is desirable to have the 1/(2 π RC CC) frequency 5 to 10 times lower than the amplifier’s natural bandwidth. One additional advantage this circuit provides is that it makes driving capacitive loads much easier. A capacitive load causes the –40 dB/decade intersection (because of the phase lag), to be above unity gain, the same as described previously. In general, this RC and CC modification can be used in both an inverting and noninverting configuration with the same results. 24 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION unity-gain concerns (continued) Original Open Loop Response Gain (dB) See Note A RF RC CC VI _ VO + RL Effective Compensated O.L. Response (without CC) CL Unstable Intersection f 0 Stable Intersection NOTE A: The difference is due to 1+RF/RC noise gain. Figure 48. Unity Gain Compensation 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 THS403x 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 phase margin of the device 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 49. A minimum value of 20 Ω should work well for most applications. For example, in 75-Ω transmission systems, setting the series resistor value to 75 Ω both isolates any capacitance loading and provides the proper line impedance matching at the source end. 360 Ω 360 Ω Input _ 20 Ω Output THS403x + CLOAD Figure 49. Driving a Capacitive Load POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 25 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION offset nulling The THS403x has very low input offset voltage for a high speed amplifier. However, if additional correction is required, the designer can make use of an offset nulling function provided on the THS4031. By placing a potentiometer between terminals 1 and 8 of the device and tying the wiper to the negative supply, the input offset can be adjusted. This is shown in Figure 50. VCC+ 0.1 µF + THS4031 _ 10 kΩ 0.1 µF VCC – Figure 50. Offset Nulling Schematic offset voltage The output offset voltage (VOO) is the sum of the input offset voltage (VIO) and both input bias currents (IIB) times the corresponding gains. The following schematic and formula can be used to calculate the output offset voltage: RF IIB– RG + VI RS – VO + ƪ ǒ Ǔƫ ƪ ǒ Ǔƫ IIB+ V OO + VIO 1 ) R R F G " IIB) RS 1 ) R R F G " IIB– RF Figure 51. Output Offset Voltage Model 26 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION general configurations When receiving low-level signals, limiting the bandwidth of the incoming signals into the system is often required. The simplest way to accomplish this is to place an RC filter at the noninverting terminal of the amplifer (see Figure 52). RG RF – VO + VI R1 V O V I C1 ǒ Ǔǒ + 1 ) RRF G 1 f –3dB Ǔ 1 + 2pR1C1 ) sR1C1 1 Figure 52. Single-Pole Low-Pass Filter If even more attenuation is needed, a multiple-pole filter is required. The Sallen-Key filter can be used for this task. For best results, the amplifier should have a bandwidth that is 8 to 10 times the filter frequency bandwidth. Otherwise, phase shift of the amplifier can occur. C1 + _ VI R1 R1 = R2 = R C1 = C2 = C Q = Peaking Factor (Butterworth Q = 0.707) R2 f C2 RG RF –3dB RG = + 2p1RC ( RF 1 2– Q ) Figure 53. 2-Pole Low-Pass Sallen-Key Filter POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 27 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION circuit-layout considerations In order to achieve the levels of high-frequency performance of the THS403x, it is essential that proper printed-circuit board high-frequency design techniques be followed. A general set of guidelines is given below. In addition, a THS403x evaluation board is available to use as a guide for layout or for evaluating the device performance. D D D D 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. 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 inch between the device power terminals and the ceramic capacitors. 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. 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. 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. general PowerPAD design considerations The THS403x is available 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 54(a) and Figure 54(b)]. This arrangement results in the leadframe being exposed as a thermal pad on the underside of the package [see Figure 54(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 surface mount with the heretofore awkward mechanical methods of heatsinking. 28 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION general PowerPAD design considerations (continued) DIE Side View (a) Thermal Pad DIE End View (b) Bottom View (c) NOTE B: The thermal pad is electrically isolated from all terminals in the package. Figure 54. Views of Thermally Enhanced DGN Package Although there are many ways to properly heatsink this device, the following steps illustrate the recommended approach. Thermal pad area (68 mils x 70 mils) with 5 vias (Via diameter = 13 mils) Figure 55. PowerPAD PCB Etch and Via Pattern 1. Prepare the PCB with a top-side etch pattern as shown in Figure 55. There should be etch for the leads as well as etch for the thermal pad. 2. Place five holes in the area of the thermal pad. These holes should be 13 mils in diameter. They are kept 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. This helps dissipate the heat generated by the THS403xDGN 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 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 THS403xDGN package should connect 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, which 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 to all the IC terminals. 8. With these preparatory steps in place, the THS403xDGN 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. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 29 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION general PowerPAD design considerations (continued) The actual thermal performance achieved with the THS403xDGN in its PowerPAD package depends on the application. In the example above, if the size of the internal ground plane is approximately 3 inches × 3 inches, then the expected thermal coefficient, θJA, is about 58.4_C/W. For comparison, the non-PowerPAD version of the THS403x IC (SOIC) is shown. For a given θJA, the maximum power dissipation is shown in Figure 56 and is calculated by the following formula: P Where: + D ǒ Ǔ T –T MAX A q JA PD = Maximum power dissipation of THS403x IC (watts) TMAX = Absolute maximum junction temperature (150°C) TA = Free-ambient air temperature (°C) θJA = θJC + θCA θJC = Thermal coefficient from junction to case θCA = Thermal coefficient from case to ambient air (°C/W) MAXIMUM POWER DISSIPATION vs FREE-AIR TEMPERATURE Maximum Power Dissipation – W 3.5 DGN Package θJA = 58.4°C/W 2 oz. Trace And Copper Pad With Solder 3 2.5 SOIC Package High-K Test PCB θJA = 98°C/W 2 TJ = 150°C DGN Package θJA = 158°C/W 2 oz. Trace And Copper Pad Without Solder 1.5 1 0.5 SOIC Package Low-K Test PCB θJA = 167°C/W 0 –40 –20 60 80 0 20 40 TA – Free-Air Temperature – °C 100 NOTE A: Results are with no air flow and PCB size = 3”× 3” Figure 56. Maximum Power Dissipation vs Free-Air Temperature 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. 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. 30 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION general PowerPAD design considerations (continued) The next thing to be considered is 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 multiamplifier devices. Because these devices have linear output stages (Class A-B), most of the heat dissipation is at low output voltages with high output currents. Figure 57 to Figure 60 shows this effect, along with the quiescent heat, with an ambient air temperature of 50°C. When using VCC = ±5 V, heat is generally not a problem, even with SOIC packages. But, when using VCC = ±15 V, the SOIC package is severely limited in the amount of heat it can dissipate. The other key factor when looking at these graphs 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, θJA decreases and the heat dissipation capability increases. The currents and voltages shown in these graphs are for the total package. For the dual amplifier package (THS4032), the sum of the RMS output currents and voltages should be used to choose the proper package. THS4031 MAXIMUM RMS OUTPUT CURRENT vs RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS VCC = ± 5 V TJ = 150°C TA = 50°C 180 1000 Maximum Output Current Limit Line | IO | – Maximum RMS Output Current – mA | IO | – Maximum RMS Output Current – mA 200 160 140 Package With θJA < = 120°C/W 120 100 SO-8 Package θJA = 167°C/W Low-K Test PCB 80 60 40 Safe Operating Area 20 4 1 2 3 | VO | – RMS Output Voltage – V VCC = ± 15 V TJ = 150°C TA = 50°C DGN Package θJA = 58.4°C/W Maximum Output Current Limit Line 100 SO-8 Package θJA = 98°C/W High-K Test PCB SO-8 Package θJA = 167°C/W Low-K Test PCB Safe Operating Area 10 0 0 THS4031 MAXIMUM RMS OUTPUT CURRENT vs RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS 5 0 3 6 9 12 | VO | – RMS Output Voltage – V 15 Figure 58 Figure 57 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 31 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION general PowerPAD design considerations (continued) THS4032 MAXIMUM RMS OUTPUT CURRENT vs RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS | IO | – Maximum RMS Output Current – mA 200 Maximum Output Current Limit Line Package With θJA ≤ 60°C/W 180 160 140 120 100 SO-8 Package θJA = 167°C/W Low-K Test PCB 80 60 Safe Operating Area 40 VCC = ± 5 V TJ = 150°C TA = 50°C Both Channels SO-8 Package θJA = 98°C/W High-K Test PCB 20 0 0 1 2 3 4 | VO | – RMS Output Voltage – V 5 Figure 59 THS4032 MAXIMUM RMS OUTPUT CURRENT vs RMS OUTPUT VOLTAGE DUE TO THERMAL LIMITS | IO | – Maximum RMS Output Current – mA 1000 VCC = ± 15 V TJ = 150°C TA = 50°C Both Channels Maximum Output Current Limit Line 100 SO-8 Package θJA = 98°C/W High-K Test PCB 10 DGN Package θJA = 58.4°C/W Safe Operating Area 1 0 SO-8 Package θJA = 167°C/W Low-K Test PCB 3 6 9 12 | VO | – RMS Output Voltage – V Figure 60 32 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 15 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 APPLICATION INFORMATION evaluation board An evaluation board is available for the THS4031 (literature number SLOP203) and THS4032 (literature Number SLOP135). This board has been configured for very low parasitic capacitance in order to realize the full performance of the amplifier. A schematic of the evaluation board is shown in Figure 61. The circuitry has been designed so that the amplifier may be used in either an inverting or noninverting configuration. For more information, please refer to the THS4031 EVM User’s Guide (literature number SLOU038) or the THS4032 EVM User’s Guide (literature number SLOU039). To order the evaluation board, contact your local TI sales office or distributor. VCC+ + C3 0.1 µF R4 301 Ω IN + C2 6.8 µF NULL R5 49.9 Ω + R3 49.9 Ω OUT THS4031 _ NULL R2 301 Ω + C4 0.1 µF C1 6.8 µF IN – VCC – R4 49.9 Ω Figure 61. THS4031 Evaluation Board POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 33 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 MECHANICAL INFORMATION D (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 14 PIN SHOWN PINS ** 0.050 (1,27) 8 14 16 A MAX 0.197 (5,00) 0.344 (8,75) 0.394 (10,00) A MIN 0.189 (4,80) 0.337 (8,55) 0.386 (9,80) DIM 0.020 (0,51) 0.014 (0,35) 14 0.010 (0,25) M 8 0.244 (6,20) 0.228 (5,80) 0.008 (0,20) NOM 0.157 (4,00) 0.150 (3,81) 1 Gage Plane 7 A 0.010 (0,25) 0°– 8° 0.044 (1,12) 0.016 (0,40) Seating Plane 0.069 (1,75) MAX 0.010 (0,25) 0.004 (0,10) 0.004 (0,10) 4040047 / D 10/96 NOTES: A. B. C. D. 34 All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion, not to exceed 0.006 (0,15). Falls within JEDEC MS-012 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 MECHANICAL INFORMATION DGN (S-PDSO-G8) PowerPAD PLASTIC SMALL-OUTLINE PACKAGE 0,38 0,25 0,65 8 0,25 M 5 Thermal Pad (See Note D) 0,15 NOM 3,05 2,95 4,98 4,78 Gage Plane 0,25 1 0°– 6° 4 3,05 2,95 0,69 0,41 Seating Plane 1,07 MAX 0,15 0,05 0,10 4073271/A 04/98 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Body dimensions include mold flash or protrusions. The package thermal performance may be enhanced by attaching an external heat sink to the thermal pad. This pad is electrically and thermally connected to the backside of the die and possibly selected leads. E. Falls within JEDEC MO-187 PowerPAD is a trademark of Texas Instruments. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 35 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 MECHANICAL INFORMATION FK (S-CQCC-N**) LEADLESS CERAMIC CHIP CARRIER 28 TERMINAL SHOWN 18 17 16 15 14 13 NO. OF TERMINALS ** 12 19 11 20 10 A B MIN MAX MIN MAX 20 0.342 (8,69) 0.358 (9,09) 0.307 (7,80) 0.358 (9,09) 28 0.442 (11,23) 0.458 (11,63) 0.406 (10,31) 0.458 (11,63) 21 9 22 8 44 0.640 (16,26) 0.660 (16,76) 0.495 (12,58) 0.560 (14,22) 23 7 52 0.739 (18,78) 0.761 (19,32) 0.495 (12,58) 0.560 (14,22) 24 6 68 25 5 0.938 (23,83) 0.962 (24,43) 0.850 (21,6) 0.858 (21,8) 84 1.141 (28,99) 1.165 (29,59) 1.047 (26,6) 1.063 (27,0) B SQ A SQ 26 27 28 1 2 3 4 0.080 (2,03) 0.064 (1,63) 0.020 (0,51) 0.010 (0,25) 0.020 (0,51) 0.010 (0,25) 0.055 (1,40) 0.045 (1,14) 0.045 (1,14) 0.035 (0,89) 0.045 (1,14) 0.035 (0,89) 0.028 (0,71) 0.022 (0,54) 0.050 (1,27) 4040140 / D 10/96 NOTES: A. B. C. D. E. 36 All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. This package can be hermetically sealed with a metal lid. The terminals are gold plated. Falls within JEDEC MS-004 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 THS4031, THS4032 100-MHz LOW-NOISE HIGH-SPEED AMPLIFIERS SLOS224C – JULY 1999 – REVISED APRIL 2000 MECHANICAL INFORMATION JG (R-GDIP-T8) CERAMIC DUAL-IN-LINE PACKAGE 0.400 (10,20) 0.355 (9,00) 8 5 0.280 (7,11) 0.245 (6,22) 1 4 0.065 (1,65) 0.045 (1,14) 0.310 (7,87) 0.290 (7,37) 0.020 (0,51) MIN 0.200 (5,08) MAX Seating Plane 0.130 (3,30) MIN 0.063 (1,60) 0.015 (0,38) 0.100 (2,54) 0°–15° 0.023 (0,58) 0.015 (0,38) 0.014 (0,36) 0.008 (0,20) 4040107/C 08/96 NOTES: A. B. C. D. E. All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. This package can be hermetically sealed with a ceramic lid using glass frit. Index point is provided on cap for terminal identification only on press ceramic glass frit seal only. Falls within MIL-STD-1835 GDIP1-T8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 37 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. Customers are responsible for their applications using TI components. In order to minimize risks associated with the customer’s applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI’s publication of information regarding any third party’s products or services does not constitute TI’s approval, warranty or endorsement thereof. Copyright 2000, Texas Instruments Incorporated