LM308N中文资料
TL H 7758LM108 LM208 LM308Operational Amplifiers
December 1994
LM108 LM208 LM308Operational Amplifiers
General Description
The LM108series are precision operational amplifiers hav-ing specifications a factor of ten better than FET amplifiers over a b 55 C to a 125 C temperature range
The devices operate with supply voltages from g 2V to g 20V and have sufficient supply rejection to use unregulat-ed supplies Although the circuit is interchangeable with and uses the same compensation as the LM101A an alternate compensation scheme can be used to make it particularly insensitive to power supply noise and to make supply by-pass capacitors unnecessary
The low current error of the LM108series makes possible many designs that are not practical with conventional ampli-fiers In fact it operates from 10M X source resistances
introducing less error than devices like the 709with 10k X sources Integrators with drifts less than 500m V sec and analog time delays in excess of one hour can be made us-ing capacitors no larger than 1m F
The LM108is guaranteed from b 55 C to a 125 C the LM208from b 25 C to a 85 C and the LM308from 0 C to a 70 C
Features
Y Maximum input bias current of 3 0nA over temperature Y Offset current less than 400pA over temperature Y Supply current of only 300m A even in saturation Y
Guaranteed drift characteristics
Compensation Circuits
Standard Compensation Circuit
C f t
R1C O R1a R2
C O e 30pF
TL H 7758–1 Bandwidth and slew rate are proportional to 1 C f Alternate Frequency Compensation
TL H 7758–2
Improves rejection of power supply noise by a factor of ten Bandwidth and slew rate are proportional to 1 C s
Feedforward Compensation
TL H 7758–3
C 1995National Semiconductor Corporation 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
(Note5)
LM108 LM208LM308 Supply Voltage g20V g18V
Power Dissipation(Note1)500mW500mW
Differential Input Current(Note2)g10mA g10mA
Input Voltage(Note3)g15V g15V
Output Short-Circuit Duration Continuous Continuous
Operating Temperature Range(LM108)b55 C to a125 C0 C to a70 C
(LM208)b25 C to a85 C
Storage Temperature Range b65 C to a150 C b65 C to a150 C
Lead Temperature(Soldering 10sec)
DIP260 C260 C
H Package Lead Temp
(Soldering10seconds)300 C300 C
Soldering Information
Dual-In-Line Package
Soldering(10seconds)260 C
Small Outline Package
Vapor Phase(60seconds)215 C
Infrared(15seconds)220 C
See AN-450‘‘Surface Mounting Methods and Their Effect on Product
Reliability’’for other methods of soldering surface mount devices
ESD Tolerance(Note6)2000V
Electrical Characteristics(Note4)
Parameter Condition
LM108 LM208LM308
Units Min Typ Max Min Typ Max
Input Offset Voltage T A e25 C0 72 02 07 5mV Input Offset Current T A e25 C0 050 20 21nA Input Bias Current T A e25 C0 82 01 57nA Input Resistance T A e25 C30701040M X Supply Current T A e25 C0 30 60 30 8mA Large Signal Voltage T A e25 C V S e g15V5030025300V mV
Gain V OUT e g10V R L t10k X
Input Offset Voltage3 010mV Average Temperature
Coefficient of Input3 0156 030m V C Offset Voltage
Input Offset Current0 41 5nA Average Temperature
Coefficient of Input0 52 52 010pA C Offset Current
Input Bias Current3 010nA Supply Current T A e a125 C0 150 4mA
Large Signal Voltage V S e g15V V OUT e g10V
2515V mV Gain R L t10k X
Output Voltage Swing V S e g15V R L e10k X g13g14g13g14V
2
Electrical Characteristics(Note4)(Continued)
Parameter Condition
LM108 LM208LM308
Units Min Typ Max Min Typ Max
Input Voltage Range V S e g15V g13 5g14V
Common Mode
8510080100dB Rejection Ratio
Supply Voltage
80968096dB Rejection Ratio
Note1 The maximum junction temperature of the LM108is150 C for the LM208 100 C and for the LM308 85 C For operating at elevated temperatures devices in the H08package must be derated based on a thermal resistance of160 C W junction to ambient or20 C W junction to case The thermal resistance of the dual-in-line package is100 C W junction to ambient
Note2 The inputs are shunted with back-to-back diodes for overvoltage protection Therefore excessive current will flow if a differential input voltage in excess of 1V is applied between the inputs unless some limiting resistance is used
Note3 For supply voltages less than g15V the absolute maximum input voltage is equal to the supply voltage
Note4 These specifications apply for g5V s V S s g20V and b55 C s T A s a125 C unless otherwise specified With the LM208 however all temperature specifications are limited to b25 C s T A s85 C and for the LM308they are limited to0 C s T A s70 C
Note5 Refer to RETS108X for LM108military specifications and RETs108AX for LM108A military specifications
Note6 Human body model 1 5k X in series with100pF
Schematic Diagram
TL H 7758–8
3
Typical Performance Characteristics LM108 LM208
Input Currents
Offset Error
Drift Error
Input Noise Voltage Power Supply Rejection
Output Impedance
Closed Loop
Voltage Gain Output Swing Supply Current
Frequency Response Open Loop
Frequency Response Large Signal
Pulse Response
Voltage Follower TL H 7758–6
4
Typical Performance Characteristics LM308
Input Currents
Offset Error
Drift Error
Input Noise Voltage Power Supply Rejection
Output Impedance
Closed Loop
Voltage Gain Output Swing Supply Current
Frequency Response Open Loop
Frequency Response Large Signal
Pulse Response
Voltage Follower TL H 7758–7
5
Typical Applications
Sample and Hold
Teflon polyethylene or
polycarbonate dielectric
capacitor
Worst case drift less than
2 5mV sec
TL H 7758–4
High Speed Amplifier with Low Drift and Low Input Current
TL H 7758–5
6
Typical Applications(Continued)
Fast Summing Amplifier
In addition to increasing Power Bandwidth 250KHz
speed the LM101A raises Small Signal Bandwidth 3 5MHz high and low frequency Slew Rate 10V m S
gain increases output
C5e 6c10b8
R f
drive capability and eliminates
thermal feedback
TL H 7758–12 Connection Diagrams
Metal Can Package
TL H 7758–13
Package is connected to Pin4(V b)
Unused pin(no internal connection)to allow for input anti-leakage guard ring on printed circuit board layout
Order Number LM108H LM108H 883
LM308AH or LM308H
See NS Package Number H08C
Dual-In-Line Package
TL H 7758–15
Top View
Order Number LM108J-8 883 LM308M or LM308N See NS Package Number J08A M08A or N08E
TL H 7758–16 Top View
Order Number LM108J 883
See NS Package Number J14A
TL H 7758–17
Order Number LM108W 883
See NS Package Number W10A
Also available per JM38510 10104
7
Physical Dimensions inches(millimeters)
Ceramic Dual-In-Line Package(J)
Order Number LM108J 883
NS Package Number J08A
Ceramic Dual-In-Line Package(J)
Order Number LM108 883
NS Package Number J14A
8
Physical Dimensions inches(millimeters)(Continued)
Metal Can Package(H)
Order Number LM108H LM108H 883or LM308H
NS Package Number H08C
S O Package(M)
Order Number LM308M
NS Package Number M08A
9
L M 108 L M 208 L M 308O p e r a t i o n a l A m p l i f i e r s
Physical Dimensions inches (millimeters)(Continued)
Molded Dual-In-Line Package (N)
Order Number LM308N NS Package Number N08E
Ceramic Flatpack Package (W)Order Number LM108AW 883or
LM108W 883
NS Package Number W10A
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