LINEAR TECHNOLOGY LT1677 Technical data

FEATURES

■

Rail-to-Rail Input and Output

■

100% Tested Low Voltage Noise:

3.2nV/√Hz Typ at 1kHz

4.5nV/√Hz Max at 1kHz

■

Offset Voltage: 60µV Max

■

Low VOS Drift: 0.2µV/°C Typ

■

Low Input Bias Current: 20nA Max

■

Wide Supply Range: 3V to ±18V

■

High A

■

High CMRR: 109dB Min

■

High PSRR: 108dB Min

■

Gain Bandwidth Product: 7.2MHz

■

Slew Rate: 2.5V/µs

■

Operating Temperature Range: –40°C to 85°C

: 7V/µV Min, RL = 10k

VOL

U

APPLICATIO S

■

Low Noise Signal Processing

■

Microvolt Accuracy Threshold Detection

■

Strain Gauge Amplifiers

■

Tape Head Preamplifiers

■

Direct Coupled Audio Gain Stages

■

Infrared Detectors

■

Battery-Powered Microphones

LT1677

Low Noise, Rail-to-Rail

Precision Op Amp

U

DESCRIPTIO

The LT®1677 features the lowest noise performance avail­able for a rail-to-rail operational amplifier: 3.2nV/√Hz
wideband noise, 1/f corner frequency of 13Hz and 90nV
peak-to-peak 0.1Hz to 10Hz noise. Low noise is combined
with outstanding precision: 20µV offset voltage and

0.2µV/°C drift, 130dB common mode and power supply
rejection and 7.2MHz gain bandwidth product. The com­mon mode range exceeds the power supply by 100mV.

The voltage gain of the LT1677 is extremely high, 19 million
(typical) driving a 10k load.

In the design, processing and testing of the device, particular
attention has been paid to the optimization of the entire
distribution of several key parameters. Consequently, the
specifications have been spectacularly improved compared
to competing rail-to-rail amplifiers.

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

All other trademarks are the property of their respective owners.

TYPICAL APPLICATIO

3V Electret Microphone Amplifier

= –100

A

PANASONIC

ELECTRET

CONDENSER

MICROPHONE

WM-61

www.panasonic.com/pic

[phone]

1.5V

R1

10k

C1

0.68µF

23Hz

HIGHPASS

V

R2

10k

U

Distribution of Offset Voltage

25

TA = 25°C

= ±15V

V

S

R3
1M

1.5V

–

2

3

LT1677

+

7

4

–1.5V

HEADPHONES

6

1677 TA01

TO PA

OR

20

15

10

PERCENT OF UNITS

5

0

–40

–30 –20

INPUT OFFSET VOLTAGE (µV)

0

–10 10 40

20 30

1677 TA02

1677fa

1

LT1677

TOP VIEW

S8 PACKAGE

8-LEAD PLASTIC SO

N8 PACKAGE
8-LEAD PDIP

1

2

3

4

8

7

6

5

V

OS

TRIM

V

OS

TRIM
+V

S

OUT

NC

–IN

+IN

–V

S

–

+

WWWU

ABSOLUTE AXI U RATI GS

PACKAGE/ORDER I FOR ATIO

UU

W

(Note 1)

Supply Voltage ...................................................... ± 22V

Input Voltages (Note 2) ............ 0.3V Beyond Either Rail

Differential Input Current (Note 2) ..................... ± 25mA

Output Short-Circuit Duration (Note 3) ............ Indefinite

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

T

= 150°C, θJA = 150°C/ W (N8)

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

Operating Temperature Range

LT1677C (Note 4) ............................. – 40°C to 85°C

LT1677I ............................................. – 40°C to 85°C

Specified Temperature Range

LT1677C (Note 5) ............................. – 40°C to 85°C

LT1677I ............................................. – 40°C to 85°C

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

V

OS

∆V
∆Temp

∆V
∆Time

I

B

I

OS

2

OS

OS

Input Offset Voltage (Note 11) 35 90 µV

Average Input Offset Drift (Note 10) SO-8

Long Term Input Voltage Stability 0.3 µV/Mo

Input Bias Current (Note 11) ±2 ±20 nA

Input Offset Current (Note 11) 415 nA

= 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless otherwise noted.

A

The ● denotes the specifications which apply over the full operating

≤ 70°C

0°C ≤ T

A

–40°C ≤ T

VCM = VS + 0.1V 150 400 µV

= VS – 0.2V, 0°C ≤ TA ≤ 70°C

V

CM

= VS – 0.3V, –40°C ≤ TA ≤ 85°C

V

CM

VCM = –0.1V 1.5 5.0 mV

= 0V, 0°C ≤ TA ≤ 70°C

V

CM

= 0V, –40°C ≤ TA ≤ 85°C

V

CM

N8

0°C ≤ TA ≤ 70°C
–40°C ≤ T

VCM = VS + 0.1V 0.19 0.40 µA

= VS – 0.2V, 0°C ≤ TA ≤ 70°C

V

CM

= VS – 0.3V, –40°C ≤ TA ≤ 85°C

V

CM

VCM = –0.1V –1.2 –0.41 µA

= 0V, 0°C ≤ TA ≤ 70°C

V

CM

= 0V, –40°C ≤ TA ≤ 85°C

V

CM

≤ 70°C

0°C ≤ T

A

–40°C ≤ T

VCM = VS + 0.1V 6 30 nA

= VS – 0.2V, 0°C ≤ TA ≤ 70°C

V

CM

= VS – 0.3V, –40°C ≤ TA ≤ 85°C

V

CM

VCM = –0.1V 20 100 nA

= 0V, 0°C ≤ TA ≤ 70°C

V

CM

VCM = 0V, –40°C ≤ TA ≤ 85°C

ORDER PART NUMBER

LT1677CS8
LT1677IS8
LT1677CN8
LT1677IN8

Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF

Lead Free Part Marking: http://www.linear.com/leadfree/

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

≤ 85°C

A

≤ 85°C

A

≤ 85°C

A

JMAX

= 150°C, θJA = 190°C/ W (S0-8)

T

JMAX

●

●

●

●

●

●

●

●

●

●

●

●

●

–2.0 – 0.45 µA

●

–2.3 – 0.47 µA

●

●

●

●

●

●

S8 PART MARKING

1677
1677I

55 150 µV
75 210 µV

180 550 µV
200 650 µV

1.8 6.0 mV

2.0 6.5 mV

0.40 2.0 µV/°C

0.20 1.5 µV/°C

±3 ±35 nA
±7 ±50 nA

0.19 0.60 µA

0.25 0.75 µA

520 nA
840 nA

10 40 nA
15 65 nA

25 150 nA
30 160 nA

1677fa

LT1677

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless

A

otherwise noted.

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

e

n

i

n

V

CM

R

IN

C

IN

CMRR Common Mode Rejection Ratio (Note 11) VS = 3V

PSRR Power Supply Rejection Ratio VS = 2.7V to 40V, VCM = VO = 1.7V 108 125 dB

A

VOL

Input Noise Voltage 0.1Hz to 10Hz (Note 7) 90 nV

VCM = V

S

180 nV

VCM = 0V 600 nV

P-P
P-P
P-P

Input Noise Voltage Density (Note 8) fO = 10Hz 5.2 nV/√Hz

= VS, fO = 10Hz 7 nV/√Hz

V

CM

= 0V, fO = 10Hz 25 nV/√Hz

V

CM

fO = 1kHz 3.2 4.5 nV/√Hz
V

= VS, fO = 1kHz 5.3 nV/√Hz

CM

= 0V, fO = 1kHz 17 nV/√Hz

V

CM

Input Noise Current Density fO = 10Hz 1.2 pA/√Hz

= 1kHz 0.3 pA/√Hz

f

O

Input Voltage Range –0.1 VS + 0.1V V

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0V

●

0V

S
S

– 0.2V V
– 0.3V V

Input Resistance Common Mode 2 GΩ

Input Capacitance 4.2 pF

V

= –0.1V to 3.1V 55 68 dB

CM

= 0V to 2.7V

V

CM

●

53 67 dB

VS = 5V

= –0.1V to 5.1V 60 73 dB

V

CM

V

= 0V to 4.7V

CM

= 3.1V to 40V, VCM = VO = 1.7V

V

S

●

58 72 dB

●

105 120 dB

Large-Signal Voltage Gain VS = 3V, RL ≥ 10k, VO = 2.5V to 0.7V 0.6 4 V/µV

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.4 3 V/µV

●

0.4 3 V/µV

VS = 3V, RL ≥ 2k, VO = 2.2V to 0.7V 0.5 1 V/µV
0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.4 0.9 V/µV

●

0.4 0.8 V/µV

VS = 3V, RL ≥ 600Ω, VO = 2.2V to 0.7V 0.20 0.43 V/µV
0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.15 0.40 V/µV

●

0.10 0.35 V/µV

VS = 5V, RL ≥ 10k, VO = 4.5V to 0.7V 0.8 5 V/µV
0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.7 4 V/µV

●

0.7 4 V/µV

VS = 5V, RL ≥ 2k, VO = 4.2V to 0.7V 0.40 0.9 V/µV
0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.35 0.8 V/µV

●

0.25 0.6 V/µV

VS = 5V, RL ≥ 600Ω, VO = 4.2V to 0.7V 0.35 0.67 V/µV
0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.30 0.60 V/µV

●

0.20 0.45 V/µV

1677fa

3

LT1677

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. VS = 3V, VCM = VO = 1.7V; VS = 5V, VCM = VO = 2.5V unless

A

otherwise noted.

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

V

OL

V

OH

I

SC

SR Slew Rate (Note 13) AV = –1 1.7 2.5 V/µs

GBW Gain Bandwidth Product (Note 11) fO = 100kHz 4.5 7.2 MHz

t

S

R

O

I

S

Output Voltage Swing Low (Note 11) Above GND

= 0.1mA 110 170 mV

I

SINK

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

●

125 200 mV
130 230 mV

Above GND
I

= 2.5mA 170 250 mV

SINK

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

●

195 320 mV
205 350 mV

Above GND
I

= 10mA 370 500 mV

SINK

0°C ≤ T
–40°C ≤ T

Output Voltage Swing High (Note 11) Below V

I

SOURCE

0°C ≤ T
–40°C ≤ T

Below V
I

SOURCE

0°C ≤ T
–40°C ≤ T

Below V
I

SOURCE

0°C ≤ T
–40°C ≤ T

≤ 70°C

A

≤ 85°C

A

S

= 0.1mA 75 170 mV

≤ 70°C

A

≤ 85°C

A

S

= 2.5mA 170 300 mV

≤ 70°C

A

≤ 85°C

A

S

= 10mA 450 700 mV

≤ 70°C

A

≤ 85°C

A

●

●

●

●

●

●

●

●

440 600 mV
465 650 mV

85 200 mV
93 250 mV

195 350 mV
205 375 mV

510 800 mV
525 850 mV

Output Short-Circuit Current (Note 3) VS = 3V 15 22 mA

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

14 20 mA

●

13 19 mA

VS = 5V 20 29 mA

≤ 70°C

0°C ≤ T

A

–40°C ≤ T

R

≥ 10k, 0°C ≤ TA ≤ 70°C

L

≥ 10k, –40°C ≤ TA ≤ 85°C

R

L

= 100kHz, 0°C ≤ TA ≤ 70°C

f

O

f

= 100kHz, –40°C ≤ TA ≤ 85°C

O

≤ 85°C

A

●

18 27 mA

●

17 25 mA

●

1.5 2.3 V/µs

●

1.2 2.0 V/µs

●

3.8 6.2 MHz

●

3.7 5.8 MHz

Settling Time 2V Step 0.1%, AV = +1 2.1 µs

Open-Loop Output Resistance I
Closed-Loop Output Resistance A

2V Step 0.01%, A

= 0 80 Ω

OUT

= 100, f = 10kHz 1 Ω

V

= +1 3.5 µs

V

Supply Current (Note 12) 2.60 3.4 mA

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

●

2.75 3.7 mA

2.80 3.8 mA

4

1677fa

LT1677

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. VS = ±15V, VCM = VO = 0V unless otherwise noted.

A

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

V

OS

Input Offset Voltage 20 60 µV

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

●

30 120 µV
45 180 µV

VCM = 15.1V 150 400 µV

= 14.8V, 0°C ≤ TA ≤ 70°C

V

CM

= 14.7V, –40°C ≤ TA ≤ 85°C

V

CM

●

●

180 550 µV
200 650 µV

VCM = –15.1V 1.5 5.0 mV
V

∆V

OS

∆Temp
∆V

OS

= –15V, 0°C ≤ TA ≤ 70°C

CM

= –15V, – 40°C ≤ TA ≤ 85°C

V

CM

Average Input Offset Drift (Note 10) SO-8

N8

Long Term Input Voltage Stability 0.3 µV/Mo

●

●

●

●

1.8 6.0 mV

2.0 6.5 mV

0.40 2.0 µV/°C

0.20 1.5 µV/°C

∆Time

I

B

Input Bias Current ±2 ± 20 nA

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

●

±3 ±35 nA
±7 ±50 nA

VCM = 15.1V 0.19 0.40 µA

= 14.8V, 0°C ≤ TA ≤ 70°C

V

CM

V

= 14.7V, –40°C ≤ TA ≤ 85°C

CM

●

●

0.20 0.60 µA

0.25 0.75 µA

VCM = –15.1V –1.2 – 0.42 µA
V

= –15V, 0°C ≤ TA ≤ 70°C

CM

= –15V, – 40°C ≤ TA ≤ 85°C

V

CM

I

OS

Input Offset Current 315 nA

≤ 70°C

0°C ≤ T

A

–40°C ≤ T

≤ 85°C

A

●

–2.0 – 0.46 µA

●

–2.3 – 0.48 µA

●

●

520 nA
840 nA

VCM = 15.1V 5 25 nA

= 14.8V, 0°C ≤ TA ≤ 70°C

V

CM

= 14.7V, –40°C ≤ TA ≤ 85°C

V

CM

●

●

835 nA

12 60 nA

VCM = –15.1V 20 105 nA
V

= –15V, 0°C ≤ TA ≤ 70°C

CM

= –15V, – 40°C ≤ TA ≤ 85°C

V

CM

e

n

Input Noise Voltage 0.1Hz to 10Hz (Note 7) 90 nV

VCM = 15V 180 nV
VCM = –15V 600 nV

●

●

25 160 nA
30 170 nA

P-P
P-P
P-P

Input Noise Voltage Density fO = 10Hz 5.2 nV/√Hz

V

= 15V, fO = 10Hz 7 nV/√Hz

CM

= –15V, fO = 10Hz 25 nV/√Hz

V

CM

fO = 1kHz 3.2 4.5 nV/√Hz

= 15V, fO = 1kHz 5.3 nV/√Hz

V

CM

V

= –15V, fO = 1kHz 17 nV/√Hz

CM

i

n

V

CM

R

IN

C

IN

Input Noise Current Density fO = 10Hz 1.2 pA/√Hz

= 1kHz 0.3 pA/√Hz

f

O

Input Voltage Range – 15.1 15.1 V

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

– 15.0 14.8 V

●

– 15.0 14.7 V

Input Resistance Common Mode 2 GΩ

Input Capacitance 4.2 pF

1677fa

5

LT1677

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. VS = ± 15V, VCM = VO = 0V unless otherwise noted.

A

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

CMRR Common Mode Rejection Ratio VCM = –13.3V to 14V 109 130 dB

●

105 124 dB

VCM = –15.1V to 15.1V 74 95 dB

= –15V to 14.7V

V

CM

●

72 91 dB

PSRR Power Supply Rejection Ratio VS = ±1.7V to ±18V 106 130 dB

●

103 125 dB

VS = 2.7V to 40V 108 125 dB

= 3.1V to 40V

V

S

A

VOL

Large-Signal Voltage Gain RL ≥ 10k, VO = ±14V 7 19 V/µV

≤ 70°C

0°C ≤ T

A

–40°C ≤ T

≤ 85°C

A

●

105 120 dB

●

413 V/µV

●

38 V/µV

RL ≥ 2k, VO = ±13.5V 0.50 0.75 V/µV
0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

0.30 0.67 V/µV

●

0.15 0.24 V/µV

RL ≥ 600Ω, VO = ±10V 0.2 0.5 V/µV

V

OL

V

OH

I

SC

Output Voltage Swing Low Above –V

I
0°C ≤ T
–40°C ≤ T

Above –V
I
0°C ≤ T
–40°C ≤ T

Above –V
I
0°C ≤ T
–40°C ≤ T

Output Voltage Swing High Below +V

I
0°C ≤ T
–40°C ≤ T

Below +V
I
0°C ≤ T
–40°C ≤ T

Below +V
I
0°C ≤ T
–40°C ≤ T

S

= 0.1mA 110 170 mV

SINK

≤ 70°C

A

≤ 85°C

A

S

= 2.5mA 170 250 mV

SINK

≤ 70°C

A

≤ 85°C

A

S

= 10mA 370 500 mV

SINK

≤ 70°C

A

≤ 85°C

A

S

= 0.1mA 110 170 mV

SOURCE

≤ 70°C

A

≤ 85°C

A

S

= 2.5mA 210 300 mV

SOURCE

≤ 70°C

A

≤ 85°C

A

S

= 10mA 520 700 mV

SOURCE

≤ 70°C

A

≤ 85°C

A

●

●

●

●

●

●

●

●

●

●

●

●

125 200 mV
130 230 mV

195 320 mV
205 350 mV

440 600 mV
450 650 mV

130 200 mV
140 250 mV

240 350 mV
250 375 mV

590 800 mV
620 850 mV

Output Short-Circuit Current (Note 3) 25 35 mA

0°C ≤ T

A

–40°C ≤ T

≤ 70°C

≤ 85°C

A

●

20 30 mA

●

18 28 mA

SR Slew Rate RL ≥ 10k (Note 9) 1.7 2.5 V/µs

≥ 10k (Note 9) 0°C ≤ TA ≤ 70°C

R

L

R

≥ 10k (Note 9) –40°C ≤ TA ≤ 85°C

L

●

1.5 2.3 V/µs

●

1.2 2.0 V/µs

GBW Gain Bandwidth Product fO = 100kHz 4.5 7.2 MHz

= 100kHz, 0°C ≤ TA ≤ 70°C

f

O

= 100kHz, –40°C ≤ TA ≤ 85°C

f

O

●

3.8 6.2 MHz

●

3.7 5.8 MHz

6

1677fa

LT1677

TIME (SECONDS)

VOLTAGE NOISE (20nV/DIV)

20 40 60 80

1677 G04

1000

ELECTRICAL CHARACTERISTICS

temperature range, otherwise specifications are at T

The ● denotes the specifications which apply over the full operating

= 25°C. VS = ± 15V, VCM = VO = 0V unless otherwise noted.

A

SYMBOL PARAMETER CONDITIONS (Note 6) MIN TYP MAX UNITS

THD Total Harmonic Distortion RL = 2k, AV = 1, fO = 1kHz, VO = 10V

t

S

R

O

I

S

Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.

Note 2: The inputs are protected by back-to-back diodes. Current limiting
resistors are not used in order to achieve low noise. If differential input
voltage exceeds ±1.4V, the input current should be limited to 25mA. If the
common mode range exceeds either rail, the input current should be
limited to 10mA.

Note 3: A heat sink may be required to keep the junction temperature
below absolute maximum.

Note 4: The LT1677C and LT1677I are guaranteed functional over the
Operating Temperature Range of –40°C to 85°C.

Note 5: The LT1677C is guaranteed to meet specified performance from
0°C to 70°C. The LT1677C is designed, characterized and expected to
meet specified performance from –40°C to 85°C but is not tested or QA
sampled at these temperatures. The LT1677I is guaranteed to meet
specified performance from – 40°C to 85°C.

Settling Time 10V Step 0.1%, AV = +1 5 µs

= +1 6 µs

V

Open-Loop Output Resistance I
Closed-Loop Output Resistance A

10V Step 0.01%, A

= 0 80 Ω

OUT

= 100, f = 10kHz 1 Ω

V

Supply Current 2.75 3.5 mA

0°C ≤ T

≤ 70°C

A

–40°C ≤ T

≤ 85°C

A

Note 6: Typical parameters are defined as the 60% yield of parameter
distributions of individual amplifier; i.e., out of 100 LT1677s, typically 60
op amps will be better than the indicated specification.

Note 7: See the test circuit and frequency response curve for 0.1Hz to
10Hz tester in the Applications Information section of the LT1677 data
sheet.

Note 8: Noise is 100% tested at ±15V supplies.
Note 9: Slew rate is measured in A

measured at ±2.5V.
Note 10: This parameter is not 100% tested. V

guaranteed by correlation to V
Note 11: V

= ±15V tests.

V

S

Note 12: V

= ±15V tests.

V

S

= 5V limits are guaranteed by correlation to VS = 3V and

S

= 3V limits are guaranteed by correlation to VS = 5V and

S

Note 13: Guaranteed by correlation to slew rate at V

= 3V and VS = ±15V tests.

V

S

P-P

●

●

V

= ±15V test.

S

0.0006 %

3.00 3.9 mA

3.10 4.0 mA

= –1; input signal is ±7.5V, output

= 3V and 5V limits are

S

= ±15V and GBW at

S

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Voltage Noise vs Frequency

100

10

–13.5V TO 14.5V

1/f CORNER 13Hz

= ±15V

V

S

RMS VOLTAGE NOISE DENSITY (nV/√Hz)

= 25°C

T

A

1

0.1

1/f CORNER 10Hz

VCM < –14.5V

1/f CORNER 8.5Hz

V

CM

FREQUENCY (Hz)

V

CM

10 1 100 1000

> 14.5V

1677 G01

0.1Hz to 10Hz Voltage Noise

VOLTAGE NOISE (20nV/DIV)

2468

TIME (SECONDS)

0.01Hz to 1Hz Voltage Noise

100

1677 G03

1677fa

7

LT1677

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Voltage Noise vs Temperature

7

VS = ±15V

= 0V

V

CM

RMS VOLTAGE NOISE DENSITY (nV/√Hz)

6

5

4

3

2

–50

–25

0

TEMPERATURE (°C)

10Hz

1kHz

50

25

100

125

1677 G08

75

Current Noise vs Frequency

10

VS = ±15V

= 25°C

T

A

VCM < –13.5V

1

1/f CORNER 90Hz

RMS CURRENT NOISE DENSITY (pA/√Hz)

1/f CORNER 60Hz

0.1
10

100 1000 10000

FREQUENCY (Hz)

1/f CORNER 180Hz

V

CM

–13.5V TO 14.5V

VCM > 14.5V

1677 G07

Input Bias Current
vs Temperature

10

VS = ±15V

9

= 0V

V

CM

8

7

6

5

4

3

INPUT BIAS CURRENT (nA)

2

1

0

–50

–25

0

TEMPERATURE (°C)

50

25

75

100

125

1677 G05

Input Bias Current
vs Temperature

600

VS = ±15V

500

400

300

INPUT BIAS CURRENT (nA)

200

100

–50

CURRENT OUT OF DUT

VCM = 14.7V
CURRENT INTO DUT

0

–25

TEMPERATURE (°C)

Warm-Up Drift

10

VS = ±15V

= 25°C

T

A

8

6

4

2

CHANGE IN OFFSET VOLTAGE (µV)

0

1

0

TIME (MINUTES)

Input Bias Current Over the
Common Mode Range

800

VS = ±15V

= 25°C

T

A

= –14V

V

CM

50

25

75

100

1677 G06

600

400

200

0

–200

–400

INPUT BIAS CURRENT (nA)

–600

–800

125

–16

VCM = –13.6V

INPUT BIAS CURRENT

VCM = –15.3V

–12

–8

–4

COMMON MODE INPUT VOLTAGE (V)

VCM = 15.15V

VCM = 14.3V

0

4

8

12

1677 G09

16

Distribution of Input Offset
Voltage Drift (N8)

50

45

40

SO PACKAGE

N PACKAGE

3

4

2

5

1677 G02

35

30

25

20

15

PERCENT OF UNITS (%)

10

5

0

–0.6 –0.2 0.2 0.6 1.0 1.4

–1.0

INPUT OFFSET VOLTAGE DRIFT (µV/°C)

VS = ±15V

= –40°C TO 85°C

T

A

167 PARTS (4 LOTS)

1677 G13

Offset Voltage Shift
vs Common Mode

2.5

2.0

1.5

1.0

0.5

0

–0.5

–1.0

OFFSET VOLTAGE (mV)

–1.5

–2.0

–2.5

–1.0

VCM – V– (V) VCM – V+ (V)

–

V

VOS IS REFERRED

1.0

Distribution of Input Offset
Voltage Drift (SO-8)

30

25

20

15

10

PERCENT OF UNITS (%)

5

0

–0.8

–0.4

INPUT OFFSET VOLTAGE DRIFT (µV/°C)

= 0V

TO V

CM

VS = ±1.5V TO ± 15V

= 25°C

T

A

5 TYPICAL PARTS

2.0

–0.8

–0.4

0 0.4 0.8 1.2

250

200

150

100

50

0

–50

–100

–150

–200

–250

+

0.4

V

1677 G10

VS = ±15V

= –40°C TO 85°C

T

A

201 PARTS (5 LOTS)

1.6 2.0

1677 G37

OFFSET VOLTAGE (µV)

8

1677fa

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LT1677

VOS vs Temperature of
Representative Units

140

VS = ±15V

VOLTAGE OFFSET (µV)

120

100

–20

–40

–60

–80

= 0V

V

CM

SO-8
N8

80

60

40

20

0

–55

–35 –15 5 25 45 65 85 105 125

TEMPERATURE (°C)

4

3

2

SUPPLY CURRENT (mA)

1

0

TA = 125°C

= 25°C

T

A

TA = –55°C

±5 ± 10 ± 15 ± 20

SUPPLY VOLTAGE (V)

1677 G11

1677 G15

Common Mode Range
vs Temperature

2.5

2.0

1.5

1.0

0.5

–0.5

–1.0

OFFSET VOLTAGE (mV)

–1.5

–2.0

–2.5

0

–1.0

125°C

–55°C

VOS IS REFERRED

–

V

VCM – V

TO V

1.0

–

(V) VCM – V

S

25°C

CM

2.0

= 0V

–0.8

VS = ±2.5V TO ± 15V

125°C

–0.4

Common Mode Rejection Ratio
vs Frequency

160

140

120

100

80

60

40

20

COMMON MODE REJECTION RATIO (dB)

0

1k 100k 1M 10M

10k

FREQUENCY (Hz)

S

+

25°C

V

(V)

–55°C

+

0.4

1677 G12

VS = ±15V
T

A

V

CM

= 25°C

= 0V

1677 G16

250

200

150

100

50

0

–50

–100

–150

–200

–250

Long-Term Stability of Four
Representative Units

5

4

OFFSET VOLTAGE CHANGE (µV)

3

2

1

0

–1

–2

–3

–4

–5

0

100 300

200

OFFSET VOLTAGE (µV)

Power Supply Rejection Ratio
vs FrequencySupply Current vs Supply Voltage

160

140

120

100

80

POSITIVE SUPPLY

60

40

20

POWER SUPPLY REJECTION RATIO (dB)

0

10 100 10k

1

FREQUENCY (Hz)

500 900

600

400

TIME (HOURS)

NEGATIVE SUPPLY

1k

700

800

1677 G14

VS = ±15V

= 25°C

T

A

100k

1677 G17

1M

Voltage Gain vs Frequency

180

140

VCM = 0V

V

= V

CM

1

100

FREQUENCY (Hz)

EE

VOLTAGE GAIN (dB)

100

–20

60

20

0.01

10k

VCM = V

VS = ±15V

= 25°C

T

A

CC

1M

1677 G18

100M

Voltage Gain vs Supply Voltage
(Single Supply)

100

TA = 25°C

TO GND

R

L

: VO = VS/2

V

CM

10

1

OPEN LOOP VOLTAGE GAIN (V/µV)

0.1

0

RL = 10k

RL = 2k

10 20 30

SUPPLY VOLTAGE (V)

1677 G19

Overshoot vs Load Capacitance

60

VS = ±15V

= 25°C

T

A

= 10k TO 2k

R

50

L

40

30

OVERSHOOT (%)

20

10

0

10

100 1000

CAPACITANCE (pF)

RISING

EDGE

FALLING

EDGE

1677 G21

1677fa

9

LT1677

FREQUENCY (MHz)

0.1

–10

VOLTAGE GAIN (dB)

30

40

50

1 10 100

1677 G34

20

10

0

–20

PHASE SHIFT (DEG)

60

80

100

40

20

0

VS = ±15V
V

CM

= 0V

C

L

= 10pF

125°C
25°C
–55°C

GAIN PHASE

UW

TYPICAL PERFOR A CE CHARACTERISTICS

PM, GBWP, SR vs Temperature

70

PHASE

60

50

GBW

3

2

SLEW RATE (V/µs) PHASE MARGIN (DEG)

1

–50

–25

SLEW

50

25

0

TEMPERATURE (°C)

Settling Time vs Output Step
(Inverting)

12

10

8

6

0.01% OF

FULL SCALE

0.1% OF

FULL SCALE

5k

V

IN

0.01% OF

FULL SCALE

= ±15V

V

S

= 15pF

C

L

GAIN BANDWIDTH PRODUCT, f

Large-Signal Transient Response

10V

Small-Signal Transient Response

50mV

8

7

0

6

5

4

100

125

1677 G22

75

–10V

O

= 100kHz (MHz)

= –1 5µs/DIV

A

VCL

V

= ±15V

S

–50mV

A

= 1 0.5µs/DIV

VCL

= ±15V

V

S

C

= 15pF

L

Settling Time vs Output Step
(Noninverting)

12

= ±15V

V

5k

–

V

+

OUT

S

= 1

A

V

10

= 25°C

T

A

V

IN

8

0.01% OF

FULL SCALE

6

2k

–

2k

+

0.01% OF

FULL SCALE

V

RL = 1k

OUT

Gain, Phase Shift vs Frequency

SETTLING TIME (µs)

50

40

30

20

10

VOLTAGE GAIN (dB)

–10

4

= ±15V

V

S

2

= –1

A

V

= 25°C

T

A

0

–6 –2 2 6

FULL SCALE

OUTPUT STEP (V)

Gain, Phase Shift vs Frequency

VS = ±15V

= 14.7V

V

CM

= 10pF

C

L

125°C
25°C
–55°C

GAIN PHASE

0

0.1

1 10 100

FREQUENCY (MHz)

0.1% OF

10–8–10 –4 0 4 8

1677 G25

100

80

PHASE SHIFT (DEG)

60

40

20

0

–20

1677 G35

4

SETTLING TIME (µs)

0.1% OF

FULL SCALE

2

0

–6 –2 2 6

OUTPUT STEP (V)

Gain, Phase Shift vs Frequency

50

40

30

20

GAIN

10

VOLTAGE GAIN (dB)

0

–10

0.1

PHASE

1 10 100

FREQUENCY (MHz)

0.1% OF

FULL SCALE

1677 G26

VS = ±15V

= –14V

V

CM

= 10pF

C

L

125°C
25°C
–55°C

1677 G36

10–8–10 –4 0 4 8

100

80

PHASE SHIFT (DEG)

60

40

20

0

–20

Output Voltage Swing
vs Load Current

– 0

+V

S

VS = ±15V

–0.1
–0.2
–0.3
–0.4
–0.5

–0.6
–0.7

0.5
125°C

0.4

25°C

0.3

OUTPUT VOLTAGE SWING (V)

0.2

–55°C

0.1

–V

+ 0

S

–8

–6

–10

–4

I

SINK

OUTPUT CURRENT (mA)

–55°C

25°C

125°C

0

2

4

6

8

–2

I

SOURCE

10

1677 G27

10

1677fa

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Closed-Loop Output Impedance
vs Frequency

100

10

1

AV = +100

0.1

OUTPUT IMPEDANCE (Ω)

0.01

0.001
100

10

AV = +1

10k

1k

FREQUENCY (Hz)

100k

1M

1677 G29

Output Short-Circuit Current
vs Time

50

= ±15V

V

S

40

30

20

10

–30

–35

–40

SHORT-CIRCUIT CURRENT (mA)

SINKING SOURCING

–45

–50

0

1

TIME FROM OUTPUT SHORT TO GND (MIN)

–55°C

25°C

125°C

125°C

–55°C

2

3

25°C

1677 G28

Total Harmonic Distortion and
Noise vs Frequency for
Noninverting Gain

0.1
ZL = 2k/15pF

= ±15V

V

S

= 10V

V

O

P-P

AV = +1, +10, +100
MEASUREMENT BANDWIDTH

0.01

= 10Hz TO 80kHz

AV = 100

0.001

TOTAL HARMONIC DISTROTION + NOISE (%)

0.0001

4

AV = 10

AV = 1

20 1k 10k 20k

100

FREQUENCY (Hz)

LT1677

1677 G30

Total Harmonic Distortion and
Noise vs Frequency for Inverting
Gain

0.1
ZL = 2k/15pF

= ±15V

V

S

= 10V

V

O

P-P

AV = –1, –10, – 100
MEASUREMENT BANDWIDTH

0.01

= 10Hz TO 80kHz

AV = –100

0.001

TOTAL HARMONIC DISTROTION + NOISE (%)

0.0001

AV = –10

AV = –1

20 1k 10k 20k

100

FREQUENCY (Hz)

1677 G31

Total Harmonic Distortion and
Noise vs Output Amplitude for
Noninverting Gain

1

0.1

0.01

0.001

TOTAL HARMONIC DISTORTION + NOISE (%)

0.0001

0.3

ZL = 2k/15pF

= ±15V

V

S

= 1kHz

f

O

= +1, +10, +100

A

V

MEASUREMENT BANDWIDTH
= 10Hz TO 22kHz

AV = 100

AV = 10

AV = 1

11030
OUTPUT SWING (V

P-P

Total Harmonic Distortion and
Noise vs Output Amplitude for
Inverting Gain

1

0.1

0.01

0.001

TOTAL HARMONIC DISTORTION + NOISE (%)

0.0001

)

1677 G32

0.3

ZL = 2k/15pF

= ±15V

V

S

= 1kHz

f

O

= –1, –10, –100

A

V

MEASUREMENT BANDWIDTH
= 10Hz TO 22kHz

AV = –100

AV = –10

AV = –1

11030
OUTPUT SWING (V

P-P

)

1677 G33

1677fa

11

LT1677

1677 F03

1k

4.7k

OUTPUT

8

7

6

4

1

2

3

15V

–15V

–

+

LT1677

4.7k

WUUU

APPLICATIO S I FOR ATIO

General

The LT1677 series devices may be inserted directly into
OP-07, OP-27, OP-37 and sockets with or without removal
of external compensation or nulling components. In addi­tion, the LT1677 may be fitted to 741 sockets with the
removal or modification of external nulling components.

Rail-to-Rail Operation

To take full advantage of an input range that can exceed
the supply, the LT1677 is designed to eliminate phase
reversal. Referring to the photographs shown in Figure 1,
the LT1677 is operating in the follower mode (A

= +1) at

V

a single 3V supply. The output of the LT1677 clips cleanly
and recovers with no phase reversal. This has the benefit
of preventing lock-up in servo systems and minimizing
distortion components.

Offset Voltage Adjustment

The input offset voltage of the LT1677 and its drift with
temperature are permanently trimmed at wafer
testing to a low level. However, if further adjustment of
V

is necessary, the use of a 10kΩ nulling potentiometer

OS

will not degrade drift with temperature. Trimming to a
value other than zero creates a drift of (V
e.g., if V

is adjusted to 300µV, the change in drift will be

OS

/300)µV/°C,

OS

1µV/°C (Figure 2).

The adjustment range with a 10kΩ pot is approximately
± 2.5mV. If less adjustment range is needed, the sensitiv­ity and resolution of the nulling can be improved by using
a smaller pot in conjunction with fixed resistors. The
example has an approximate null range of ±200µV
(Figure 3).

10k

1

–

2

INPUT

3

8

LT1677

+

4

–15V

Figure 2. Standard Adjustment

Figure 3. Improved Sensitivity Adjustment

15V

7

6

OUTPUT

1677 F02

12

Input = – 0.5V to 3.5V LT1677 Output

3V

2V

1V

0V

– 0.5V

Figure 1. Voltage Follower with Input Exceeding the Supply Voltage (VS = 3V)

1577 F01a

– 0.5V

3V

2V

1V

0V

1577 F01b

1677fa

WUUU

APPLICATIO S I FOR ATIO

LT1677

Offset Voltage and Drift

Thermocouple effects, caused by temperature gradients
across dissimilar metals at the contacts to the input
terminals, can exceed the inherent drift of the amplifier
unless proper care is exercised. Air currents should be
minimized, package leads should be short, the two input
leads should be close together and maintained at the same
temperature.

The circuit shown to measure offset voltage is also used as
the burn-in configuration for the LT1677, with the supply
voltages increased to ± 20V (Figure 4).

50k*

15V

–

2

100Ω*

3

50k*

Figure 4. Test Circuit for Offset Voltage and
Offset Voltage Drift with Temperature

LT1677

+

7

6

V

1000V

OUT =

4

*RESISTORS MUST HAVE LOW
THERMOELECTRIC POTENTIAL

–15V

V

OUT

OS

1677 F04

Unity-Gain Buffer Application

When R

≤ 100Ω and the input is driven with a fast, large-

F

signal pulse (>1V), the output waveform will look as
shown in the pulsed operation diagram (Figure 5).

During the fast feedthrough-like portion of the output, the
input protection diodes effectively short the output to the
input and a current, limited only by the output short-circuit
protection, will be drawn by the signal generator. With

≥ 500Ω, the output is capable of handling the current

R

F

requirements (IL ≤ 20mA at 10V) and the amplifier stays
in its active mode and a smooth transition will occur.

R

F

–

OUTPUT

+

LT1677

Figure 5. Pulsed Operation

2.5V/µs

1677 F05

As with all operational amplifiers when RF > 2k, a pole will
be created with R

and the amplifier’s input capacitance,

F

creating additional phase shift and reducing the phase
margin. A small capacitor (20pF to 50pF) in parallel with R

F

will eliminate this problem.

Noise Testing

The 0.1Hz to 10Hz peak-to-peak noise of the LT1677 is
measured in the test circuit shown (Figure 6a). The fre­quency response of this noise tester (Figure 6b) indicates
that the 0.1Hz corner is defined by only one zero. The test
time to measure 0.1Hz to 10Hz noise should not exceed
ten seconds, as this time limit acts as an additional zero to
eliminate noise contributions from the frequency band
below 0.1Hz.

Measuring the typical 90nV peak-to-peak noise perfor­mance of the LT1677 requires special test precautions:

1. The device should be warmed up for at least five
minutes. As the op amp warms up, its offset voltage
changes typically 3µV due to its chip temperature
increasing 10°C to 20°C from the moment the power
supplies are turned on. In the ten-second measurement
interval these temperature-induced effects can easily
exceed tens of nanovolts.

2. For similar reasons, the device must be well shielded
from air currents to eliminate the possibility of
thermoelectric effects in excess of a few nanovolts,
which would invalidate the measurements.

3. Sudden motion in the vicinity of the device can also
“feedthrough” to increase the observed noise.

Current noise is measured in the circuit shown in Figure 7
and calculated by the following formula:

/

12

2

⎡

e

⎢

()

no

⎣

i

=

n

2

nV

−

130

()

M

1 101

()()

•

Ω

101

⎤
⎥
⎦

The LT1677 achieves its low noise, in part, by operating
the input stage at 100µA versus the typical 10µA of most
other op amps. Voltage noise is inversely proportional
while current noise is directly proportional to the square

1677fa

13

LT1677

WUUU

APPLICATIO S I FOR ATIO

0.1µF

100k

100

90

80

10Ω

*DEVICE UNDER TEST
NOTE: ALL CAPACITOR VALUES ARE FOR
NONPOLARIZED CAPACITORS ONLY

–

*

LT1677

+

VOLTAGE GAIN
= 50,000

2k

4.7µF

Figure 6a. 0.1Hz to 10Hz Noise Test Circuit

100Ω

500k

500k

Figure 7

100k

–

+

LT1677

24.3k

+

LT1001

–

100k

0.1µF

1677 F07

70

4.3k

22µF

2.2µF

110k

SCOPE
× 1

= 1M

R

IN

1677 F06a

60

GAIN (dB)

50

40

30

0.01 1 10 100

0.1
FREQUENCY (Hz)

1677 F06b

Figure 6b. 0.1Hz to 10Hz Peak-to-Peak
Noise Tester Frequency Response

root of the input stage current. Therefore, the LT1677’s
current noise will be relatively high. At low frequencies, the
low 1/f current noise corner frequency (≈ 90Hz) mini­mizes current noise to some extent.

e

no

In most practical applications, however, current noise will
not limit system performance. This is illustrated in the
Total Noise vs Source Resistance plot (Figure 8) where:

Total Noise = [(op amp voltage noise)
+ (current noise RS)2]

1/2

2

+ (resistor noise)

2

1000

100

TOTAL NOISE DENSITY (nV/√Hz)

R

R

SOURCE RESISTANCE = 2R

10

1

0.1

VS = ±15V
T

AT 1kHz

AT 10Hz

RESISTOR
NOISE ONLY

1 10 100

SOURCE RESISTANCE (kΩ)

= 25°C

A

1677 F08

Figure 8. Total Noise vs Source Resistance

Three regions can be identified as a function of source
resistance:

(i) R

≤ 400Ω. Voltage noise dominates

S

(ii) 400Ω ≤ RS ≤ 50k at 1kHz

400Ω ≤ RS ≤ 8k at 10Hz

(iii) RS > 50k at 1kHz

RS > 8k at 10Hz

Current noise
dominates

}

Resistor noise
dominates

}

Clearly the LT1677 should not be used in region (iii), where
total system noise is at least six times higher than the
voltage noise of the op amp, i.e., the low voltage noise
specification is completely wasted. In this region the
LT1792 or LT1793 is the best choice.

1677fa

14

WUUU

APPLICATIO S I FOR ATIO

LT1677

Rail-to-Rail Input

The LT1677 has the lowest voltage noise, offset voltage
and highest gain when compared to any rail-to-rail op
amp. The input common mode range for the LT1677 can
exceed the supplies by at least 100mV. As the common
mode voltage approaches the positive rail (+V

– 0.7V),

S

the tail current for the input pair (Q1, Q2) is reduced,
which prevents the input pair from saturating (refer to the
Simplified Schematic). The voltage drop across the load
resistors R

, RC2 is reduced to less than 200mV, degrad-

C1

ing the slew rate, bandwidth, voltage noise, offset voltage
and input bias current (the cancellation is shut off).

When the input common mode range goes below 1.5V
above the negative rail, the NPN input pair (Q1, Q2) shuts
off and the PNP input pair (Q8, Q9) turns on. The offset
voltage, input bias current, voltage noise and bandwidth
are also degraded. The graph of Offset Voltage Shift vs
Common Mode shows where the knees occur by display­ing the change in offset voltage. The change-over points
are temperature dependent, see the graph Common Mode
Range vs Temperature.

Rail-to-Rail Output

The rail-to-rail output swing is achieved by using transis­tor collectors (Q28, Q29) instead of customary class A-B
emitter followers for the output stage. Referring to the
Simplified Schematic, the output NPN transistor (Q29) sinks
the current necessary to move the output in the negative
direction. The change in Q29’s base emitter voltage is re­flected directly to the gain node (collectors of Q20 and Q16).
For large sinking currents, the delta V

of Q29 can domi-

BE

nate the gain. Figure 9 shows the change in input voltage
for a change in output voltage for different load resistors
connected between the supplies. The gain is much higher
for output voltages above ground (Q28 sources current)
since the change in base emitter voltage of Q28 is attenu­ated by the gain in the PNP portion of the output stage.
Therefore, for positive output swings (output sourcing
current) there is hardly any change in input voltage for any
load resistance. Highest gain and best linearity is achieved
when the output is sourcing current, which is the case in
single supply operation when the load is ground referenced.
Figure 10 shows gains for both sinking and sourcing load
currents for a worst-case load of 600Ω.

RL = 600

RL = 1k

R

= 10k

L

INPUT VOLTAGE (50µV/DIV)

0 5 10 15–5–10–15

TA = 25°C

= ±15V

V

S

CONNECTED TO 0V

R

L

MEASURED ON TEKTRONIX 577 CURVE TRACER

Figure 9. Voltage Gain Split Supply

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (5µV/DIV)

= 25°C

T

A

= 5V

V

S

= 600Ω

R

L

MEASURED ON TEKTRONIX 577 CURVE TRACER

Figure 10. Voltage Gain Single Supply

OUTPUT VOLTAGE (V)

34210

R

L

RL TO 0V

5

TO 5V

1677fa

15

LT1677

U

TYPICAL APPLICATIO S

Microvolt Comparator with Hysteresis

10M5%15k

7

3

+

INPUT

POSITIVE FEEDBACK TO ONE OF THE NULLING TERMINALS
CREATES APPROXIMATELY 5µV OF HYSTERESIS. OUTPUT
CAN SINK 16mA

INPUT OFFSET VOLTAGE IS TYPICALLY CHANGED LESS THAN
5µV DUE TO THE FEEDBACK

2

–

LT1677

1

6

4

1%

15k
1%

3V

OUTPUT

1677 TA03

Precision High Side Current Sense

R11

R10

232Ω

3V Strain Gauge Amplifier

3V

R8

R9

3.4Ω

1k

R*

R*

7.5Ω

R*

R2

R*

5Ω

R3

5.49kR5698Ω

+

–

R2
5Ω

*OMEGA SG-3/350LY11
350Ω, 1%
ALL OTHER RESISTORS 1%

2 • R* + R6

= ≅ 1000

A

V

()

TRIM R11 FOR BRIDGE BALANCE

()

R2 + (R*/2)

R6

R4

5.49k

R4

3V

LT1677

R7

22.1Ω

V

OUT

R*

FOR TEMP
COMPENSATION

R*

OF GAIN

R6

22.1Ω

1677 TA06

SOURCE

LOAD

R

LINE

0.1Ω

< 36V

3V < V

S

R

IN

1k

2

–

7

6

LT1677

3

+

4

ZETEX
BC856B

V

R

OUT

20k

1677 TA07

OUT

V

I

LOAD

OUT

= R

LINE

= 2V/AMP

R

OUT

R

IN

1677fa

16

TYPICAL APPLICATIO S

3V Super Electret Microphone Amplifier with DC Servo

LT1677

U

PANASONIC

ELECTRET

CONDENSER

MICROPHONE

WM-61

[phone]

2N3906

–1.5V

1.5V

10pF

2

3

C1

–

+

1M

1.5V

LT1677

–1.5V

1.5V

7Hz POLE FOR SERVO

16kHz

R1

ROLL OFF

7

6

4

C4

1µF

R3
1M

–

2

LT1677

3

+

R2
80k

R4
8k

–

2

LT1677

3

+

C3

0.022µF

1.5V

7

6

4

–1.5V

C2

100pF

1.5V

7

6

4

–1.5V

2N3906

R5

2k

20kHz
ROLL OFF

TO

HEADPHONES

1677 TA05

1677fa

17

LT1677

WW

SI PLIFIED SCHE ATIC

S

+V

R34

R32

2k

1.5k

Q28

Q34

Q32

Q35

C1

+

40pF

R1

500Ω

C2

R2

50Ω

+

200µA

Q18

80pF

OUT

R20

R19

R29

10Ω

Q29

C4

20pF

+

C3

+

40pF

Q27

R3

100Ω

Q23

2k

Q20

2k

160µA

Q19

Q31

R54

100Ω

Q26

Q30

100µA

Q22

50µA

R23A

10k

R26

R30

Q14 Q16

Q38

Q25

Q15

R23B

100Ω

2k

10k

R25

R16

R14

R15

S

–V

1677 SS

1k

1k

1k

1k

Q17

R24

R21

R13

S

S

< 0.7V BELOW +V

> 0.7V BELOW +V

CM

CM

0µA V

ID = 100µA V

S

S

< 0.7V BELOW +V

> 0.7V BELOW +V

CM

CM

50µA V

IC = 200µA V

S

S

100Ω

< 1.5V ABOVE –V

> 1.5V ABOVE –V

CM

100Ω

CM

200µA V

100Ω

IA, IB = 0µA V

1677fa

Q11

Q4 Q7

8

PAD

C2B

C2A

R

1k

R

6k

C10

81pF

+

100µA

C1B

C1A

1k

R

PAD

6k

1

R

Q12

Q6

Q10

Q2B

Q3

Q1B Q2A

Q1A

D1

D2

Q5

D4

D3

–IN

+IN

50µA

ID

IC

R9

200Ω

R8

200Ω

Q21

Q13

Q8 Q9

Q24

×2

IB

IA

18

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

.400*

(10.160)

MAX

87 6

.255 ± .015*

(6.477 ± 0.381)

5

LT1677

12

.300 – .325

(7.620 – 8.255)

.065

(1.651)

.008 – .015

(0.203 – 0.381)

+.035

.325

–.015
+0.889

8.255

()

–0.381

NOTE:

1. DIMENSIONS ARE

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

INCHES

MILLIMETERS

TYP

.045 – .065

(1.143 – 1.651)

.100

(2.54)

BSC

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

.045 ±.005

.160

±.005

.228 – .244

(5.791 – 6.197)

.245
MIN

.050 BSC

.189 – .197

(4.801 – 5.004)

8

3

NOTE 3

7

4

(3.302 ± 0.127)

.018 ± .003

(0.457 ± 0.076)

5

6

.130 ± .005

.120

(3.048)

MIN

.150 – .157

(3.810 – 3.988)

NOTE 3

.020

(0.508)

MIN

N8 1002

.030 ±.005

TYP

RECOMMENDED SOLDER PAD LAYOUT

.010 – .020

(0.254 – 0.508)

.008 – .010

(0.203 – 0.254)

NOTE:

1. DIMENSIONS IN

2. DRAWING NOT TO SCALE

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

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.

× 45°

.016 – .050

(0.406 – 1.270)

INCHES

(MILLIMETERS)

(1.346 – 1.752)

0°– 8° TYP

(0.355 – 0.483)

.053 – .069

.014 – .019

TYP

1

2

3

4

.004 – .010

(0.101 – 0.254)

.050

(1.270)

BSC

SO8 0303

1677fa

19

LT1677

TYPICAL APPLICATIO

U

This 2-wire remote Geophone preamp operates on a
current-loop principle and so has good noise immunity.
Quiescent current is ≈10mA for a V

of 2.5V. Excitation

OUT

will cause AC currents about this point of ~± 4mA for a
V

of ~± 1V max. The op amp is configured for a voltage

OUT

2-Wire Remote Geophone Preamp

+

6mA

V

R

R8

–

V

11Ω

3V

C

A

R6

4.99k

R7

24.9k

R1 + R

+

||

R4

≅ 107

L

R

www.geospacecorp.com/default.htm

R2 + R3

AV =

C3
220µF

GEOSPACE

GS-20DX

= 630Ω

R

L

GEOPHONE

[phone]

R4
14k

R1

365Ω

2

–

–

LT1677

3

+

R3

16.2k

+

LINEAR

TECHNOLOGY

LM334Z

LT1431CZ

gain of ~107. Components R5 and Q1 convert the voltage
into a current for transmission back to R10, which con­verts it into a voltage again. The LM334 and 2N3904 are
not temperature compensated so the DC output contains
temperature information.

R9

20Ω

Q1

R2

100k

7

4

C2

0.1µF

6

2N3904

R5
243Ω

C4

1000pF

1677 TA04

12V

R10
250Ω

V

OUT

2.5V ±1V

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C-Load is a trademark of Linear Technology Corporation.

Linear Technology Corporation

20

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone]

●

www.linear-tech.com

to 1000pF, IB = 200pA Max

LOAD

LT 0306 REV A • PRINTED IN USA

© LINEAR TECHNOLOGY CORPORATION 2000

1677fa