LM148,149-349,741.PDF

February 1995

LM148/LM149 Series Quad 741 Op Amp

LM148/LM248/LM348 Quad 741 Op Amps

LM149/LM349 Wide Band Decompensated (A V (MIN) e 5)

General Description

The LM148 series is a true quad 741. It consists of four

independent, high gain, internally compensated, low power

operational amplifiers which have been designed to provide

functional characteristics identical to those of the familiar

741 operational amplifier. In addition the total supply current

for all four amplifiers is comparable to the supply current of

a single 741 type op amp. Other features include input off-

set currents and input bias current which are much less than

those of a standard 741. Also, excellent isolation between

amplifiers has been achieved by independently biasing each

amplifier and using layout techniques which minimize ther-

mal coupling. The LM149 series has the same features as

the LM148 plus a gain bandwidth product of 4 MHz at a gain

of 5 or greater.

The LM148 can be used anywhere multiple 741 or 1558

type amplifiers are being used and in applications where

amplifier matching or high packing density is required.

Features

Y 741 op amp operating characteristics

Y Low supply current drain 0.6 mA/Amplifier

Y Class AB output stageÐno crossover distortion

Y Pin compatible with the LM124

Y Low input offset voltage

1 mV

Y Low input offset current

4 nA

Y Low input bias current

30 nA

Y Gain bandwidth product

LM148 (unity gain) 1.0 MHz

LM149 (A V t 5) 4 MHz

Y High degree of isolation between amplifiers 120 dB

Y Overload protection for inputs and outputs

Schematic Diagram

TL/H/7786±1

*1 pF in the LM149

C 1995 National Semiconductor Corporation

TL/H/7786

RRD-B30M115/Printed in U. S. A.

Absolute Maximum Ratings

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

(Note 4)

LM148/LM149

LM248

LM348/LM349

Supply Voltage

g 22V

g 18V

Differential Input Voltage

g 44V

g 36V

Output Short Circuit Duration (Note 1)

Continuous

Power Dissipation (P d at 25 § C) and

Thermal Resistance ( i jA ), (Note 2)

Molded DIP (N) P d

750 mW

i jA

100 § C/W

Cavity DIP (J) P d

1100 mW

800 mW

700 mW

i JA

110 § C/W

Maximum Junction Temperature (T jMAX )

150 § C

110 § C

100 § C

Operating Temperature Range

b 55 § C s T A s a 125 § C b 25 § C s T A s a 85 § C § C s A sa 70 § C

Storage Temperature Range

b 65 § Cto a 150 § C b 65 § Cto a 150 § C b 65 § Cto a 150 § C

Lead Temperature (Soldering, 10 sec.) Ceramic

300 § C

Lead Temperature (Soldering, 10 sec.) Plastic

260 § C

Soldering Information

Dual-In-Line Package

Soldering (10 seconds)

260 § C

Small Outline Package

Vapor Phase (60 seconds) 215 § C 215 § C 215 § C

Infrared (15 seconds) 220 § C 220 § C 220 § C

See AN-450 ``Surface Mounting Methods and Their Effect on Product Reliability'' for other methods of soldering surface mount

devices.

ESD tolerance (Note 5)

500V

Electrical Characteristics (Note 3)

Parameter

Conditions

LM148/LM149

LM248

LM348/LM349

Units

Min Typ Max Min Typ Max Min Typ Max

Input Offset Voltage

T A e 25 § C, R S s 10 k X

1.0 5.0

1.0 6.0

1.0 6.0 mV

Input Offset Current

T A e 25 § C

4 25

4 50

4 50 nA

Input Bias Current

T A e 25 § C

30 100

30 200

30 200 nA

Input Resistance

T A e 25 § C

0.8 2.5

M X

Supply Current All Amplifiers T A e 25 § C, V S e g 15V

2.4 3.6

2.4 4.5

2.4 4.5 mA

Large Signal Voltage Gain T A e 25 § C, V S e g 15V

V OUT e g 10V, R L t 2k X

50 160

25 160

V/mV

Amplifier to Amplifier

T A e 25 § C, f e 1Hzto20kHz

Coupling

(Input Referred) See Crosstalk b 120

b 120

Test Circuit

Small Signal Bandwidth

LM148 Series

1.0

MHz

T A e 25 § C

LM149 Series

4.0

MHz

Phase Margin

LM148 Series (A V e 1)

degrees

T A e 25 § C

LM149 Series (A V e 5)

degrees

Slew Rate

LM148 Series (A V e 1)

0.5

V/ m s

T A e 25 § C

LM149 Series (A V e 5)

2.0

V/ m s

Output Short Circuit Current T A e 25 § C

Input Offset Voltage

R S s 10 k X

6.0

7.5

7.5 mV

Input Offset Current

125

100 nA

Input Bias Current

325

500

400 nA

Electrical Characteristics (Note 3) (Continued)

Parameter

Conditions

LM148/LM149

LM248

LM348/LM349

Units

Min Typ Max Min Typ Max Min Typ Max

R L l 2k X

Output Voltage Swing V S e g 15V, R L e 10 k X

V/mV

g 12 g 13 g 12 g 13 g 12 g 13

R L e 2k X g 10

g 12

g 10

g 12

g 10

g 12

Input Voltage Range

V S e g 15V

g 12

Ratio

Supply Voltage Rejection R S s 10 k X , g 5V s V S s g 15V 77 96 77 96 77 96 dB

Note 1: Any of the amplifier outputs can be shorted to ground indefinitely; however, more than one should not be simultaneously shorted as the maximum junction

temperature will be exceeded.

Note 2: The maximum power dissipation for these devices must be derated at elevated temperatures and is dicated by T jMAX , i jA , and the ambient temperature,

T A . The maximum available power dissipation at any temperature is P d e (T jMAX b T A )/ i jA or the 25 § CP dMAX , whichever is less.

Note 3: These specifications apply for V S e g 15V and over the absolute maximum operating temperature range (T L s T A s T H ) unless otherwise noted.

Note 4: Refer to RETS 148X for LM148 military specifications and refer to RETS 149X for LM149 military specifications.

Note 5: Human body model, 1.5 k X in series with 100 pF.

70 90

Cross Talk Test Circuit

TL/H/7786±6

TL/H/7786±7

e Ê OUT

101 c e OUT

Crosstalk eb 20 log

(dB)

V S e g 15V

Application Hints

The LM148 series are quad low power 741 op amps. In the

proliferation of quad op amps, these are the first to offer the

convenience of familiar, easy to use operating characteris-

tics of the 741 op amp. In those applications where 741 op

amps have been employed, the LM148 series op amps can

be employed directly with no change in circuit performance.

The LM149 series has the same characteristics as the

LM148 except it has been decompensated to provide a

wider bandwidth. As a result the part requires a minimum

gain of 5.

The package pin-outs are such that the inverting input of

each amplifier is adjacent to its output. In addition, the am-

plifier outputs are located in the corners of the package

which simplifies PC board layout and minimizes package

related capacitive coupling between amplifiers.

The input characteristics of these amplifiers allow differen-

tial input voltages which can exceed the supply voltages. In

addition, if either of the input voltages is within the operating

common-mode range, the phase of the output remains cor-

rect. If the negative limit of the operating common-mode

range is exceeded at both inputs, the output voltage will be

positive. For input voltages which greatly exceed the maxi-

mum supply voltages, either differentially or common-mode,

resistors should be placed in series with the inputs to limit

the current.

Like the LM741, these amplifiers can easily drive a 100 pF

capacitive load throughout the entire dynamic output volt-

age and current range. However, if very large capacitive

loads must be driven by a non-inverting unity gain amplifier,

a resistor should be placed between the output (and feed-

back connection) and the capacitance to reduce the phase

shift resulting from the capacitive loading.

The output current of each amplifier in the package is limit-

ed. Short circuits from an output to either ground or the

power supplies will not destroy the unit. However, if multiple

output shorts occur simultaneously, the time duration should

be short to prevent the unit from being destroyed as a result

of excessive power dissipation in the IC chip.

As with most amplifiers, care should be taken lead dress,

component placement and supply decoupling in order to

ensure stability. For example, resistors from the output to an

input should be placed with the body close to the input to

minimize ``pickup'' and maximize the frequency of the feed-

back pole which capacitance from the input to ground cre-

ates.

A feedback pole is created when the feedback around any

amplifier is resistive. The parallel resistance and capaci-

tance from the input of the device (usually the inverting in-

put) to AC ground set the frequency of the pole. In many

instances the frequency of this pole is much greater than

the expected 3 dB frequency of the closed loop gain and

consequently there is negligible effect on stability margin.

However, if the feedback pole is less than approximately six

times the expected 3 dB frequency a lead capacitor should

be placed from the output to the input of the op amp. The

value of the added capacitor should be such that the RC

time constant of this capacitor and the resistance it parallels

is greater than or equal to the original feedback pole time

constant.

Large Signal Voltage Gain V S e g 15V, V OUT e g 10V,

Common-Mode Rejection R S s 10 k X

Typical Performance Characteristics

Supply Current

Input Bias Current

Voltage Swing

Positive Current Limit

Negative Current Limit

Output Impedance

Common-Mode Rejection

Open Loop Frequency

Ratio

Response

Bode Plot LM148

Large Signal Pulse

Bode Plot LM149

Response (LM148)

Response (LM149)

TL/H/7786±3

Typical Performance Characteristics (Continued)

Small Signal Pulse

Undistorted Output

Response (LM148)

Response (LM149)

Voltage Swing

Inverting Large Signal Pulse

Gain Bandwidth

Slew Rate

Response (LM149)

Inverting Large Signal Pulse

Input Noise Voltage and

Positive Common-Mode

Response (LM148)

Noise Current

Input Voltage Limit

TL/H/7786±4

Negative Common-Mode Input

Voltage Limit

TL/H/7786±5

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