LM146/LM346 Programmable Quad Operational Amplifiers
May 1999
LM146/LM346 Programmable Quad Operational Amplifiers
General Description
The LM146 series of quad op amps consists of four independent, high gain, internally compensated, low power, programmable 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 current for bandwidth or optimize noise figure for a given source resistance. In a similar way, other amplifier characteristics 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
(ISET = 10 µA) n Programmable electrical characteristics n Battery-powered operation n Low supply current: 350 µA/amplifier n Guaranteed gain bandwidth product: 0.8 MHz min n Large DC voltage gain: 120 dB n Low noise voltage: 28 n Wide power supply range: ± 1.5V to ± 22V n Class AB output stage–no crossover distortion n Ideal pin out for Biquad active filters n Input bias currents are temperature compensated PROGRAMMING EQUATIONS Total Supply Current = 1.4 mA (ISET/10 µA) Gain Bandwidth Product = 1 MHz (ISET/10 µA) Slew Rate = 0.4V/µs (ISET/10 µA) Input Bias Current ≅ 50 nA (ISET/10 µA) ISET = Current into pin 8, pin 9 (see schematic-diagram)
Connection Diagram
Dual-In-Line Package
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Top View Order Number LM146J, LM146J/883, LM346M or LM346N See NS Package Number J16A, M16A or N16A
© 1999 National Semiconductor Corporation
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Schematic Diagram
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Absolute Maximum Ratings (Notes 1, 5)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. LM146 LM346 ± 22V ± 18V Supply Voltage ± 30V ± 30V Differential Input Voltage (Note 1) ± 15V ± 15V CM Input Voltage (Note 1) Power Dissipation (Note 2) 900 mW 500 mW Output Short-Circuit Duration (Note 3) Continuous Continuous Operating Temperature Range −55˚C to +125˚C 0˚C to +70˚C Maximum Junction Temperature 150˚C 100˚C Storage Temperature Range −65˚C to +150˚C −65˚C to +150˚C Lead Temperature (Soldering, 10 seconds) 260˚C 260˚C Thermal Resistance (θjA), (Note 2) Cavity DIP (J) Pd 900 mW 900 mW 100˚C/W 100˚C/W θjA 115˚C/W Small Outline (M) θjA Molded DIP (N) Pd 500 mW 90˚C/W θjA Soldering Information Dual-In-Line Package Soldering (10 seconds) +260˚C +260˚C Small Outline Package Vapor Phase (60 seconds) +215˚C +215˚C Infrared (15 seconds) +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 rating is to be determined.
DC Electrical Characteristics
(VS = ± 15V, ISET = 10 µA), (Note 4) Parameter Input Offset Voltage Input Offset Current Input Bias Current Supply Current (4 Op Amps) Large Signal Voltage Gain Input CM Range CM Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing Short-Circuit Gain Bandwidth Product Phase Margin Slew Rate Input Noise Voltage Channel Separation Input Resistance Input Capacitance Input Offset Voltage Conditions Min VCM = 0V, RS≤50Ω, TA = 25˚C VCM = 0V, TA = 25˚C VCM = 0V, TA = 25˚C TA = 25˚C RL = 10 kΩ, ∆VOUT = ± 10V, TA = 25˚C TA = 25˚C RS≤10 kΩ, TA = 25˚C RS≤10 kΩ, TA = 25˚C, VS = ± 5 to ± 15V RL≥10 kΩ, TA = 25˚C TA = 25˚C TA = 25˚C TA = 25˚C TA = 25˚C f = 1 kHz, TA = 25˚C RL = 10 kΩ, ∆VOUT = 0V to ± 12V, TA = 25˚C TA = 25˚C TA = 25˚C VCM = 0V, RS≤50Ω
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LM146 Typ 0.5 2 50 1.4 100 1000 Max 5 20 100 2.0 50 Min
LM346 Typ 0.5 2 50 1.4 1000 Max 6 100 250 2.5
Units mV nA nA mA V/mV V dB dB V 35 mA MHz Deg V/µs
± 13.5
80 80
± 14
100 100
± 13.5
70 74
± 14
100 100
± 12
5 0.8
± 14
20 1.2 60 0.4 28 120 1.0 2.0 0.5 6 35
± 12
5 0.5
± 14
20 1.2 60 0.4 28 120 1.0 2.0 0.5 7.5
dB MΩ pF mV
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DC Electrical Characteristics
(VS = ± 15V, ISET = 10 µA), (Note 4) Parameter Input Offset Current Input Bias Current Supply Current (4 Op Amps) Large Signal Voltage Gain Input CM Range CM Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing RS≤50Ω VCM = 0V VCM = 0V
(Continued)
Conditions Min
LM146 Typ 2 50 1.7 50 1000 Max 25 100 2.2 25 Min
LM346 Typ 2 50 1.7 1000 Max 100 250 2.5
Units nA nA mA V/mV V dB dB V
RL = 10 kΩ, ∆VOUT = ± 10V
± 13.5
70 76 RS≤50Ω, VS = ± 5V to ± 15V RL≥10 kΩ
± 14
100 100
± 13.5
70 74
± 14
100 100
± 12
± 14
± 12
± 14
DC Electrical Characteristic
(VS = ± 15V, ISET = 10 µA) Parameter Input Offset Voltage Input Bias Current Supply Current (4 Op Amps) Gain Bandwidth Product Conditions Min VCM = 0V, RS≤50Ω, TA = 25˚C VCM = 0V, TA = 25˚C TA = 25˚C TA = 25˚C 80 LM146 Typ 0.5 7.5 140 100 Max 5 20 250 50 Min LM346 Typ 0.5 7.5 140 100 Max 7 100 300 mV nA µA kHz Units
DC Electrical Characteristics
(VS = ± 1.5V, ISET = 10 µA) Parameter Input Offset Voltage Input CM Range CM Rejection Ratio Output Voltage Swing Conditions Min VCM = 0V, RS≤50Ω, TA = 25˚C TA = 25˚C RS≤50Ω, TA = 25˚C RL≥10 kΩ, TA = 25˚C LM146 Typ 0.5 Max 5 Min LM346 Typ 0.5 Max 7 mV V 80 dB V Units
± 0.7
80
± 0.7 ± 0.6
± 0.6
Note 1: For supply voltages less than ± 15V, 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, θjA, and the ambient temperature, TA. The maximum available power dissipation at any temperature is Pd = (TjMAX - TA)/θjA or the 25˚C PdMAX, 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.
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Typical Performance Characteristics
Input Bias Current vs ISET Supply Current vs ISET Open Loop Voltage Gain vs ISET
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Slew Rate vs ISET
Gain Bandwidth Product vs ISET
Phase Margin vs ISET
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Input Offset Voltage vs ISET
Common-Mode Rejection Ratio vs ISET
Power Supply Rejection Ratio vs ISET
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Typical Performance Characteristics
Open Voltage Swing vs Supply Voltage
(Continued)
Input Voltage Range vs Supply Voltage
Input Bias Current vs Input Common-Mode Voltage
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Input Bias Current vs Temperature
Input Offset Current vs Temperature
Supply Current vs Temperature
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Open Loop Voltage Gain vs Temperature
Gain Bandwidth Product vs Temperature
Slew Rate vs Temperature
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Typical Performance Characteristics
Input Noise Voltage vs Frequency
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Input Noise Current vs Frequency
Power Supply Rejection Ratio vs Frequency
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Voltage Follower Pulse Response
Voltage Follower Transient Response
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Transient Response Test Circuit
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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 voltage 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, (ICL+), of the device increases with ISET whereas the negative output current (ICL−) is independent of ISET. Figure 1 illustrates the above.
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FIGURE 1. Output Current Limit vs ISET
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Application Hints
(Continued)
Input Capacitance: The input capacitance, CIN, of the 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 1⁄2π (R1||R2) (CIN + CS). Make sure that this pole occurs at least 2 octaves beyond the expected −3 dB frequency 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(CS + CIN), where RI is the input resistance of the circuit.
power decreases proportionally and the VOSremains constant. The usable GBW range of the op amp is 10 kHz to 3.5−4 MHz.
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FIGURE 2. Temperature Effect on the GBW: The GBW (gain bandwidth 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, of the device, the GBW product will decrease with increasing temperature. Compensation can be provided by creating an ISET current directly proportional to temperature (see typical applications). Isolation Between Amplifiers: The LM146 die is isothermally layed out such that crosstalk between all 4 amplifiers is in excess of −105 dB (DC). Optimum isolation (better than −110 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 typical behaviour is shown in Figure 3. The device is fully predictable. As the set current, ISET, increases, the speed, the bias current, and the supply current increase while the noise
FIGURE 3. LM146 Typical Characteristics Low Power Supply Operation: The quad op amp operates down to ± 1.3V supply. Also, since the internal circuitry is biased through programmable current sources, no degradation 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.
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FIGURE 4. LM146 vs LM4250
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Typical Applications
Dual Supply or Negative Supply Blasing Single (Positive) Supply Blasing
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Current Source Blasing with Temperature Compensation
Blasing all 4 Amplifiers with Single Current Source
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• The LM334 provides an ISET directly proportional to absolute temperature. This cancels the slight GBW product Temperature coefficient of the LM346.
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• For ISET1 ≅ ISET2 resistors R1 and R2 are not required if a slight error between the 2 set currents can be tolerated. If not, then use R1 = R2 to create a 100 mV drop across these resistors.
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Active Filters Applications
Basic (Non-Inverting “State Variable”) Active Filter Building Block
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Note. All resistor values are given in ohms.
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Active Filters Applications
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A Simple-to-Design BP, LP Filter Building Block
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• If resistive biasing is used to set the LM346 performance, the Qo of 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
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• For the eventual use of amplifier C, see comments on the previous page.
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Active Filters Applications
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A 3-Amplifier Notch Filter (or Elliptic Filter Building Block)
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Circuit Synthesis Equations
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• For nothing but a notch output: RIN = R, C' = C.
Capacitorless Active Filters (Basic Circuit)
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Active Filters Applications
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1. Pick up a convenient value for b; (b < 1) 2. Adjust Qo through R5 3. Adjust Ho(BP) through R4 4. Adjust fo through RSET. This adjusts the unity gain frequency (fu) of the op amp.
A 4th Order Butterworth Low Pass Capacitorless Filter
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Ex: fc = 20 kHz, Ho (gain of the filter) = 1, Q01 = 0.541, Qo2 = 1.306. • Since for this filter the GBW product of all 4 amplifiers has been designed to be the same (z1 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
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• For better performance, use a matched NPN pair.
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Miscellaneous Applications
(Continued) Circuit Shutdown
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• By pulling the SET pin(s) to V− the 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
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Miscellaneous Applications
(Continued)
X10 Micropower Instrumentation Amplifier with Buffered Input Guarding
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• CMRR: 100 dB (typ) • Power dissipation: 0.4 mW
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Physical Dimensions
inches (millimeters) unless otherwise noted
Cavity Dual-In-Line Package (J) Order Number LM146J, LM146J/883 NS Package Number J16A
S.O. Package (M) Order Number LM346M NS Package Number M16A
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LM146/LM346 Programmable Quad Operational Amplifiers
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
Molded Dual-In-Line Package (N) Order Number LM346N NS Package Number N16A
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