Datasheet

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LT1028/LT1128

1028fb

Typical applicaTion

FeaTures DescripTion

Ultralow Noise Precision

High Speed Op Amps

The LT

1028(gain of –1 stable)/LT1128(gain of +1 stable)

achieve a new standard of excellence in noise performance

with 0.85nV/√Hz 1kHz noise, 1.0nV/√Hz 10Hz noise. This

ultralow noise is combined with excellent high speed

specifications (gain-bandwidth product is 75MHz for

LT1028, 20MHz for LT1128), distortion-free output, and

true precision parameters (0.1µV/°C drift, 10µV offset

voltage, 30 million voltage gain). Although the LT1028/

LT1128 input stage operates at nearly 1mA of collector

current to achieve low voltage noise, input bias current

is only 25nA.

The LT1028/LT1128’s voltage noise is less than the noise

of a 50Ω resistor. Therefore, even in very low source

impedance transducer or audio amplifier applications,

the LT1028/LT1128’s contribution to total system noise

will be negligible.

L, LT, LTC , LT M, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Ultralow Noise 1M TIA Photodiode Amplifier

applicaTions

Voltage Noise

1.1nV/√Hz Max at 1kHz

0.85nV/√Hz Typ at 1kHz

1.0nV/√Hz Typ at 10Hz

35nV

P-P

Typ, 0.1Hz to 10Hz

Voltage and Current Noise 100% Tested

Gain-Bandwidth Product

LT1028: 50MHz Min

LT1128: 13MHz Min

Slew Rate

LT1028: 11V/µs Min

LT1128: 5V/µs Min

Offset Voltage: 40µV Max

Drift with Temperature: 0.8µV/°C Max

Voltage Gain: 7 Million Min

Available in 8-Lead SO Package

Low Noise Frequency Synthesizers

High Quality Audio

Infrared Detectors

Accelerometer and Gyro Amplifiers

350Ω Bridge Signal Conditioning

Magnetic Search Coil Amplifiers

Hydrophone Amplifiers

Voltage Noise vs Frequency

FREQUENCY (Hz)

0.1

100

1028 TA02

VOLTAGE NOISE DENSITY (nV/√Hz)

0.1

1/f CORNER = 3.5Hz

1/f CORNER = 14Hz

TYPICAL

MAXIMUM

= 15V

= 25°C

–

OUT

= ~0.4V + I

• 1M

–

LT1028

0.1µF

JFET

NXP

BF862

PHOTO

DIODE

SFH213

4.32k

1028 TA01

0.5pF

4.99k

= ±15V

Summary of content (28 pages)

PAGE 1
LT1028/LT1128 Ultralow Noise Precision High Speed Op Amps Features Description Voltage Noise 1.1nV/√Hz Max at 1kHz 0.85nV/√Hz Typ at 1kHz 1.0nV/√Hz Typ at 10Hz 35nVP-P Typ, 0.1Hz to 10Hz n Voltage and Current Noise 100% Tested n Gain-Bandwidth Product LT1028: 50MHz Min LT1128: 13MHz Min n Slew Rate LT1028: 11V/µs Min LT1128: 5V/µs Min n Offset Voltage: 40µV Max n Drift with Temperature: 0.
PAGE 2
LT1028/LT1128 Absolute Maximum Ratings (Note 1) Supply Voltage –55°C to 105°C................................................... ±22V 105°C to 125°C................................................... ±16V Differential Input Current (Note 9)........................±25mA Input Voltage...............................Equal to Supply Voltage Output Short-Circuit Duration........................... Indefinite Operating Temperature Range LT1028/LT1128AM, M (OBSOLETE)....
PAGE 3
LT1028/LT1128 Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT1028ACN8#PBF N/A LT1028ACN8 8-Lead PDIP 0°C to 70°C LT1028CN8#PBF N/A LT1028CN8 8-Lead PDIP 0°C to 70°C LT1128ACN8#PBF N/A LT1128ACN8 8-Lead PDIP 0°C to 70°C LT1128CN8#PBF N/A LT1128CN8 8-Lead PDIP 0°C to 70°C LT1028CS8#PBF LT1028CS8#TRPBF 1028 8-Lead Plastic Small Outline 0°C to 70°C LT1128CS8#PBF LT1128CS8#TRPBF 1128 8-Lead Plastic Small Outline 0
PAGE 4
LT1028/LT1128 Electrical Characteristics The l denotes the specifications which apply over the operating temperature range –55°C ≤ TA ≤ 125°C. VS = ±15V, unless otherwise noted.
PAGE 5
LT1028/LT1128 Electrical Characteristics The l denotes the specifications which apply over the operating temperature range –40°C ≤ TA ≤ 85°C. VS = ±15V, unless otherwise noted. (Note 11) LT1028AC LT1128AC SYMBOL PARAMETER VOS Input Offset Voltage ∆VOS ∆Temp Average Input Offset Drift IOS IB CONDITIONS MIN TYP l 20 (Note 8) l 0.2 Input Offset Current VCM = 0V l 20 Input Bias Current VCM = 0V l ±35 LT1028C LT1128C MAX MIN TYP MAX UNITS 95 35 150 µV 0.8 0.25 1.
PAGE 6
LT1028/LT1128 Typical Performance Characteristics 10Hz Voltage Noise Distribution 180 120 RMS VOLTAGE NOISE (µV) 140 NUMBER OF UNITS 10 VS = ±15V TA = 25°C 500 UNITS MEASURED FROM 4 RUNS 158 148 160 Wideband Voltage Noise (0.1Hz to Frequency Indicated) Wideband Noise, DC to 20kHz 100 80 70 57 60 40 28 20 0 8 0.6 74 3 2 2 2 12 3 21 1 0.8 1.0 1.2 1.4 1.6 1.8 2.0 VOLTAGE NOISE DENSITY (nV/√Hz) VERTICAL SCALE = 0.5µV/DIV HORIZONTAL SCALE = 0.5ms/DIV 1 VS = ±15V TA = 25°C 1 0.
PAGE 7
LT1028/LT1128 Typical Performance Characteristics Distribution of Input Offset Voltage 50 VS = ±15V TA = 25°C 800 UNITS TESTED FROM FOUR RUNS 16 40 14 UNITS (%) 10 12 10 8 6 20 10 0 –10 –20 4 –30 2 –40 0 –50 –40 –30 –20 –10 0 10 20 30 40 50 OFFSET VOLTAGE (µV) –50 –50 –25 METAL CAN (H) PACKAGE 8 50 25 0 75 TEMPERATURE (°C) 100 DUAL-IN-LINE PACKAGE PLASTIC (N) OR CERDIP (J) 0 1 2 3 4 TIME AFTER POWER ON (MINUTES) 50 30 BIAS CURRENT 10 OFFSET CURRENT 50 25 75 0 TEMPERATURE (°C) SUPPL
PAGE 8
LT1028/LT1128 Typical Performance Characteristics LT1028 Gain, Phase vs Frequency Voltage Gain vs Frequency 60 40 50 50 60 40 40 30 30 GAIN 20 20 10 20 0 0 –20 0.01 0.
PAGE 9
LT1028/LT1128 Typical Performance Characteristics LT1028 Large-Signal Transient Response LT1028 Slew Rate, Gain-Bandwidth Product Over Temperature LT1028 Small-Signal Transient Response 50mV 5V/DIV 20mV/DIV –10V 17 SLEW RATE (V/µs) 10V –50mV 1028 G28 1µs/DIV AV = –1, RS = RF = 2k, CF = 15pF 90 VS = ±15V 0.
PAGE 10
LT1028/LT1128 Typical Performance Characteristics 140 –3 VS = ±15V –4 4 3 VS = ±5V TO ±15V 2 1 V– 50 25 0 75 TEMPERATURE (°C) –50 –25 100 120 100 LT1128 LT1028 80 60 40 20 0 125 10 100k 10k 1k FREQUENCY (Hz) 100 0.1 AV = –1000 RL = 2k AV = 1000 RL = 600Ω VO = 20VP-P VS = ±15V TA = 25°C 10 FREQUENCY (kHz) 1 100 TOTAL HARMONIC DISTORTION (%) TOTAL HARMONIC DISTORTION (%) AV = 1000 RL = 600Ω VO = 20VP-P f = 1kHz VS = ±15V TA = 25°C RL = 10k 0.01 INVERTING GAIN 0.001 0.
PAGE 11
LT1028/LT1128 Applications Information – Noise Voltage Noise vs Current Noise The LT1028/LT1128’s less than 1nV/√Hz voltage noise is three times better than the lowest voltage noise heretofore available (on the LT1007/1037). A necessary condition for such low voltage noise is operating the input transistors at nearly 1mA of collector currents, because voltage noise is inversely proportional to the square root of the collector current.
PAGE 12
LT1028/LT1128 Applications Information – Noise Noise Testing – Voltage Noise The LT1028/LT1128’s RMS voltage noise density can be accurately measured using the Quan Tech Noise Analyzer, Model 5173 or an equivalent noise tester. Care should be taken, however, to subtract the noise of the source resistor used. Prefabricated test cards for the Model 5173 set the device under test in a closed-loop gain of 31 with a 60Ω source resistor and a 1.8k feedback resistor. The noise of this resistor combination is 0.
PAGE 13
LT1028/LT1128 Applications Information – Noise Noise Testing – Current Noise Current noise density (In) is defined by the following formula, and can be measured in the circuit shown in Figure 4. ⎡e 2 − 31• 18.4nV/ Hz 2 ⎤ ⎢ no ⎥⎦ ln = ⎣ 20k • 31 ( ) 1/2 1.8k 10k 60Ω 10k 10Hz voltage noise density is sample tested on every lot. Devices 100% tested at 10Hz are available on request for an additional charge. 10Hz current noise is not tested on every lot but it can be inferred from 100% testing at 1kHz.
PAGE 14
LT1028/LT1128 Applications Information General 10k* 15V The LT1028/LT1128 series devices may be inserted directly into OP-07, OP-27, OP-37, LT1007 and LT1037 sockets with or without removal of external nulling components. In addition, the LT1028/LT1128 may be fitted to 5534 sockets with the removal of external compensation components. 2 200Ω* 10k* The input offset voltage of the LT1028/LT1128 and its drift with temperature, are permanently trimmed at wafer testing to a low level.
PAGE 15
LT1028/LT1128 Applications Information Frequency Response C1 The LT1028’s Gain, Phase vs Frequency plot indicates that the device is stable in closed-loop gains greater than +2 or –1 because phase margin is about 50° at an open-loop gain of 6dB. In the voltage follower configuration phase margin seems inadequate. This is indeed true when the output is shorted to the inverting input and the noninverting input is driven from a 50Ω source impedance.
PAGE 16
LT1028/LT1128 Typical Applications Strain Gauge Signal Conditioner with Bridge Excitation 15V LT1021-5 3 5.0V + 2 – 7 330Ω 6 LT1128 4 –15V REFERENCE OUTPUT 350Ω BRIDGE 3 301k* 10k ZERO TRIM 2 2 7 – + 6 LT1028 + 4 *RN60C FILM RESISTORS 6 LT1028 7 – 0V TO 10V OUTPUT 1µF 30.1k* 5k GAIN TRIM 49.9Ω* –15V 15V 3 15V 330Ω 4 THE LT1028’s NOISE CONTRIBUTION IS NEGLIGIBLE COMPARED TO THE BRIDGE NOISE.
PAGE 17
LT1028/LT1128 Typical Applications Paralleling Amplifiers to Reduce Voltage Noise + A1 LT1028 1.5k – 7.5Ω 470Ω 4.7k + A2 LT1028 1.5k – – 7.5Ω LT1028 + An LT1028 OUTPUT + 470Ω 1.5k – 7.5Ω 470Ω 1. ASSUME VOLTAGE NOISE OF LT1028 AND 7.5Ω SOURCE RESISTOR = 0.9nV/√Hz. 2. GAIN WITH n LT1028s IN PARALLEL = n • 200. 3. OUTPUT NOISE = √n • 200 • 0.9nV/√Hz. OUTPUT NOISE 0.9 4. INPUT REFERRED NOISE = = nV/√Hz. n • 200 √n 5. NOISE CURRENT AT INPUT INCREASES √n TIMES. 2µV 6.
PAGE 18
LT1028/LT1128 Typical Applications Phono Preamplifier 10Ω 787Ω 15V 2 3 + 0.33µF 6 LT1028 47k 10k 7 – 100pF 0.1µF OUTPUT 4 –15V ALL RESISTORS METAL FILM MAG PHONO INPUT 1028 TA06 Tape Head Amplifier 499Ω 0.1µF 31.
PAGE 19
LT1028/LT1128 Typical Applications Low Noise, Wide Bandwidth Instrumentation Amplifier –INPUT + 300Ω LT1028 – 820Ω 10k 68pF 50Ω 10Ω 820Ω – OUTPUT LT1028 300Ω LT1028 +INPUT – 68pF + + 10k GAIN = 1000, BANDWIDTH = 1MHz INPUT REFERRED NOISE = 1.5nV/√Hz AT 1kHz WIDEBAND NOISE –DC to 1MHz = 3µVRMS IF BW LIMITED TO DC TO 100kHz = 0.55µVRMS 1028 TA08 Gyro Pick-Off Amplifier GYRO TYPICAL– NORTHROP CORP.
PAGE 20
LT1028/LT1128 Typical Applications Super Low Distortion Variable Sine Wave Oscillator R1 C1 0.047 20Ω 20Ω C2 0.047 2k 1VRMS OUTPUT 1.5kHz TO 15kHz 1 f= 2πRC WHERE R1C1 = R2C2 4.7k 15V + 2k ( LT1028 R2 – 5.6k 2.4k ) LT1004-1.2V 10pF 22k 15µF + 100k 560Ω LT1055 TRIM FOR LOWEST DISTORTION + 20k MOUNT 1N4148s IN CLOSE PROXIMITY – 2N4338 10k 10k <0.0018% DISTORTION AND NOISE.
PAGE 21
LT1028/LT1128 Schematic Diagram NULL 8 R5 130Ω NULL 1 V+ 7 R6 130Ω Q4 R2 3k R1 3k 1.1mA R10 400Ω Q16 3 1 Q8 1 Q11 Q1 Q2 R11 100Ω Q9 Q24 4.5µA OUTPUT 6 Q25 1.5µA Q12 Q13 R12 240Ω Q14 1.5µA INVERTING INPUT 2 Q22 C3 250pF Q10 4.5µA 4.5µA Q26 Q6 4.5µA 3 R10 C2 500Ω Q18 Q5 Q7 500µA R11 400Ω Q19 900µA 3 NONINVERTING INPUT 400µA C1 257pF Q17 900µA 2.3mA C4 35pF Q27 0 1.
PAGE 22
LT1028/LT1128 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. J8 Package 3-Lead CERDIP (Narrow .300 Inch, Hermetic) (Reference LTC DWG # 05-08-1110) CORNER LEADS OPTION (4 PLCS) .023 – .045 (0.584 – 1.143) HALF LEAD OPTION .045 – .068 (1.143 – 1.650) FULL LEAD OPTION .005 (0.127) MIN .405 (10.287) MAX 8 7 6 5 .025 (0.635) RAD TYP .220 – .310 (5.588 – 7.874) 1 .300 BSC (7.62 BSC) 2 3 4 .200 (5.080) MAX .015 – .060 (0.
PAGE 23
LT1028/LT1128 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. N Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510 Rev I) .400* (10.160) MAX 8 7 6 5 1 2 3 4 .255 ±.015* (6.477 ±0.381) .300 – .325 (7.620 – 8.255) .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .045 – .065 (1.143 – 1.651) .065 (1.651) TYP .100 (2.54) BSC .130 ±.005 (3.302 ±0.127) .120 (3.048) .020 MIN (0.
PAGE 24
LT1028/LT1128 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610 Rev G) .050 BSC .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 8 .245 MIN .160 ±.005 .010 – .020 × 45° (0.254 – 0.508) NOTE: 1. DIMENSIONS IN 5 .150 – .157 (3.810 – 3.988) NOTE 3 1 RECOMMENDED SOLDER PAD LAYOUT .053 – .069 (1.346 – 1.752) 0°– 8° TYP .016 – .050 (0.406 – 1.
PAGE 25
LT1028/LT1128 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S Package 16-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610 Rev G) .386 – .394 (9.804 – 10.008) NOTE 3 .045 ±.005 .050 BSC 16 N 14 13 12 11 10 9 N .245 MIN .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) 1 .030 ±.005 TYP 15 2 3 N/2 N/2 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.
PAGE 26
LT1028/LT1128 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. H Package 8-Lead TO-5 Metal Can (.230 Inch PCD) (Reference LTC DWG # 05-08-1321) .040 (1.016) MAX .335 – .370 (8.509 – 9.398) DIA .305 – .335 (7.747 – 8.509) .050 (1.270) MAX SEATING PLANE .165 – .185 (4.191 – 4.699) GAUGE PLANE .010 – .045* (0.254 – 1.143) REFERENCE PLANE .500 – .750 (12.700 – 19.050) .016 – .021** (0.406 – 0.533) .027 – .045 (0.686 – 1.143) 45° .
PAGE 27
LT1028/LT1128 Revision History (Revision history begins at Rev B) REV DATE DESCRIPTION B 10/12 Replaced the Typical Application. PAGE NUMBER 1 1028fb 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.
PAGE 28
LT1028/LT1128 Typical Application Low Noise Infrared Detector 5V 10Ω + 1k 100µF 33Ω + SYNCHRONOUS DEMODULATOR 100µF 10k* OPTICAL CHOPPER WHEEL 5V 5V 1000µF 3 + IR RADIATION 10k* 267Ω 39Ω 2 PHOTOELECTRIC PICK-OFF 2 7 + LT1028 – 1/4 LTC1043 6 13 8 4 12 10k –5V INFRA RED ASSOCIATES, INC.