LM6142AMJ/883 - National Semiconductor

TL/H/12057

LM6142 Dual and LM6144 Quad High Speed/Low Power

17 MHz Rail-to-Rail Input-Output Operational Amplifiers

March 1995

LM6142 Dual and LM6144 Quad

High Speed/Low Power 17 MHz Rail-to-Rail

Input-Output Operational Amplifiers

General Description

Using patent pending new circuit topologies, the

LM6142/44 provides new levels of performance in applica-

tions where low voltage supplies or power limitations previ-

ously made compromise necessary. Operating on supplies

of 1.8V to over 24V, the LM6142/44 is an excellent choice

for battery operated systems, portable instrumentation and

others.

The greater than rail-to-rail input voltage range eliminates

concern over exceeding the common-mode voltage range.

The rail-to-rail output swing provides the maximum possible

dynamic range at the output. This is particularly important

when operating on low supply voltages.

High gain-bandwidth with 650 mA/Amplifier supply current

opens new battery powered applications where previous

higher power consumption reduced battery life to unaccept-

able levels. The ability to drive large capacitive loads with-

out oscillating functionally removes this common problem.

Features At VSe5V. Typ unless noted.

YRail-to-rail input CMVR b0.25V to 5.25V

YRail-to-rail output swing 0.005V to 4.995V

YWide gain-bandwidth: 17 MHz at 50 kHz (typ)

YSlew rate:

Small signal, 5V/ms

Large signal, 30V/ms

YLow supply current 650 mA/Amplifier

YWide supply range 1.8V to 24V

YCMRR 107 dB

YGain 108 dB with RLe10k

YPSRR 87 dB

Applications

YBattery operated instrumentation

YDepth sounders/fish finders

YBarcode scanners

YWireless communications

YRail-to-rail in-out instrumentation amps

Connection Diagrams

8-Pin CDIP

TL/H/12057–14

Top View

8-Pin DIP/SO

TL/H/12057–1

Top View

14-Pin DIP/SO

TL/H/12057–2

Top View

Ordering Information

Package

Temperature Range Temperature Range

Drawing

NSC

Industrial Military

b40§Ctoa

85§Cb55§Ctoa

125§C

8-Pin Molded DIP LM6142AIN, LM6142BIN N08E

8-Pin Small Outline LM6142AIM, LM6142BIM M08A

14-Pin Molded DIP LM6144AIN, LM6144BIN N14A

14-Pin Small Outline LM6144AIM, LM6144BIM M14A

8-Pin CDIP LM6142AMJ/883 D08C

C1995 National Semiconductor Corporation RRD-B30M75/Printed in U. S. A.

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

ESD Tolerance (Note 2) 2500V

Differential Input Voltage 15V

Voltage at Input/Output Pin (Va)a0.3V, (Vb)b0.3V

Supply Voltage (VabVb) 35V

Current at Input Pin g10 mA

Current at Output Pin (Note 3) g25 mA

Current at Power Supply Pin 50 mA

Lead Temperature (soldering, 10 sec) 260§C

Storage Temp. Range b65§Ctoa

150§C

Junction Temperature (Note 4) 150§C

Operating Ratings (Note 1)

Supply Voltage 1.8V sVas24V

Junction Temperature Range

LM6142, LM6144 b40§CsTJsa85§C

Thermal Resistance (iJA)

N Package, 8-Pin Molded DIP 115§C/W

M Package, 8-Pin Surface Mount 193§C/W

N Package, 14-Pin Molded DIP 81§C/W

M Package, 14-Pin Surface Mount 126§C/W

5.0V DC Electrical Characteristics

Unless otherwise specified, all limits guaranteed for TJe25§C, Vae5.0V, Vbe0V, VCM eVOeVa/2 and RLl1MXto

Va/2. Boldface limits apply at the temperature extremes.

LM6144AI LM6144BI

Symbol Parameter Conditions Typ LM6142AI LM6142BI Units

(Note 5) Limit Limit

(Note 6) (Note 6)

VOS Input Offset Voltage 0.3 1.0 2.5 mV

2.2 3.3 max

TCVOS Input Offset Voltage 3mV/§C

Average Drift

IBInput Bias Current 170 250 300

max

0V sVCM s5V 180 280

526 526

IOS Input Offset Current 3 30 30 nA

80 80 max

RIN Input Resistance, CM126 MX

CMRR Common Mode 0V sVCM s4V 107 84 84

min

Rejection Ratio 78 78

0V sVCM s5V 82 66 66

79 64 64

PSRR Power Supply 5V sVas24V 87 80 80

Rejection Ratio 78 78

VCM Input Common-Mode b0.25 00

Voltage Range 5.25 5.0 5.0

AVLarge Signal RLe10k 270 100 80 V/mV

Voltage Gain 70 33 25 min

VOOutput Swing RLe100k 0.005 0.01 0.01 V

0.013 0.013 max

4.995 4.98 4.98 V

4.93 4.93 min

RLe10k 0.02 V max

4.97 V min

RLe2k 0.06 0.1 0.1 V

0.133 0.133 max

4.90 4.86 4.86 V

4.80 4.80 min

5.0V DC Electrical Characteristics

Unless Otherwise Specified, All Limits Guaranteed for TJe25§C, Vae5.0V, Vbe0V, VCM eVOeVa/2 and RLl1MX

to Va/2. Boldface limits apply at the temperature extremes. (Continued)

LM6144AI LM6144BI

Symbol Parameter Conditions Typ LM6142AI LM6142BI Units

(Note 5) Limit Limit

(Note 6) (Note 6)

ISC Output Short Sourcing 13 10 8 mA

Circuit Current 4.9 4 min

LM6142

35 35 mA

max

Sinking 24 10 10 mA

5.3 5.3 min

35 35 mA

max

ISC Output Short Sourcing 8 6 6 mA

Circuit Current 33min

LM6144

35 35 mA

max

Sinking 22 8 8 mA

44min

35 35 mA

max

ISSupply Current Per Amplifier 650 800 800 mA

880 880 max

5.0V AC Electrical Characteristics

Unless Otherwise Specified, All Limits Guaranteed for TJe25§C, Vae5.0V, Vbe0V, VCM eVOeVa/2 and RLl1MX

to VS/2. Boldface limits apply at the temperature extremes.

LM6144AI LM6144BI

Symbol Parameter Conditions Typ LM6142AI LM6142BI Units

(Note 5) Limit Limit

(Note 6) (Note 6)

SR Slew Rate 8 Vp-p @VCC 12V 25 15 13 V/ms

RSl1kX13 11 min

GBW Gain-Bandwidth Product f e50 kHz 17 10 10 MHz

66min

wmPhase Margin 38 Deg

Amp-to-Amp Isolation 130 dB

enInput-Referred f e1 kHz 16 nV

0Hz

Voltage Noise

inInput-Referred f e1 kHz 0.22 pA

0Hz

Current Noise

T.H.D. Total Harmonic Distortion f e10 kHz, RLe10 kX, 0.003 %

2.7V DC Electrical Characteristics

Unless Otherwise Specified, All Limits Guaranteed for TJe25§C, Vae2.7V, Vbe0V, VCM eVOeVa/2 and RLl1MX

to Va/2. Boldface limits apply at the temperature extreme

LM6144AI LM6144BI

Symbol Parameter Conditions Typ LM6142AI LM6142BI Units

(Note 5) Limit Limit

(Note 6) (Note 6)

VOS Input Offset Voltage 0.4 1.8 2.5 mV

4.3 4.3 max

IBInput Bias Current 150 250 300 nA

526 526 max

IOS Input Offset Current 4 30 30 nA

80 80 max

RIN Input Resistance 128 MX

CMRR Common Mode 0V sVCM s1.8V 90

min

Rejection Ratio 0V sVCM s2.7V 76

PSRR Power Supply 3V sVas5V 79

Rejection Ratio

VCM Input Common-Mode b0.25 0 0 V min

Voltage Range 2.95 2.7 2.7 V max

AVLarge Signal RLe10k 55 V/mV

Voltage Gain min

VOOutput Swing RLe10 kX0.019 0.08 0.08 V

0.112 0.112 max

2.67 2.66 2.66 V

2.25 2.25 min

ISSupply Current Per Amplifier 510 800 800 mA

880 880 max

2.7V AC Electrical Characteristics

Unless Otherwise Specified, All Limits Guaranteed for TJe25§C, Vae2.7V, Vbe0V, VCM eVOeVa/2 and RLl1MX

to Va/2. Boldface limits apply at the temperature extreme

LM6144AI LM6144BI

Symbol Parameter Conditions Typ LM6142AI LM6142BI Units

(Note 5) Limit Limit

(Note 6) (Note 6)

GBW Gain-Bandwidth Product f e50 kHz 9 MHz

wmPhase Margin 36 Deg

GmGain Margin 6 dB

24V Electrical Characteristics

Unless Otherwise Specified, All Limits Guaranteed for TJe25§C, Vae24V, Vbe0V, VCM eVOeVa/2 and RLl1MX

to VS/2. Boldface limits apply at the temperature extreme

LM6144AI LM6144BI

Symbol Parameter Conditions Typ LM6142AI LM6142BI Units

(Note 5) Limit Limit

(Note 6) (Note 6)

VOS Input Offset Voltage 1.3 2 3.8 mV

4.8 4.8 max

IBInput Bias Current 174 nA

max

IOS Input Offset Current 5nA

max

RIN Input Resistance 288 MX

CMRR Common Mode 0V sVCM s23V 114

min

Rejection Ratio 0V sVCM s24V 100

PSRR Power Supply 0V sVCM s24V 87

Rejection Ratio

VCM Input Common-Mode b0.25 0 0 V min

Voltage Range 24.25 24 24 V max

AVLarge Signal RLe10k 500 V/mV

Voltage Gain min

VOOutput Swing RLe10 kX0.07 0.15 0.15 V

0.185 0.185 max

23.85 23.81 23.81 V

23.62 23.62 min

ISSupply Current Per Amplifier 750 1100 1100 mA

1150 1150 max

GBW Gain-Bandwidth Product f e50 kHz 18 MHz

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is

intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Charactenstics.

Note 2: Human body model, 1.5 kXin series with 100 pF.

Note 3: Applies to both single-supply and split-supply operation. Continuous short circuit operation at elevated ambient temperature can result in exceeding the

maximum allowed junction temperature of 150§C.

Note 4: The maximum power dissipation is a function of TJ(max),iJA, and TA. The maximum allowable power dissipation at any ambient temperature is PDe

(Tj(max) bTA)/iJA. All numbers apply for packages soldered directly into a PC board.

Note 5: Typical values represent the most likely parametric norm.

Note 6: All limits are guaranteed by testing or statistical analysis.

Note 7: For guaranteed military specifications see military datasheet MNLM6142AM-X.

Typical Performance Characteristics TAe25§C, RLe10 kXUnless Otherwise Specified

Supply Voltage

Supply Current vs

Supply Voltage

Offset Voltage vs

Supply Voltage

Bias Current vs

Offset Voltage vs VCM Offset Voltage vs VCM Offset Voltage vs VCM

Bias Current vs VCM Bias Current vs VCM Bias Current vs VCM

Open-Loop Transfer

Function

Open-Loop Transfer

Function

Open-Loop Transfer

Function

TL/H/12057–3

Typical Performance Characteristics

TAe25§C, RLe10 kXUnless Otherwise Specified (Continued)

Source Current

Output Voltage vs

Source Current

Output Voltage vs

Source Current

Output Voltage vs

Sink Current

Output Voltage vs

Sink Current

Output Voltage vs

Sink Current

Output Voltage vs

TL/H/12057–4

Gain and Phase vs Load Gain and Phase vs Load vs Frequency

Distortion aNoise

GBW vs Supply

TL/H/12057–11

Typical Performance Characteristics

TAe25§C, RLe10 kXUnless Otherwise Specified (Continued)

Load, 3V Supply

Open Loop Gain vs

Load, 5V Supply

Open Loop Gain vs

Load, 24V Supply

Open Loop Gain vs

Unity Gain Freq vs VSCMRR vs Frequency Crosstalk vs Frequency

PSRR vs Frequency Noise Voltage vs Frequency Noise Current vs Frequency

TL/H/12057–5

NE vs R Source

TL/H/12057–12

LM6142/44 Application Ideas

The LM6142 brings a new level of ease of use to opamp

system design.

With greater than rail-to-rail input voltage range concern

over exceeding the common-mode voltage range is elimi-

nated.

Rail-to-rail output swing provides the maximum possible dy-

namic range at the output. This is particularly important

when operating on low supply voltages.

The high gain-bandwidth with low supply current opens new

battery powered applications, where high power consump-

tion, previously reduced battery life to unacceptable levels.

To take advantage of these features, some ideas should be

kept in mind.

ENHANCED SLEW RATE

Unlike most bipolar opamps, the unique phase reversal pre-

vention/speed-up circuit in the input stage causes the slew

rate to be very much a function of the input signal amplitude.

Figure 1

shows how excess input signal, is routed around

the input collector-base junctions, directly to the current mir-

rors.

The LM6142/44 input stage converts the input voltage

change to a current change. This current change drives the

current mirrors through the collectors of Q1– Q2, Q3– Q4

when the input levels are normal.

If the input signal exceeds the slew rate of the input stage,

the differential input voltage rises above two diode drops.

This excess signal bypasses the normal input transistors,

(Q1– Q4), and is routed in correct phase through the two

additional transistors, (Q5, Q6), directly into the current mir-

rors.

This rerouting of excess signal allows the slew-rate to in-

crease by a factor of 10 to 1 or more. (See

Figure 2

As the overdrive increases, the opamp reacts better than a

conventional opamp. Large fast pulses will raise the slew-

rate to around 30V to 60V/ms.

Slew Rate vs DVIN

VSeg5V

TL/H/12057–7

FIGURE 2

This effect is most noticeable at higher supply voltages and

lower gains where incoming signals are likely to be large.

This new input circuit also eliminates the phase reversal

seen in many opamps when they are overdriven.

This speed-up action adds stability to the system when driv-

ing large capacitive loads.

DRIVING CAPACITIVE LOADS

Capacitive loads decrease the phase margin of all opamps.

This is caused by the output resistance of the amplifier and

the load capacitance forming an R-C phase lag network.

This can lead to overshoot, ringing and oscillation. Slew rate

limiting can also cause additional lag. Most opamps with a

fixed maximum slew-rate will lag further and further behind

when driving capacitive loads even though the differential

input voltage raises. With the LM6142, the lag causes the

slew rate to raise. The increased slew-rate keeps the output

following the input much better. This effectively reduces

phase lag. After the output has caught up with the input, the

differential input voltage drops down and the amplifier set-

tles rapidly.

TL/H/12057–6

FIGURE 1

LM6142/44 Application Ideas

(Continued)

These features allow the LM6142 to drive capacitive loads

as large as 1000 pF at unity gain and not oscillate. The

scope photos (

Figure 3a

and

) above show the LM6142

driving a l000 pF load. In

Figure 3a

, the upper trace is with

no capacitive load and the lower trace is with a 1000 pF

load. Here we are operating on g12V supplies with a 20

Vp-p pulse. Excellent response is obtained with a Cfof

l0 pF. In

Figure 3b

, the supplies have been reduced to

g2.5V, the pulse is 4 Vp-p and Cfis 39 pF. The best value

for the compensation capacitor is best established after the

board layout is finished because the value is dependent on

board stray capacity, the value of the feedback resistor, the

closed loop gain and, to some extent, the supply voltage.

Another effect that is common to all opamps is the phase

shift caused by the feedback resistor and the input capaci-

tance. This phase shift also reduces phase margin. This ef-

fect is taken care of at the same time as the effect of the

capacitive load when the capacitor is placed across the

feedback resistor.

The circuit shown in

Figure 4

was used for these scope

photos.

TL/H/12057–8

FIGURE 3a

TL/H/12057–9

FIGURE 3b

TL/H/12057–10

FIGURE 4

Typical Applications

FISH FINDER/ DEPTH SOUNDER.

The LM6142/44 is an excellent choice for battery operated

fish finders. The low supply current, high gain-bandwidth

and full rail to rail output swing of the LM6142 provides an

ideal combination for use in this and similar applications.

ANALOG TO DIGITAL CONVERTER BUFFER

The high capacitive load driving ability, rail-to-rail input and

output range with the excellent CMR of 82 dB, make the

LM6142/44 a good choice for buffering the inputs of A to D

converters.

3 OPAMP INSTRUMENTATION AMP WITH RAIL-TO-

RAIL INPUT AND OUTPUT

Using the LM6144, a 3 opamp instrumentation amplifier with

rail-to-rail inputs and rail to rail output can be made. These

features make these instrumentation amplifiers ideal for sin-

gle supply systems.

Some manufacturers use a precision voltage divider array of

5 resistors to divide the common-mode voltage to get an

input range of rail-to-rail or greater. The problem with this

method is that it also divides the signal, so to even get unity

gain, the amplifier must be run at high closed loop gains.

This raises the noise and drift by the internal gain factor and

lowers the input impedance. Any mismatch in these preci-

sion resistors reduces the CMR as well. Using the LM6144,

all of these problems are eliminated.

In this example, amplifiers A and B act as buffers to the

differential stage

(Figure 5).

These buffers assure that the

input impedance is over 100 MXand they eliminate the

requirement for precision matched resistors in the input

stage. They also assure that the difference amp is driven

from a voltage source. This is necessary to maintain the

CMR set by the matching of R1– R2 with R3– R4.

TL/H/12057–13

FIGURE 5

The gain is set by the ratio of R2/R1 and R3 should equal

R1 and R4 equal R2. Making R4 slightly smaller than R2

and adding a trim pot equal to twice the difference between

R2 and R4 will allow the CMR to be adjusted for optimum.

With both rail to rail input and output ranges, the inputs and

outputs are only limited by the supply voltages. Remember

that even with rail-to-rail output, the output can not swing

past the supplies so the combined common mode voltage

plus the signal should not be greater than the supplies or

limiting will occur.

SPICE MACROMODEL

A SPICE macromodel of this and many other National Semi-

conductor opamps is available at no charge from the NSC

Customer Response Group at 800-272-9959.

Physical Dimensions inches (millimeters)

8-Pin Ceramic Sidebrazed

Dual-In-Line Package

Order Number LM6142AMJ/883

NS Package Number D08C

8-Pin Small Outline Package

Order Number LM6142AIM or LM6142BIM

NS Package Number M08A

Physical Dimensions inches (millimeters) (Continued)

14-Pin Small Outline Package

Order Number LM6144AIM or LM6144BIM

NS Package Number M14A

8-Pin Molded Dual-In-Line Package

Order Number LM6142AIN or LM6142BIN

NS Package Number N08E

LM6142 Dual and LM6144 Quad High Speed/Low Power

17 MHz Rail-to-Rail Input-Output Operational Amplifiers

Physical Dimensions inches (millimeters) (Continued)

14-Pin Molded Dual-In-Line Package

Order Number LM6144AIN or LM6144BIN

NS Package Number N14A

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failure to perform, when properly used in accordance support device or system, or to affect its safety or

with instructions for use provided in the labeling, can effectiveness.

be reasonably expected to result in a significant injury

to the user.

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