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TL/H/5654

LM146/LM246/LM346 Programmable Quad Operational Amplifiers

November 1994

LM146/LM246/LM346 Programmable Quad

Operational Amplifiers

General Description

The LM146 series of quad op amps consists of four inde-

pendent, high gain, internally compensated, low power, pro-

grammable amplifiers. Two external resistors (RSET) allow

the user to program the gain bandwidth product, slew rate,

supply current, input bias current, input offset current and

input noise. For example, the user can trade-off supply cur-

rent for bandwidth or optimize noise figure for a given

source resistance. In a similar way, other amplifier charac-

teristics can be tailored to the application. Except for the

two programming pins at the end of the package, the

LM146 pin-out is the same as the LM124 and LM148.

Features (ISETe10 mA)

YProgrammable electrical characteristics

YBattery-powered operation

YLow supply current 350 mA/amplifier

YGuaranteed gain bandwidth product 0.8 MHz min

YLarge DC voltage gain 120 dB

YLow noise voltage 28 nV/0Hz

YWide power supply range g1.5V to g22V

YClass AB output stage–no crossover distortion

YIdeal pin out for Biquad active filters

YInput bias currents are temperature compensated

Connection Diagram (Dual-In-Line Package, Top View)

TL/H/5654–1

Order Number LM146J, LM146J/883,

LM246J, LM346M or LM346N

See NS Package Number J16A, M16A or N16A

PROGRAMMING EQUATIONS

Total Supply Current e1.4 mA (ISET/10 mA)

Gain Bandwidth Product e1 MHz (ISET/10 mA)

Slew Rate e0.4V/ms(I

SET/10 mA)

Input Bias Current j50 nA (ISET/10 mA)

ISET eCurrent into pin 8, pin 9 (see schematic-

diagram)

ISET eVabVbb0.6V

RSET

Schematic Diagram

TL/H/5654–2

C1995 National Semiconductor Corporation RRD-B30M115/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.

(Note 5)

LM146 LM246 LM346

Supply Voltage g22V g18V g18V

Differential Input Voltage (Note 1) g30V g30V g30V

CM Input Voltage (Note 1) g15V g15V g15V

Power Dissipation (Note 2) 900 mW 500 mW 500 mW

Output Short-Circuit Duration (Note 3) Continuous Continuous Continuous

Operating Temperature Range b55§Ctoa

125§Cb25§Ctoa

85§C0

Ctoa

70§C

Maximum Junction Temperature 150§C 110§C 100§C

Storage Temperature Range b65§Ctoa

150§Cb65§Ctoa

150§C

Lead Temperature (Soldering, 10 seconds) 260§C 260§C 260§C

Thermal Resistance (ijA), (Note 2)

Cavity DIP (J) Pd 900 mW 900 mW 900 mW

ijA 100§C/W 100§C/W 100§C/W

Small Outline (M) ijA 115§C/W

Molded DIP (N) Pd 500 mW

ijA 90§C/W

Soldering Information

Dual-In-Line Package

Soldering (10 seconds) a260§Ca260§Ca260§C

Small Outline Package

Vapor Phase (60 seconds) a215§Ca215§Ca215§C

Infrared (15 seconds) a220§Ca220§Ca220§C

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

devices.

ESD rating is to be determined.

DC Electrical Characteristics (VSeg15V, ISETe10 mA, Note 4)

Parameter Conditions LM146 LM246/LM346 Units

Min Typ Max Min Typ Max

Input Offset Voltage VCMe0V, RSs50X,T

25§C 0.5 5 0.5 6 mV

Input Offset Current VCMe0V, TAe25§C 2 20 2 100 nA

Input Bias Current VCMe0V, TAe25§C 50 100 50 250 nA

Supply Current (4 Op Amps) TAe25§C 1.4 2.0 1.4 2.5 mA

Large Signal Voltage Gain RLe10 kX,DVOUTeg10V, 100 1000 50 1000 V/mV

TAe25§C

Input CM Range TAe25§Cg13.5 g14 g13.5 g14 V

CM Rejection Ratio RSs10 kX,T

25§C 80 100 70 100 dB

Power Supply Rejection Ratio RSs10 kX,T

25§C, 80 100 74 100 dB

VSeg5tog

15V

Output Voltage Swing RLt10 kX,T

25§Cg12 g14 g12 g14 V

Short-Circuit TAe25§C 5 20 35 5 20 35 mA

Gain Bandwidth Product TAe25§C 0.8 1.2 0.5 1.2 MHz

Phase Margin TAe25§C 60 60 Deg

Slew Rate TAe25§C 0.4 0.4 V/ms

Input Noise Voltage fe1 kHz, TAe25§C 28 28 nV/0Hz

Channel Separation RLe10 kX,DVOUTe0V to 120 120 dB

g12V, TAe25§C

Input Resistance TAe25§C 1.0 1.0 MX

Input Capacitance TAe25§C 2.0 2.0 pF

Input Offset Voltage VCMe0V, RSs50X0.5 6 0.5 7.5 mV

Input Offset Current VCMe0V 2 25 2 100 nA

Input Bias Current VCMe0V 50 100 50 250 nA

Supply Current (4 Op Amps) 1.7 2.2 1.7 2.5 mA

DC Electrical Characteristics (Continued) (VSeg15V, ISETe10 mA, Note 4)

Parameter Conditions LM146 LM246/LM346 Units

Min Typ Max Min Typ Max

Large Signal Voltage Gain RLe10 kX,DVOUTeg10V 50 1000 25 1000 V/mV

Input CM Range g13.5 g14 g13.5 g14 V

CM Rejection Ratio RSs50X70 100 70 100 dB

Power Supply Rejection Ratio RSs50X,76 100 74 100 dB

VSeg5V to g15V

Output Voltage Swing RLt10 kXg12 g14 g12 g14 V

DC Electrical Characteristic (VSeg15V, ISETe1mA)

Parameter Conditions LM146 LM246/LM346 Units

Min Typ Max Min Typ Max

Input Offset Voltage VCMe0V, RSs50X, 0.5 5 0.5 7 mV

TAe25§C

Input Bias Current VCMe0V, TAe25§C 7.5 20 7.5 100 nA

Supply Current (4 Op Amps) TAe25§C 140 250 140 300 mA

Gain Bandwidth Product TAe25§C 80 100 50 100 kHz

DC Electrical Characteristics (VSeg1.5V, ISETe10 mA)

Parameter Conditions LM146 LM246/LM346 Units

Min Typ Max Min Typ Max

Input Offset Voltage VCMe0V, RSs50X, 0.5 5 0.5 7 mV

TAe25§C

Input CM Range TAe25§Cg0.7 g0.7 V

CM Rejection Ratio RSs50X,T

25§C80 80dB

Output Voltage Swing RLt10 kX,T

25§Cg0.6 g0.6 V

Note 1: For supply voltages less than g15V, the absolute maximum input voltage is equal to the supply voltage.

Note 2: The maximum power dissipation for these devices must be derated at elevated temperatures and is dictated by TjMAX,ijA, and the ambient temperature,

TA. The maximum available power dissipation at any temperature is Pde(TjMAX -T

)/ijA or the 25§CP

dMAX, whichever is less.

Note 3: 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 4: These specifications apply over the absolute maximum operating temperature range unless otherwise noted.

Note 5: Refer to RETS146X for LM146J military specifications.

Typical Performance Characteristics

Input Bias Current vs ISET Supply Current vs ISET

Open Loop Voltage Gain

vs ISET

TL/H/5654–3

Typical Performance Characteristics

Slew Rate vs ISET vs ISET

Gain Bandwidth Product

Phase Margin vs ISET

vs ISET

Input Offset Voltage

Ratio vs ISET

Common-Mode Rejection

Ratio vs ISET

Power Supply Rejection

Supply Voltage

Output Voltage Swing vs

Supply Voltage

Input Voltage Range vs

Voltage

Input Common-Mode

Input Bias Current vs

Temperature

Input Bias Current vs

Temperature

Input Offset Current vs

Temperature

Supply Current vs

TL/H/5654–4

Typical Performance Characteristics (Continued)

Open Loop Voltage Gain

vs Temperature

Gain Bandwidth Product

vs Temperature

Slew Rate vs

Temperature

Input Noise Voltage vs

Frequency

Input Noise Current vs

Frequency

Power Supply Rejection

Ratio vs Frequency

Voltage Follower Pulse

Response

Voltage Follower Transient

Response

TL/H/5654–5

Transient Response Test Circuit

TL/H/5654–6

Application Hints

Avoid reversing the power supply polarity; the device will

fail.

Common-Mode Input Voltage: The negative common-

mode voltage limit is one diode drop above the negative

supply voltage. Exceeding this limit on either input will result

in an output phase reversal. The positive common-mode

limit is typically 1V below the positive supply voltage. No

output phase reversal will occur if this limit is exceeded by

either input.

Output Voltage Swing vs ISET:For a desired output volt-

age swing the value of the minimum load depends on the

positive and negative output current capability of the op

amp. The maximum available positive output current,

(ICLa), of the device increases with ISET whereas the nega-

tive output current (ICLb) is independent of ISET.

Figure 1

illustrates the above.

TL/H/5654–7

FIGURE 1. Output Current Limit vs ISET

Input Capacitance: The input capacitance, CIN,ofthe

LM146 is approximately 2 pF; any stray capacitance, CS,

(due to external circuit circuit layout) will add to CIN. When

resistive or active feedback is applied, an additional pole is

added to the open loop frequency response of the device.

For instance with resistive feedback (

Figure 2

), this pole

occurs at (/2q(R1

R2) (CIN aCS). Make sure that this pole

occurs at least 2 octaves beyond the expected b3 dB fre-

quency corner of the closed loop gain of the amplifier; if not,

place a lead capacitor in the feedback such that the time

constant of this capacitor and the resistance it parallels is

equal to the RI(CSaCIN), where RIis the input resistance

of the circuit.

TL/H/5654–9

FIGURE 2

Temperature Effect on the GBW: The GBW (gain band-

width product), of the LM146 is directly proportional to ISET

and inversely proportional to the absolute temperature.

When using resistors to set the bias current, ISET,ofthe

device, the GBW product will decrease with increasing tem-

perature. Compensation can be provided by creating an

ISET current directly proportional to temperature (see typical

applications).

Isolation Between Amplifiers: The LM146 die is isother-

mally layed out such that crosstalk between

all 4

amplifiers

is in excess of b105 dB (DC). Optimum isolation (better

than b110 dB) occurs between amplifiers A and D, B and

C; that is, if amplifier A dissipates power on its output stage,

amplifier D is the one which will be affected the least, and

vice versa. Same argument holds for amplifiers B and C.

LM146 Typical Performance Summary: The LM146 typi-

cal behaviour is shown in

Figure 3

. The device is fully pre-

dictable. As the set current, ISET, increases, the speed, the

bias current, and the supply current increase while the noise

power decreases proportionally and the VOS remains con-

stant. The usable GBW range of the op amp is 10 kHz to

3.5b4 MHz.

TL/H/5654–8

FIGURE 3. LM146 Typical Characteristics

Low Power Supply Operation: The quad op amp operates

down to g1.3V supply. Also, since the internal circuitry is

biased through programmable current sources, no degrada-

tion of the device speed will occur.

Speed vs Power Consumption: LM146 vs LM4250 (single

programmable). Through

Figure 4

, we observe that the

LM146’s power consumption has been optimized for GBW

products above 200 kHz, whereas the LM4250 will reach a

GBW of no more than 300 kHz. For GBW products below

200 kHz, the LM4250 will consume less power.

TL/H/5654–10

FIGURE 4. LM146 vs LM4250

Typical Applications

Dual Supply or Negative Supply Biasing

ISETj

b0.6V

RSET

Current Source Biasing

with Temperature Compensation

ISETe67.7 mV

RSET

#The LM334 provides an ISET directly proportional to

absolute temperature. This cancels the slight GBW product

Temperature coefficient of the LM346.

Single (Positive) Supply Biasing

ISETjVab0.6V

RSET

Biasing all 4 Amplifiers

with Single Current Source

ISET1

ISET2

eR2

R1,I

SET1aISET2e67.7 mV

RSET

#For ISET1jISET2 resistors R1 and R2 are not required

if a slight error between the 2 set currents can be tolerated.

If not, then use R1 eR2 to create a 100 mV drop across

these resistors.

TL/H/5654–11

Active Filters Applications

Basic (Non-Inverting ‘‘State Variable’’) Active Filter Building Block

TL/H/5654–12

#The LM146 quad programmable op amp is especially suited for active filters because of their adequate GBW product

and low power consumption.

Circuit synthesis equations (for circuit analysis equations, consult with the LM148 data sheet).

Need to know desired: foecenter frequency measured at the BP output

Qoequality factor measured at the BP output

Hoegain at the output of interest (BP or HP or LP or all of them)

#Relation between different gains: Ho(BP) e0.316 cQocHo(LP);H

o(LP) e10 cHo(HP)

#RcCe5.033 c10b2

(sec)

#For BP output: RQe#3.478 QobHo(BP)

105bHo(BP)

105c3.748 cQoJb1

IN e#3.478 Qo

Ho(BP)

b1J

RQ a10b5

#For HP ouput: RQe1.1 c105

3.478 Qo(1.1 bHo(HP))bHo(HP)

IN e

1.1

Ho(HP)

RQ a10b5

Note. All resistor values are given in ohms.

#For LP output: RQe11 c105

3.478 Qo(11bHo(LP))bHo(LP)

IN e

Ho(LP)

RQ a10b5

#For BR (notch) output: Use the 4th amplifier of the LM146 to sum the LP and HP outputs of the basic filter.

TL/H/5654–13

0RH

e0.316 fnotch

Determine RFaccording to the desired gains: Ho(BR) Àfkkfnotch

eRF

Ho(LP),H

o(BR) Àfllfnotch

eRF

Ho(HP)

#Where to use amplifier C: Examine the above gain relations and determine the dynamics of the filter. Do not allow slew rate limiting in any output (VHP,V

BP,

VLP), that is:

VIN(peak) k63.66 c103cISET

10 mAc1

focHo

(Volts)

If necessary, use amplifier C, biased at higher ISET, where you get the largest output swing.

Deviation from Theoretical Predictions: Due to the finite GBW products of the op amps the fo,Q

owill be slightly different from the theoretical predictions.

freal jfo

1a2f

GBW

real jQo

1b3.2 focQo

GBW

Active Filters Applications (Continued)

A Simple-to-Design BP, LP Filter Building Block

TL/H/5654–14

#If resistive biasing is used to set the LM346 performance, the Qoof this filter building block is nearly insensitive to the op amp’s GBW product temperature drift; it

has also better noise performance than the state variable filter.

Circuit Synthesis Equations

Ho(BP) eQoHo(LP);RcCe0.159

ocR; RIN eRQ

Ho(BP)

Ho(LP)

#For the eventual use of amplifier C, see comments on the previous page.

A 3-Amplifier Notch Filter (or Elliptic Filter Building Block)

TL/H/5654–15

Circuit Synthesis Equations

RcCe0.159

ocR; RIN e0.159 cfo

CÊcf2notch

Ho(BR)

fkkfnotch

RIN

Ho(BR)

fllfnotch

eCÊ

#For nothing but a notch output: RINeR, CÊeC.

Active Filters Applications (Continued)

Capacitorless Active Filters (Basic Circuit)

TL/H/5654–16

#This is a BP, LP, BR filter. The filter characteristics are created by using the tunable frequency response of the LM346.

#Limitations: Qok10, focQok1.5 MHz, output voltage should not exceed Vpeak(out) s63.66 c103

cISET(mA)

10 mA

(V)

#Design equations: a eR6 aR5

R6 ,beR2

R1 aR2,ceR3

R3 aR4,deR7

R8 aR7,eeR10

R( aR10,f

o(BP) efu0b

a,H

o(BP) eacc, Ho(LP) ec

b,Q

oe0acb

o(BR) efo(BP), #1bc

bJjfo(BP) (C kk1) provided that d eHo(BP) ce, Ho(BR) eR10

R9 .

#Advantage: foQo,H

ocan be independently adjusted; that is, the filter is extremely easy to tune.

#Tuning procedure (ex. BP tuning)

1. Pick up a convenient value for b; (b k1)

2. Adjust Qothrough R5

3. Adjust Ho(BP) through R4

4. Adjust fothrough RSET. This adjusts the unity gain frequency (fu) of the op amp.

A 4th Order Butterworth Low Pass Capacitorless Filter

TL/H/5654–17

Ex: fce20 kHz, Ho(gain of the filter) e1, Q01 e0.541, Qo2 e1.306.

#Since for this filter the GBW product of all 4 amplifiers has been designed to be the same (E1 MHz) only one current source can be used to bias the circuit. Fine

tuning can be further accomplished through Rb.

Miscellaneous Applications

A Unity Gain Follower

with Bias Current Reduction

#For better performance, use a matched NPN pair.

Circuit Shutdown

#By pulling the SET pin(s) to Vbthe op amp(s) shuts down and its output

goes to a high impedance state. According to this property, the LM346

can be used as a very low speed analog switch.

Voice Activated Switch and Amplifier

TL/H/5654–18

Miscellaneous Applications (Continued)

X10 Micropower Instrumentation Amplifier with Buffered Input Guarding

TL/H/5654–19

#CMRR: 100 dB (typ)

#Power dissipation: 0.4 mW

Physical Dimensions inches (millimeters)

Cavity Dual-In-Line Package (J)

Order Number LM146J, LM146J/883 or LM246J

NS Package Number J16A

S.O. Package (M)

Order Number LM346M

NS Package Number M16A

LM146/LM246/LM346 Programmable Quad Operational Amplifiers

Physical Dimensions inches (millimeters) (Continued)

Molded Dual-In-Line Package (N)

Order Number LM346N

NS Package Number N16A

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