LT1638CS8_技术文档

LT1638/LT1639

1.2MHz, 0.4V/µs

Over-The-Top^TMMicropower

Rail-to-Rail Input and Output

Op Amps

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FEATURES

DESCRIPTION

The LT^®1638 is a low power dual rail-to-rail input and output

operationalamplifieravailableinthestandard8-pinPDIPand

SO packages as well as the 8-lead MSOP package. The

LT1639 is a low power quad rail-to-rail input and output

operational amplifier offered on the standard 14-pin PDIP

and surface mount packages.

Operates with Inputs Above V⁺

■

Rail-to-Rail Input and Output

Low Power: 230µA per Amplifier Max

■

Gain Bandwidth Product: 1.2MHz

Slew Rate: 0.4V/µs

High Output Current: 25mA Min

Specified on 3V, 5V and ±15V Supplies

Reverse Battery Protection to 18V

No Supply Sequencing Problems

High Voltage Gain: 1500V/mV

Single Supply Input Range: –0.4V to 44V

High CMRR: 98dB

The LT1638/LT1639 op amps operate on all single and

split supplies with a total voltage of 2.5V to 44V drawing

only 170µA of quiescent current per amplifier. These

amplifiers are reverse battery protected and draw no

current for reverse supply up to 18V.

The input range of the LT1638/LT1639 includes both

supplies,andauniquefeatureofthisdeviceisitscapability

to operate over the top with either or both of its inputs

above V⁺. The inputs handle 44V, both differential and

common mode, independent of supply voltage. The input

stage incorporates phase reversal protection to prevent

falseoutputsfromoccurringevenwhentheinputsare22V

below the negative supply. Protective resistors are

included in the input leads so that current does not

become excessive when the inputs are forced below the

negativesupply.TheLT1638/LT1639candriveloadsupto

25mAandstillmaintainrail-to-railcapability.Theopamps

are unity-gain stable and drive all capacitive loads up to

1000pF when optional output compensation is used.

No Phase Reversal

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APPLICATIONS

■

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.

Over-The-Top is a trademark of Linear Technology Corporation.

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TYPICAL APPLICATION

Output Voltage vs Input Voltage

Over-The-Top Comparator with 100mV Hysteresis Centered at 0mV

5V

0V

V

CC

10k

1M

V1

V

CC

V

CC

1M

+

A

B

V0

1/2 LT1638

1M

–

10k

1M

1638/39 TA01

V2

1638/39 TA02

V

= 5V, V

= 0V TO 44V, t = 27µs

CM PD

CC

1

LT1638/LT1639

W W

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ABSOLUTE MAXIMUM RATINGS

(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

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

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

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

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

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PACKAGE/ORDER INFORMATION

TOP VIEW

+

OUT A

–IN A

+IN A

1

2

3

4

5

6

7

14 OUT D

13 –IN D

1

2

3

4

8

7

6

5

OUT A

–IN A

+IN A

V

OUT A

–IN A

+IN A

1

2

3

4

8 V+

OUT B

–IN B

+IN B

7 OUT B

6 –IN B

5 +IN B

A

B

D

C

A

12 +IN D

–

V

+

B

V

11

V

–

V

MS8 PACKAGE

8-LEAD PLASTIC MSOP

+IN B

–IN B

OUT B

10 +IN C

S8 PACKAGE

8-LEAD PLASTIC SO

N8 PACKAGE

8-LEAD PDIP

9

8

– IN C

OUT C

T_JMAX= 150°C, θ_JA= 250°C/ W (MS8)

T_JMAX= 150°C, θ_JA= 130°C/ W (N8)

_JMAX= 150°C, θ_JA= 190°C/ W (S8)

T

N PACKAGE

S PACKAGE

14-LEAD PDIP 14-LEAD PLASTIC SO

ORDER PART NUMBER

LT1638CMS8

ORDER PART NUMBER

T_JMAX= 150°C, θ_JA= 110°C/ W (N)

T

_JMAX= 150°C, θ_JA= 150°C/ W (S)

LT1638CN8

LT1638CS8

LT1638IS8

LT1638IN8

ORDER PART NUMBER

MS8 PART MARKING

S8 PART MARKING

LT1639CN

LT1639IN

LT1639CS

LT1639IS

1638

1638I

LTCY

Consult factory for Military grade parts.

ELECTRICAL CHARACTERISTICS

V_S= 3V, 0V; V_S= 5V, 0V; V_CM= V_OUT= half supply, T_A= 25°C, unless otherwise noted. (Note 3)

SYMBOL

PARAMETER

CONDITIONS

LT1638 N, S Packages

MIN

TYP

MAX

UNITS

V

OS

Input Offset Voltage

200

600

850

950

µV

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

LT1639 N, S Packages

300

350

700

950

µV

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

1050

A

LT1638C MS8 Package

900

1150

1250

µV

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

Input Offset Voltage Drift

(Note 7)

LT1638/LT1639 N, S Packages

LT1638CMS8

●

2

2.5

6

7

µV/°C

I

Input Offset Current

●

1

6

2.5

nA

µA

OS

V

= 44V (Note 4)

CM

2

LT1638/LT1639

ELECTRICAL CHARACTERISTICS

V_S= 3V, 0V; V_S= 5V, 0V; V_CM= V_OUT= half supply, T_A= 25°C, unless otherwise noted. (Note 3)

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

I

Input Bias Current

●

20

8

0.1

50

30

nA

µA

nA

B

V

S

= 44V (Note 4)

CM

V = 0V

Input Noise Voltage

0.1Hz to 10Hz

f = 1kHz

1

µV

P-P

e

Input Noise Voltage Density

Input Noise Current Density

Input Resistance

20

0.3

nV/√Hz

pA/√Hz

n

i

f = 1kHz

n

R

Differential

Common Mode, V = 0V to 44V

1

1.4

2.5

5.5

MΩ

IN

CM

C

Input Capacitance

5

pF

V

IN

Input Voltage Range

●

0

44

CMRR

Common Mode Rejection Ratio

V

CM

V

CM

= 0V to V – 1V

●

88

80

98

88

dB

CC

= 0V to 44V (Note 8)

A

Large-Signal Voltage Gain

V = 3V, V = 500mV to 2.5V, R = 10k

200

133

100

1500

V/mV

VOL

S

O

L

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

V = 5V, V = 500mV to 4.5V, R = 10k

400

250

200

1500

V/mV

S

O

L

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

V

Output Voltage Swing Low

Output Voltage Swing High

Short-Circuit Current (Note 2)

V = 3V, No Load

●

3

8

mV

OL

OH

S

V = 3V, I

= 5mA

250

450

S

SINK

V = 5V, No Load

●

3

500

8

700

mV

S

V = 5V, I

S

= 10mA

SINK

V = 3V, No Load

●

2.94

2.25

2.98

2.40

V

S

V = 3V, I

= 5mA

S

SOURCE

V = 5V, No Load

●

4.94

3.8

4.98

4.0

V

S

V = 5V, I

S

= 10mA

SOURCE

I

V = 3V, Short to GND

10

15

25

mA

SC

S

V = 3V, Short to V

S

CC

V = 5V, Short to GND

15

20

25

mA

S

V = 5V, Short to V

S

CC

PSRR

Power Supply Rejection Ratio

Reverse Supply Voltage

V = 3V to 12.5V, V = V = 1V

●

90

18

100

27

dB

V

S

CM

O

I = –100µA per Amplifier

S

Minimum Operating Supply Voltage

2.4

170

2.7

V

I

Supply Current per Amplifier

(Note 5)

230

275

µA

S

●

GBW

SR

Gain Bandwidth Product

(Note 4)

f = 1kHz

650

550

500

1075

0.38

kHz

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

Slew Rate

(Note 6)

A = –1, R = ∞

0.210

0.185

0.170

V/µs

V

L

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

3

LT1638/LT1639

ELECTRICAL CHARACTERISTICS V_S=

±15V, V_CM= 0V, V_OUT= 0V, T_A= 25°C, unless otherwise noted. (Note 3)

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

V

OS

Input Offset Voltage

LT1638 N, S Packages

250

800

1000

1100

µV

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

LT1639 N, S Packages

350

400

900

1100

1200

µV

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

LT1638C MS8 Package

1050

1250

1350

µV

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

Input Offset Voltage Drift

(Note 7)

LT1638/LT1639 N, S Packages

LT1638CMS8

●

2

2.5

6

7

µV/°C

I

Input Offset Current

Input Bias Current

●

1

20

1

6

nA

OS

50

B

Input Noise Voltage

Input Noise Voltage Density

Input Noise Current Density

Input Resistance

0.1Hz to 10Hz

f = 1kHz

µV

P-P

e

20

0.3

nV/√Hz

pA/√Hz

n

i

n

f = 1kHz

R

Differential

Common Mode, V = –15V to 14V

1

2.5

500

MΩ

IN

CM

C

Input Capacitance

4.5

pF

V

IN

Input Voltage Range

●

–15

80

29

CMRR

Common Mode Rejection Ratio

Large-Signal Voltage Gain

V

= –15V to 29V

88

dB

CM

A

VOL

V = ±14V, R = 10k

200

125

100

500

V/mV

O

L

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

V

OL

Output Voltage Swing

No Load

●

14.9

13.7

14.95

14.0

V

I

= ±10mA

OUT

I

Short-Circuit Current (Note 2)

Short to GND

0°C ≤ T ≤ 70°C

25

20

15

40

mA

SC

●

A

–40°C ≤ T ≤ 85°C

A

PSRR

Power Supply Rejection Ratio

Supply Current per Amplifier

V = ±1.5V to ±22V

S

●

90

100

205

dB

I

280

350

µA

S

●

GBW

SR

Gain Bandwidth Product

Slew Rate

f = 1kHz

750

650

600

1200

0.4

kHz

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

A = –1, R = ∞, V = ±10V,

0.225

0.2

0.18

V/µs

V

L

O

0°C ≤ T ≤ 70°C

●

A

–40°C ≤ T ≤ 85°C

A

Note 4: V = 5V limits are guaranteed by correlation to V = 3V and

The

● denotes specifications which apply over the full specified

S

V = ±15V tests.

S

temperature range.

Note 5: V = 3V limits are guaranteed by correlation to V = 5V and

Note 1: Absolute Maximum Ratings are those values beyond which the

S

V = ±15V tests.

S

life of a device may be impaired.

Note 6: Guaranteed by correlation to slew rate at V = ±15V and GBW

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 LT1638C/LT1639C are guaranteed to meet 0°C to 70°C

specifications and are designed, characterized and expected to meet

the extended temperature limits, but are not tested at –40°C and 85°C.

The LT1638I/LT1639I are guaranteed to meet the extended

temperature limits.

S

at V = 3V and V = ±15V tests.

S

Note 7: This parameter is not 100% tested.

Note 8: The spec implies a typical offset voltage at V = 44 of 2mV and

CM

a maximum offset voltage at V = 44 of 5mV.

CM

4

LT1638/LT1639

W

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TYPICAL PERFORMANCE CHARACTERISTICS

Input Bias Current vs

Common Mode Voltage

Supply Current vs Supply Voltage

Minimum Supply Voltage

400

300

280

260

240

220

200

180

160

140

120

100

10000

8000

6000

V

= 5V, 0V

S

T

= 125°C

A

200

100

T

= 25°C

A

T

= –55°C

A

60

40

0

T

= 25°C

A

–100

T

A

= –55°C

20

T

= –55°C

T

= 125°C

T

A

= 125°C

A

–200

–300

T

= 25°C

0

A

–20

–40

–400

0

1

2

3

4

5

0

5

10 15 20 25 30 35 40 45

SUPPLY VOLTAGE (V)

4.0

4.4

5.2

5.6

44

4.8

TOTAL SUPPLY VOLTAGE (V)

COMMON MODE VOLTAGE (V)

1638/39 G02

1638/39 G01

1638/39 G03

Output Saturation Voltage vs

Load Current (Output High)

Output Saturation Voltage vs

Load Current (Output Low)

Output Saturation Voltage vs

Input Overdrive

1

100

10

1

V

= ±2.5V

V

= ±2.5V

OD

V

= ±2.5V

OD

S

NO LOAD

= 30mV

T

A

= 125°C

OUTPUT HIGH

0.1

T

= 125°C

A

T

A

= 25°C

T

A

= 25°C

0.1

0.01

OUTPUT LOW

T

A

= –55°C

T

= –55°C

A

0.01

0.001

0.01

0.1

1

10

10 20

40

60 70 80 100

90

0.001

0.01

0.1

1

10

0

30

50

SOURCING LOAD CURRENT (mA)

SINKING LOAD CURRENT (mA)

INPUT OVERDRIVE (mV)

1638/39 G04

1638/39 G06

1638/39 G05

Noise Voltage Density vs

Frequency

Input Noise Current Density

vs Frequency

0.1Hz to 10Hz Noise Voltage

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

70

60

50

40

30

20

10

0

V

= ±2.5

S

0

1

2

3

4

5

6

7

8

9

10

1

10

100

1k

1

10

100

1k

TIME (SEC)

FREQUENCY (Hz)

1638/39 G08

1638/39 G09

1638/39 G07

5

LT1638/LT1639

TYPICAL PERFORMANCE CHARACTERISTICS

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Gain and Phase Shift vs

Frequency

Gain Bandwith Product vs

Temperature

Slew Rate vs Temperature

100

90

80

70

60

50

40

1500

1400

1300

1200

1100

1000

900

0.60

0.55

0.50

0.45

0.40

0.35

0.30

0.25

f = 1kHz

V

= ±2.5V

S

RISING, V = ±15V

80

S

PHASE

70

V

= ±15V

RISING, V = ±2.5V

S

60

50

30

20

GAIN

40

30

20

10

0

FALLING, V = ±2.5V

S

10

0

FALLING, V = ±15V

V

S

= ±2.5V

S

–10

–20

800

1

10

100

1000

0

25

50

75 100 125

–50

0

25

TEMPERATURE (°C)

50

75 100 125

–50

–25

FREQUENCY (kHz)

TEMPERATURE (°C)

1638/39 G12

1638/39 G13

1638/39 G14

Gain Bandwidth Product and

Phase Margin vs Supply Voltage

Gain Bandwidth Product and

Phase Margin vs Load Resistance

PSRR vs Frequency

1500

1400

1300

1200

1100

1000

60

50

40

30

20

10

1500

1400

1300

1200

1100

1000

900

60

50

40

30

20

10

0

90

80

70

60

50

40

30

20

10

0

V

A

= ±2.5V

V

= ±2.5V

S

V

F

S

= –1

R = R = 100k

G

f = 1kHz

PHASE MARGIN

POSITIVE SUPPLY

GAIN BANDWIDTH

NEGATIVE SUPPLY

GAIN BANDWIDTH

PRODUCT

800

–10

100

–10

1

10

LOAD RESISTANCE (kΩ)

0

5

10 15 20 25 30

35 40

TOTAL SUPPLY VOLTAGE (V)

45

1

10

100

1000

FREQUENCY (kHz)

1638/39 G17

1638/39 G16

1638/39 G15

CMRR vs Frequency

Output Impedance vs Frequency

Channel Separation vs Frequency

120

110

100

90

130

120

110

100

90

10k

1k

V

= ±15V

V

= ±2.5V

S

V

S

= ±15V

S

A

V

= 10

80

100

10

A

V

= 100

70

60

50

A

V

= 1

80

40

1

70

30

60

0.1

20

0.1

1

10

100

1000

1

10

100

1

10

FREQUENCY (kHz)

100

1000

FREQUENCY (kHz)

1638/39 G20

1638/39 G18

1638/39 G19

6

LT1638/LT1639

W

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TYPICAL PERFORMANCE CHARACTERISTICS

Settling Time to 0.1% vs

Output Step

Capacitive Load Handling,

Undistorted Output Swing

vs Frequency

Overshoot vs Capacitive Load

100

90

80

70

60

50

40

30

20

10

0

10

8

35

30

25

20

15

10

5

V

= ±15V

V

= 5V, 0V

DISTORTION ≤ 1%

L

S

V

S

= ±15V

= 2.5V

R = 20k

CM

A

= 1

V

I

= 150µA

SOURCE

6

A

= –1

V

4

2

0

A

= 5

V

A

= 1

–2

–4

–6

–8

–10

V

A

= 10

A

= –1

25

V

= ±2.5V

S

A

= 1

V

0

20

30

35

10

100

1000

10000

5

10

15

0.1

1

10

100

CAPACITIVE LOAD (pF)

SETTLING TIME (µs)

FREQUENCY (kHz)

1638/39 G22

1638/39 G23

1638/39 G21

Total Harmonic Distortion + Noise

vs Frequency

Total Harmonic Distortion + Noise

vs Load Resistance

Total Harmonic Distortion + Noise

vs Output Voltage

10

1

10

1

10

1

V

A

V

= 3V TOTAL

= 1

R

CM

= 10k, f = 1kHz

V

= 3V, 0V

S

V

L

S

V

= HALF SUPPLY

= 2V

OUT

P-P

= 2V AT 1kHz

A = –1, V = ±1.5V

= 1.2V

IN

P-P

V

S

CM

A

= –1, V = 3V, 0V

R

L

= 20k

S

= 1, V = ±1.5V

S

= 1, V = 3V, 0V

S

V

= ±1.5V

= ±1V

S

IN

0.1

V

= 3V, 0V

IN

S

= 0.5V TO 2.5V

0.01

0.001

0.01

A

= –1

= 1

V

= 3V, 0V

= 0.2V TO 2.2V

A

S

IN

V

0.001

0

1

2

3

0.01

0.1

1

10

100

0.1

1

10

100

OUTPUT VOLTAGE (V

)

P-P

FREQUENCY (Hz)

LOAD RESISTANCE TO GROUND (kΩ)

1638/39 G26

1638/39 G24

1638/39 G25

Open-Loop Gain

Large-Signal Response

Small-Signal Response

V

= ±15V

S

R = 2k

L

R = 10k

L

R = 50k

L

V_S= ±15V

A_V= 1

V

_S= ±15V

A_V= 1

_L= 15pF

1638/39 G29

1638/39 G28

C

–20V

–10V

0V

10V

20V

OUTPUT VOLTAGE (5V/DIV)

1638/39 G27

7

LT1638/LT1639

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APPLICATIONS INFORMATION

Supply Voltage

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.

TheinputstageoftheLT1638/LT1639incorporatesphase

reversal protection to prevent the output from phase

reversing for inputs up to 22V below V^–. There are no

clamping diodes between the inputs and the maximum

differential input voltage is 44V.

The positive supply pin of the LT1638/LT1639 should be

bypassedwithasmallcapacitor(typically0.1µF)withinan

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 LT1638/LT1639 are protected against reverse battery

voltagesupto18V. Intheeventareversebatterycondition

occurs, the supply current is less than 1nA.

Output

The LT1638/LT1639 can be shut down by removingV⁺. In

this condition the input bias current is less than 0.1nA,

even if the inputs are 44V above the negative supply.

The output of the LT1638/LT1639 can swing within 20mV

of the positive rail with no load, and within 3mV of the

negative rail with no load. When monitoring voltages

within 20mV of the positive rail or within 3mV of the

negative rail, gain should be taken to keep the output from

clipping. The LT1638/LT1639 are capable of sinking and

sourcing over 40mA on ±15V supplies; sourcing current

capability is reduced to 20mA at 5V total supplies as noted

in the electrical characteristics.

At temperatures greater than 70°C, when operating the

LT1638/LT1639 on total supplies of 10V or more, the

supply must not be brought up faster than 1V/µs. Increas-

ing the bypass capacitor and/or adding a small resistor in

series with the supply will limit the rise time.

Inputs

The LT1638/LT1639 are 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 1000pF,

at all output currents.

The LT1638/LT1639 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

–20nA. When the input common mode voltage is within

0.5Vofthepositiverail, theNPNstageisoperatingandthe

input bias current is typically 40nA. Increases in tempera-

ture will cause the voltage at which operation switches

from the PNP input stage to the NPN input stage to move

towards V⁺. The input offset voltage of the NPN stage is

untrimmed and is typically 600µV.

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 non-

linear common mode rejection. If the op amp is operating

inverting there is no common mode induced distortion. If

theopampisoperatinginthePNPinputstage(inputisnot

within 0.8V of V⁺), the CMRR is very good, typically 98dB.

When the LT1638 switches between input stages there is

significant nonlinearity in the CMRR. Lower load resis-

tance increases the output crossover distortion, but has

no effect on the input stage transition distortion. For low-

estdistortiontheLT1638/LT1639shouldbeoperatedsingle

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.

A Schottky diode in the collector of each NPN transistor

allow the LT1638/LT1639 to operate over the top, 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 8µA at room temperature. The

inputoffsetvoltageistypically2mVwhenoperatingabove

V⁺. The LT1638/LT1639 will operate with its inputs 44V

above V^–regardless of V⁺.

8

LT1638/LT1639

U

W U U

APPLICATIONS INFORMATION

Gain

mance in single supply applications where the load is

returned to ground. The typical performance curve of

Open-Loop Gain for various loads shows the details.

The open-loop gain is almost independent of load when

the output is sourcing current. This optimizes perfor-

U

TYPICAL APPLICATIONS

V

CC

With 1.2MHz bandwidth, Over-The-Top capability, re-

verse-battery protection and rail-to-rail input and output

features, the LT1638/LT1639 are ideal candidates for

general purpose applications.

R5

100k

+

–

1/4 LT1639

LT1634-1.2V

The lowpass slope limiting filter in Figure 1 limits the

maximum dV/dT (not frequency) that it passes. When the

input signal differs from the output by one forward diode

drop, D1 or D2 will turn on. With a diode on, the voltage

across R2 will be constant and a fixed current, V_DIODE/R2,

will flow through capacitor C1, charging it linearly instead

of exponentially. The maximum slope that the circuit will

pass is equal to V_DIODEdivided by (R2)(C1). No matter

how fast the input changes the output will never change

any faster than the dV/dT set by the diodes and (R2)(C).

D1

D2

R3

100k

–

R1

1k

V

OUT

1/4 LT1639

R2

V

IN

+

C1

R4

100k

LT1634-1.2V

D4

D3

D1

–

+

1/4 LT1639

D2

FOR R2 = 50k, C1 = 500pF,

MAXIMUM SLOPE = 0.048V/µs

R6

100k

R1

R2

d

dt

1.2V

(R2)(C1)

1638/39 F02

V

+

V

OUT

=

IN

V

EE

C1

V

1/2 LT1638

OUT

V

d

dt

D

V

=

OUT(MAX)

(R2)(C1)

–

FOR R1 = 10k, R2 = 100k, C1 = 1000pF

d

V

= 0.006V/µs

1638/39 F01

OUT(MAX)

Response of Slope Limiting Filter

dt

Figure 1. Lowpass Slope Limiting Filter

V_OUT

A modification of this application is shown in Figure 2

using references instead of diodes to set the maximum

slope. By using references, the slope is independent of

temperature. A scope photo shows a 1V_P-P, 2kHz input

signal with a 2V pulse added to the sine wave; the circuit

passes the 2kHz signal but limits the slope of the pulse.

V_IN

1638/39 TA02

The application in Figure 3 utilizes the Over-The-Top

capabilities of the LT1638. The 0.2Ω resistor senses the

load current while the op amp and NPN transistor form a

closed loop making the collector current of Q1

Figure 2. Lowpass Slope Limiting Filter with 0TC

9

LT1638/LT1639

U

TYPICAL APPLICATIONS

proportional to the load current. As a convenient monitor,

the2kloadresistorconvertsthecurrentintoavoltage.The

positive supply rail, V⁺, is not limited to the 5V supply of

the op amp and could be as high as 44V.

The Figure 4 application uses the LT1638 in conjunction

with the LT1634 micropower shunt reference. The supply

current of the op amp also biases the reference. The drop

across resistor R1 is fixed at 1.2V generating an output

current equal to 1.2V/R1.

+

V

200Ω

V

CC

V

CC

LT1634-1.2

R1

5V

0.2Ω

+

Q1

1/2 LT1638

+

2N3904

200Ω

–

1.2V

R1

0V TO 4.3V

1/2 LT1638

I

=

OUT

2k

I

LOAD

–

I

OUT

1638/39 F03

V

= (2Ω)(I )

LOAD

OUT

1638/39 F04

Figure 3. Positive Supply Rail Current Sense

Figure 4. Current Source

W

SI PLIFIED SCHE ATIC

+

V

Q2

Q1

Q3

Q22

D1

D2

D3

R1

R2

1k

6k

Q19

Q4

–IN

+IN

Q17

Q18

Q20

OUT

Q7

Q8

Q11 Q12

R3

1k

+

Q16

10µA

Q15

Q9

Q10

Q13

Q14

Q21

R4

8k

R5

8k

Q5

Q6

D4

D5

–

V

ONE AMPLIFIER

1638/39 SS

U

Dimensions in inches (millimeters) unless otherwise noted.

PACKAGE DESCRIPTION

MS8 Package

8-Lead Plastic MSOP

(LTC DWG # 05-08-1660)

0.118 ± 0.004*

(3.00 ± 0.102)

8

7

6

5

0.040 ± 0.006

(1.02 ± 0.15)

0.034 ± 0.004

(0.86 ± 0.102)

0.007

(0.18)

0° – 6° TYP

0.118 ± 0.004**

(3.00 ± 0.102)

SEATING

PLANE

0.192 ± 0.004

(4.88 ± 0.10)

0.012

(0.30)

REF

0.021 ± 0.006

(0.53 ± 0.015)

0.006 ± 0.004

(0.15 ± 0.102)

0.0256

(0.65)

TYP

MSOP (MS8) 1197

1

2

3

4

*

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

10

LT1638/LT1639

U

Dimensions in inches (millimeters) unless otherwise noted.

PACKAGE DESCRIPTION

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.400*

(10.160)

MAX

0.130 ± 0.005

0.300 – 0.325

0.045 – 0.065

(3.302 ± 0.127)

(1.143 – 1.651)

(7.620 – 8.255)

8

1

7

6

5

0.065

(1.651)

TYP

0.255 ± 0.015*

(6.477 ± 0.381)

0.009 – 0.015

(0.229 – 0.381)

0.125

0.020

(0.508)

MIN

(3.175)

MIN

+0.035

–0.015

2

4

3

0.325

N8 1197

0.100 ± 0.010

(2.540 ± 0.254)

0.018 ± 0.003

+0.889

8.255

(

)

(0.457 ± 0.076)

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.189 – 0.197*

(4.801 – 5.004)

0.010 – 0.020

(0.254 – 0.508)

7

5

8

6

× 45°

0.053 – 0.069

(1.346 – 1.752)

0.004 – 0.010

(0.101 – 0.254)

0.008 – 0.010

(0.203 – 0.254)

0°– 8° TYP

0.150 – 0.157**

(3.810 – 3.988)

0.228 – 0.244

(5.791 – 6.197)

0.016 – 0.050

0.406 – 1.270

0.050

(1.270)

TYP

0.014 – 0.019

(0.355 – 0.483)

*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH

SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE

SO8 0996

**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD

FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

1

2

3

4

N Package

14-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.770*

(19.558)

MAX

0.300 – 0.325

(7.620 – 8.255)

0.045 – 0.065

0.130 ± 0.005

(3.302 ± 0.127)

(1.143 – 1.651)

14

13

12

11

10

9

8

7

0.020

(0.508)

MIN

0.255 ± 0.015*

(6.477 ± 0.381)

0.065

(1.651)

TYP

0.009 – 0.015

(0.229 – 0.381)

+0.035

1

2

3

5

6

4

0.325

0.005

(0.125)

MIN

0.100 ± 0.010

(2.540 ± 0.254)

–0.015

0.125

(3.175)

MIN

0.018 ± 0.003

N14 1197

+0.889

8.255

(0.457 ± 0.076)

(

)

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

S Package

14-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

0.337 – 0.344*

(8.560 – 8.738)

0.010 – 0.020

14

13

12

11

10

9

8

× 45°

0.053 – 0.069

(1.346 – 1.752)

0.004 – 0.010

(0.101 – 0.254)

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

0° – 8° TYP

0.228 – 0.244

(5.791 – 6.197)

0.150 – 0.157**

(3.810 – 3.988)

0.050

(1.270)

TYP

0.014 – 0.019

(0.355 – 0.483)

0.016 – 0.050

0.406 – 1.270

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

S14 0695

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

1

2

3

4

5

6

7

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-

tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.

11

LT1638/LT1639

U

TYPICAL APPLICATION

The battery monitor in Figure 5 also demonstrates the

LT1638’s ability to operate with its inputs above the

positive rail. In this application, a conventional amplifier

would be limited to a battery voltage between 5V and

ground, but the LT1638 can handle battery voltages as

high as 44V. When the battery is charging, Amp B senses

the voltage drop across R_S. The output of Amp B causes

Q2 to drain sufficient current through R_Bto balance the

input of Amp B. Likewise, Amp A and Q1 form a closed

loopwhenthebatteryisdischarging. Thecurrentthrough

Q1 or Q2 is proportional to the current in R_Sand this

currentflowsintoR_Gandisconvertedintoavoltage. Amp

D buffers and amplifies the voltage across R_G. Amp C

compares the output of Amp A and Amp B to determine

the polarity of current through R_S. The scale factor for

V_OUTwithS1openis1V/A. WithS1closedthescalefactor

is 1V/100mA and currents as low as 500µA can be

measured.

R , 0.2Ω

R , 2k

S

A

Q1

2N3904

CHARGER

VOLTAGE

+

A

+

1/4 LT1639

R

A

2k

',

I

BATT

C

LOGIC

–

1/4 LT1639

–

R , 2k

B

Q2

2N3904

LOGIC HIGH (5V) = CHARGING

+

LOGIC LOW (0V) = DISCHARGING

B

1/4 LT1639

R

, 2k

'

B

+

–

+

LOAD

D

R

G

V

OUT

1/4 LT1639

V

= 12V

10k

BATT

–

S1

10k

90.9k

1638/39 F05

V

OUT

S1 = OPEN, GAIN = 1

S1 = CLOSED, GAIN = 10

R

S

= R

A

B

I

=

AMPS

BATT

V

= 5V, 0V

(R )(R /R )(GAIN) GAIN

S

G

A

Figure 5. Battery Monitor

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

Input/Output Common Mode Includes Ground, 70µV V

and 2.5µV/°C Drift (Max), 200kHz GBW, 0.07V/µs Slew Rate

LT1078/LT1079

LT2078/LT2079

Dual/Quad 55µA Max, Single Supply, Precision Op Amps

Dual/Quad 17µA Max, Single Supply, Precison Op Amps

Dual/Quad Precision, Rail-to-Rail Input and Output Op Amps

OS(MAX)

LT1178/LT1179

LT2178/LT2179

Input/Output Common Mode Includes Ground, 70µV V

and 4µV/°C Drift (Max), 85kHz GBW, 0.04V/µs Slew Rate

OS(MAX)

LT1366/LT1367

LT1490/LT1491

475µV V , 500V/mV A , 400kHz GBW

OS(MAX)

VOL(MIN)

Dual/Quad Over-The-Top Micropower, Rail-to-Rail Input and

Output Op Amps

Single Supply Input Range: –0.4V to 44V, Micropower 50µA

per Amplifier, Rail-to-Rail Input and Output, 200kHz GBW

LT1636

Single Over-The-Top Micropower Rail-to-Rail Input and Output

Op Amp

55µA Supply Current, V

Extends 44V above V ,

CM EE

Independent of V ; MSOP Package, Shutdown Function

CC

16389f LT/TP 1098 4K • PRINTED IN USA

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

12

●

LINEAR TECHNOLOGY CORPORATION 1998

(408)432-1900 FAX:(408)434-0507 www.linear-tech.com


型号：	LT1638CS8
厂家：	Linear
描述：	1.2MHz, 0.4V/us Over-The-TopTM Micropower Rail-to-Rail Input and Output Op Amps 1.2MHz的， 0.4V / us的过度的TopTM微功耗轨至轨输入和输出运算放大器运算放大器
文件：	总12页 (文件大小：326K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LT1638CS8 [Linear]

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LT1638IDD#TRPBF

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