TC915 TELEDYNE | Alldatasheet
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“40 TELEDYNE TC915 tts HIGH-VOLTAGE, AUTO-ZEROED OPERATIONAL AMPLIFIER FEATURES ‘ GENERAL DESCRIPTION WW High-Voltage Oporation...cscsesennerneenerent 1 SV The TC915is a high-voltage, high-performance CMOS, Low Offset Voltage ..csmerenenrnnermennen 10 HV Max chopper-stabilized operational amplifier. it can operate from Low Offset Voltage Drift..vnscnennenrnnnO0.2UVPC — the same +15V power supplies commonly used to power Low Input Bias Current ...emsssnesinssn-200 pA Max bipolar op amps, such as the OPO7 and 741. Previous ™ Wide Common-Mode were limited to operating from +7.5V power supplies. Voltage Range .srnrovinesennennenenesnnes 1 BV to +13V The TC915's maximum Vos specification is only 10 nV, Low Input Voltage Noise almost a factor of 7 improvement over the industry-standard
1 Pin Compatible With ICL7650 In addition to low initial offset errors, the nulling circuitry
Output Clamp Speeds Overload Recovery Time ensures excellent performance over time and temperature. Long-term drift, which results in periodic recalibration, is effectively eliminated. The nuliing circuitry continues to op- erate over the full temperature range, whereas laser and *zener zap" trimming are only done at a single temperature. The resutt is a significant decrease in temperature-induced errors. FUNCTIONAL DIAGRAM OUTPUT 6 uur. ~ ‘CLAMP oe TC915 } output | > : ° Low ourpuT IMPEDANCE BUFFER © Ce & A TO Vg ORC r @e @e % D OCp B ® ® i et
1 EXTCLKIN +
‘ INT CLK OUT 1 CAANDCREXTERNAL CAPACITORS Foe ouy Cys Cg=0.4 pF Leeeeeeeneneeneend os 233 i 6-11
The TC915 operates from dual- or single-power sup- ORDERING INFORMATION plies. Supply current is typically 1 mA with #15V supplies._§ ———————- Single supply operation extends from +7V to +32V, andthe pens p, Temperature brs input common-mode range extends to Vs~. For battery op- PartNo. Package Range Vos eration, see the low-power TC900 data sheet. TCOISCPA —8-Pin OCto+70°C = 10 The TC915's open-loop gain is 120 dB minimum. Unlike Plastic DIP the TC7650, the TC915's gain is independent of load resis- | TC915iJA 8-Pin CerDIP- ~25°C to +85°C 10 pV tance, The low-impedance output will drive a 10 kK load to TCOTSMJA__6-Pin CarDIP SECO +125°C «10 +14V. An output clamp circuit is provided to minimize over- TCS{SCPDi4Pin___—~O*Cto470"C——*104NV load recovery time. . Plastic DIP UA uses two amplifiers i ae on vollage TC91SUD __14PinCeDiP__—-25°Cto+85°C —*10nV errors. A main amplifier is always in the signal path, which — +Go5m3p-—74.Pin GeDIP EBC 10 IBS TO BV prevents switching spikes at the output, A seperate nulling CotEMID_14-PinCerDIP_=S5°C 10 +125°C _ 10 uv amplifier alternately corrects its own Vos error and then the main amplfier’s Vos error. Only two external capacitors are required to store the nulling error voltages. All active nulling circuitry, including switches and oscillators, are included on- chip. TC915 does not require complicated processing and testing procedures associated with laser or *zener zap" Vos trimming schemes. Simplified fabrication and high yields combine to make the TC915 one of the lowest-priced precision op amps available. It is available in 8-pin and 14- pin plastic or ceramic dual-in-line packages. Dice are avail- able for hybrid applications. PIN CONFIGURATION calije {14] inTEXT CLOCK cat of al] [3] input a bd Nc r3] fiz] INT cLock ~neut[2] vs (GUARD) a. ourpur snpuT[4] TC91s = fii] vg tnput [3 | [e] ourpuT _ sinpuT [5] [10] ourPuT vs[4] [5] clamp we cauaroy LS] [9] output CLAMP vs [7] 18] Crer (NC = NO INTERNAL CONNECTION
HIGH-VOLTAGE, AUTO-ZEROED OPERATIONAL AMPLIFIER TC915 ABSOLUTE MAXIMUM RATINGS Total Supply Voltage (Vs* to Vs") .annsnnussnnenntnne 36 Package Power Dissipation (Ta = +25°C) Lead Temperature (Soklering, 10 60) ..v.c:snss300°C —‘Stato-sensitive device. Unused devices must be stored in conductive Operating Temperature Range above those listed under Absolute Maximum Ratings may cause CF DeVICE oassenneinnnninnnenneennneeO°C 10 +70°C —_ pemanent damage ta he davice. These are stress Taings only and i" -o 0 operation of the device at these or any other conditions above [DeVoe ..nnsnnnnnnennnnnnnnn=@5°C 10 +85°C those incited in the operational sections of the specticaione is not M Device oo... esseessessssnseessernessssseeseee “B5°C 10 +125°C implied. Exposure to Absolute Maximum Rating Conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS: Vs = +15V, Ta = +25°C, unless otherwise indicated. ‘Symbol Parameter Test Conditions [min [Typ | Max | Unit Input Vos Input Offset Voltage [= [= 7 0 Tw TCVos Input Offset Voltage vs °C < Ta < 470°C 0.01 VPC ‘Temperature Coefficient -25°C < Ty < +85°C = uve ip input Bias Current Ta 425°C pA OC < Ta < +70°C pA 25°C = Ta < +85°C pA os input Offset Current | — | 50 | pA °N Input Voltage Noise 0.1 to 1 Hz, Rs < 1002 02 BVp.p _ 0.1 to 10 Hz, Rg < 1000 08 ue. CMRR ‘Common-Mode Rejection Ratio Vs~ = Vow = Vs"-2 [120 [| 140 [ — | CMVR Common-Mode Voltage Range [ vs | — | Vs-2 | V Row ‘Open-Loop voltage Gain RL = 10 kQ, Vo= #10V [120 | 140 | = | 8 Vour Output Voltage Swing Ru=10k0 | veet [=] ver12 [TV Bw Closed-Loop Bandwidth _____ Closed-Loop Gain = +1 L-— | | — | Mxz ‘Slew Rate __RL= 10 0, CL = 50 pF C=] Vius PSRR Power Supply Rejection Ratio Vs = $5V to +16V [120 | 140 | @B Vs ‘Supply Voltage Operating Range (Note 1) [5 [ — | 26 |v is Quiescent Supply Ve= 2150 es ee NOTE: 1. Single supply operation: Ve" = 47V to +32V. Theory of Operation During the second phase, the B switches close and the - Asswitches open. The nulling amplifier's inputs now sample Figure 1 shows the major elements ofthe TC915. There the offset voltage of the main amplifier. The nulling amplifier are two amplifiers: a main (signal) amplifier and a nulling drives the main amplifier’s nulling input to cancel the main amplifier. Both have offset-nulling capability. The mainam- —ampifier's offset voltage. Capacitor Cg stores the nulling Plifier is always connected to the output. The nulling ampli- —Vottage of the main amplifier while the nulling amplifier is fier altemately samples and adjusts its own offset, then the being nulled on the next cycle. often tne (nell SHOE Ret, , . The TC915 design also incorporates an additional out- A two-phase operation nulls the main amplifier. During put buffer stage. The buffer provides a low-impedance the first phase, the A pair of switches close, while the B Sutput traditionally associated with bipolar op amps. Some Switches open. The nulling amp's inputs are shorted and its. CMOS chopper-stabilized amplifiers, such as the TC7650, output is fed back to the nulling input. Capacitor Cacharges have a high-output impedance which makes open-loop gain toa voltage which will maintain the nulling amp in its nulled proportional oload resistance. The TC915's open-loop gain Ls is not dependent on load resistance. 8-35, 2160 6-13
HIGH-VOLTAGE, AUTO-ZEROED OPERATIONAL AMPLIFIER TC915 MAIN v AMPLIFIER } Pp © ouTPUT ‘ANALOG INPUT | | & ULL, LOW IMPEDANCE Bd BUFFER NULL 8 or] AMPLIFIER Toss oe Aj ; Sacer oO O CAPACITORS Figure 1 The TC915 Contains Nulling and Main Amplifiesr (Offset Correction Voltages Are Stored on Two External Capacitors) Pin Compatibility Cx and Cg should be 0.1 uF film capacitors. Mylar Since the TC915 operates from the same +15V power °@Pacitors are suitable. supplies as bipolar op amps, upgrading existing circuits is simple. The bipolar op amp's nulling and compensation COMponent Selection components are removed and the TC915's nulling capaci- The two required capacitors, Ca and Cp, have optimum tors are added. values, depending on the clock or chopping frequency. For On the 8-pin mini-DIP, the external null storage capaci- the preset internal clock, the correct value is 0.1 uF. To tors are connected to pins 1 and 8. On most other opera- maintain the same relationship between the chopping fre- tional amplifiers these are left open or used for offset. quency and the nulling time constant, the capacitor values potentiometer or compensation capacitor connections. should be scaled in proportion to the external clock, if used. For OPS and OPO7 operational amplifiers, replacing. High-quality, film-type capacitors (such as Mylar) are pre- the offset null potentiometer between pins 1 and withtwo ferred, Ceramic or other lower-grade capacitors may be capacitors from the pins to Vs~ converts the OPO5/07 pin suitable in some applications. For fast settling at initial configuration for TC915 operation. The 741 is easily up- _ turn-on, lowdielectric absorption capacitors (suchas polypro- graded by removing the nulling potentiometer between pin _pylene) should be used. With ceramic capacitors, several 4and pins 1 and 5, then connecting capacitors frompin4to seconds may be required to settle to 1 uV. pins 1 and 8, For LM108 devices, the compensation capaci- toris replaced by the external nulling capacitors. TheLM101/ - - 748/709 pinouts are similarly modified by removing any Ve VS Vg circuit connections to pin 5. Pin 5 on the TC915 is the output ° 9 9 clamp connection. Other operational amplifiers may use this am 2 7 pin as an offset or compensation point. ° 7 ° iy The minor modifications needed to retrofit a TC915 to wo, i 64 existing sockets make prototyping and circuit verification 5 4 3] TOs straightforward. ° “ oT" a Os Nulling Capacitors 7 q o The offset voltage correction capacitors are connected Ca Ce "Cy toC, and Cg, The common capacitor connection is made to Vs" (pin 4) on the 8-pin packages afid to capacitor return 14-PIN PACKAGE @-PIN PACKAGE (Crer, pin 8) on the 14-pin packages. The common connec- {PINS IS INTERNALLY CONNECTED TO PIN 7 tion should be made through a separate PC trace or wire, to IN THE 14-PIN PACKAGE) avoid voltage drops. Internally, Vs~ is connected to Crer. parse Goce Goer 036 2161 6714
Clock Operation Figures 4 and 5. For the clamp to be fully effective, the The internal oscillator is set for a 1000 Hz nominal Li i actos the Clamp cifpid should be 2100 ka 5 ° ; ¢ enthe clampisused, the clamp OFF leakage will add frequency on boththe 8-pinand 14-pinDIPs. Withthe ¥4-pin 44 input bias current. However, clamp leakage is the OFF device, the 250 Hz internal frequency is available at the Std is typically only 1 pA. INTERNAL CLOCK OUTPUT (pin 12). A 1000 Hz nominal ‘typical " ignal willbe present at the EXTERNAL CLOCK INPUT (pin ' 43) wih INT/EXT high or open. This is the intemal clock !PUt Bias Current signal before a divide-by-four operation. The TC915 inputs are never disconnected from the The 14-pin device can be driven by an external clock. main internal amplifier. The null amplifier samples the input The INT/EXT input (pin 14) has an internal pull-up and may _ offset voltage and corrects DC errors and drift by storing be left open for internal clock operation. If an external clock compensating voltages on extemal capacitors. However, is used, INT/EXT must be tied to Vs" (pin 7) to disable the the sampling causes charge transfer at the inputs. internal clock. The external clock signal is applied to the The impulse current is not usually a problem, because external clock input. the amount of charge transferred is very small. Care should The external clock amplitude should swing between be exercised, however, when replacing high-input bias \\Vs* and ground for power supplies up to +6V, and between —_ current bipolar op amps. Conventional design practice is to. Vs* and Vs* -6V for higher supply voltages. When the cancel bias current by matching the input impedances external clock is generated by +5V logic, capacitive cou- (Figure 6a). The TC915 has an input bias current of only pling to pin 13 (through a 0.1 uF capacitor) will provide adequate drive. Saran Dan RUE EERE At low frequencies the external clock duty cycle is not | INTERNAL PosITVE critical, since an intemal divide-by-four gives the desired CLAMP BIAS 50% switching duty cycle. The offset storage correction | #N§- Vy V§-07V capacitors are charged only whenthe external clock input is | P-CHANNEL high. A 50% to 80% external clock positive duty cycle is desired for frequencies above 500 Hz to guarantee tran- | on sients settle before the internal switches open. The external clock input can also be used as a strobe | N-CHANNEL input. If a stobe signal is connected at the extemal clock input, 80 that it is low during the time an overload signal is ITEGNAL NEGATIVE applied, neither capacitor will be charged. This function can = Vg + Vp = Vg 40.7V be used to prevent input transients from overloading the Toss nulling circuitry. Leakage currents at the capacitor pins are OUTPUT PIN very low, minimizing offset voltage drift during strobe opera- tion. Figure 3 Internal Clamp Circuit Output Clamp O.1pF 0.1 pF Chopper-stabilized systems can show long overload recovery times. If the output is driven to either supply rail, iM ‘output saturation occurs; the inputs are no longer held at a Al “Virtual ground." The Vos null circuit treats the differential INPUT a signal as an offset and tries to correct it by charging the ouput external capacitors. The nulling circuit also saturates, Once | the input signal retums to normal, the response time is | 4 Ry lengthened by the long recovery time of the nulling amplifier | and external capacitors. | Through the external-clamp connection, the TC915 R3 + (RIUR2) > 100 ka Rg | eliminates the overload recovery problem by reducing the FOR FULL CLAMP EFFECT Ry } feedback network gain before the output voltage reaches MOERTCAGROTOne TO | either supply rail. . . Vg WITH 6-PIN PACKAGE cS | The outputclamp circuit is shown in Figure3, withtypical inverting and noninverting circuit connections shown in Figure 4 Noninverting Amplifier With Optional Clamp 837 2162 A-01 . .
TYPICAL CHARACTERISTICS CURVES Supply Current Input Offset Voltage 400 vs + Supply Voltage ss Common-Mode Voltage rae TT fest “TTA - CeCe BUCCI eC eer BCC = CELE MESGGCR0RII SGC BEEP CEE ‘TEEPTT TTL 0 2 4 6 8 10 12 14 16 18 20 15-12 -9 6-3 0 43 46 49 412 415 + SUPPLY VOLTAGE (V) INPUT COMMON-MODE VOLTAGE (V) Gain and Phase Output Voltage Swing 5 vs Frequency ws ‘e vs Load Resistance TINTS 2 eee PL UU A Pa AUN fof No 3 ESI LN NI A xm I aL i eth i OTITIS SO E, TA “FTE Ta lil Ci 100 1k 10k 100k 1M 100 tk 10k 100k 1M Input Common-Mode Voltage Input Offset Voltage Range vs + Supply Voltage 0 vs Clock Frequency pee gC UM z 11] /) a | eoeeme CME al Crepe Z /| bt hea BT Vai $4 | | TAN eee TT er Y SSS <8 Be iil COT ss Sees o 2 4 6 6 10 12 4 16 100 tk 10k SUPPLY VOLTAGE (V) EXT CLOCK INPUT FREQUENCY (Hz)
2164 A-03 “~
HIGH-VOLTAGE, AUTO-ZEROED OPERATIONAL AMPLIFIER TC915 TYPICAL CHARACTERISTICS CURVES (Cont.) Input Offset Voltage Input Voltage Noise ; vs + Supply Voltage peas TTT ele wh PTA panel SCOT CC Fatototyses te f. LA pape ey Th PRA Baton CAPLET ‘yaa 6 8 10 12 14 16 18 20 SUPPLY VOLTAGE (V) Negative Overload Positive Overload Recovery Time Recovery Time [Ais | | LLL eel WET rat Tel _| ee reel LTH scneneven TT TTT | ann tT TTT Tre TT fae Sef scae=svow |( {| Tt | HORIZONTAL SCALE = 50 ms/DIV HORIZONTAL SCALE = 50 ma/DIV