Datasheet LT1884 Datasheet (Linear Technology)

FEATURES

LT1884/LT1885

Dual/Quad Rail-to-Rail

Output, Picoamp Input

Precision Op Amps

U

DESCRIPTIO

■

Offset Voltage: 50µV Max (LT1884A)

■

Input Bias Current: 400pA Max (LT1884A)

■

Offset Voltage Drift: 0.8µV/°C Max

■

Rail-to-Rail Output Swing

■

Operates with Single or Split Supplies

■

Open-Loop Voltage Gain: 1 Million Min

■

1mA Maximum Supply Current Per Amplifier

■

Slew Rate: 1V/µs

■

Standard Pinouts

U

APPLICATIO S

■

Thermocouple Amplifiers

■

Bridge Transducer Conditioners

■

Instrumentation Amplifiers

■

Battery-Powered Systems

■

Photo Current Amplifiers

■

Precision Integrators

■

Precision Current Sources

The LT®1884/LT1885 op amps bring high accuracy input performance to amplifiers with rail-to-rail output swing while providing faster response than other precision amplifiers. Input offset voltage is trimmed to less than 50µV and the low drift maintains this accuracy over the operating temperature range. Input bias currents are an ultralow 400pA maximum.

The amplifiers work on any total power supply voltage between 2.7V and 36V (fully specified from 5V to ±15V). Output voltage swings to within 40mV of the negative supply and 220mV of the positive supply make these amplifiers good choices for low voltage single supply operation.

Slew rates of 1V/µs with a supply current of less than 1mA per amplifier give superior response and settling time performance in a low power precision amplifier.

The dual LT1884 is available with standard pinouts in 8-pin SO and PDIP packages. The quad LT1885 is also in the standard pinout 14-pin SO package.

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

TYPICAL APPLICATIO

–IN

GUARD

+IN

U

Input Fault Protected Instrumentation Amplifier

1M

10pF

+

1/4 LT1885

–

1M

22pF

TRIM FOR

AC CMRR

3

+

1/4 LT1885

–

1/4 LT1885

5

+

10k

R

G/2

R

G/2

10k

9.76k

–

1/4 LT1885 OUT

+

2•10k

GAIN =

500Ω

TRIM FIRST

FOR DC CMRR

1884 TA01

R

G

1

LT1884/LT1885

TOP VIEW

S PACKAGE

14-LEAD PLASTIC SO

1 2 3 4 5 6 7

14 13 12 11 10

9 8

OUT A

–IN A

+IN A

V

+

+IN B –IN B

OUT B

OUT D –IN D +IN D V

–

+IN C –IN C OUT C

A

D

C

B

WWWU

ABSOLUTE AXI U RATI GS

(Note 1)

Supply Voltage (V+ to V–) ....................................... 40V

Differential Input Voltage (Note 2) .........................±10V

Input Voltage .................................................... V+ to V

Input Current (Note 2) ........................................ ±10mA

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

UU

W

PACKAGE/ORDER I FOR ATIO

ORDER

PART NUMBER

TOP VIEW

OUT A

1

–IN A

2

+IN A

N8 PACKAGE 8-LEAD PDIP

A

3

–

V

4

T

= 150°C, θJA = 130°C/W (N8)

JMAX

T

= 150°C, θJA = 190°C/W (S8)

JMAX

+

8

V OUT B

7

–IN B

6

B

+IN B

5

S8 PACKAGE

8-LEAD PLASTIC SO

LT1884CN8 LT1884CS8 LT1884ACN8 LT1884ACS8 LT1884IN8 LT1884IS8 LT1884AIN8 LT1884AIS8

S8 PART MARKING

1884 1884A

1884I 1884AI

Operating Temperature Range (Note 4) .. –40°C to 85°C Specified Temperature Range (Note 5)... – 40°C to 85°C

–

Maximum Junction Temperature .......................... 150°C

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

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

ORDER

PART NUMBER

LT1885CS LT1885IS

T

= 150°C, θJA = 110°C/W

JMAX

Consult factory for Military grade parts.

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Single supply operation VEE = 0, VCC = 5V; VCM = VCC/2 unless otherwise noted. (Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

I

OS

2

Input Offset Voltage (LT1884A) 25 50 µV

< 70°C ● 85 µV

0°C < T

A

–40°C < T

Input Offset Voltage (LT1884/LT1885) 30 80 µV

0°C < T –40°C < T

Input Offset Voltage Drift (Note 6) 0°C < TA < 70°C ● 0.3 0.8 µV/°C

–40°C < T

Input Offset Current (LT1884A) 100 300 pA

Input Offset Current (LT1884/LT1885) 150 900 pA

0°C < T –40°C < T

< 85°C ● 110 µV

A

< 70°C ● 125 µV

A

< 85°C ● 150 µV

A

< 85°C ● 0.3 0.8 µV/°C

A

< 70°C ● 400 pA

A

< 85°C ● 500 pA

A

< 70°C ● 1200 pA

A

< 85°C ● 1400 pA

A

LT1884/LT1885

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Single supply operation VEE = 0, VCC = 5V; VCM = VCC/2 unless otherwise noted. (Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

I

B

e

n

i

n

V

CM

CMRR Common Mode Rejection Ratio 1V < VCM < 4V 108 128 dB

PSRR Power Supply Rejection Ratio VEE = 0, VCM = 1.5V; 2.7V < VCC < 32V ● 108 132 dB

A

VOL

V

OL

V

OH

I

S

I

SC

GBW Gain-Bandwidth Product f = 20kHz 1.2 2 MHz t

S

+

SR

–

SR

Input Bias Current (LT1884A) 100 400 pA

< 70°C ● 500 pA

0°C < T

A

–40°C < T

< 85°C ● 600 pA

A

Input Bias Current (LT1884/LT1885) 150 900 pA

0°C < T

< 70°C ● 1200 pA

A

–40°C < T

Input Noise Voltage 0.1Hz to 10Hz 0.4 µV

< 85°C ● 1400 pA

A

P-P

Input Noise Voltage Density f = 1kHz 9.5 nV/√Hz Input Noise Current Density f = 1kHz 0.05 pA/√Hz Input Voltage Range VEE + 1.0 VCC – 1.0 V

1.2V < V

● V

< 3.8V ● 106 dB

CM

+ 1.2 VCC – 1.2 V

EE

Minimum Operating Supply Voltage ● 2.4 2.7 V Large-Signal Voltage Gain RL = 10k; 1V < V

RL = 2k; 1V < V

RL = 1k; 1V < V

< 4V 500 1600 V/mV

OUT

< 4V 400 800 V/mV

OUT

< 4V 300 400 V/mV

OUT

● 350 V/mV

● 300 V/mV

● 200 V/mV

Output Voltage Swing Low No Load ● 20 40 mV

= 100µA ● 25 50 mV

I

SINK

I

= 1mA ● 70 150 mV

SINK

= 5mA ● 270 600 mV

I

SINK

Output Voltage Swing High No Load ● 120 220 mV (Referred to V

)I

CC

= 100µA ● 130 230 mV

SOURCE

= 1mA ● 180 300 mV

I

SOURCE

I

= 5mA ● 360 600 mV

SOURCE

Supply Current per Amplifier VCC = 3V 0.45 0.65 0.85 mA

● 1.30 mA

VCC = 5V 0.50 0.65 0.9 mA

● 1.4 mA

VCC = 12V 0.50 0.70 1.0 mA

● 1.5 mA

Short-Circuit Current V

Settling Time 0.01%, V

Short to GND ● 15 30 mA

OUT

V

Short to V

OUT

= –1, RL = 2k

A

V

CC

= 1.5V to 3.5V, 10 µs

OUT

● 15 30 mA

Positive Slew Rate AV = –1 0.45 0.9 V/µs

● 0.36 V/µs

Negative Slew Rate AV = –1 0.35 0.7 V/µs

● 0.25 V/µs

3

LT1884/LT1885

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Single supply operation VEE = 0, VCC = 5V; VCM = VCC/2 unless otherwise noted. (Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

∆V

OS

∆IB+ Noninverting Bias Current Match 200 600 pA

∆CMRR Common Mode Rejection Match (Notes 7, 9) ● 104 125 dB ∆PSRR Positive Power Supply Rejection Match VEE = 0V, VCM = 1.5V, 2.7V < VCC < 32V, ● 104 126 dB

Offset Voltage Match (LT1884A) 30 70 µV

< 70°C ● 125 µV

0°C < T

A

–40°C < T

< 85°C ● 160 µV

A

Offset Voltage Match (LT1884/LT1885) (Note 7) 35 125 µV

< 70°C ● 195 µV

0°C < T

A

–40°C < T

< 85°C ● 235 µV

A

Offset Voltage Match Drift (Notes 6, 7) ● 0.4 1.2 µV/°C

(LT1884A) 0°C < T

< 70°C ● 700 pA

A

–40°C < T

< 85°C ● 850 pA

A

Noninverting Bias Current Match (Notes 7, 9) 250 1200 pA (LT1884/LT1885) 0°C < T

< 70°C ● 1600 pA

A

–40°C < T

< 85°C ● 1900 pA

A

(Notes 7, 9)

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Split supply operation VS = ±15V; VCM = 0V unless otherwise noted. (Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

I

OS

I

B

e

n

i

n

V

CM

CMRR Common Mode Rejection Ratio –13.5V < VCM < 13.5V ● 114 130 dB

Input Offset Voltage (LT1884A) 25 50 µV

< 70°C ● 85 µV

0°C < T

A

–40°C < T

< 85°C ● 110 µV

A

Input Offset Voltage (LT1884/LT1885) 30 80 µV

< 70°C ● 125 µV

0°C < T

A

–40°C < T

< 85°C ● 150 µV

A

Input Offset Voltage Drift (Note 6) 0°C < TA < 70°C ● 0.3 0.8 µV/°C

–40°C < T

< 85°C ● 0.3 0.8 µV/°C

A

Input Offset Current (LT1884A) 150 300 pA

0°C < T

< 70°C ● 400 pA

A

–40°C < T

< 85°C ● 500 pA

A

Input Offset Current (LT1884/LT1885) 150 900 pA

< 70°C ● 1200 pA

0°C < T

A

–40°C < T

< 85°C ● 1400 pA

A

Input Bias Current (LT1884A) 150 400 pA

< 70°C ● 500 pA

0°C < T

A

–40°C < T

< 85°C ● 600 pA

A

Input Bias Current (LT1884/LT1885) 150 900 pA

< 70°C ● 1200 pA

0°C < T

A

–40°C < T

Input Noise Voltage 0.1Hz to 10Hz 0.4 µV

< 85°C ● 1400 pA

A

P-P

Input Noise Voltage Density f = 1kHz 9.5 nV/√Hz Input Noise Current Density f = 1kHz 0.05 pA/√Hz Input Voltage Range VEE + 1.0 VCC – 1.0 V

● V

+ 1.2 VCC – 1.2 V

EE

4

LT1884/LT1885

ELECTRICAL CHARACTERISTICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Split supply operation VS = ±15V; VCM = 0V unless otherwise noted. (Note 5)

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

+PSRR Positive Power Supply Rejection Ratio VEE = –15V, VCM = 0V; 1.5V < VCC < 18V ● 114 132 dB –PSRR Negative Power Supply Rejection Ratio VCC = 15V, VCM = 0V; –1.5V < VEE < –18V ● 106 132 dB

Minimum Operating Supply Voltage ● ±1.2 ±1.35 V

A

VOL

V

OL

V

OH

I

S

I

SC

GBW Gain-Bandwidth Product f = 20kHz 1.5 2.2 MHz t

S

+

SR

–

SR

∆V

OS

+

∆I

B

∆CMRR Common Mode Rejection Match (Notes 7, 9) ● 106 125 dB ∆+PSRR Positive Power Supply Rejection Match VEE = –15V, VCM = 0V, 1.5V < VCC < 18V, ● 108 124 dB

∆–PSRR Negative Power Supply Rejection Match VCC = 15V, VCM = 0V, –1.5V < VEE < –18V, ● 102 132 dB

Large-Signal Voltage Gain RL = 10k; –13.5V < V

RL = 2k; –13.5V < V

RL = 1k; –12V < V

< 13.5V 1000 1600 V/mV

OUT

< 13.5V 250 420 V/mV

OUT

< 12V 100 230 V/mV

OUT

● 700 V/mV

● 175 V/mV

● 75 V/mV

Output Voltage Swing Low No Load ● 20 40 mV (Referred to V

)I

EE

= 100µA ● 25 50 mV

SINK

I

= 1mA ● 70 150 mV

SINK

= 5mA ● 270 600 mV

I

SINK

Output Voltage Swing High No Load ● 160 220 mV (Referred to V

)I

CC

= 100µA ● 160 230 mV

SOURCE

I

= 1mA ● 180 300 mV

SOURCE

= 5mA ● 360 600 mV

I

SOURCE

Supply Current Per Amplifier VS = ±15V 0.85 1.1 mA

● 1.6 mA

Short-Circuit Current V

Settling Time 0.01%, V

Short to V

OUT

V

Short to V

OUT

A

= –1, RL = 2k

V

EE CC

= –5V to 5V, 17 µs

OUT

● 15 50 mA

● 15 30 mA

Positive Slew Rate AV = –1 0.5 1.0 V/µs

● 0.4 V/µs

Negative Slew Rate AV = –1 0.40 0.7 V/µs

● 0.26 V/µs

Offset Voltage Match (LT1884A) (Note 7) 35 70 µV

< 70°C ● 125 µV

0°C < T

A

–40°C < T

< 85°C ● 160 µV

A

Offset Voltage Match (LT1884/LT1885) (Note 7) 35 125 µV

< 70°C ● 175 µV

0°C < T

A

–40°C < T

< 85°C ● 235 µV

A

Offset Voltage Match Drift (Note 6, 7) ● 0.4 1.1 µV/°C Noninverting Bias Current Match (Notes 7, 8) 200 600 pA

(LT1884A) 0°C < T

< 70°C ● 700 pA

A

–40°C < T

< 85°C ● 850 pA

A

Noninverting Bias Current Match (Notes 7, 8) 240 1200 pA (LT1884/LT1885) 0°C < T

< 70°C ● 1600 pA

A

–40°C < T

< 85°C ● 1900 pA

A

(Notes 7, 9)

5

LT1884/LT1885

FREQUENCY (Hz)

VOLTAGE GAIN (dB)

100

90 80 70 60 50 40 30 20 10

0 –10 –20

PHASE SHIFT (DEG)

–80 –90 –100 –110 –120 –130 –140 –150 –160 –170 –180

18845 G06

10k 100k 1M 10M

PHASE SHIFT

GAIN

ELECTRICAL CHARACTERISTICS

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

Note 2: The inputs are protected by back-to-back diodes. If the differential input voltage exceeds 0.7V, the input current should be limited to less than 10mA.

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

Note 4: The LT1884C/LT1885C and LT1884I/LT1885I are guaranteed functional over the operating temperature range of –40°C to 85°C.

Note 6: This parameter is not 100% tested. Note 7: Matching parameters are the difference between amplifiers A and

B in the LT1884 and between amplifiers A and D and B and C in the LT1885.

Note 8: This parameter is the difference between the two noninverting input bias currents.

Note 9: ∆CMRR and ∆PSRR are defined as follows: CMRR and PSRR are measured in µV/V on each amplifier. The difference is calculated in µV/V and then converted to dB.

Note 5: The LT1884C/LT1885C are designed, characterized and expected to meet specified performance from –40°C to 85°C but are not tested or QA sampled at these temperatures. LT1884I is guaranteed to meet specified performance from –40°C to 85°C.

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Input Offset Voltage

Distribution of Offset Voltage Drift

24

VS = ±15V

20

16

12

8

PERCENT OF UNITS (%)

4

0

–0.9 –0.7 –0.5 –0.3 –0.1 0.1 0.3 0.5 0.7 0.9

OFFSET VOLTAGE DRIFT (µV/°C)

18845 G01

vs Temperature

200

TEMPCO: –55°C TO 125°C 10 REPRESENTATIVE UNITS

150

100

50

0

–50

–100

INPUT OFFSET VOLTAGE (µV)

–150

–200

–50 –30 –10 10 30 50 70 90 110125

TEMPERATURE (°C)

18845 G02

V

vs I

OUT

VS = ±15V

SINK

100µA

I

SINK

125°C

25°C

–55°C

500

400

300

) (mV)

EE

– V

200

OUT

(V

100

0 10µA 1mA 10mA

18845 G03

V

vs I

OUT

500

VS = ±15V

400

300

) (mV)

OUT

– V

200

CC

(V

100

0 10µA 1mA 10mA

6

SOURCE

100µA

I

SOURCE

25°C

125°C

–55°C

18845 G04

Gain vs Frequency

140

120

100

80

60

GAIN (dB)

40

20

0

–20

0.1 1 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)

VS = ±15V

Gain, Phase Shift vs Frequency

18845 G05

UW

FREQUENCY (Hz)

1

10

100

1000

10 100 1000

18845 G09

VOLTAGE NOISE DENSITY (nV/√Hz)

CURRENT NOISE DENSITY (fA/√Hz)

CURRENT NOISE

VOLTAGE NOISE

TYPICAL PERFOR A CE CHARACTERISTICS

LT1884/LT1885

CMRR vs Frequency

140 130 120 110 100

90 80 70 60 50 40 30

COMMON MODE REJECTION (dB)

20 10

0

10 100 10k

1

1k

FREQUENCY (Hz)

100k

1M

18845 G07

PSRR vs Frequency

140 130 120 110 100

90 80 70 60 50 40 30

SUPPLY POWER REJECTION (dB)

20 10

0

1

POSITIVE SUPPLY

10 100 10k

0.1Hz to 10Hz Noise 0.01Hz to 1Hz Noise

NOISE VOLTAGE (O.2µV/DIV)

VS = ±15V

= 25°C

T

A

NOISE VOLTAGE (O.2µV/DIV)

VS = ±15V

= 25°C

T

A

NEGATIVE SUPPLY

1k

FREQUENCY (Hz)

VS = ±15V

100k

18845 G08

1M

Vn, In vs Frequency

Slew Rate vs Temperature

1.4

RISING

= ±15V

V

RISING

V

= ±5V

S

FALLING

= ±5V

V

S

1.2

1.0

0.8

SLEW RATE (V/µs)

0.6

FALLING

= ±15V

V

S

0.4

TIME (2s/DIV)

Settling Time to 0.01% vs Output Step

10

VS = ±15V

8 6 4 2 0

–2

OUTPUT STEP (V)

–4 –6 –8

–10

02

AV = 1

A

V

4 6 8 1012141618

SETTLING TIME (µs)

= 1

AV = –1

18845 G10

18845 G13

Supply Current per Amplifier vs Supply Voltage

1.25

1.00

0.75

0.50

SUPPLY CURRENT (mA)

0.25

20

0

TIME (20s/DIV)

TA = 85°C

TA = 25°C

TA = –40°C

8164

122420

SUPPLY VOLTAGE (V)

18845 G11

32

28

36

18845 G14

40

–50 –30 –10 10 30 50 70 90 110

TEMPERATURE (°C)

Input Bias Current vs Common Mode Voltage

1000

TA = 25°C

750

500

250

0

–250

–500

INPUT BIAS CURRENT (pA)

–750

–1000

–10 –5 5

–15

COMMON MODE VOLTAGE (V)

I

BIAS

+

–

0

18845 G12

10

LTXXXX • TPCXX

15

7

LT1884/LT1885

FREQUENCY (Hz)

1k

GAIN (dB)

10k 100k 1M 10M 100M

18845 G17

10

0

–10

–20

–30

–40

VS = ±2.5V

VS = ±15V

FREQUENCY (Hz)

1k

GAIN (dB)

10k 100k 1M 10M 100M

18845 G19

10

0

–10

–20

–30

–40

C

LOAD

= 500pF

C

LOAD

= 0pF

C

LOAD

= 100pF

C

LOAD

= 300pF

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Channel Separation vs Frequency

–20 –30 –40 –50 –60 –70 –80 –90

CHANNEL SEPARATION (dB)

–100

–110 –120

1k 10k 100k 1M 10M

100

FREQUENCY (Hz)

Gain vs Frequency vs C (AV = 1)

10

0

–10

LOAD

18845 G16

Gain vs Frequency (AV = 1)

Gain vs Frequency vs C

LOAD

(AV = –1)

GAIN (dB)

5V/DIV

–20

C

= 330pF

–30

–40

1k

LOAD

= 150pF

C

LOAD

C

= 50pF

LOAD

= 0pF

C

LOAD

10k 100k 1M 10M 100M

FREQUENCY (Hz)

Large-Signal Response

VS = ±15V

= RG = 10k

R

F

A

= –1

V

50µs/DIV

18845 G18

18845 G20

20mV/DIV

Small-Signal Response

VS = ±15V

= RG = 10k

R

F

A

= –1

V

2µs/DIV

18845 G21

8

WUUU

APPLICATIO S I FOR ATIO

LT1884/LT1885

The LT1884/LT1885 dual op amp features exceptional input precision with rail-to-rail output swing. Slew rate and small-signal bandwidth are superior to other amplifiers with comparable input precision. These characteristics make the LT1884/LT1885 a convenient choice for precision low voltage systems and for improved AC performance in higher voltage precision systems. Maintaining the advantage of the precision inherent in the amplifier depends upon proper applications circuit design and board layout.

Preserving Input Precision

Preserving the input voltage accuracy of the LT1884/ LT1885 requires that the applications circuit and PC board layout do not introduce errors comparable to or greater than the 30µV offset. Temperature differentials across the input connections can generate thermocouple voltages of 10s of microvolts. PC board layouts should keep connections to the amplifier’s input pins close together and away from heat dissipating components. Air currents across the board can also generate temperature differentials.

The extremely low input bias currents, 100pA, allow high accuracy to be maintained with high impedance sources and feedback networks. The LT1884/LT1885’s low input bias currents are obtained by using a cancellation circuit on-chip. This causes the resulting I uncorrelated, as implied by the IOS specification being comparable to the I the input resistances in each input lead, as is commonly recommended with most amplifiers. The impedance at either input should be kept as small as possible to minimize total circuit error.

. The user should not try to balance

BIAS

+

and I

BIAS

–

to be

interconnect, with the guard driven to the same common mode voltage as the amplifier inputs.

Input Common Mode Range

The LT1884/LT1885 output is able to swing close to each power supply rail, but the input stage is limited to operating between VEE + 0.8V and VCC – 0.9V. Exceeding this common mode range will cause the gain to drop to zero; however, no gain reversal will occur.

Input Protection

The inverting and noninverting input pins of the LT1884/ LT1885 have limited on-chip protection. ESD protection is provided to prevent damage during handling. The input transistors have voltage clamping and limiting resistors to protect against input differentials up to 10V. Short transients above this level will also be tolerated. If the input pins may be subject to a sustained differential voltage above 10V, external limiting resistors should be used to prevent damage to the amplifier. A 1k resistor in each input lead will provide protection against a 30V differential voltage.

Capacitive Loads

The LT1884/LT1885 can drive capacitive loads up to 300pF when configured for unity gain. The capacitive load driving capability increases as the amplifier is used in higher gain configurations. Capacitive load driving may also be increased by decoupling the capacitance from the output with a small resistance.

Input Bias Currents

PC board layout is important to ensure that leakage currents do not corrupt the low I high precision, high impedance circuits, the input pins should be surrounded by a guard ring of PC board

of the amplifier. In

BIAS

While it may be tempting to seek out a JFET amplifier for low input bias current, remember that bipolar devices improve with temperature while JFETs degrade.

9

LT1884/LT1885

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.400*

(10.160)

MAX

876

0.255 ± 0.015* (6.477 ± 0.381)

1234

5

0.300 – 0.325

(7.620 – 8.255)

0.065

(1.651)

0.009 – 0.015

(0.229 – 0.381)

+0.035

0.325 –0.015

+0.889

8.255

()

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

TYP

0.045 – 0.065

(1.143 – 1.651)

0.100

(2.54)

BSC

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

8

0.228 – 0.244

(5.791 – 6.197)

0.189 – 0.197* (4.801 – 5.004)

7

6

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.018 ± 0.003

(0.457 ± 0.076)

5

0.150 – 0.157** (3.810 – 3.988)

0.020

(0.508)

MIN

N8 1098

10

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*

DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

**

DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

× 45°

0°– 8° TYP

0.016 – 0.050

(0.406 – 1.270)

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

TYP

1

3

2

4

0.004 – 0.010

(0.101 – 0.254)

0.050

(1.270)

BSC

SO8 1298

PACKAGE DESCRIPTIO

LT1884/LT1885

U

Dimensions in inches (millimeters) unless otherwise noted.

S Package

14-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.337 – 0.344* (8.560 – 8.738)

13

12

11

14

10

8

9

0.228 – 0.244

(5.791 – 6.197)

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*

DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

**

DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

×

°

45

0.016 – 0.050

(0.406 – 1.270)

0° – 8° TYP

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

TYP

0.150 – 0.157** (3.810 – 3.988)

1

3

2

4

0.050

(1.270)

BSC

5

7

6

0.004 – 0.010

(0.101 – 0.254)

S14 1298

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.

11

LT1884/LT1885

TYPICAL APPLICATIO

U

16-Bit Voltage Output DAC on ±5V Supply

5V

1.65k

LT1634

4.096V

+

LT1884

–

5V

–5V

R

COM

LTC®1597

REFR1

R

DAC

OFS

33pF

–

LT1884

+

5V

–5V

V

OUT

–4.096V TO 4.096V

18845 TA02

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LT1112 Dual Picoamp Input Op Amp VOS = 60µV Max LT1114 Quad Picoamp Input Op Amp VOS = 60µV Max LT1167 Gain Programmable Instrumentation Amp Gain Error = 0.08% Max LT1490 Micropower Rail-to-Rail Input and Output Op Amp Over-The-TopTM Common Mode Range LT1793 Low Noise JFET Op Amp IB = 10pA Max LT1881/LT1882 Picoamp Input Rail-to-Rail Output Op Amp Lower Input Bias Currents Than LT1884/LT1885 LTC2050 Zero Drift Op Amp in SOT-23 VOS = 3µV Max, Rail-to-Rail Output Over-The-Top is a trademark of Linear Technology Corporation.

18845f LT/TP 0400 4K • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 2000

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear-tech.com