Datasheet LTC1051, LTC1053 Datasheet (LINEAR TECHNOLOGY)

FEATURES

LTC1051/LTC1053

Dual/Quad Precision

Zero-Drift Operational Amplifiers

With Internal Capacitors

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DESCRIPTIO

■

Dual/Quad Low Cost Precision Op Amp

■

No External Components Required

■

Maximum Offset Voltage: 5µV

■

Maximum Offset Voltage Drift: 0.05µV/°C

■

Low Noise 1.5µV

■

Minimum Voltage Gain: 120dB

■

Minimum PSRR: 120dB

■

Minimum CMRR: 114dB

■

Low Supply Current: 1mA/Op Amp

■

Single Supply Operation: 4.75V to 16V

■

Input Common Mode Range Includes Ground

■

Output Swings to Ground

■

Typical Overload Recovery Time: 3ms

■

Pin Compatible with Industry Standard Dual and

(0.1Hz to 10Hz)

P-P

Quad Op Amps

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APPLICATIO S

■

Thermocouple Amplifiers

■

Electronic Scales

■

Medical Instrumentation

■

Strain Gauge Amplifiers

■

High Resolution Data Acquisition

■

DC Accurate R C Active Filters

, LTC and LT are registered trademarks of Linear Technology Corporation.

The LTC®1051/LTC1053 are high performance, low cost dual/quad zero-drift operational amplifiers. The unique achievement of the LTC1051/LTC1053 is that they integrate on chip the sample-and-hold capacitors usually required externally by other chopper amplifiers. Further, the LTC1051/LTC1053 offer better combined overall DC and AC performance than is available from other chopper stabilized amplifiers with or without internal sample/hold capacitors.

The LTC1051/LTC1053 have an offset voltage of 0.5µV, drift of 0.01µV/°C, DC to 10Hz, input noise voltage typically

1.5µV

and typical voltage gain of 140dB. The slew rate

P-P

of 4V/µs and gain bandwidth product of 2.5MHz are achieved with only 1mA of supply current per op amp.

Overload recover times from positive and negative saturation conditions are 1.5ms and 3ms respectively, about a 100 or more times improvement over chopper amplifiers using external capacitors.

The LTC1051 is available in an 8-lead standard plastic dual-in-line package as well as a 16-pin SW package. The LTC1053 is available in a standard 14-pin plastic package and an 18-pin SO. The LTC1051/LTC1053 are plug in replacements for most standard dual/quad op amps with improved performance.

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TYPICAL APPLICATIO

High Performance Low Cost Instrumentation Amplifier LTC1051 Noise Spectrum

120

6

5

–

LTC1051

+

1/2

R2

–5V

100

80

7

4

1051/53 TA01a

VOLTAGE NOISE DENSITY (nV√Hz)

60

40

20

10

100 1k 10k

FREQUENCY (Hz)

R1

5V

R2

2

8

–

1/2

LTC1051

3

V

+

IN

R1 = 499Ω, 0.1% R2 = 100k, 0.1% GAIN = 201 MEASURED CMRR ~ 120dB AT DC MEASURED INPUT V MEASURED INPUT NOISE 2µV

3µV

OS

P-P

1

(DC – 10Hz)

R1

V

IN

1051/53 TA01b

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1

LTC1051/LTC1053

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ABSOLUTE AXI U RATI GS

(Note 1)

Total Supply Voltage (V+ to V–) ............................ 16.5V

Input Voltage ........................ (V+ + 0.3V) to (V– – 0.3V)

Output Short-Circuit Duration .......................... Indefinite

Operating Temperature Range

LTC1051M, LTC1051AM

LTC1051C/LTC1053C ......................... – 40°C to 85°C

Storage Temperature Range ................. –65°C to 150°C

Lead Temperature (Soldering, 10 sec)..................300°C

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W

PACKAGE/ORDER I FOR ATIO

TOP VIEW

OUT A

1

–IN A

2

+IN A

3

–

V

4

N8 PACKAGE 8-LEAD PDIP

T

= 150°C, θJA = 110°C/W

JMAX

J8 PACKAGE

8-LEAD CERDIP

+

V

8

OUT B

7

–IN B

6

+IN B

5

OBSOLETE PACKAGE

Consider the N8 Package as an Alternate Source

TOP VIEW

1

NC

2

NC

3

OUT A

4

–IN A

5

+IN A

–

6

V

7

NC

8

NC

SW PACKAGE

16-LEAD PLASTIC SO

T

= 150°C, θJA = 90°C/W

JMAX

Consult LTC Marketing for parts specified with wider operating temperature ranges.

16

NC

15

NC

+

14

V

13

OUT B

12

–IN B

11

+IN B

10

NC

9

NC

ORDER PART

NUMBER

LTC1051CN8 LTC1051MJ8 LTC1051CJ8 LTC1051AMJ8 LTC1051ACJ8

ORDER PART

NUMBER

LTC1051CSW LTC1053CSW

OUT A

–IN A

+IN A

+IN B

–IN B

OUT B

TOP VIEW

1

OUT A

2

–IN A

3

+IN A

+

4

V

5

+IN B

6

–IN B

7

OUT B

N PACKAGE

14-LEAD PDIP

T

= 150°C, θJA = 65°C/W

JMAX

TOP VIEW

1

NC

2

3

4

+

5

V

6

7

8

9

NC

SW PACKAGE

18-LEAD PLASTIC SO

T

= 150°C, θJA = 85°C/W

JMAX

(OBSOLETE) .. –55°C to 125°C

ORDER PART

OUT D

14

–IN D

13

+IN D

12

–

V

11

+IN C

10

–IN C

9

OUT C

8

NUMBER

LTC1053CN

ORDER PART

18

NC

17

OUT D

16

–IN D

15

+IN D

–

14

V

13

+IN C

12

–IN C

11

OUT C

10

NC

NUMBER

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = ±5V unless otherwise noted.

LTC1051/LTC1053 LTC1051A

PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

Input Offset Voltage ±0.5 ±5 ±0.5 ±5 µV Average Input Offset Drift ● ±0.0 ±0.05 ±0.0 ±0.05 µV/°C

Long Term Offset Drift 50 50 nV/√Mo

Input Bias Current ±15 ±65 ±15 ±50 pA

LTC1051C/LTC1053C

● ±135 ±100 pA

Input Offset Current (All Grades) ±30 ±125 ±30 ±100 pA

● ±175 ±150 pA

Input Noise Voltage (Note 2) RS = 100Ω, DC to 10Hz 1.5 1.5 2 µV

RS = 100Ω, DC to 1Hz 0.4 0.4 µV

P-P P-P

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LTC1051/LTC1053

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = ±5V unless otherwise noted.

LTC1051/LTC1053 LTC1051A

PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

Input Noise Current f = 10Hz 2.2 2.2 fA/√Hz

Common Mode Rejection Ratio, CMRR VCM = V

Differential CMRR VCM = V

LTC1051, LTC1053 (Note 3)

Power Supply Rejection Ratio VS = ±2.375V to ±8V ● 116 140 120 140 dB

Large Signal Voltage Gain RL = 10k, V

Maximum Output Voltage Swing RL = 10k ● ±4.5 ±4.85 ±4.7 ±4.85 V

Slew Rate RL = 10k, CL = 50pF 4 4 V/µs

Gain Bandwidth Product 2.5 2.5 MHz

Supply Current/Op Amp No Load 1 2 1 2 mA

Internal Sampling Frequency 3.3 3.3 kHz

–

to 2.7V 106 130 114 130 dB

● 100 110 dB

–

to 2.7V 112 112 dB

= ±4V ● 116 160 120 160 dB

OUT

R

= 100k ±4.5 ±4.95 ±4.95 V

L

● 2.5 2.5 mA

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = ±5V unless otherwise noted.VS = 5V, GND unless otherwise noted.

LTC1051A/LTC1051/LTC1053

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Offset Voltage ±0.5 ±5 µV

Input Offset Drift ±0.01 ±0.05 µV/°C

Input Bias Current ±10 ±50 pA

Input Offset Current ±20 ±80 pA

Input Noise Voltage DC to 10Hz 1.8 µV Supply Current/Op Amp No Load ● 1.5 mA

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

Note 2: For guaranteed noise specification contact LTC Marketing.

Note 3: Differential CMRR for the LTC1053 is measured between

amplifiers A and D, and amplifiers B and C.

P-P

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LTC1051/LTC1053

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TYPICAL PERFOR A CE CHARACTERISTICS

Common Mode Input Range vs Supply Voltage

8

6

4

2

0

–2

–4

COMMON MODE RANGE (V)

–6

–8

0

12345678

SUPPLY VOLTAGE (±V)

VCM = V

–

Supply Current vs Supply Voltage Per Op Amp

1.50 TA = 25°C

1.25

(mA)

S

1.00

0.75

0.50

SUPPLY CURRENT, I

0.25

0

4

TOTAL SUPPLY VOLTAGE V+ TO V– (V)

81012

6

1051/53 G01

14 16

1051/53 G04

Sampling Frequency vs Supply Voltage

4.0 TA = 25°C

(kHz)

3.5

S

3.0

2.5

SAMPLING FREQUENCY, f

2.0

4

681012

TOTAL SUPPLY VOLTAGE, V+ TO V– (V)

14 16

1051/53 G02

Sampling Frequency vs Temperature

VS = ±5V

5

(kHz)

S

4

3

2

SAMPLING FREQUENCY, f

1

–50

0

–25

AMBIENT TEMPERATURE, TA (°C)

25

Supply Current vs Temperature Per Op Amp Gain/Phase vs Frequency

2.0 VS = ±5V

1.8

1.6

1.4

(mA)

S

1.2

1.0

0.8

0.6

SUPPLY CURRENT, I

0.4

0.2

0

–50

–25

AMBIENT TEMPERATURE, TA (°C)

0

75

100

1051/53 G05

50

25

VOLTAGE GAIN (dB)

–20

–40

125

120

100

80

60

40

20

0

100 10k 100k 10M

1k 1M

FREQUENCY (Hz)

50

75

100

1051/53 G03

VS = ±5V

= 100pF

C

L

≥ 1k

R

L

= 25°C

T

A

1051/53 G06

125

60

80

PHASE SHIFT (DEGREES)

100

120

140

160

180

200

220

Output Short-Circuit Current vs Supply Voltage

6

(mA)

4

OUT

I

2

0

–10

–20

SHORT-CIRCUIT OUTPUT CURRENT, I

–30

4

TOTAL SUPPLY VOLTAGE, V+ TO V– (V)

SOURCE

I

SINK

81012

6

4

CMRR vs Frequency Gain/Phase vs Frequency

≥ 1k

1051/53 G09

–60

–80

PHASE SHIFT (DEGREES)

–100

–120

–140

–160

–180

–200

–220

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–

V

= V

OUT

+

V

= V

OUT

14 16

1051/53 G07

160

140

120

100

80

CMRR (dB)

60

40

VS = ±5V

20

= 25°C

T

A

AC COMMON MODE IN = 0.5V

0

1 100 1k

10 10k 100k

P-P

FREQUENCY (Hz)

1051/53 G08

120

100

80

60

40

20

VOLTAGE GAIN (dB)

0

–20

–40

100 10k 100k 10M

1k 1M

FREQUENCY (Hz)

VS = ±2.5V C R T

A

= 100pF

L L

= 25°C

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LTC1051/LTC1053

INPUT

OUTPUT

Overload Recovery

400mV

0

–5V

AV = –100

= ±5V

V

S

LTC1051/LTC1053 DC to 10Hz Noise

VS = ±5V

= 25°C

T

A

1µV

0.5ms

1051/53 G10

1.4µV

OUTPUT

50mV

INPUT

100mV

P-P

Small Signal Transient Response Large Signal Transient Response

OUTPUT

/DIV

A

= 1, RL = 10k, CL = 100pF

V

= ±5V, TA = 25°C

V

S

2µs/DIV

1051/53 G11

2V/DIV

INPUT

6V

A

= 1, RL = 10k, CL = 100pF

V

= ±5V, TA = 25°C

V

S

2µs/DIV

1051/53 G12

1 SEC

TEST CIRCUITS

Electrical Characteristics Test Circuit DC 10Hz Noise Test Circuit

1M

+

V

1k

2

3

–

LTC1051

+

1/2

8

6

OUTPUT

4

–

V

R

L

10Ω

100k

2

–

1/2

LTC1051

3

+

FOR 1Hz NOISE BW INCREASE ALL THE CAPACITORS BY A FACTOR OF 10.

158k 316k 475k

6

0.1µF 0.01µF

475k

10 SEC

–

LT1012

+

0.01µF

TO X-Y RECORDER

1051/53 TC01

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LTC1051/LTC1053

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APPLICATIO S I FOR ATIO

ACHIEVING PICOAMPERE/MICROVOLT PERFORMANCE

Picoamperes

In order to realize the picoampere level of accuracy of the LTC1051/LTC1053, proper care must be exercised. Leakage currents in circuitry external to the amplifier can significantly degrade performance. High quality insulation should be used (e.g., Teflon, Kel-F); cleaning of all insulating surfaces to remove fluxes and other residues will probably be necessary —particularly for high temperature performance. Surface coating may be necessary to provide a moisture barrier in high humidity environments.

Board leakage can be minimized by encircling the input connections with a guard ring operated at a potential close to that of the inputs: in inverting configurations, the guard ring should be tied to ground; in noninverting connections, to the inverting input. Guarding both sides of the printed circuit board is required. Bulk leakage reduction depends on the guard ring width.

Microvolts

Thermocouple effects must be considered if the LTC1051/ LTC1053’s ultra low drift op amps are to be fully utilized. Any connection of dissimilar metals forms a thermoelectric junction producing an electric potential which varies with temperature (Seebeck effect.) As temperature sensors, thermocouples exploit this phenomenon to produce useful information. In low drift amplifier circuits, this effect is a primary source of error.

Avoid connectors, sockets, switches and relays where possible. In instances where this is not possible, attempt to balance the number and type of junctions so that differential cancellation occurs. Doing this may involve deliberately introducing junctions to offset unavoidable junctions.

When connectors, switches, relays and/or sockets are necessary, they should be selected for low thermal EMF activity. The same techniques of thermally balancing and coupling the matching junctions are effective in reducing the thermal EMF errors of these components.

Resistors are another source of thermal EMF errors. Table 1 shows the thermal EMF generated for different resistors. The temperature gradient across the resistor is important, not the ambient temperature. There are two junctions formed at each end of the resistor and if these junctions are at the same temperature, their thermal EMFs will cancel each other. The thermal EMF numbers are approximate and vary with resistor value. High values give higher thermal EMF.

Table 1. Resistor Thermal EMF

RESISTOR TYPE THERMAL EMF/°C GRADIENT

Tin Oxide ~mV/°C

Carbon Composition ~450µV/°C

Metal Film ~20µV/°C

Wire Wound

Evenohm ~2µV/°C

Manganin ~2µV/°C

Connectors, switches, relay contacts, sockets, resistors, solder, and even copper wire are all candidates for thermal EMF generation. Junctions of copper wire from different manufacturers can generate thermal EMFs of 200nV/°C— 4 times the maximum drift specification of the LTC1051/ LTC1053. The copper/kovar junction, formed when wire or printed circuit traces contact a package lead, has a thermal EMF of approximately 35µV/°C—700 times the maximum drift specification of the LTC1051/LTC1053.

Minimizing thermal EMF-induced errors is possible if judicious attention is given to circuit board layout and component selection. It is good practice to minimize the number of junctions in the amplifier’s input signal path.

6

Input Bias Current, Clock Feedthrough

At ambient temperatures below 60°C, the input bias current of the LTC1051/LTC1053 op amps’ is dominated by the small amount of charge injection occurring during the sampling and holding of the op amps’ input offset voltage. The average value of the resulting current pulses is 10pA to 15pA with sign convention shown in Figure 1.

+

I

B

–

I

B

TA < 60°CT

+

1/2

LTC1051

–

(a) (b)

Figure 1. LTC1051 Bias Current

+

I

B

–

I

B

+

LTC1051

–

1/2

> 85°C

A

1051/53 F01

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APPLICATIO S I FOR ATIO

RS = 0,

=11V/V

A

V

20mV/DIV

= 0,

R

S

=101V/V

A

V

20mV/DIV

= 100k,

R

S

=11V/V

A

V

20mV/DIV

R

= 100k,

S

=101V/V

A

V

20mV/DIV

LTC1051/LTC1053

R2

100k

R1 1k

R

S

–

LTC1051

+

1/2

100µs/DIV

(a)

Figure 2. Clock Feedthrough

As the ambient temperature rises, the leakage current of the input protection devices increases, while the charge injection component of the bias current, for all practical purposes, stays constant. At elevated temperatures (above 85°C) the leakage current dominates and the bias current of both inputs assumes the same sign.

The charge injection at the op amp input pins will cause small output spikes. This phenomenon is often referred to as “clock feedthrough” and can be easily observed when the closed-loop gain exceeds 10V/V (Figure 2). The magnitude of the clock feedthrough is temperature independent but it increases when the closed-loop gain goes up, when the source resistance increases and when the gain setting resistors increase (Figure 2a, 2b). It is important to note that the output small spikes are centered at 0V level and do not add to the output offset error budget. For instance, with RS = 1MΩ, the typical output offset voltage of Figure 2c is:

V

OS(OUT)

≈ 108 • I

+

+ 101V

B

OS(IN)

A 10pA bias current will yield an output of 1mV ±100µV. The output clock feedthrough can be attenuated by lowering the value of the gain setting resistors, i.e. R2 = 10k, R1 = 100Ω, instead of 100k and 1k (Figure 2).

Clock feedthrough can also be attenuated by adding a capacitor across the feedback resistor to limit the circuit bandwidth below the internal sampling frequency (Figure 3).

Input Capacitance

The input capacitance of the LTC1051/LTC1053 op amps is approximately 12pF. When the LTC1051/LTC1053 op amps are used with feedback factors approaching unity,

100µs/DIV

(b)

(c)

1051/53 F02

the feedback resistor value should not exceed 7k for industrial temperature range and 5k for military temperature range. If a higher feedback resistor value is required, a feedback capacitor of 20pF should be placed across the feedback resistor. Note that the most common circuits with feedback factors approaching unity are unity gain followers and instrumentation amplifier front ends. (See Figure 4.)

R

= 100k

S

A

=101V/V

V

20mV/DIV

= 1MΩ

R

S

=101V/V

A

V

100µs/DIV

C

R1 1k

R

S

Figure 3. Adding a Feedback Capacitor to Eliminate Clock Feedthrough

R1

Figure 4. Operating the LTC1051 with Feedback Factors Approaching Unity

1000pF

–

LTC1051

+

–

LTC1051

+

1/2

R2

100k

2

3

R2 < 7k, IF R1 > >R2

2

3

1

1051/53 F03

1

1051/53 F04

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LTC1051/LTC1053

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APPLICATIO S I FOR ATIO

LTC1051/LTC1053 as AC Amplifiers

Although initially chopper stabilized op amps were designed to minimize DC offsets and offset drifts, the LTC1051/LTC1053 family, on top of its outstanding DC characteristics, presents efficient AC performance. For instance, at single 5V supply, each op amp typically consumes 0.5mA and still provides 1.8MHz gain bandwidth product and 3V/µs slew rate. This, combined with almost distortionless swing to the supply rails (Figure 8), makes the LTC1051/LTC1053 op amps nearly general purpose. To further expand this idea (the “aliasing” phenomenon) which can occur under AC conditions, should be described and properly evaluated.

20dBV

15dB

/DIV

–100

B: MAG RANGE: 9dBV

START: 100Hz X: 1825Hz

fIN = 750Hz f

CLK

BW: 47.742Hz Y: –70.72dBV

– f

IN

2f

IN

STATUS: PAUSED

STOP: 5 100Hz

2f

– f

CLK

Aliasing

The LTC1051/LTC1053 are equipped with internal circuitry to minimize aliasing. Aliasing, no matter how small, occurs when the input signal approaches and exceeds the internal sampling rate. Aliasing is caused by the sampled data nature of the chopper op amps. A generalized study of this phenomenon is beyond the scope of a data sheet; however, a set of rules of thumb can answer many questions:

1. Alias signals can be generally defined as output AC signals at a frequency of nf

± mfIN. The nf

CLK

term is the

CLK

internal sampling frequency of the chopper stabilized op amps and its harmonics; mf

is the frequency of the input

IN

signal and its harmonics, if any.

RMS: 25

R2 10k

2

3

–

LTC1051

+

1/2

–5V

5V

0.1µF

1

V

OUT

50pF

0.1µF

1051/53 F05a

80dB

R1 1k

f

IN

0.8V

P-P

IN

8

Figure 5a. Output Voltage Spectrum of 1/2 LTC1051 Operating as an Inverting Amplifier with Gain of 10, and Amplifying a 750Hz/800mV, Input AC Signal

20dBV

15dB

/DIV

–100

A: MAG RANGE: 11dBV

CENTER: 10 000Hz X: 5550Hz

– f

6f

CLK

IN

BW: 95.485Hz Y: –63.91dBV

fIN = 10kHz

STATUS: PAUSED

RMS: 25

SPAN: 10 000Hz

74dB

Figure 5b. Same as Figure 5a, but the AC Input Signal is 900mV, 10kHz

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APPLICATIO S I FOR ATIO

LTC1051/LTC1053

2. If we arbitrarily accept that “aliasing” occurs when output alias signals reach an amplitude of 0.01% or more of the output signal, then: the approximate minimum frequency of an AC input signal which will cause aliasing is equal to the internal clock frequency multiplied by the square root of the op amp feedback factor. For instance, with closed-loop gain of –10, the feedback factor is 1/11 and if f

= 2.6kHz, alias signals can be detected when

CLK

the frequency of the input signal exceeds 750Hz to 800Hz (Figure 5a).

3. The number of alias signals increases when the input signal frequency increases (Figure 5b).

13dBV

15dB

/DIV

B: MAG RANGE: 9dBV

STATUS: PAUSED

RMS: 25

4. When the frequency, f , the alias signal(s) amplitude(s) directly scale with

f

CLOCK

, of the input signal is less than

IN

the amplitude of the incoming signal. The output “signal to alias ratio” cannot be increased by just boosting the input signal amplitude. However, when the input AC signal frequency well exceeds the clock frequency, the amplitude of the alias signals does not directly scale with the input amplitude. The “signal to alias ratio” increases when the output swings closely to the rails. (See Figure 5b and Figure 7.) It is important to note that the LTC1051/ LTC1053 op amps, under light loads (RL ≥ 10k), swing closely to the supply rails without generating harmonic distortion (Figure 8).

10k

–

LTC1051

+

5V

0.1µF

1/2

50pF

83.5dB

10k

–107

CENTER: 2 625Hz X: 2535Hz

NOTE: THE f ALIAS FREQUENCY IS 95dB DOWN FROM THE OUTPUT LEVEL

– fIN = 85Hz

CLK

Figure 6a. Output Voltage Spectrum of 1/2 LTC1051 Operating as a Unity-Gain Inverting Amplifier. VS = ±5V, RL = 10k, CL = 50pF, VIN = 8V

Figure 6b. Output Voltage Spectrum of 1/2 LTC1051 Operating as a Unity-Gain Inverting Amplifier. VS = ±5V, RL = 10k, CL = 50pF, VIN = 8V

BW: 19.097Hz Y: –74.16dBV

2f

– f

CLK

13dBV

15dB

5f

CLK

fIN – 2f

NOTE: ALL ALIAS FREQUENCY 80dB TO 84dB DOWN FROM OUTPUT

IN

f

CLK

B: MAG RANGE: 9dBV

15dB

/DIV

–107

CENTER: 10 000Hz X: 10000Hz

– f

IN

CLK

fIN = 2.685kHz

6f

– f

CLK

2 • f

IN

CLK

SPAN: 2 000Hz

, 2.685kHz

P-P

CLK

, 10kHz

P-P

BW: 95.485Hz

Y: 7.98dBV

fIN = 10kHzfIN – f

= 10kHz

V

IN

8V

P-P

STATUS: PAUSED

RMS: 50

SPAN: 10 000Hz

1kHz

80dB

–5V

0.1µF

1051/53 F05a

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LTC1051/LTC1053

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APPLICATIO S I FOR ATIO

5. For unity-gain inverting configuration, all the alias frequencies are 80dB to 84dB down from the output signal (Figures 6a, 6b). Combined with excellent THD under wide swing, the LTC1051/LTC1053 op amps make efficient unity gain inverters.

For gain higher than –1, the “signal to alias” ratio decreases at an approximate rate of –6dB per decade of closed-loop gain (Figure 9).

6. For closed-loop gains of –10 or higher, the “signal to alias” ratio degrades when the value of the feedback gain setting resistor increases beyond 50k. For instance, the

SYSTEM BUSY, ONLY ABORT COMMANDS ALLOWED RANGE: 11dBV

20dBV

15dB

/DIV

STATUS: PAUSED

68dB value of Figure 7 decreases to 56dB if a (1k, 100k) resistor set is used to set the gain of –100.

7. When the LTC1051/LTC1053 are used as noninverting

amplifiers, all the previous approximate rules of thumb apply with the following exceptions: when the closed-loop gain is 10(V/V) and below, the “signal to alias” ratio is 1dB to 3dB less than the inverting case; when the closed-loop gain is 100(V/V), the degradation can be up to 9dB, especially when the input signal is much higher than the clock frequency (i.e. fIN = 10kHz).

8. The signal/alias ratio performance improves when the

op amp has bandlimited loop gain.

R2

10k

–

LTC1051

+

1/2

5V

0.1µF

V

OUT

50pF

68dB

100Ω

90mV

10kHz

R1

P-P

–100

CENTER: 10 000Hz X: 5475Hz

CLK

– f

BW: 95.485Hz Y: –58.05dBV

IN

fIN =10kHz6f

SPAN: 10 000Hz

–5V

0.1µF

1051/53 F07

Figure 7. Output Voltage Spectrum of 1/2 LTC1051 Operating as an Inverting Amplifier with a Gain of –100 and Amplifiying a 90mV

, 10kHz Input Signal. With a 9V

P-P

Output Swing the Measured 2nd Harmonic (20kHz)

P-P

was 75 Down from the 10kHz Input Signal

10

9

8

7

6

5

± SWING (±V)

4

OUT

V

3

2

1

0

01k2k3k

RL (LOAD RESISTANCE,Ω)

VS = ±8V, TA ≤85°C

VS = ±5V, TA ≤85°C

VS = ±2.5V, TA ≤85°C

NEGATIVE SWING POSITIVE SWING

4k

6k 7k 8k 9k 10k

5k

1051/53 G08

90

80

70

60

50

40

30

20

10

OUTPUT SIGNAL TO ALIAS SIGNAL(S) RATIO (dB)

1

INVERTING CLOSED-LOOP GAIN

VS = ±5V

≤10kHz

f

IN

1051/53 G09

10010

Figure 8. Output Voltage Swing vs Load Figure 9. Signal to Alias Ratio vs

Closed-Loop Gain

10

10513fa

TYPICAL APPLICATIO S

LTC1051/LTC1053

U

Obtaining Ultralow VOS Drift and Low Noise

The dual chopper op amp buffers the inputs of A1 and corrects its offset voltage and offset voltage drift. With the R, C values shown, the power-up warm up time is typically 20 seconds. The step response of the composite amplifier

B

+

5

OUT

+

1/2

LTC1051

R4

6

–

R5

R3

7

C1

C2

1051/53 AC01a

2

–

1/2

LTC1051

3

+

3

+

2

–

A

1

5V

R2

R1

1

8

6

A1

does not present settling tails. The LT1007 should be used when extremely low noise; VOS and VOS drift are sought when the input source resistance is low—for instance a 350Ω strain gauge bridge. The LT1012 or equivalent should be used when low bias current (100pA) is also

OUT

required in conjunction with DC to 10Hz low noise and low

and VOS drift. The measured typical input offset

V

OS

voltages were less than 2µV.

A1 R1 R2 R3 R4 R5 C1 C2 e

LT1007 3k 2k 340k 10k 100k 0.01µF 0.001µF 0.1µV

LT1012* 750Ω 57Ω 250k 10k 100k 0.01µF 0.001µF 0.3µV

* Interchange connections A and B .

** Noise measured in a 10 sec window. Peak-to-peak noise was also measured for 10 continuous minutes: With the LT1007 op amp the recorded noise was less than 0.2µV

and DC-10Hz.

(DC – 1Hz)** e

OUT

P-P

(DC – 10Hz)**

OUT

0.15µV

LTC1051/LT1007 Peak-to-Peak Noise

VS = ±5V

0.2µV/DIV

1 SEC/DIV

DC TO 1Hz

NOISE

DC TO 10Hz

NOISE

1051/53 AC01b

P-P

0.4µV

P-P

for both DC-1Hz

P-P

10513fa

11

LTC1051/LTC1053

+

–

+

1/4

LTC1053

+

–

1/4

LTC1053

+

–

1/4

LTC1053

1/4

LTC1053

9

10

12

13

2

3

5

6

7

1

14

10k

10k 10k

10k

20k

10k

8

4

11

0.1µF

5V

–5V

I

OUT

R

LOAD

1051/53 AC03

20k

10k 10k

R

G

V1

V2

• I

OUT

= 2(V2 – V1)/R

G

• BW = 100Hz

•

IOUTMAX

= 1mA

TYPICAL APPLICATIO S

Paralleling Choppers to Improve Noise Differential Voltage to Current Converter

R2

R1

V

IN

2

–

1/4

LTC1053

3

+

R2

R1

6

–

1/4

LTC1053

5

+

R2

R1

9

–

1/4

LTC1053

10

+

NOTE: THIS CIRCUIT CAN ALSO BE USED AS A DIFFERENCE AMPLIFIER FOR STRAIN GAUGES. CONNECT R2/3 AND R1/3 FROM NONINVERTING INPUTS, SHORTED TOGETHER, TO GROUND AND TO SOURCE RESPECTIVELY.

RR

1

R

7

R

8

V

= 3(R2/R1); INPUT DC – 10Hz NOISE

OUT/VIN

= NOISE OF EACH PARALLELED OP AMP/√3

≅ 0.8µV

P-P

U

5V

0.1µF

4

13

–

LTC1053

12

+

1/4

–5V

14

V

OUT

11

0.1µF

1051/53 AC02

12

Multiplexed Differential Thermometer

100Ω

1k

TYPE K

+–

0.1µF

100Ω

–

TYPE K

1k

+–

0.1µF

100Ω

+

0.1µF

5V

2

7

K

LT1025A

–

GND

R

4

5

255k

0.068µF

2

–

LTC1053

3

+

6

–

LTC1053

5

+

9

–

LTC1053

10

+

1/4

255k

0.068µF

1/4

255k

0.068µF

1/4

1

T2

7

T1

8

ABSOLUTE TEMPERATURE

10k

5V

10k

13

10k

4

–

1/4

14

LTC1053

12

+

11

– T1 OR T

REF

OUTPUT (DIFFERENTIAL TEMPERATURE)

– T2(10mV PER °C)

REF

1051/53 AC04

10513fa

S1

10k

T

REF

ALL FIXED RESISTORS ARE 1% METAL FILM OUTPUT = T ACCURACY = (±0.1% FROM 25°C TO 150°C)

–

+

1/2

LTC1051

3

2

1

1k

0.22µF

100k

5V

V

OUT1

V

OUT2

1µF

–

+

1/2

LTC1051

5

6

7

4

8

1k

0.22µF

0.0047µF

100k

1µF

8

7

11

12

1413

1µF

5

6

2

3

17

1518

416

–

+

–

+

INPUT 1

INPUT 2

GAIN = 101V/DIV

CMRR >100dB V

OS

≅ 3µV

INPUT REFERRED NOISE ≅ 2µV

P-P

1051/53 AC06

LTC1043

TYPICAL APPLICATIO S

Six Decade Log Amplifier

LTC1051/LTC1053

U

Dual Instrumentation Amplifier

10k

0.1%

V

IN

1nA < IIN <1mA

Q1: TEL LAB TYPE Q81 ADJUST 2M POR. FOR NONLINEARITIES

2

3

–

1/2

LTC1051

+

V

OUT =

Q1 Q10.0022µF 22pF

3k

0.1%

15.8k

0.1%

1

LOG V

–2V

IN

3

2

1k

0.1%

+

–

2M

1/2

LTC1051

0.1µF

1N4148

5V

2.5V

0.1µF

7

1/2

LTC1051

4

–5V

2.5M

8

0.1%

–

6

+

5

LT1009

1051/53 AC05

Linearized Platinum Signal Conditioner

250k*

8

1

4

10k*

274k*

50k ZERO ADJUST

8.25k*

2.4k

LT1009

2.5V

5V

(LINEARITY CORRECTION LOOP)

2k

7

1µF

RP = ROSEMOUNT 118MFRTD *1% FILM RESISTOR TRIM SEQUENCE:

1/2 LTC1043

SET SENSOR TO 0°C VALUE. ADJUST ZERO FOR 0V OUT SET SENSOR TO 100°C VALUE. ADJUST GAIN FOR 1.000V OUT SET SENSOR TO 400°C VALUE. ADJUST LINEARITY FOR 4.000V OUT REPEAT AS REQUIRED. FOR MORE INFORMATION REFER TO AN3

8

11

12

1µF

887Ω

1413

R

P

I

100Ω

K

AT 0°C

5

15

1/2 LTC1043

4

2

3

0.01µF

1µF

0V TO 4V =

GAIN

ADJUST

8.06k*

0°C TO 400°C

±0.05°C

7

1k

5k

1k

1051/53 AC07

10513fa

1µF

5

6

+

LTC1051

–

1/2

6

18

1716

13

LTC1051/LTC1053

PACKAGE DESCRIPTIO

.300 BSC

(7.62 BSC)

.008 – .018

(0.203 – 0.457)

NOTE: LEAD DIMENSIONS APPLY TO SOLDER

DIP/PLATE OR TIN PLATE LEADS

0° – 15°

(1.143 – 1.650)

CORNER LEADS OPTION

.045 – .068

FULL LEAD

OPTION

U

J Package

8-Lead CERDIP (Narrow 0.300, Hermetic)

(LTC DWG # 05-08-1110)

(4 PLCS)

.023 – .045

(0.584 – 1.143)

HALF LEAD

OPTION

.045 – .065

(1.143 – 1.651)

.014 – .026

(0.360 – 0.660)

N Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

.015 – .060

(0.381 – 1.524)

.100

(2.54)

BSC

.405

.200

(5.080)

MAX

.125

3.175 MIN

.005

(0.127)

MIN

.025

(0.635)

RAD TYP

(10.287)

MAX

87

12

65

3

4

OBSOLETE PACKAGE

.220 – .310

(5.588 – 7.874)

J8 0801

.255 ± .015*

(6.477 ± 0.381)

.300 – .325

(7.620 – 8.255)

.065

(1.651)

.008 – .015

(0.203 – 0.381)

+.035

.325

–.015 +0.889

8.255

()

–0.381

TYP

NOTE:

1. DIMENSIONS ARE

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)

.045 – .065

(1.143 – 1.651)

.100

(2.54)

BSC

INCHES

MILLIMETERS

14-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

.770*

(19.558)

MAX

14

2

11

1213

31

5

4

8910

7

6

(7.620 – 8.255)

(0.203 – 0.381)

8.255

()

NOTE:

1. DIMENSIONS ARE

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)

N Package

.300 – .325

.008 – .015

+.035

.325

–.015

+0.889 –0.381

.018 ± .003

(0.457 ± 0.076)

INCHES

MILLIMETERS

.130 ± .005

(3.302 ± 0.127)

.120

(3.048)

MIN

(0.508)

(3.302 ± 0.127)

.020

(0.508)

MIN

.020

MIN

N8 1002

.130 ± .005

.120

(3.048)

MIN

.255 ± .015*

(6.477 ± 0.381)

.400*

(10.160)

MAX

87 6

1234

(1.143 – 1.651)

.005

(0.125)

.100

MIN

(2.54)

BSC

.045 – .065

5

.065

(1.651)

TYP

.018 ± .003

(0.457 ± 0.076)

N14 1002

14

10513fa

PACKAGE DESCRIPTIO

.030 ±.005

TYP

N

.420 MIN

U

SW Package

16-Lead Plastic Small Outline (Wide 0.300)

(LTC DWG # 05-08-1620)

.050 BSC

.045 ±.005

.325

±.005

16

N

NOTE 3

.398 – .413

(10.109 – 10.490)

NOTE 4

15 1413121110 9

LTC1051/LTC1053

.394 – .419

(10.007 – 10.643)

.005

(0.127)

RAD MIN

.009 – .013

(0.229 – 0.330)

.030 ±.005

TYP

.420 MIN

.005

(0.127)

RAD MIN

123 N/2

RECOMMENDED SOLDER PAD LAYOUT

.291 – .299

(7.391 – 7.595)

NOTE 4

.010 – .029

(0.254 – 0.737)

NOTE 3

× 45°

.016 – .050

(0.406 – 1.270)

18-Lead Plastic Small Outline (Wide 0.300)

.050 BSC

N

123 N/2

RECOMMENDED SOLDER PAD LAYOUT

.291 – .299

(7.391 – 7.595)

NOTE 4

.010 – .029

(0.254 – 0.737)

× 45°

.093 – .104

(2.362 – 2.642)

0° – 8° TYP

SW Package

(LTC DWG # 05-08-1620)

.045 ±.005

.093 – .104

(2.362 – 2.642)

N

1

.325 ±.005

NOTE 3

0° – 8° TYP

1

.050

(1.270)

BSC

.014 – .019

(0.356 – 0.482)

16

1718

2345

TYP

.447 – .463

(11.354 – 11.760)

NOTE 4

14 131211

15

6

78

N/2

78

(0.940 – 1.143)

10

N/2

9

.037 – .045

(0.940 – 1.143)

.037 – .045

.004 – .012

(0.102 – 0.305)

.394 – .419

(10.007 – 10.643)

NOTE:

1. DIMENSIONS IN

2. DRAWING NOT TO SCALE

3. 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

4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)

S16 (WIDE) 0502

NOTE:

1. DIMENSIONS IN

2. DRAWING NOT TO SCALE

3. 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

4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)

INCHES

(MILLIMETERS)

INCHES

(MILLIMETERS)

.009 – .013

(0.229 – 0.330)

.050

(1.270)

NOTE 3

.016 – .050

(0.406 – 1.270)

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 represen-

BSC

(0.356 – 0.482)

.014 – .019

TYP

.004 – .012

(0.102 – 0.305)

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

S18 (WIDE) 0502

10513fa

15

LTC1051/LTC1053

U

TYPICAL APPLICATIO S

DC Accurate, 3rd Order, 100Hz, Butterworth Antialiasing Filter Dynamic Range

C1

0.1µF

0.1

60dB

R1

16.5kR2118kR321k

V

IN

C

0.1µF

WIDEBAND NOISE 9µV THD + NOISE ≅ 0.0012%, 1V

(OUT) < 5µV

V

OS

RMS

0.1µF

RMS

C2

< VIN < 2V

2

3

RMS

8V

+

1/2

LTC1051

–

–8V

, VS = ±8V

0.1µF

1

V

OUT

1051/53 AC08

0.01

THD + NOISE (%)

0.001

0.0001

0.1 1.0 5.0 VIN (V

), fIN = 30Hz

RMS

DC Accurate, 18-Bit, 4th Order Antialiasing Bessel (Linear Phase), 100Hz, Lowpass Filter Dynamic Range

0.1

0.01

THD + NOISE (%)

0.001

VS = ±8V

V

IN

R1A

10k

0.22µF

R2A

10k

C1A

0.022µF

R3A

26.7k

–

1/2

CA

LTC1051

+

0.022µF

R1B

50k

CB

R3B

412k

R2B

50k

0.0022µF

–

1/2

LTC1051

+

C1B

V

OUT

VS = ±5V

VS = ±8V

1051/53 AC09

80dB

100dB

120dB

60dB

80dB

100dB

WIDEBAND RMS NOISE 4.5µV THD + NOISE ≅ 0.0005% (= 106dB DYNAMIC RANGE), 2V VOS OUT < 10µV

RMS

≤ VIN ≤ 3V

RMS

1051/53 AC10

0.0001

0.1 1.0 5.0 VIN (V

), fIN = 30Hz

RMS

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LTC1047 Dual µPower Zero-Drift 0p Amp IS = 80µA/0p Amp, 16-Lead SW Package

LTC1049 Low Power Zero-Drift 0p Amp IS = 200µA, SO-8 Package

LTC1050 Precision Zero-Drift Op Amp with Internal VOS (Max) = 5µV, V

Capacitors

LTC2050/LTC2051/LTC2052 Single/Dual/Quad Zero-Drift 0p Amps SOT-23/MS8/GN16 Packages

LTC2053 Zero-Drift Instrumentation Amp Resistor Programmable Gain, R-R

Linear Technology Corporation

16

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear.com

SUPPLY

(Max) = 16.5V

LW/TP 1202 1K REV A • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1990

120dB

1051/53 AC11

10513fa

Datasheet LTC1051, LTC1053 Datasheet (LINEAR TECHNOLOGY)

Specifications and Main Features

Frequently Asked Questions

User Manual