LM2895P ,AUDIO POWE RAMPLIFIERApplications
I Compact AM-FM radios
I Battery operated tape player amplifiers
I Line driver
..
LM2900 ,Quad Amplifier LM2900, LM3900 QUADRUPLE NORTON OPERATIONAL AMPLIFIERS SLOS059 – JULY 1979 – REVISED SEPTEMBER 199 ..
LM2900D ,Quadruple Operational Amplifier LM2900, LM3900 QUADRUPLE NORTON OPERATIONAL AMPLIFIERS SLOS059 – JULY 1979 – REVISED SEPTEMBER 199 ..
LM2900DR ,Quadruple Operational Amplifiermaximum ratings over operating free-air temperature range (unless otherwise noted)LM2900 LM3900 UNI ..
LM2900N ,LM2900/LM3900/LM3301 Quad AmplifiersLM2900/LM3900/LM3301QuadAmplifiersFebruary1995LM2900/LM3900/LM3301QuadAmplifiersGeneralDescription
LM2900N ,LM2900/LM3900/LM3301 Quad AmplifiersFeaturesYWide single supply voltage 4 V to 32 VTheLM2900seriesconsistsoffourindependent,dualinput,D ..
LM7121IM5 ,175 MHz Tiny Low Power Voltage Feedback AmplifierElectrical Characteristics (Continued)+ −= = = = = >Unless otherwise specified, all limits guarante ..
LM7121IM5X ,175 MHz Tiny Low Power Voltage Feedback AmplifierFeaturesThe LM7121 is a high performance operational amplifier (Typical unless otherwise noted) V = ..
LM7121IMX ,175 MHz Tiny Low Power Voltage Feedback AmplifierLM7121 235 MHz Tiny Low Power Voltage Feedback AmplifierAugust 1999LM7121235 MHz Tiny Low Power Vol ..
LM7121IN ,175 MHz Tiny Low Power Voltage Feedback AmplifierElectrical Characteristics+ −Unless otherwise specified, all limits guaranteed for T = 25˚C, V = +1 ..
LM7131ACM ,Tiny High Speed Single Supply Operational AmplifierElectrical Characteristics (Continued)+ − += = = = = =Unless otherwise specified, all limits guaran ..
LM7131ACM5 ,Tiny High Speed Single Supply Operational AmplifierElectrical Characteristics+ − += = = = = =Unless otherwise specified, all limits guaranteed for T 2 ..
LM2895P
AUDIO POWE RAMPLIFIER
Fig" Natiqnal
Semiconductor
LM1895/LM2895 Audio Power Amplifier
General Description
The LM1895 is a 6V audio power amplifier designed to de-
liver 1W into Mt. Utilizing a unique patented compensation
scheme, the LM1895 is ideal for sensitive AM radio applica-
tions. This new circuit technique exhibits lower noise, lower
distortion, and less AM radiation than conventional designs.
The amplifier’s supply range (3V--9V) is ideal for battery op-
eration. The LM1895 is packaged in an 8-pin miniDiP for
minimum PC board space. For higher supplies Ns > 9V)
the LM2895 is available in an 11-lead single-in-line package.
The 11-iead package has been redesigned, resulting in a
slightly degraded thermal characteristic shown in the figure
Device Dissipation vs Ambient Temperature.
Features
a Guaranteed low crossover distortion
a Low AM radiation
a Low noise
I: av. Mt, Po = 250 mW
II Wide supply operation 3V-15V (LM2895)
a Low distortion
II No turn on "pop"
I: Smooth waveform clipping
a 8-pin miniDlP (LM1895)
a 12V, 40, Po = 4W (LM2895)
n Tested for low crossover distortion
Applications
a Compact AM-FM radios
ll Battery operated tape player amplifiers
u Line driver
Typical Applications
I 10 M tll
- 330 "
IOJ pF
TL/H/7919-1
FIGURE 1. LM1895 with Av = 500, aw = 5 kHz, AM Radio
Appllcatlon (Vm = 4.2 mV for Full Power Output)
Order Number LM1895N or LM2895P
See NS Package Number NOSE or P11A
SGBZW'l/SGBI-WW
LM1895/LM2895
Absolute Maximum Ratings
If MIIItary/Aerospace specified devlces are required, Operating Temperature(Note1) 0'C to +70''C
please contact the National Semiconductor Sales Storage Temperature -65t to + 150°C
Ill',':,':,',',',,:','"'"'' for availability and speclflcatlons. Jun cti on T emp er ature 150.0
UPPY o age . "
LM 1895 Vs == 12V Lead Temperature (Soldering, 10 soc.) 260 C
LM2895 Vs = 18V
Electrical Characteristics
Unless otherwise specified, TA = 25'C, Av = 200 (46 dB). For the LM1895, Vs == 6V and RL = 40. For the LM2895, TTAB =
25''C, Vs == 12V and RL = Aft. Test circuit shown in Figure 2.
Parameter Conditions LM1896 LM2895 Units
Min Typ Max Mln Typ Max
Supply Current Po = W 8 14 12 20 mA
Operating Supply Voltage 3 10 3 15 V
OutputPower THD = 10%,f = 1 kHz
LM1895N vs = 6v, RL = 4n ) _ tt 0.9 1.1 w
vs = 9V, RL = en TA 25 C 1.1 w
LM2895P vs = 12v. RL = t'// _ It 3.6 4.3 w
vs = 12v. RL = en TTAB 25 C 2.5 w
Distortion f = 1 kHz
Po --- 50 mW 0.27 0.27 %
Po = 0.5W 0.20 0.20 %
Po = 1.0W 0.15 %
f = 20 kHz, Po = 100 mW, Vs = 3.6V 3.0 3.0 %
Crossover Distortion f --- 20 kHz, RL = Mt, Po = 100 mW,
VCC = 3.6V
PowerSupply Rejection Cay = 100 itF, f = 1 kHz, GIN = 0.1 WF
Ratio (PSRR) Output Referred, VRIPPLE = 250 mV 40 52 40 52 dB
Noise Equivalent Input Noise Rs = o,
Cm = 0.1 wt', BW -- 20 -20 kHz 1.4 1.4 #v
CCIR/ARM 1.4 1.4 WV
Wideband 2.0 2.0 p.V
DC Output Level 2.8 3.0 3.2 5.6 6.0 6.4 V
Input Impedance 50 150 350 50 150 350 kn
input Offset Voltage . 5 5 mV
Input Bias Current 120 120 nA
Note 1: For operation at ambient temperature greater than 25'C, the LM1895/LM2895 must be derated based on a maximum junction temperature using a thermal
resistance which depends upon mounting tet)hrtiques.
Typical Performance Characteristics
LM1895 Maximum Devlce - 3 dB Bandwidth vs
LM2895 Device Dissipation Dlsslpatlon vs Ambient Voltage Galn for Stable
vs Ambient Temperature Temperature Operation
' mo to' 'h
g ' M S " t u
T nu Iur tm '" g g. N .
, ' 'li'. n F, " m
6 t " g I' M
ll 4 g u g u Am
g a b" , 3. mm»:
2 ts' " I "
II " 20 M 40 so IO " so ' lo t8 " In " " n l) 0 1m IN :00 An [00 MO
Tv-hilt' TEIPEMTUE Ctl) TA - At"rE0 TEMIATUIE Cet Att WIV)
TL/H/7919-2
‘1-174
Typical Performance Characteristics (Continued)
AM Recovered Audlo and Nolse
vs Fleld Strength for Different
Speaker Lead Placement
GAIN (II)
HEWVEHED
AUDI!) "
«1 «mm
II}!!! "
THD (K!
IBIS! II"!
"I" ill}. LOWE!
IBIS! IITN SPEAK“ tlAllS
RECOVERED AUDIO All) “01!! REF 50 «W,
Mt " I ll
HELD “REIT"! (MIN)
THD and Galn " Frequency
AV = 46 dB, BW = 30 kHz
(mu (m
GAIN (n!
run 00
" ‘0le '00tk " "tttttthe
FREQUENCY Ire)
Power Supply Rejection
THD and Galn vs Frequency
Av = 54 dB, BW = 30 kHz
m 501M200 M " " 5111“!”
FMttlmlC8 (HI)
THD and Galn vs Frequency
Av = 40 dB, aw = 20 kHz
20 511190100 mu " 'etire2tlk
rnenusucv tke)
GAIN (“D
THD 1%)
GAIN (Cl)
" WIMIW SW“ "
THD and Gain vs Frequency
Ag = 54 dB, BW == 5kHz
" ttle Mk
FHEIIUEIcV Oh)
THD and Gain " Frequency
Av = 34 dB, aw = 50 kHz
20 5010.2“ ©0tt " 51mm
FREQUEICVMI)
Ratio (Referred to the Power Output vs Supply Total Harmonic Dlstortlon
Output) " Frequency V vs Power
- mm; "at"
h" w ' ; CW3: Uh
r, Clvus' m g t'j--e' iris,
1.; " 's 3 E v 1 n m
." a . ,
, 39 t E "
s i' , g
it n g E
, .. 1 f,
E w mes . Wt '
" " l F cm -0.l " E
a " Ag . m n 0.1
w 100 " ma 0 2 . I I 10 12 thilt 0.1 "
rneuumcv (1m sumv VMTABE M gum" pomp (w)
Power Dissipation vs Power Dlsslpatlon "
Output Power, RL = an Output Power, RL = 40.
mm: THO us mam It -11v TM
" Itt . 12V " '
_ LN *
, " ' t.5 se
.-. v; . " 5 .
g " g 115
g u g Lu
:?, " E ll."
" IIs " 015
I " " " " " 0 " " " " "
mmur IMIER MI OUTPUT NW!!! (WI
TL/H/791B.-3
SGBZW'l/SGSI-W'l
LM1895/LM2895
Equivalent Schematic
BOOTSTRAP
OUTPUT
v -N. - END
3ts) 4(3) 5(9) 5(6)
BYPASS +INPUT -tNPttT
TL/H/N19-4
Pin 7 no connection on LM1895
Pins 4. 7, IO, 11 no connection on LM2895
( ) indicates pin number for LM2895
Typical Applications (Continued)
470 pF
Wu o-l
SC',.,-'' LM1'95 O VOUT
H5 100k
MO --l
Qi""' J",, I "'
- TL/H/7g19-5
FIGURE 2. Ampllerr wlth Av = 200, BW == 30 kHz
External Components (Figure a
Components
1.R1,R5
Comments
Sets voltage gain, AV = 1 + R1/R5
Bootstrap resistor sets drive current for output stage and allows pin 2 to go
above Vs
Works with Co to stabilize output stage
Input coupling capacitor. Pin 4 is at a DC potential of Vs/ 2. Low frequency
pole set by:
f = " R.NC4
Feedback capacitor. Ensure unity gain at DC. Also a low frequency pole at:
= br H505
Bootstrap Capacitor, used to increase drive to output stage. A low frequency
pole is set by:
= " R202
Compensation capacitor. This stabilizes the amplifier and adjusts the
bandwidth. See curve of bandwidth vs allowable gain
Improves power supply rejection. (See Typical Performance Curves).
Increasing C3 increases turn-on delay
Output coupling capacitor. Isolates pin 1 from the load. Low frequency pole
set by:
f == " CcRL
Works with Ro to stabilize output stage
Provides power supply filtering
Connection Diagrams
Dual-In-Llne Package
Single-ln-Llne Package
ounuv .2
BOOTSTRAP -
mass "
till -
LM1895
a v-!.. q \,s,.,,,,Y
''-HIs
BYPASS -
1mo - Lam;
Top Vlew
TL/H/7919-6 7
OUTPUT -
NC BDOTSTRAP -- 'l".'.',',
ml --1 C)
-ttt -
tte---
_..-.?
TL/H/7819-7
Top View
5683W1/968L W1
LM1895/LM2895
Application Hints
AM Radios
The LM1895/LM2895 have been designed to till a wide
range of audio power applications. A common problem with
IC audio power amplifiers has been poor signaI-to-noise per-
formance when used in AM radio applications. In a typical
radio application, the loopstick antenna is in close proximity
to the audio amplifier. Current flowing in the speaker and
power supply leads can cause electromagnetic coupling to
the loopstick. resulting in system oscillation. In addition,
most audio power amplifiers are not optimized for lowest
noise because of compensation requirements. If noise from
the audio amplifier radiates into the AM section, the sensitiv-
ity and signal-to-noise ratio will be degraded.
The LM1895 exhibits extremely low wideband noise due in
part to an external capacitor Cl which is used to tailor the
bandwidth. The circuit shown in Figure 2 is capable of a
signal-to-noise ratio in excess of 60 dB referred to 50 mW.
Capacitor C1 not only limits the closed loop bandwidth, it
also provides overall loop compensation. Neglecting C5 in
Figure a the gain is:
AUDIO AT
SPEAKER
RECOVERED
NOISE AT
SPEAKER
Ill" FROM lODPSTICK
I SAME CONDITIONS FOR
RECOVERED AUDIO AND NOISE REF 50 mW.
0.01 tht 1 10
FIELD STRENGTH (mVl'M)
TL/H/7919-8
FIGURE 3. improved AM Sensitivity
Over Conventional Design
S+Avaro
A s =---
vis) S+wo
R1+R5 1
where AV“?! ttto - m
A curve of --3 dB BW (mo) vs AV is shown in the Typical
Performance Curves.
Figure 3 shows a plot of recovered audio as a function of
field strength in pV/M. The receiver section in this example
is an LM3820. The power amplifier is located about two
inches from the loopstick antenna. Speaker leads run paral-
lel to the loopstick and are 1/8 inch from it. Referenced to a
20 dB S/N ratio, the improvement in noise performance
over conventional designs is about 10 dB. This corresponds
to an increase in usable sensitivity of about 8.5 dB.
sun vs
VOUT VOUT
TL/H/7919-9
FIGURE 4. Printed Circuit Board Layout for LM1895
This datasheet has been :
www.ic-phoenix.com
Datasheets for electronic components.
National Semiconductor was acquired by Texas Instruments.
corp/docs/irwestor_relations/Pr_09_23_201 1_national_semiconductor.html
This file is the datasheet for the following electronic components:
LM2895P - product/Im2895p?HQS=TI-nulI-nu|I-dscatalog-df-pf-nulI-wwe
LM2895 - product/Im2895?HQS=T|-nu|I-null-dscatalog-df—pf—nulI-wwe
LM1895 - productllm1895?HQS=T|—nu||—nu|I-dscatalog-df-pf-nulI-wwe
LM1895N - product/Im1895n?HQS=T|-nu|I-null-dscatalog-df-pf-nuIl-wwe
LM1895 - product/Im1895?HQS=T|—nu|l-nu|I-dscataIog-df-pf-null-wwe
LM2895P - product/Im2895p?HQS=T|-nulI-nuIl-dscatalog-df-pf-nulI-wwe
LM2895 - productllm2895?HQS=T|—nu||—nu|I-dscatalog-df-pf-nulI-wwe
LM1895N - product/Im1895n?HQS=T|-nu|I-null-dscatalog-df-pf-nuIl-wwe
