ANALOG DEVICES LT 1490 ACS8 Datasheet

FEATURES

■

Rail-to-Rail Input and Output

■

Single Supply Input Range: –0.4V to 44V

■

Micropower: 50

■

MSOP Package

■

Specified on 3V, 5V and ±15V Supplies

■

High Output Current: 20mA

■

Output Drives 10,000pF with Output Compensation

■

Reverse Battery Protection to 18V

■

No Supply Sequencing Problems

■

High Voltage Gain: 1500V/mV

■

High CMRR: 98dB

■

No Phase Reversal

■

Gain Bandwidth Product: 200kHz

µµ

µA/Amplifier Max

µµ

U

APPLICATIO S

■

Battery- or Solar-Powered Systems

Portable Instrumentation Sensor Conditioning

■

Supply Current Sensing

■

Battery Monitoring

■

Micropower Active Filters

■

4mA to 20mA Transmitters

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

LT1490/LT1491

Dual and Quad

Micropower Rail-to-Rail

Input and Output Op Amps

U

DESCRIPTIO

The dual LT®1490 and quad LT1491 op amps operate on all single and split supplies with a total voltage of 2V to 44V drawing only 40µA of quiescent current per amplifier. These amplifiers are reverse supply protected; they draw no current for reverse supply up to 18V. The input range of the LT1490/ LT1491 includes both supplies and the output swings to both supplies. Unlike most micropower op amps, the LT1490/ LT1491 can drive heavy loads; their rail-to-rail outputs drive 20mA. The LT1490/LT1491 are unity-gain stable and drive all capacitive loads up to 10,000pF when optional 0.22µF and 150Ω compensation is used.

The LT1490/LT1491 have a unique input stage that operates and remains high impedance when above the positive supply. The inputs take 44V both differential and common mode even when operating on a 3V supply. Built-in resistors protect the inputs for faults below the negative supply up to 22V. There is no phase reversal of the output for inputs 22V below V– or 44V above V–, independent of V+.

The LT1490 dual op amp is available in the 8-pin MSOP, SO and PDIP packages. The quad LT1491 is available in the 14-pin SO and PDIP packages.

For new designs it is recommended that the LT1490A/ LT1491A be used instead of the LT1490/LT1491. See the LT1490A/LT1491A data sheet for details.

TYPICAL APPLICATIO

CHARGER

VOLTAGE

U

R

S

0.2Ω

I

BATT

LOAD

I

= = AMPS

BATT

(RS)(RG/RA)(GAIN)

A

2k

R

A

'

2k

R

B

2k

R

B

'

2k

+

= 12V

V

BATT

V

OUT

Battery Monitor

+

A

1/4 LT1491

–

+

B

1/4 LT1491

–

V

OUT

GAIN

Q1

2N3904

Q2

2N3904

S1

S1 = OPEN, GAIN = 1 S1 = CLOSED, GAIN = 10

R 10k

–

C

1/4 LT1491

+

LOGIC HIGH (5V) = CHARGING LOGIC LOW (0V) = DISCHARGING

+

G

10k

D

1/4 LT1491

–

90.9k

= R

R

A

VS = 5V, 0V

B

LOGIC

V

OUT

1490/91 TA01

1

LT1490/LT1491

WWWU

ABSOLUTE AXI U RATI GS

(Note 1)

Total Supply Voltage (V+ to V–) .............................. 44V

Input Differential Voltage ......................................... 44V

Input Current ......................................................±25mA

Output Short-Circuit Duration (Note 2).........Continuous

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

U

W

U

PACKAGE/ORDER INFORMATION

ORDER PART

TOP VIEW

+

1

OUT A

2

–IN A +IN A

MS8 PACKAGE

8-LEAD MSOP

T T T

A

3

–

4

V

S8 PACKAGE

8-LEAD PLASTIC SO

= 150°C, θJA = 250°C/ W (MS8)

JMAX

= 150°C, θJA = 130°C/ W (N8)

JMAX

= 150°C, θJA = 190°C/ W (S8)

JMAX

8

V

7

OUT B

6

–IN B

B

5

+IN B

N8 PACKAGE 8-LEAD PDIP

Consult factory for Military grade parts.

NUMBER

LT1490CMS8 LT1490CN8 LT1490CS8 LT1490IN8 LT1490IS8

MS8 PART MARKING

LTBB

S8 PART MARKING

1490 1490I

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

Specified Temperature Range (Note 3) .. –40°C to 85°C

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

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

(For new designs, use the LT1490A or LT1491A)

TOP VIEW

OUT A

1

–IN A

2

+IN A

+IN B –IN B

OUT B

N PACKAGE

14-LEAD PDIP

A

3

+

V

4 5

B

6 7

T

= 150°C, θJA = 110°C/ W (N)

JMAX

T

= 150°C, θJA = 150°C/ W (S)

JMAX

OUT D

14

–IN D

13

D

+IN D

12

–

V

11

+IN C

10

C

– IN C

9

OUT C

8

S PACKAGE

14-LEAD PLASTIC SO

ORDER PART

NUMBER

LT1491CN LT1491CS LT1491IN LT1491IS

ELECTRICAL CHARACTERISTICS

range, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; VCM = V

The ● denotes specifications which apply over the full operating temperature

= half supply, unless otherwise noted. (Note 3)

OUT

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

Input Offset Voltage LT1490 N Package 220 800 µV

0°C ≤ T

≤ 70°C ● 1000 µV

A

–40°C ≤ TA ≤ 85°C ● 1100 µV LT1490 S Package 220 950 µV

0°C ≤ TA ≤ 70°C ● 1200 µV –40°C ≤ T

≤ 85°C ● 1300 µV

A

LT1491 N Package 300 1100 µV 0°C ≤ T

≤ 70°C ● 1350 µV

A

–40°C ≤ TA ≤ 85°C ● 1450 µV LT1490CMS8 Package, LT1491 S Package 350 1450 µV

0°C ≤ TA ≤ 70°C ● 1650 µV –40°C ≤ T

≤ 85°C ● 1750 µV

A

VOS TC Input Offset Voltage Drift 0°C ≤ TA ≤ 70°C (Note 7) ● 24 µV/°C

–40°C ≤ TA ≤ 85°C (Note 7) ● 24 µV/°C

I

OS

Input Offset Current ● 0.2 0.8 nA

VCM = 44V (Note 4) ● 0.8 µA

I

B

Input Bias Current ● 48 nA

VCM = 44V (Note 4) ● 410 µA V

= 0V 0.1 nA

S

Input Noise Voltage 0.1Hz to 10Hz 1 µV

P-P

2

LT1490/LT1491

ELECTRICAL CHARACTERISTICS

range, otherwise specifications are at TA = 25°C. VS = 3V, 0V; VS = 5V, 0V; VCM = V

The ● denotes specifications which apply over the full operating temperature

= half supply, unless otherwise noted. (Note 3)

OUT

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

e

n

i

n

R

IN

Input Noise Voltage Density f = 1kHz 50 nV/√Hz Input Noise Current Density f = 1kHz 0.03 pA/√Hz Input Resistance Differential 6 17 MΩ

Common Mode, VCM = 0V to 44V 4 11 MΩ

C

IN

Input Capacitance 4.6 pF Input Voltage Range ● 044V

CMRR Common Mode Rejection Ratio V

(Note 4) V

A

VOL

Large-Signal Voltage Gain VS = 3V, VO = 500mV to 2.5V, RL = 10k 200 1500 V/mV

= 0V to VCC – 1V ● 84 98 dB

CM

= 0V to 44V ● 80 98 dB

CM

0°C ≤ TA ≤ 70°C ● 133 V/mV –40°C ≤ T

≤ 85°C ● 100 V/mV

A

VS = 5V, VO = 500mV to 4.5V, RL = 10k 400 1500 V/mV 0°C ≤ T

≤ 70°C ● 250 V/mV

A

–40°C ≤ TA ≤ 85°C ● 200 V/mV

V

OL

Output Voltage Swing Low VS = 3V, No Load ● 22 50 mV

VS = 3V, I

= 5mA ● 250 450 mV

SINK

VS = 5V, No Load ● 22 50 mV VS = 5V, I V

= 5V, I

S

V

OH

Output Voltage Swing High VS = 3V, No Load ● 2.95 2.978 V

V

= 3V, I

S

= 5mA ● 250 500 mV

SINK

= 10mA 330 500 mV

SINK

= 5mA ● 2.55 2.6 V

SOURCE

VS = 5V, No Load ● 4.95 4.978 V VS = 5V, I

I

SC

Short-Circuit Current (Note 2) VS = 3V, Short to GND 10 15 mA

VS = 3V, Short to V

= 10mA ● 4.30 4.6 V

SOURCE

CC

10 30 mA

VS = 5V, Short to GND 15 25 mA VS = 5V, Short to V

CC

PSRR Power Supply Rejection Ratio VS = 2.5V to 12.5V, V

= VO = 1V ● 84 98 dB

CM

15 30 mA

Minimum Operating Supply Voltage ● 2 2.5 V Reverse Supply Voltage IS = –100µA per Amplifier ● 18 27 V

I

S

Supply Current per Amplifier 40 50 µA (Note 5)

● 55 µA

GBW Gain Bandwidth Product f = 1kHz 110 180 kHz

(Note 4) 0°C ≤ T

≤ 70°C ● 100 kHz

A

–40°C ≤ TA ≤ 85°C ● 90 kHz

SR Slew Rate AV = –1, RL = ∞ 0.035 0.06 V/µs

(Note 6) 0°C ≤ TA ≤ 70°C ● 0.031 V/µs

–40°C ≤ TA ≤ 85°C ● 0.030 V/µs

3

LT1490/LT1491

ELECTRICAL CHARACTERISTICS

range, otherwise specifications are at TA = 25°C. VS = ±15V, VCM = 0V, V

The ● denotes specifications which apply over the full operating temperature

= 0V, unless otherwise noted. (Note 3)

OUT

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

OS

Input Offset Voltage LT1490 N, S Package 250 1200 µV

≤ 70°C ● 1400 µV

0°C ≤ T

A

–40°C ≤ T

≤ 85°C ● 1500 µV

A

LT1491 N Package 350 1250 µV 0°C ≤ T

≤ 70°C ● 1500 µV

A

–40°C ≤ T

≤ 85°C ● 1600 µV

A

LT1490CMS8 Package, LT1491 S Package 400 1600 µV 0°C ≤ T

≤ 70°C ● 1850 µV

A

–40°C ≤ T

≤ 85°C ● 1950 µV

A

VOS TC Input Offset Voltage Drift 0°C ≤ TA ≤ 70°C (Note 7) ● 36 µV/°C

–40°C ≤ T

I

OS

I

B

Input Offset Current ● 0.2 0.8 nA Input Bias Current ● 48 nA Input Noise Voltage 0.1Hz to 10Hz 1 µV

e

n

i

n

R

IN

Input Noise Voltage Density f = 1kHz 50 nV/√Hz Input Noise Current Density f = 1kHz 0.03 pA/√Hz Input Resistance Differential 6 17 MΩ

Common Mode, V

C

IN

Input Capacitance 4.6 pF

≤ 85°C (Note 7) ● 36 µV/°C

A

= –15V to 14V 15000 MΩ

CM

P-P

Input Voltage Range ● –15 29 V

CMRR Common Mode Rejection Ratio V A

VOL

V

O

I

SC

Large-Signal Voltage Gain VO = ±14V, RL = 10k 100 250 V/mV

Output Voltage Swing No Load ● ±14.9 ±14.978 V

Short-Circuit Current (Note 2) Short to GND ±20 ±25 mA

= –15V to 29V ● 80 98 dB

CM

≤ 70°C ● 75 V/mV

0°C ≤ T

A

–40°C ≤ T

I

OUT

I

OUT

0°C ≤ T –40°C ≤ T

≤ 85°C ● 50 V/mV

A

= ±5mA ● ±14.5 ±14.750 V = ±10mA ±14.5 ±14.670 V

≤ 70°C ● ±15 mA

A

≤ 85°C ● ±10 mA

A

PSRR Power Supply Rejection Ratio VS = ±1.25V to ±22V ● 88 98 dB I

S

Supply Current per Amplifier 50 70 µA

● 85 µA

GBW Gain Bandwidth Product f = 1kHz 125 200 kHz

≤ 70°C ● 110 kHz

0°C ≤ T

A

–40°C ≤ T

≤ 85°C ● 100 kHz

A

SR Slew Rate AV = –1, RL = ∞, VO = ±10V, 0.0375 0.07 V/µs

Measure at V 0°C ≤ T

= ±5V

O

≤ 70°C ● 0.0330 V/µs

A

–40°C ≤ TA ≤ 85°C ● 0.0300 V/µs

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

Note 2: A heat sink may be required to keep the junction temperature below absolute maximum. This depends on the power supply voltage and how many amplifiers are shorted.

Note 3: The LT1490C/LT1491C are guaranteed to meet specified performance from 0°C to 70°C. The LT1490C/LT1491C 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.

4

The LT1490I/LT1491I are guaranteed to meet specified performance from –40°C to 85°C.

Note 4: V V

S

Note 5: V V

S

Note 6: Guaranteed by correlation to slew rate at V at V

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

S

= ±15V tests.

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

S

= ±15V tests.

= 3V and VS = ±15V tests.

S

= ±15V and GBW

S

Note 7: This parameter is not 100% tested.

COMMON MODE VOLTAGE (V)

4.0

INPUT BIAS CURRENT (nA)

2000

6000

5.6

1490/91 G03

30

10

4000

20

0

–10

4.4

4.8

5.2

44

TA = 125°C

TA = –55°C

TA = 25°C

VS = 5V, 0V

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Supply Current vs Supply Voltage

80

70

60

50

40

30

20

10

SUPPLY CURRENT PER AMPLIFIER (µA)

0

515

10

0

TOTAL SUPPLY VOLTAGE (V)

TA = 125°C

TA = 25°C

T

= –55°C

A

25 45

30

20

35

40

1490/91 G01

Minimum Supply Voltage

400

300

200

100

–100

–200

–300

CHANGE IN INPUT OFFSET VOLTAGE (µV)

–400

0

TA = 25°C

TA = 125°C

1

2

TOTAL SUPPLY VOLTAGE (V)

–55°C

T

A =

3

4

LT1490/LT1491

Input Bias Current vs Common Mode Voltage

5

1490/91 G02

Output Saturation Voltage vs Load Current (Output High)

1

VS = ±2.5V

= 30mV

V

OD

T

= 125°C

0.1

OUTPUT SATURATION VOLTAGE (V)

0.01

0.001 0.01 0.1 1 10

A

TA = 25°C

TA = –55°C

SOURCING LOAD CURRENT (mA)

0.1Hz to 10Hz Noise Voltage

VS = ±2.5V

1490/90 G04

Output Saturation Voltage vs Load Current (Output Low)

1

VS = ±2.5V

= 30mV

V

OD

T

= 125°C

0.1

TA = 25°C

OUTPUT SATURATION VOLTAGE (V)

0.01

0.001 0.01 0.1 1 10

A

TA = –55°C

SINKING LOAD CURRENT (mA)

Noise Voltage Density vs Frequency

80

70

60

1490/90 G05

Output Saturation Voltage vs Input Overdrive

100

90 80 70 60 50 40 30 20

OUTPUT SATURATION VOLTAGE (mV)

10

0

20

30

10 90

0

INPUT OVERDRIVE (mV)

40

OUTPUT HIGH

OUTPUT LOW

60

50

70

Input Noise Current vs Frequency

0.35

0.30

0.25

0.20

VS = ±2.5V NO LOAD

80

1490/91 G06

100

NOISE VOLTAGE (400nV/DIV)

2468

TIME (SEC)

1490 G07

10103579

INPUT NOISE VOLTAGE DENSITY (nV/√Hz)

INPUT NOISE CURRENT DENSITY (pA/√Hz)

0.15

0.10

0.05

0

1

10 100 1k

FREQUENCY (Hz)

1490/91 G09

50

40

30

1

10 100 1k

FREQUENCY (Hz)

1490/91 G08

5

LT1490/LT1491

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Gain and Phase Shift vs Frequency

70 60 50 40 30

20

GAIN (dB)

10

0

–10 –20 –30

1

PHASE

GAIN

10 100 1000 FREQUENCY (kHz)

Gain Bandwidth Product and Phase Margin vs Supply Voltage

250

240

230

220

210

200

190

180

170

GAIN BANDWIDTH PRODUCT (kHz)

RL = 10k

160

f = 1kHz

150

515

10

0

TOTAL SUPPLY VOLTAGE (V)

PHASE MARGIN

GAIN BANDWIDTH

25 45

30

20

VS = ±2.5V

1490/91 G10

35

40

1490/91 G13

100

80 60

PHASE SHIFT (DEG)

40 20

0 –20 –40 –60 –80 –100

60

50

PHASE MARGIN (DEG)

40

30

20

COMMON MODE REJECTION RATIO (dB)

10

Gain Bandwidth Product vs Temperature

260

f = 1kHz

240

220

200

180

160

140

GAIN BANDWIDTH PRODUCT (kHz)

120

100

–50

–25

V

S

0

= ±3V

50

25

TEMPERATURE (°C)

CMRR vs Frequency

120

100

80

60

40

20

1

VS = ±15V

VS = ±1.5V

10

FREQUENCY (kHz)

VS = ±15V

75

100

1490/91 G11

100

1490 G14

Slew Rate vs Temperature

0.12

0.10

0.08

SLEW RATE (V/µs)

0.06

0.04

125

–50

–25

0

TEMPERATURE (°C)

PSRR vs Frequency

80

VS = ±2.5V

70 60 50 40

30 20

NEGATIVE SUPPLY

10

0

–10

POWER SUPPLY REJECTION RATIO (dB)

–20

1

FREQUENCY (kHz)

RISING, VS = ±15V

RISING, V

FALLING, VS = ±15V

FALLING, V

50

25

POSITIVE SUPPLY

10 100

75

= ±1.5V

S

= ±1.5V

S

100

1490/91 G12

1490/91 G15

125

Gain Bandwidth Product and Phase Margin vs Load Resistance

350

300

PHASE MARGIN

250

200

150

100

GAIN BANDWIDTH PRODUCT (kHz)

50

1

LOAD RESISTANCE (kΩ)

GAIN BANDWIDTH

10 100

6

VS = ±2.5V

= –1

A

V

R

= RG = 100k

F

f = 1kHz

1490/91 G16

80

70

60

50

40

30

20

130

120

110

PHASE MARGIN (DEG)

100

CHANNEL SEPARATION (dB)

Channel Separation vs Frequency

VS = ±15V

90

80

70

60

50

40

0.1

1 10 100

FREQUENCY (kHz)

1490/91 G17

Output Impedance vs Frequency

10k

VS = ±2.5V

1k

= 100

A

V

100

AV = 10

10

OUTPUT IMPEDANCE (Ω)

0.1

AV = 1

1

0.1

1 10 100

FREQUENCY (kHz)

1490/91 G18

UW

TYPICAL PERFOR A CE CHARACTERISTICS

LT1490/LT1491

Undistorted Output Swing vs Frequency

35

VS = ±15V

30

)

25

P-P

20

15

10

OUTPUT SWING (V

VS = ±2.5V

5

0

0.1

1 10 100

FREQUENCY (kHz)

DISTORTION ≤1%

Total Harmonic Distortion + Noise vs Frequency

10

VS = 3V, 0V

= 2V

V

OUT

P-P

VCM = 1.2V

= 50k

R

L

1

0.1

THD + NOISE (%)

0.01

0.001

AV = –1

AV = 1

0.01 1 10

0.1

FREQUENCY (kHz)

1490/91 G19

1490/91 G22

Settling Time to 0.1% vs Output Step

10

VS = ±15V

8 6 4 2 0

–2

OUTPUT STEP (V)

–4 –6

–8

–10

0

20 60

AV = –1

40

80

SETTLING TIME (µs)

AV = 1

100

120

Total Harmonic Distortion + Noise vs Load Resistance

10

VS = 3V TOTAL

= 1

A

V

= 2V

V

1

0.1

THD + NOISE (%)

0.01

0.001

0.1 10 100

AT 1kHz

IN

P-P

VS = ±1.5V

= ±1V

V

IN

V

= 3V, 0V

S

= 0.5V TO 2.5V

V

IN

VS = 3V, 0V

= 0.2V TO 2.2V

V

IN

1

LOAD RESISTANCE TO GROUND (kΩ)

AV = –1

140

1490/91 F20

1490/91 G23

160

Capacitive Load Handling, Overshoot vs Capacitive Load

100

VS = 5V, 0V

90 80 70 60 50 40

OVERSHOOT (%)

30 20 10

0

= 170µA

I

SOURCE

A

= 1 AV = 2 AV = 5

V

10 100 1000 10000

CAPACITIVE LOAD (pF)

AV = 10

1490/91 G21

Total Harmonic Distortion + Noise vs Output Voltage

10

RL = 10k

= HALF SUPPLY

V

CM

f = 1kHz

1

AV = –1

= ±1.5V

V

S

0.1

THD + NOISE (%)

0.01 AV = 1

= 3V, 0V

V

S

0.001 023

AV = 1

= ±1.5V

V

S

1

OUTPUT VOLTAGE (V

V

P-P

AV = –1

= 3V, 0V

S

)

1490/91 G24

Open-Loop Gain Large-Signal Response Small-Signal Response

VS = ±15V

RL = 2k

= 50k

R

(100µV/DIV)

CHANGE IN INPUT OFFSET VOLTAGE

L

–10V 0V 10V 1490/91 G25

OUTPUT VOLTAGE (5V/DIV)

RL = 10k

VS = ±15V

= –1

A

V

1490/91 G26

V

S

A

V

= ±15V = 1

1490/91 G27

7

LT1490/LT1491

WUUU

APPLICATIO S I FOR ATIO

Supply Voltage

The positive supply pin of the LT1490/LT1491 should be bypassed with a small capacitor (about 0.01µF) within an inch of the pin. When driving heavy loads an additional

4.7µF electrolytic capacitor should be used. When using split supplies, the same is true for the negative supply pin.

The LT1490/LT1491 are protected against reverse battery voltages up to 18V. In the event a reverse battery condition occurs, the supply current is less than 1nA.

The LT1490/LT1491 can be shut down by removing V+. In this condition the input bias current is less than 0.1nA, even if the inputs are 44V above the negative supply.

When operating the LT1490/LT1491 on total supplies of 30V or more, the supply must not be brought up faster than 1µs. This is especially true if low ESR bypass capaci- tors are used. A series RLC circuit is formed from the supply lead inductance and the bypass capacitor. 5Ω of resistance in the supply or the bypass capacitor will dampen the tuned circuit enough to limit the rise time.

The inputs are protected against excursions as much as 22V below V– by an internal 1k resistor in series with each input and a diode from the input to the negative supply. There is no output phase reversal for inputs up to 22V below V–. There are no clamping diodes between the inputs and the maximum differential input voltage is 44V.

Output

The output voltage swing of the LT1490/LT1491 is affected by input overdrive as shown in the typical performance curves. When monitoring voltages within 100mV of either rail, gain should be taken to keep the output from clipping.

The output of the LT1490/LT1491 can be pulled up to 18V beyond V+ with less than 1nA of leakage current, provided that V+ is less than 0.5V.

The normally reverse-biased substrate diode from the output to V– will cause unlimited currents to flow when the output is forced below V–. If the current is transient and limited to 100mA, no damage will occur.

Inputs

The LT1490/LT1491 have two input stages, NPN and PNP (see the Simplified Schematic), resulting in three distinct operating regions as shown in the Input Bias Current vs Common Mode typical performance curve.

For input voltages about 0.8V or more below V+, the PNP input stage is active and the input bias current is typically –4nA. When the input voltage is about 0.5V or less from V+, the NPN input stage is operating and the input bias current is typically 18nA. Increases in temperature will cause the voltage at which operation switches from the PNP stage to the NPN stage to move towards V+. The input offset voltage of the NPN stage is untrimmed and is typically 600µV.

A Schottky diode in the collector of each NPN transistor of the NPN input stage allows the LT1490/LT1491 to operate with either or both of its inputs above V+. At about 0.3V above V+ the NPN input transistor is fully saturated and the input bias current is typically 4µA at room temperature. The input offset voltage is typically 700µV when operating above V+. The LT1490/LT1491 will operate with its inputs 44V above V– regardless of V+.

The LT1490/LT1491 is internally compensated to drive at least 200pF of capacitance under any output loading conditions. A 0.22µF capacitor in series with a 150Ω resistor between the output and ground will compensate these amplifiers for larger capacitive loads, up to 10,000pF, at all output currents.

Distortion

There are two main contributors of distortion in op amps: output crossover distortion as the output transitions from sourcing to sinking current and distortion caused by nonlinear common mode rejection. Of course, if the op amp is operating inverting there is no common mode induced distortion. When the LT1490 switches between input stages there is significant nonlinearity in the CMRR. Lower load resistance increases the output crossover distortion, but has no effect on the input stage transition distortion. For lowest distortion the LT1490/LT1491 should be operated single supply, with the output always sourcing current and with the input voltage swing between ground and (V+ – 0.8V). See the Typical Performance Characteristics curves.

8

WUUU

APPLICATIO S I FOR ATIO

LT1490/LT1491

Gain

The open-loop gain is almost independent of load when the output is sourcing current. This optimizes perfor-

U

TYPICAL APPLICATIO S

Square Wave Oscillator Optional Output Compensation for

+

1/2 LT1490

–

59k

R

50k

1490/91 TA02

V

OUT

5V

100k

C

0.1µF

1

f =

2RC

= 5V

V

OUT

= 200µA

I

S

AT VS = 5V, R = 50k, C = 1nF OUTPUT IS 5kHz SLEW LIMITED TRIANGLE WAVE

WITH 5V SUPPLY

P-P

mance in single supply applications where the load is returned to ground. The typical performance photo of Open-Loop Gain for various loads shows the details.

Capacitive Loads Greater Than 200pF

V

IN

+

1/2 LT1490

–

CL ≤ 10,000pF

0.22µF

150Ω

1490/91 TA04

WW

SI PLIFIED SCHE ATIC

Q1

D1

R1 30k

Q4

+

2µA

Q5

ONE AMPLIFIER

–IN

+IN

R2 1k

Q7

R3 1k

Q9

D5

Q6

D4

Q8

Q10

D2

Q2

Q11 Q12

Q13 Q14

R4 40k

R5 40k

Q15

D3

Q3

Q17 Q20

Q16 Q18

Q19

Q22

Q21

OUT

1490/91 SS

+

V

–

V

9

LT1490/LT1491

PACKAGE DESCRIPTIO

0.007

(0.18)

0.021

± 0.006

(0.53 ± 0.015)

* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,

PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

° – 6° TYP

0

U

Dimensions in inches (millimeters) unless otherwise noted.

MS Package

8-Lead Plastic MSOP

(LTC DWG # 05-08-1660)

0.118 ± 0.004* (3.00 ± 0.102)

0.193 ± 0.006

(4.90 ± 0.15)

SEATING

PLANE

0.040

± 0.006

(1.02 ± 0.15)

0.012 (0.30)

0.0256

REF

(0.65)

BSC

0.034 ± 0.004

(0.86 ± 0.102)

0.006 ± 0.004

(0.15 ± 0.102)

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

8

7

12

6

5

0.118 ± 0.004**

4

3

(3.00 ± 0.102)

MSOP (MS8) 1098

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)

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)

TYP

0°– 8° TYP

0.045 – 0.065

(1.143 – 1.651)

0.100

(2.54)

BSC

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.018 ± 0.003

(0.457 ± 0.076)

0.020

(0.508)

MIN

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

TYP

0.004 – 0.010

(0.101 – 0.254)

0.050

(1.270)

BSC

0.255 ± 0.015* (6.477 ± 0.381)

0.228 – 0.244

(5.791 – 6.197)

0.400* (10.160)

876

12

0.189 – 0.197* (4.801 – 5.004)

7

8

1

2

MAX

6

3

5

4

3

N8 1098

5

0.150 – 0.157**

4

(3.810 – 3.988)

SO8 1298

10

PACKAGE DESCRIPTIO

U

Dimensions in inches (millimeters) unless otherwise noted.

N Package

14-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.770*

(19.558)

MAX

14

0.255 ± 0.015* (6.477 ± 0.381)

11

1213

8910

LT1490/LT1491

0.300 – 0.325

(7.620 – 8.255)

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)

0.020

(0.508)

MIN

0.130 ± 0.005

(3.302 ± 0.127)

0.125

(3.175)

MIN

0.005

(0.125)

MIN

S Package

14-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

13

14

0.228 – 0.244

(5.791 – 6.197)

2

(2.54)

31

0.045 – 0.065

(1.143 – 1.651)

0.100

BSC

0.337 – 0.344* (8.560 – 8.738)

12

6

9

7

0.065

(1.651)

TYP

0.018 ± 0.003

(0.457 ± 0.076)

N14 1098

8

0.150 – 0.157** (3.810 – 3.988)

5

4

11

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)

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.

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

TYP

1

3

2

4

0.050

(1.270)

BSC

5

7

6

0.004 – 0.010

(0.101 – 0.254)

S14 1298

11

LT1490/LT1491

TYPICAL APPLICATIO

R2

47k

R1 33k

3

+

1/4 LT1491

2

–

C1 1µF

R4

1.6M

1

R3 10k

0.47µF

D1

1N4148

C2

R5 100k

5

6

U

+

1/4 LT1491

–

R8

620k

20Hz OSCILLATORCADENCE OSCILLATOR

R6

10k

R7

16k

Ring-Tone Generator

60V

R16

100k

Q1

IRF628

C3

0.047µF

R9

300k

7

R11 10k

10

C4

0.068µF

R10

SMOOTHING FILTER

620k

+

1/4 LT1491

9

–

0.01µF

8

13

–

1/4 LT1491

12

R12

10k

C5

R13

130k

R14 10k

R15 47k

+

Z1

15V

100k

4

14

C7

R24

11

420

47µF

2N3904

R17

620Ω

R18

100Ω

R23

4.7k

R25

4.7k

Q3

R26 2k

OPTO1*

Q5 2N3904

LOAD

R21 150Ω

C6

0.033µF

1490/1491 TA03

*LED OF OPTO1 ILLUMINATES WHEN THE PHONE IS OFF THE HOOK SEE DESIGN NOTE DN134 FOR AN EXPLANATION OF THE CIRCUIT

IRF9620

POWER AMPLIFIER

Q2

–180V

Z2

15V

R20

100k

R19 620Ω

Q4 2N3906

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

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, 500V/mV A

OS(MAX)

, Improved Version of the LT1490/LT1491

OS(MAX)

C-Load is a trademark of Linear Technology Corporation.

, 100nV/°C, 1MHz GBW,

OS(MAX)

, 400kHz GBW

VOL(MIN)

UP TO TEN PHONES

OS(MAX)

12

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417 ● (408) 432-1900 FAX: (408) 434-0507

●

TELEX: 499-3977 ● www.linear-tech.com

14901fb LT/LCG 0600 2K REV B • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1996

ANALOG DEVICES LT 1490 ACS8 Datasheet

Specifications and Main Features

Frequently Asked Questions

User Manual