1 TC911A TC911B AUTO-ZEROED OPERATIONAL AMPLIFIERS 2 FEATURES GENERAL DESCRIPTION ■ The TC911 CMOS auto-zeroed operational amplifier is the first complete monolithic chopper-stabilized amplifier. Chopper operational amplifiers like the ICL7650/7652 and LTC1052 require user-supplied, external offset compensation storage capacitors. External capacitors are not required with the TC911. Just as easy to use as the conventional OP07 type amplifier, the TC911 significantly reduces offset voltage errors. Pinout matches the OP07/741/7650 8-pin mini-DIP configuration. Several system benefits arise by eliminating the external chopper capacitors: lower system parts count, reduced assembly time and cost, greater system reliability, reduced PC board layout effort and greater board area utilization. Space savings can be significant in multiple-amplifier designs. Electrical specifications include 15µV maximum offset voltage, 0.15µV/°C maximum offset voltage temperature coefficient. Offset voltage error is five times lower than the premium OP07E bipolar device. The TC911 improves offset drift performance by eight times. The TC911 operates from dual or single power supplies. Supply current is typically 350µA. Single 4.5V to 16V supply operation is possible, making single 9V battery operation possible. The TC911 is available in 2 package types: 8-pin plastic DIP and SOIC. ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ First Monolithic Chopper-Stabilized Amplifier With On-Chip Nulling Capacitors Offset Voltage .................................................... 5µV Offset Voltage Drift .................................. 0.05µV/°C Low Supply Current ...................................... 350µA High Common-Mode Rejection .................... 116dB Single Supply Operation ....................... 4.5V to 16V High Slew Rate ............................................. 2.5V/µs Wide Bandwidth ............................................1.5MHz High Open-Loop Voltage Gain (RL = 10 kΩ) .................................................... 120dB Low Input Voltage Noise (0.1 Hz to 1 Hz) .......................................... 0.65µVP-P Pin Compatible With ICL7650 Lower System Parts Count ORDERING INFORMATION Part No. Package TC911ACOA TC911ACPA 8-Pin SOIC 8-Pin Plastic DIP 8-Pin SOIC 8-Pin Plastic DIP TC911BCOA TC911BCPA Temperature Range Maximum Offset Voltage 0°C to +70°C 0°C to +70°C 15µV 15µV 0°C to +70°C 0°C to +70°C 30µV 30µV 5 7 VDD – INPUT 2 + INPUT 3 VSS 4 6 OUTPUT + INPUT 3 VSS 4 TC911ACPA TC911BCPA 8 NC NC 1 8 NC NC 1 – INPUT 2 5 NC 7 VDD TC911ACOA 6 OUTPUT TC911BCOA 5 NC NC = NO INTERNAL CONNECTION VDD VSS 4 7 2 + A B * INTERNAL OSCILLATOR (fOSC ≈ 200 Hz) B * A 3 + MAIN AMPLIFIER 7 TC911 + – LOW IMPEDANCE OUTPUT BUFFER 6 OUTPUT – 8 *NOTE: Internal capacitors. No external capacitors required. TC911/A/B-7 9/11/96 TELCOM SEMICONDUCTOR, INC. 6 V CORRECTION AMPLIFIER OS – +INPUT 4 PIN CONFIGURATION (SOIC and DIP) FUNCTIONAL BLOCK DIAGRAM –INPUT 3 3-263 AUTO-ZEROED MONOLITHIC OPERATIONAL AMPLIFIERS TC911A TC911B Package Power Dissipation (TA = ≤ 70°C) Plastic DIP ...................................................... 730mW Plastic SOIC ................................................... 470mW ABSOLUTE MAXIMUM RATINGS* Total Supply Voltage (VDD to VSS) ........................... +18V Input Voltage ........................ (VDD + 0.3V) to (VSS – 0.3V) Current into Any Pin .................................................10mA While Operating ................................................100µA Storage Temperature Range ................ – 65°C to +150°C Lead Temperature (Soldering, 10 sec) ................. +300°C Operating Temperature Range C Device ................................................ 0°C to +70°C *Static-sensitive device. Unused devices should be stored in conductive material. Stresses above 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 above those indicated in the operational sections of the specifications is not implied. ELECTRICAL CHARACTERISTICS: VS = ±5V, TA = +25°C, unless otherwise indicated. Min TC911A Typ Max Min TC911B Typ Max Unit — — — 5 0.05 0.05 15 0.15 0.15 — — — 15 0.1 0.1 30 0.25 0.25 µV µV/°C µV/°C — — — — — — — 110 — — — 5 — 0.65 11 116 70 3 4 20 1 — — — — — — — — — — 105 — — — 10 — 0.65 11 110 120 4 6 40 1 — — — pA nA nA pA nA µVP-P µVP-P dB VSS — VDD – 2 VSS — VDD – 2 V 115 120 — 110 120 — dB RL = 10 kΩ VSS + 0.3 Closed Loop Gain = +1 — — 1.5 VDD – 0.9 — VSS + 0.3 — — 1.5 VDD – 0.9 — V MHz RL = 10 kΩ, CL = 50 pF ±3.3V to ±5.5V — 112 2.5 — — — — 105 2.5 — — — V/µs dB Split Supply Single Supply VS = ±5V ±3.3 6.5 — — — 350 ±8 16 600 ±3.3 6.5 — — — — ±8 16 800 V V µA Symbol Parameter Test Conditions VOS TCVOS TA = +25°C 0°C ≤ TA ≤ +70°C –25°C ≤ TA ≤ +85°C (Note 1) TA = +25°C 0°C ≤ TA ≤ +70°C –25°C ≤ TA ≤ +85°C TA = +25°C TA = +85°C 0.1 to 1 Hz, RS ≤ 100Ω 0.1 to 10 Hz, RS ≤ 100Ω VSS ≤ VCM ≤ VDD – 2.2 IB IOS eN CMRR CMVR AOL VOUT BW SR PSRR VS IS Input Offset Voltage Average Temperature Coefficient of Input Offset Voltage Average Input Bias Current Average Input Offset Current Input Voltage Noise Common-Mode Rejection Ratio Common-Mode Voltage Range Open-Loop Voltage Gain Output Voltage Swing Closed Loop Bandwidth Slew Rate Power Supply Rejection Ratio Operating Supply Voltage Range Quiescent Supply Current RL = 10 kΩ, VOUT = ±4V NOTES: 1. Characterized; not 100% tested. 3-264 TELCOM SEMICONDUCTOR, INC. AUTO-ZEROED MONOLITHIC OPERATIONAL AMPLIFIERS 1 TC911A TC911B TYPICAL CHARACTERISTICS Supply Current vs. ± Supply Voltage 450 TA = +25°C VS = ±5V VS = ±5V 400 300 200 INPUT OFFSET VOLTAGE (µV) SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 600 500 400 350 300 250 100 200 –100 0 2 3 4 5 6 7 ± SUPPLY VOLTAGE (V) 8 CLOSED-LOOP GAIN (dB) 40 PHASE 30 VS = ±5V TA = +25°C RL = 10 kΩ GAIN 20 180 135 90 10 45 0 0 –10 –45 –20 –90 –30 –135 –40 10k 100k 1M FREQUENCY (Hz) TA = +25°C 25 20 3 15 10 5 0 –50 0 50 100 AMBIENT TEMPERATURE (°C) –6 –5 –4 –3 –2 –1 0 1 2 3 4 INPUT COMMON-MODE VOLTAGE (V) 150 4 Output Voltage Swing vs. Load Resistance 5.8 225 PHASE (deg) 50 30 Large Signal Output Switching Waveform Gain and Phase vs. Frequency 2 35 INPUT VERTICAL SCALE = 2 V/DIV RL = 10 kΩ TA = +25°C OUTPUT VERTICAL SCALE = 1 V/DIV 0V –180 10M 5.0 ± OUTPUT VOLTAGE (V) 700 Input Offset Voltage vs. Common-Mode Voltage Supply Current vs. Temperature TA = +25°C VS = ±5V 4.2 +SWING 5 3.4 2.6 1.8 1.0 100 HORIZONTAL SCALE = 2 µs/DIV –SWING 1k 10k 100k 1M LOAD RESISTANCE (Ω) 6 7 8 TELCOM SEMICONDUCTOR, INC. 3-265 AUTO-ZEROED MONOLITHIC OPERATIONAL AMPLIFIERS TC911A TC911B Pin Compatibility The CMOS TC911 is pin compatible with the industry standard ICL7650 chopper-stabilized amplifier. The ICL7650 must use external 0.1µF capacitors connected at pins 1 and 8. With the TC911, external offset voltage error canceling capacitors are not required. On the TC911 pins 1, 8 and 5 are not connected internally. The ICL7650 uses pin 5 as an optional output clamp connection. External chopper capacitors and clamp connections are not necessary with the TC911. External circuits connected to pins 1, 8 and 5 will have no effect. The TC911 can be quickly evaluated in existing ICL7650 designs. Since external capacitors are not required, system part count, assembly time, and total system cost are reduced. Reliability is increased and PC board layout eased by having the error storage capacitors integrated on the TC911 chip. The TC911 pinout matches many existing op amps: 741, LM101, LM108, OP05–OP08, OP-20, OP-21, ICL7650 and ICL7652. In many applications operating from +5V supplies the TC911 offers superior electrical performance and can be a functional pin-compatible replacement. Offset voltage correction potentiometers, compensation capacitors, and chopper-stabilization capacitors can be removed when retrofitting existing equipment designs. Thermocouple Errors Heating one joint of a loop made from two different metallic wires causes current flow. This is known as the Seebeck effect. By breaking the loop, an open circuit voltage J3 = J4 J2 = J5 NO TEMPERATURE DIFFERENTIAL AND SAME METALLIC CONNECTION J1 = J6 J2 J1 J3 (Seebeck voltage) can be measured. Junction temperature and metal type determine the magnitude. Typical values are 0.1µV/°C to 10µV/°C. Thermal-induced voltages can be many times larger than the TC911 offset voltage drift. Unless unwanted thermocouple potentials can be controlled, system performance will be less than optimum. Unwanted thermocouple junctions are created when leads are soldered or sockets/connectors are used. Low thermo-electric coefficient solder can reduce errors. A 60% Sn/36% Pb solder has 1/10 the thermal voltage of common 64% Sn/36% Pb solder at a copper junction. The number and type of dissimilar metallic junctions in the input circuit loop should be balanced. If the junctions are kept at the same temperature, their summation will add to zero-canceling errors (Figure 1). Shielding precision analog circuits from air currents — especially those caused by power dissipating components and fans — will minimize temperature gradients and thermocouple-induced errors. Avoiding Latch-Up Junction-isolated CMOS circuits inherently contain a parasitic p-n-p-n transistor circuit. Voltages exceeding the supplies by 0.3V should not be applied to the device pins. Larger voltages can turn the p-n-p-n device on, causing excessive device power supply current and excessive power dissipation. TC911 power supplies should be established at the same time or before input signals are applied. If this is not possible input current should be limited to 0.1mA to avoid triggering the p-n-p-n structure. Overload Recovery PACKAGE PIN The TC911 recovers quickly from the output saturation. Typical recovery time from positive output saturation is 20msec. Negative output saturation recovery time is typically 5msec. J6 J4 J5 + – J2 V2 – + J1 V1 – J3 V3 + VT = V1 + V2 + V3 – V4 – V5 – V6 = 0 + J4 V4 – + V5 J5 – + V6 VT = 0 – J6 Figure 1. Unwanted Thermocouple Errors Eliminated by Reducing Thermal Gradients and Balancing Junctions 3-266 TELCOM SEMICONDUCTOR, INC. AUTO-ZEROED MONOLITHIC OPERATIONAL AMPLIFIERS 1 TC911A TC911B TYPICAL APPLICATIONS +9V TC911 TEMP OUT +15V 18 kΩ TC911 3 + 2 – 2 Thermometer Circuit 10-Volt Precision Reference REF02 7 R2 ADJ 6 VOUT = 10V V REF 4 3 R1 – 0.1 µF 6.4V VOUT + 3.6 kΩ R3 4 6.4 kΩ R3 + R1 VOUT = VTEMP 1 + R2 R3X R1 [ ( d VOUT dT K=1+ = [ ( 1 + R2 R +R 3 1 R3 X R1 R2 – VREF R 1 )] [ d (VTEMP ) )] dT ] ≈ K (2.1 mV/°C) R2 5 R3X R1 Programmable Gain Amplifier With Input Multiplexer +5V –5V GND +5V –5V IN1 IN2 IN3 IN4 TC911 + IC1b VOUT 6 – IC1b A1 A2 A3 A4 WR +5V –5V X1 X 10 18 k Ω X 100 99 k Ω X 1000 999 kΩ INPUT CHANNEL SELECT GAIN SELECT 68HC11 WR LATCH A1 A2 A3 A4 7 GND 2 kΩ 1 kΩ 1 kΩ 8 IC1a, b, = Quad Analog Switch TELCOM SEMICONDUCTOR, INC. 3-267