LTC1100 Precision, Chopper-Stabilized Instrumentation Amplifier U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Offset Voltage: 10µV Max Offset Voltage Drift: 50nV/°C Max Bias Current: 50pA Max Offset Current: 50pA Max Gain Nonlinearity: 8ppm Max Gain Error: ±0.05% Max CMRR: 104dB 0.1Hz to 10Hz Noise: 2µVP-P Single 5V Supply Operation 8-Pin MiniDIP The LTC1100 is a high precision instrumentation amplifier using chopper-stabilization techniques to achieve outstanding DC performance. The input DC offset is typically 1µV while the DC offset drift is typically 10nV/°C; a very low bias current of 50pA is also achieved. The LTC1100 is self-contained; that is, it achieves a differential gain of 100 without any external gain setting resistor or trim pot. The gain linearity is 8ppm and the gain drift is 4ppm/°C. The LTC1100 operates from a single 5V supply up to ±8V. The output typically swings 300mV from its power supply rails with a 10k load. UO APPLICATI ■ ■ ■ S An optional external capacitor can be added from pin 7 to pin 8 to tailor the device’s 18kHz bandwidth and to eliminate any unwanted noise pickup. Thermocouple Amplifiers Strain Gauge Amplifiers Differential to Single-Ended Converters The LTC1100 is also offered in a 16-pin surface mount package with selectable gains of 10 or 100. The LTC1100 is manufactured using Linear Technology’s enhanced LTCMOSTM silicon gate process. LTCMOS is a trademark of Linear Technology Corporation UO TYPICAL APPLICATI Single 5V Supply, DC Instrumentation Amplifier –VIN 1 8 2 7 3 LTC1100 4 6 5 VOUT 0.01µF VIN V+ = 5V 0.1µF VOUT = 100 [VIN – (–VIN)] LTC1100 • TA01 1 LTC1100 W W W AXI U U ABSOLUTE RATI GS Operating Temperature Range LTC1100M/AM ................................ −55°C to 125°C LTC1100C/AC .................................... −40°C to 85°C Output Short Circuit Duration ......................... Indefinite Storage Temperature Range ................ −65°C to 150°C Total Supply Voltage (V + to V −) ............................. 18V Input Voltage ....................... (V + + 0.3V) to (V − − 0.3V) Lead Temperature (Soldering, 10 sec)................. 300°C U W U PACKAGE/ORDER I FOR ATIO ORDER PART NUMBER TOP VIEW 8 VOUT CMRR 2 7 COMP –VIN 3 6 VIN V– 4 5 V+ GND REF 1 J8 PACKAGE 8-LEAD CERAMIC DIP N8 PACKAGE 8-LEAD PLASTIC DIP ORDER PART NUMBER TOP VIEW NC 1 16 NC GND REF 2 LTC1100ACN8 LTC1100CJ8 LTC1100CN8 LTC1100AMJ8 LTC1100MJ8 15 VOUT G = 10 3 14 G = 10 CMRR 4 13 COMP NC 5 12 NC –VIN 6 11 VIN V– 7 10 V+ NC 8 9 TJMAX = 150°C, θJA = 100°C/W (J) TJMAX = 110°C, θJA = 130°C/W (N) LTC1100ACS LTC1100CS NC S PACKAGE 16-LEAD PLASTIC SOL TJMAX = 110°C, θJA = 100°C/W Contact factory for Industrial grade parts ELECTRICAL CHARACTERISTICS VS = ± 5V, RL = 10k, CC = 1000pF, unless otherwise specified. PARAMETER CONDITIONS Gain Error TA = 25°C LTC1100ACN (Note 3) MIN TYP MAX TA = 25°C ● LTC1100CN/CJ TYP MAX UNITS 0.01 0.05 0.10 0.01 0.075 0.150 ±% ±% 3 12 8 30 3 12 20 60 ppm ppm ±1 ±10 ±1 ±10 µV ±5 ±100 ±5 ±100 nV/°C ● Gain Nonlinearity MIN Input Offset Voltage (Note 1) Input Offset Voltage Drift (Note 1) Input Noise Voltage DC to 10Hz, TA = 25°C 1.9 Input Bias Current TA = 25°C 2.5 50 120 2.5 65 135 pA pA 10 50 10 65 pA ● ● Input Offset Current ● Common-Mode Rejection Ratio VCM = 2.3V to −4.7V (Note 2) ● 104 Power Supply Rejection Ratio VS = ±2.375V to ±8V ● 120 Output Voltage Swing RL = 2k, VS = ±8V RL =10k, VS = ±8V ● ● – 7.2 – 7.7 Supply Current TA = 25°C ● µVP-P 1.9 115 90 110 dB 105 6.2 7.5 2.4 3.4 2.8 4.0 dB – 7.2 – 7.7 2.4 3.4 6.2 7.5 V V 3.3 4.5 mA mA Internal Sampling Frequency TA = 25°C 2.8 2.8 kHz Bandwidth TA = 25°C 18 18 kHz 2 LTC1100 ELECTRICAL CHARACTERISTICS VS = ± 5V, RL = 10k, CC = 1000pF, unless otherwise specified. PARAMETER CONDITIONS Gain Error TA = 25°C LTC1100AMJ (Note 3) MIN TYP MAX TA = 25°C (Note 1) Input Offset Voltage Drift (Note 1) Input Noise Voltage DC to 10Hz, TA = 25°C Input Bias Current TA = 25°C Input Offset Current ● UNITS 0.05 0.11 0.01 0.075 0.150 ±% ±% 3 8 40 3 20 65 ppm ppm ±1 ±10 ±1 ±10 µV ±5 ±100 ±5 ±100 nV/°C ● Input Offset Voltage LTC1100MJ TYP MAX 0.01 ● Gain Nonlinearity MIN 1.9 5 µVP-P 1.9 ● 50 300 ● 80 5 65 450 pA pA 120 pA Common-Mode Rejection Ratio VCM = −4.7V to 2.3V ● 100 90 dB Power Supply Rejection Ratio VS = ±2.375V to ±8V ● 115 95 dB Output Voltage Swing RL = 10k, VS = ±8V RL = 2k, VS = ±8V ● ● – 7.4 – 7.0 Supply Current TA = 25°C 7.4 6.0 – 7.4 – 7.0 2.4 2.4 4.2 ● 7.4 6.0 V V 3.3 4.6 mA mA Internal Sampling Frequency TA = 25°C 2.8 2.8 kHz Bandwidth TA = 25°C 18 18 kHz ELECTRICAL CHARACTERISTICS VS = ±5V, RL = 10k, CC = 1000pF, unless otherwise specified. PARAMETER CONDITIONS Gain Error TA = 25°C, A V =100 A V =100 A V =10 A V =10 Gain Nonlinearity TA = 25°C, A V =100 A V =100 A V =10 A V =10 Input Offset Voltage (Note 1) Input Offset Voltage Drift (Note 1) Input Noise Voltage DC to 10Hz, TA = 25°C Input Bias Current TA = 25°C LTC1100ACS (Note 3) MIN TYP MAX 0.01 ● 0.01 ● 3 12 1 ● ● ● Common-Mode Rejection Ratio Power Supply Rejection Ratio 0.05 0.10 0.04 0.10 0.01 8 30 8 25 3 12 1 0.01 VCM = −4.7V to 2.3V, A V =100 A V =10 ● ● 104 95 VS = ±2.375V to ±8V ● 120 UNITS 0.075 0.150 0.060 0.150 ±% ±% ±% ±% 20 60 10 40 ppm ppm ppm ppm ±1 ±10 ±1 ±10 µV ±100 ±5 ±100 nV/°C 1.9 ● LTC1100CS TYP MAX ±5 µVP-P 1.9 2.5 50 120 2.5 65 135 pA pA 10 50 10 65 pA ● Input Offset Current MIN 115 90 85 105 110 dB dB dB 3 LTC1100 ELECTRICAL CHARACTERISTICS PARAMETER CONDITIONS Output Voltage Swing RL=10k, VS = ±8V RL= 2k, VS = ±8V Supply Current TA = 25°C VS = ± 5V, RL = 10k, CC = 1000pF, unless otherwise specified. ● ● LTC1100ACS (Note 3) MIN TYP MAX MIN LTC1100CS TYP MAX UNITS – 7.2 – 7.7 – 7.2 – 7.7 6.2 7.5 V V 3.3 4.5 mA mA 6.2 7.5 2.4 3.4 ● 2.8 4.0 2.4 3.4 Internal Sampling Frequency TA = 25°C 2.8 2.8 kHz Bandwidth TA = 25°C 18 180 18 180 kHz kHz G = 100 G = 10 The ● denotes the specifications which apply over the full operating temperature range. Note 1: These parameters are guaranteed by design. Thermocouple effects preclude measurement of these voltage levels in high speed automatic test systems. VOS is measured to a limit determined by test equipment capability. Note 2: See Applications Information, Single Supply Operation. Note 3: Please consult Linear Technology Marketing. W BLOCK DIAGRA S 2 R R 14 7 5 (V +) 99R – 1 3 10 (V+) 99R 2 R 90R – 9R 3 + 6 8 6 4 − R 13 – + 15 R = 2.5k + 90R 9R 11 R = 2.5k + 4 (V –) 7 (V – ) LTC1100 • BD02 LTC1100 • BD01 NOTE: FOR A VOLTAGE GAIN OF 10V/V SHORT PIN 2 TO 3, AND PIN 14 TO 15. U W TYPICAL PERFOR A CE CHARACTERISTICS 0.05 DIFFERENTIAL GAIN (dB) VS = ±8V RL = 50k 0.03 0.02 0.01 0 –0.01 –50 210 40 180 35 PHASE GAIN (G = 100) –25 75 0 25 50 TEMPERATURE (°C) 100 125 150 30 120 25 90 20 60 GAIN (G = 10) 15 30 10 5 100 0 1k 10k 100k –30 1M FREQUENCY (Hz) LTC1100 • TPC01 4 45 LTC1100 • TPC02 25 20 PHASE SHIFT (DEGREES) GAIN ERROR (±%) 0.04 Gain Nonlinearity vs Temperature Gain, Phase vs Frequency GAIN NONLINEARITY (ppm) Gain Error vs Temperature VS = ±8V RL = 50k 15 10 5 0 –5 –50 –25 75 0 25 50 TEMPERATURE (°C) 100 125 LTC1100 • TPC03 LTC1100 U W TYPICAL PERFOR A CE CHARACTERISTICS Power Supply Rejection Ratio vs Frequency Supply Current vs Supply Voltage 150 POWER SUPPLY REJECTION RATIO (dB) 3 TA = 25°C 2 TA = 125°C 1 8 125 100 75 50 25 2 6 10 12 14 16 4 8 TOTAL SUPPLY VOLTAGE V+ TO V – (V) 1k 10 100 FREQUENCY (Hz) 1 CMRR vs Frequency 3 – 2 6 0 0.1 + 1 ±7 ±6 VS = ±5V, TA ≤ 85°C ±5 NEGATIVE ±4 ±3 POSITIVE VS = ±2.5V, TA ≤ 85°C NEGATIVE POSITIVE ±1 10 100 1k FREQUENCY (Hz) 10k 100k 0 1 2 3 4 5 6 7 8 LOAD RESISTANCE (kΩ) 0 TA = 25°C – 60 –120 9 10 TA = –55°C –180 –200 –6 –5 –4 –3 –2 –1 0 1 2 COMMON-MODE VOLTAGE (V) 3 LTC1100 • TPC10 NGE ±4 ±6 ±5 SUPPLY VOLTAGE (V) ±8 ±7 8 RL = 100k RL = 2k 6 5 4 3 2 1 1k 10k FREQUENCY (Hz) 100k Internal Sampling Frequency vs Supply Voltage 4 TA = –55°C 90 75 60 45 30 3 TA = 25°C 2 TA = 125°C 1 15 0 0 4 E RA LTC1100 • TPC09 SAMPLING FREQUENCY (kHz) VOLTAGE NOISE DENSITY (nV/ √ Hz) BIAS CURRENT (pA) 60 ±3 7 0 100 105 VS = ±5V 120 MOD VS = ±5V 9 Voltage Noise vs Frequency TA = 125°C ON- LTC1100 • TPC08 Bias Current vs Common-Mode Voltage 180 MM LTC1100 • TPC06 0 LTC1100 • TPC07 240 E CO Undistorted Output Swing vs Frequency POSITIVE ±2 LTC1100 20 ATIV ±2 100k VS = ±8V, TA ≤ 85°C ±8 NEGATIVE G = 10, RC = ∞ CC = 0pF NEG –4 10 ±9 CC 1 40 G = 100, RC = 100k CC = 10pF VOUT ± SWING (V) CMRR (dB) RC 60 300 10k ±10 80 –2 Output Voltage Swing vs Load 120 G = 100, RC = ∞ CC = 0pF 0 LTC1100 • TPC05 LTC1100 • TPC04 100 POS GE RAN M E CO ITIV 2 -M MON –8 0.1 18 ODE 4 –6 0 0 TA = 25°C 6 PEAK-TO-PEAK OUTPUT SWING (V) SUPPLY CURRENT (mA) TA = –55°C COMMON-MODE RANGE (V) 4 360 Common-Mode Range vs Supply Voltage 10 100 1k 10k FREQUENCY (Hz) 100k LTC1100 • TPC11 2 6 10 12 14 16 4 8 TOTAL SUPPLY VOLTAGE V + TO V – (V) 18 LTC1100 • TPC12 5 LTC1100 U W TYPICAL PERFOR A CE CHARACTERISTICS Large-Signal Transient Response G = 100, VS = ±5V Small-Signal Transient Response G = 100, VS = ±5V Overload Recovery G = 100, VS = ±5V 1V/DIV 50mV/DIV 2V/DIV 2V/DIV 10µs/DIV 5µs/DIV 10µs/DIV LTC1100 • TPC13 LTC1100 • TPC15 LTC1100 • TPC14 Large-Signal Transient Response G = 10 (LTC1100CS Only), VS = ±5V Small-Signal Transient Response G = 10 (LTC1100CS Only), VS = ±5V Overload Recovery G = 10 (LTC1100CS Only), VS = ±5V 1V/DIV 50ms/DIV 2V/DIV 2V/DIV 10µs/DIV 10µs/DIV LTC1100 • TPC16 1µs/DIV LTC1100 • TPC17 LTC1100 • TPC18 U U U PIN FUNCTIONS 8-Pin DIP (16-Pin SO) Pin 1 (2) GND REF: Connect to system ground. This sets the zero reference for the internal op amps. Pin 2 (4) CMRR: This pin tailors the gain of the internal amplifiers to maximize AC CMRR. For applications which emphasize CMRR requirements, connect a 100k resistor and a 10pF capacitor in series from CMRR to ground. See the Applications section. Pin 3 (6) –VIN: Inverting Input. Pin 4 (7) V – : Negative Supply. Pin 5 (10) V + : Positive Supply. Pin 6 (11) VIN: Noninverting Input. Pin 7 (13) COMP: This pin reduces the bandwidth of the internal amplifiers for applications at or near DC. Clock feedthrough from the internal sampling clock can also be 6 suppressed by using the COMP pin. The standard compensation circuit is a capacitor from COMP to VOUT, sized to provide an RC pole with the internal 247k resistor (22.5k for LTC1100CS in gain-of-10 mode). See the Applications section. Pin 8 (15) VOUT: Signal Output. 16-Pin SO Package Only (3) G = 10: Short to pin (2) for gain of 10. Leave disconnected for gain of 100. (14) G = 10: Short to pin (15) for gain of 10. Leave disconnected for gain of 100. NOTE: Both pins must be shorted or open to provide correct gain. (1),(5),(8),(9),(12),(16) NC: No Internal Connection. LTC1100 U W U UO APPLICATI S I FOR ATIO Common-Mode Rejection Aliasing Due to very precise matching of the internal resistors, no trims are required to obtain a DC CMRR of better than 100dB. However, things change as frequency rises. The inverting amplifier is in a gain of 1.01 (1.1 for gain of 10), while the noninverting amplifier is in a gain of 99 (9 for gain of 10). As frequency rises, the higher gain amplifier hits its gain-bandwidth limit long before the low gain amplifier, degrading CMRR. The solution is straightforward — slow down the inverting amplifier to match the noninverting amp. Figure 1 shows the recommended circuit. The problem is less pronounced in the LTC1100CS in gain-of-10 mode; no CMRR trims are necessary. The LTC1100 is a chopper-stabilized instrumentation amplifier; like all sampled systems it exhibits aliasing behavior for input frequencies at or near the internal sampling frequency. The LTC1100 incorporates specialized anti-aliasing circuitry which typically attenuates aliasing products by ≥ 60dB; however, extremely sensitive systems may still have to take precautions to avoid aliasing errors. For more information, see the LTC1051/ LTC1053 data sheet. − 3 + 6 − 8 LTC1100 + 2 100k 10pF LTC1100 • TA02 Figure 1. Improving AC CMRR Overcompensation Many instrumentation amplifier applications process DC or low frequency signals only; consequently the 18kHz (180kHz for G = 10) bandwidth of the LTC1100 can be reduced to minimize system errors or reduce transmitted clock noise by using the COMP pin. A feedback cap from COMP to VOUT will react with the 247k internal resistor (22.5k for G = 10) to limit the bandwidth, as in Figure 2. Single Supply Operation The LTC1100 will operate on a single 5V supply, and the common-mode range of the internal op amps includes ground; single supply operation is limited only by the output swing of the op amps. The internal inverting amplifier has a negative saturation limit of 5mV typically, setting the minimum common-mode limit at 5mV/1.01 (or 1.1 for gain of 10). The inputs can be biased above ground as shown in Figure 3. Low cost biasing components can be used since any errors appear as a common-mode term and are rejected. The minimum differential input voltage is limited by the swing of the output op amp. Lightly loaded, it will swing down to 5mV, allowing differential input voltages as low as 50µV (450µV for gain of 10). Single supply operation limits the LTC1100 to positive differential inputs only; negative inputs will give a saturated zero output. 5V 5V RBIAS 6 CB – + − 8 OUTPUT 0V TO 5V 4, 1 7 LTC1100 6 5 LTC1100 SENSOR 3 3 + 1N4148 8 f 3dB = LTC1100 • TA04 1 2 π R INT × CB R INT = 247k FOR G = 100 22.5k FOR G = 10 Figure 3. LTC1100 • TA03 Figure 2. Overcompensation to Reduce System Bandwidth Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 7 LTC1100 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. J8 Package 8-Lead Ceramic DIP CORNER LEADS OPTION (4 PLCS) 0.023 – 0.045 (0.584 – 1.143) HALF LEAD OPTION 0.290 – 0.320 (7.366 – 8.128) 0.200 (5.080) MAX 0.045 – 0.068 (1.143 – 1.727) FULL LEAD OPTION 0.008 – 0.018 (0.203 – 0.457) 0.015 – 0.060 (0.381 – 1.524) 0.405 (10.287) MAX 0.005 (0.127) MIN 8 6 7 5 0.025 (0.635) RAD TYP 0.220 – 0.310 (5.588 – 7.874) 0° – 15° 1 0.045 – 0.068 (1.143 – 1.727) 0.385 ± 0.025 (9.779 ± 0.635) 2 3 4 0.125 3.175 0.100 ± 0.010 MIN (2.540 ± 0.254) 0.014 – 0.026 (0.360 – 0.660) NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP OR TIN PLATE LEADS. N8 Package 8-Lead Plastic DIP 0.300 – 0.320 (7.620 – 8.128) 0.045 – 0.065 (1.143 – 1.651) ( ) 8 7 6 5 0.065 (1.651) TYP 0.009 – 0.015 (0.229 – 0.381) +0.025 0.325 –0.015 +0.635 8.255 –0.381 0.400 (10.160) MAX 0.130 ± 0.005 (3.302 ± 0.127) 0.250 ± 0.010 (6.350 ± 0.254) 0.125 (3.175) MIN 0.045 ± 0.015 (1.143 ± 0.381) 0.020 (0.508) MIN 1 2 4 3 0.018 ± 0.003 (0.457 ± 0.076) 0.100 ± 0.010 (2.540 ± 0.254) S Package 16-Lead Plastic SOL 0.005 (0.127) RAD MIN 0.398 – 0.413 (10.109 – 10.490) (NOTE 2) 0.291 – 0.299 (7.391 – 7.595) (NOTE 2) 0.010 – 0.029 × 45° (0.254 – 0.737) 0.093 – 0.104 (2.362 – 2.642) 0.037 – 0.045 (0.940 – 1.143) 16 15 14 13 12 11 10 9 0° – 8° TYP 0.009 – 0.013 (0.229 – 0.330) NOTE 1 0.050 (1.270) TYP 0.016 – 0.050 (0.406 – 1.270) 8 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 ● FAX: (408) 434-0507 ● TELEX: 499-3977 0.394 – 0.419 (10.007 – 10.643) NOTE 1 0.014 – 0.019 (0.356 – 0.482) TYP NOTE: 1. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS. THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS. 2. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). Linear Technology Corporation 0.004 – 0.012 (0.102 – 0.305) 1 2 3 4 5 6 7 8 LT/GP 0594 2K REV B • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1994