SPT9101 125 MSPS SAMPLE-AND-HOLD AMPLIFIER FEATURES APPLICATIONS * * * * * * * * * * * * * * Second Source of AD9101 350 MHz Sampling Bandwidth 125 MHz Sampling Rate Excellent Hold Mode Distortion -75 dB at 50 MSPS (23 MHz VIN) -62 dB at 100 MSPS (48 MHz VIN) 7 ns Acquisition Time to 0.1% <1 ps Aperture Jitter 66 dB Feedthrough Rejection at 50 MHz Low Spectral Noise Density Test Instrumentation Equipment RF Demodulation Systems High Performance CCD Capture Digital Sampling Oscilloscopes Commercial and Military Radar High-Speed DAC Deglitching The performance of this device makes it an excellent front end driver for a wide range of ADCs on the market today. Significant improvements in dynamic performance can be achieved by using this device ahead of virtually all ADCs that do not have an internal track-and-hold. GENERAL DESCRIPTION The SPT9101 is a high-speed track-and-hold amplifier designed for a wide range of use. The SPT9101 is capable of sampling at speeds up to 125 MSPS with resolutions ranging from 8 to 12 bits. Trim programmable internal hold and compensation capacitors provide for optimized input bandwidth and slew rate versus noise performance. The SPT9101 is offered in 20-lead SOIC and LCC packages over the industrial temperature range and in die form. Contact the factory for military and /833 package options. BLOCK DIAGRAM VIn Sampler + + 4X Amp - CHOLD 3R R CLK NCLK RTN VOUT ABSOLUTE MAXIMUM RATING (Beyond which damage may occur)1 Supply Voltages Supply Voltage (+VS) ................................ -0.5 V to +6 V Supply Voltage (-VS) ................................. -6 V to +0.5 V Output Currents Continuous Output Current ................................... 70 mA Temperature Operating Temperature .............................. -40 to +85 C Junction Temperature ......................................... +150 C Lead, Soldering (10 seconds) ............................. +220 C Storage ..................................................... -65 to +150 C Input Voltages Analog Input Voltage ................................................ 5 V CLK, NCLK Input ....................................... -5 V to +0.5 V Note 1: Operation at any Absolute Maximum Ratings is not implied. See Electrical Specifications for proper nominal applied conditions in typical application. ELECTRICAL SPECIFICATIONS +VS=+5.0 V, -VS=-5.2 V, RLOAD=100 , unless otherwise specified. PARAMETERS DC Performance Gain VIN = 0.5 V TEST CONDITIONS TEST LEVEL +25 C Full Temp. +25 C Full Temp. +25 C Full Temp. +25 C Full Temp. I VI I VI V V VI V Full Temp. V Input Capacitance Input Resistance Full Temp. +25 C Full Temp. +25 C Full Temp. VI I VI V VI Clock Inputs Input Bias Current Input Low Voltage Input High Voltage +25 C Full Temp. Full Temp. VI VI VI Offset VIN = 0 V Output Resistance Output Short Circuit Current PSRR VS = 0.5 V p-p Pedestal Sensitivity to Pos. Supply VS = 0.5 V p-p Pedestal Sensitivity to Neg. Supply VS = 0.5 V p-p Analog Input/Output Maximum Output Voltage Range6 Input Bias Current MIN 3.93 3.9 SPT9101 TYP MAX UNITS 4.07 4.1 10 30 0.5 60 43 4 V/V V/V mV mV mA dB mV/V 8 mV/V 4.0 3 37 2.4 2.7 15 100 2 450 -1.0 3 -1.8 -0.8 30 35 30 -1.5 V A A pF k A V V Track Mode Dynamics Bandwidth (-3 dB) VOut = 1.0 V p-p Full Temp. Slew Rate 4 V Output Step Full Temp. Overdrive Recovery Time1 To 0.1% Integrated Output Noise BW = 5 to 200 MHz IV IV V V Input RMS Spectral Noise V 10 MHz 150 1100 180 1400 55 270 3.9 MHz V/s ns V nV Hz SPT9101 2 12/30/99 ELECTRICAL SPECIFICATIONS +VS=+5.0 V, -VS=-5.2 V, RLOAD=100 , unless otherwise specified. PARAMETERS Hold Mode Dynamics Worst Harmonic VOut = 2 V p-p Worst Harmonic VOut = 2 V p-p Worst Harmonic VOut = 2 V p-p Worst Harmonic VOut = 2 V p-p Sampling Bandwidth2 VIN = 0.5 V p-p Hold Noise3 (RMS) Droop Rate Feedthrough Rejection (50 MHz) VOut = 2 V p-p Maximum Hold Time, VIN=0 V Track-and-Hold Switching Aperture Delay Aperture Jitter Pedestal Offset, VIN=0 V Transient Amplitude Settling Time to 4 mV Glitch Product4 VIN = 0 V Hold-to-Track Switching Acquisition Time to 0.1% 2 V Output Step Acquisition Time to 0.01% 2 V Output Step Power Supply5 +VS Voltage -VS Voltage Power Dissipation TEST CONDITIONS TEST LEVEL 23 MHz, 50 MSPS +25 C 48 MHz, 100 MSPS +25 C 48 MHz, 100 MSPS Full Temp. 48 MHz, 125 MSPS +25 C -3 dB, +25 C MIN SPT9101 TYP V -75 IV -62 IV MAX UNITS dB FS -57 dB FS -53 dB FS V -57 dB FS V 350 MHz +25 C VIN=0.0 V, +25 C Full Temp. V V V 150 x tH -40 -66 Full Temp. IV +25 C +25 C +25 C Full Temp. VIN = 0 V, Full Temp. Full Temp. +25 C V V I VI V V V -250 <1 10 +25 C V 7 +25 C Full Temp. IV IV 11 14 16 Full Temp, Track Mode Full Temp, Clocked Mode Full Temp, Track Mode Full Temp, Clocked Mode Full Temp, Track Mode Full Temp, Clocked Mode VI VI VI VI VI VI 54 44 54 44 551 449 65 55 65 55 663 561 100 mV/s mV/s dB 200 ns 25 35 8 4 20 ps ps rms mV mV mV ns pV-s ns ns ns mA mA mA mA mW mW 1 Time to recover within rated error band from 160% overdrive. 2 Sampling bandwidth is defined as the -3 dB frequency response of the input sampler to the hold capacitor when operating in the sampling mode. It is greater than tracking bandwidth because it does not include the bandwidth of the output amplifier. 3 Hold mode noise is proportional to the length of time a signal is held. For example, if the hold time (tH) is 20 ns, the accumulated noise is typically 3 V (150 mV/s x 20 ns). This value must be combined with the track mode noise to obtain total noise. 4 Total energy of worst case track-to-hold or hold-to-track glitch. JC (LCC) = +6 C/W JA (SOIC) = +85 C/W in still air at +25 C ambient. 5Clocked mode is specified with a 50% clock duty cycle. 6Analog input voltage should be limited 0.8 volts to maintain device in linear range. Typical thermal impedances: SPT9101 3 12/30/99 TEST LEVEL CODES TEST LEVEL All electrical characteristics are subject to the following conditions: All parameters having min/ max specifications are guaranteed. The Test Level column indicates the specific device testing actually performed during production and Quality Assurance inspection. Any blank section in the data column indicates that the specification is not tested at the specified condition. TEST PROCEDURE I 100% production tested at the specified temperature. II 100% production tested at TA=25 C, and sample tested at the specified temperatures. III QA sample tested only at the specified temperatures. IV Parameter is guaranteed (but not tested) by design and characterization data. V Parameter is a typical value for information purposes only. VI 100% production tested at TA = 25 C. Parameter is guaranteed over specified temperature range. Aperature Delay Figure 1 - Timing Diagram Input Acquisition Time Observed at Hold Capacitor Output Observed at Amplifier Output CLK Hold Track Track-to-Hold Settling Hold NCLK TIMING SPECIFICATION DEFINITIONS TRACK-TO-HOLD SETTLING TIME ACQUISITION TIME The time required for the output to settle to within 4 mV of its final value. This is the time it takes the SPT9101 to acquire the analog signal at the internal hold capacitor when it makes a transition from hold mode to track mode. (See figure 1.) The acquisition time is measured from the 50% input clock transition point to the point when the signal is within a specified error band at the internal hold capacitor (ahead of the output amplifier). It does not include the delay and settling time of the output amplifier. Because the signal is internally acquired and settled at the hold capacitor before the output voltage has settled, the sampler can be put in hold mode before the output has settled. APERTURE DELAY The aperture delay time is the interval between the leading edge transition of the clock input and the instant when the input signal was equal to the held value. It is the difference in time between the digital hold switch delay and the analog signal propagation time. Because the analog propagation time is longer than the digital delay in the SPT9101, the aperture delay is a negative value. SPT9101 4 12/30/99 Figure 2 - Typical Interface Circuit + + 2.2 F 2.2 F -A5.2 NOTES: +A5 1) Vt = Threshold voltage: a) For TTL or CMOS Clock input 15 VIN RTN 10 -A5.2 11 IN+ X 4 Vt 18 +VS Vt b) For ECL Clock input VOUT -A5.2 3k 1k Vt 6,7,16 2) Unless otherwise specified, all capacitors are 0.01 or 0.1 F, surface mount. 3) X = Termination (if required). 330 220 2 CLK IN 1k 3k GND 330 -A5.2 VCC +A5 9 VOUT CLK NCLK 1,2 3 8 SPT9101 VIN +A5 5 +VS 4 +VS 18 +VS -VS 17 -VS 13 -VS -VS 12 -A5.2 CLKIN 220 96850 R 8 VEE 4) CLKIN a) TTL/CMOS 11 R SPT, HCMP96850 IN- LE 6 GND 1,16 b) ECL: Direct Input 12 THEORY OF OPERATION CLOCK DRIVER CIRCUIT (CLK, NCLK PINS) The SPT9101 is a monolithic 125 MSPS track and hold amplifier built on a very high-speed complementary bipolar process. It is pin and functionally compatible with the AD9101. It is a two stage design with a sampler driving a hold capacitor followed by a noninverting output buffer amplifier with gain of 4. The first stage sampler is based on a current amplifier in noninverting gain of one configuration with inverting input connected to the output. The hold switch is integrated into this closed-loop first stage amplifier. CADEKA highly recommends that a differential ECL clock be used to drive the SPT9101. Both the 10KH and 100KH family of ECL logic can be used. The typical interface diagram, figure 2, shows the use of a SPT HCMP96850 high-speed comparator. The comparator has a typical propagation delay of 2.4 ns, very low offset of 3 mV, and a minimum tracking bandwidth of 300 MHz. The comparator shown has been set up in a feedthrough operation mode with latch enable connected to a logic high. The output buffer amplifier is in a noninverting gain of 4 configuration with inverting input connected to a resistor divider driven from the output. The noninverting input from the hold capacitor employs input bias current cancellation which results in excellent droop rate performance. The sampler and amplifier stages both employ complementary current amplifiers for high-speed, low-distortion performance. The threshold voltage (Vt) can be set using a resistor divider as shown in note 1 of figure 2. The configuration shown in note 1a is for a TTL/CMOS clock input and the configuration shown in note 1b is for an ECL clock input. The differential output of the comparator is directly fed to the SPT9101 clock input. The comparator can also be driven with a sinewave input, with the threshold voltage (Vt) adjusted to produce the desired track/hold duty cycle ratio. TYPICAL INTERFACE CIRCUIT Note 4a shows the resistor divider configuration for a TTL/ CMOS clock input. If an ECL clock is used it can be directly fed into the comparator. BOOTSTRAP CAPACITOR OUTPUT LEVEL SHIFTING (RTN PIN) The SPT9101 does not require the bootstrap capacitor that is required on the AD9101 between pins 3 and 19. Because pins 3 and 19 are No Connects on the SPT9101, it will work well in existing AD9101 sockets. The RTN pin is tied to the output buffer amplifier internal feedback resistor network as shown in the block diagram. Normally this pin is tied to ground for a 4x gain output amplifier configuration. However, this pin may be configured in other ways as long as certain guidelines are met. SPT9101 5 12/30/99 The RTN pin may be tied to an external voltage to generate an offset at the output. VOut must be kept to less than 2.7 V typical output swing. VOut, with an external reference voltage at the RTN pin, is represented by the following formula: SAMPLER FOR 12-BIT ADC APPLICATION The SPT9101 was specifically designed for applications where improved bandwidth performance is required. Figure 3 shows as simple block diagram of the SPT9101 as a sampler ahead of the SPT7922 12-bit, 30 MSPS ADC. VOut = 4 VIN - 3 VRef where VRef = voltage at RTN pin and | VOut | 2.7 V Figure 3 - Sampler for 12-Bit ADC The following options are generally not recommended due to the possibility of degraded noise performance of the device: the RTN pin can also be tied to an external resistor to reduce the gain but performance may degrade due to increased noise from the external resistor. Also RTN can be left open for unity gain mode, however, noise will increase. VIN In all cases, VIN must be kept to -0.5 V VIN +0.5 V for rated performance. SPT9101 SPT7922 Clock 1 12 Clock 2 The graph below entitled Improved Dynamic Performance Using the SPT9101 shows the performance with and without the SPT9101. The SPT9101 significantly extends the dynamic performance range of the converter. PERFORMANCE CHARACTERISTICS SPT9101 Hold Mode Distortion vs. Temperature Droop Rate vs Temperature -65 Input Frequency = 50 MHz Clock Frequency = 100 MHz Hold = 4 ns Track = 6 ns 40 dB 0 mV/us -40 Worst Harmonic -80 -120 -20 0 20 40 60 -60 -50 80 -25 0 50 75 100 Temperature (C) Temperature (C) SPT9101 Hold Mode Distortion vs Input Frequency Improved Dynamic Performance Using the SPT9101 -75 70 -70 Worst Harmonic SPT9101 & SPT7922 TDE (dB) dB 25 -65 Clock Frequency = 100 MHz Track = 6 ns Hold = 4 ns -60 60 SPT7922 50 (FS = 28 MSPS) -55 1 10 40 100 Input Frequency (MHz) 5 10 15 20 FIN (MHz) SPT9101 6 12/30/99 PACKAGE OUTLINES 20-Lead LCC A H SYMBOL G Bottom View B C Pin 1 MIN INCHES MAX MILLIMETERS MIN MAX A .040 typ 1.02 B C .050 typ 0.055 1.27 1.40 0.045 1.14 D E F 0.345 0.054 0.360 0.066 .020 typ 8.76 1.37 9.14 1.68 0.51 G H 0.022 0.028 0.075 0.56 0.71 1.91 F D E 20-Lead SOIC SYMBOL 20 A B 1 INCHES MIN MAX A B C D E 0.291 0.394 0.496 0.050 typ 0.014 0.299 0.419 0.512 F 0.004 G H I 0.093 0.009 0.016 . MILLIMETERS MIN MAX 7.60 10.65 13.00 0.019 7.40 10.00 12.60 1.27 typ 0.35 0.012 0.10 0.30 0.104 0.013 0.050 2.35 0.23 0.40 2.65 0.32 1.27 0.49 C G F H D I E SPT9101 7 12/30/99 PIN ASSIGNMENTS PIN FUNCTIONS Name RTN +VS GND CLK NCLK -VS N/C VIN VOUT RTN 1 20 VOut RTN 2 19 N/C N/C 3 18 -VS +VS 4 17 -VS +VS 5 16 GND GND 6 15 VIn GND 7 14 N/C +VS 8 13 -VS +VS 9 12 -VS CLK 10 11 NCLK SOIC RTN RTN N/C 1 2 3 VIN N/C 20 16 VOut GND 17 19 18 N/C -VS -VS 4 LCC (Bottom View) 5 I/O I I I I I I I O Function Gain Set Resistor Return +5 V Power Supply Ground True ECL T/H Clock Complement ECL T/H Clock -5.2 V Power Supply No Connection Analog Signal Input Analog Signal Output +VS +VS 6 GND 15 7 GND 14 8 +VS 12 11 10 9 -VS -VS NCLK CLK +VS 13 ORDERING INFORMATION PART NUMBER SPT9101SIS SPT9101SIC SPT9101SCU PACKAGE TYPE 20L SOIC 20L LCC Die* TEMPERATURE RANGE -40 to +85 C -40 to +85 C +25 C *Please see die specification for guranteed electrical performance. SPT9101 8 12/30/99