LM3820N ,AM RADIO SYSTEMFeatures
I Input protection diodes
I Good control on sensitivity
I Improved sm and tweet
..
LM3822MM-1.0 ,Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM OutputLM3822 Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM OutputNovember 2000L ..
LM3822MM-2.0 ,Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM OutputGeneral Description1.8 µA)The LM3822 Current Gauge provides easy to use precisionn 50 msec sampling ..
LM3824MM-1.0 ,Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM OutputPin Description (High-Side, LM3824)Pin Name Function1 SENSE+, V High side of internal current sense ..
LM3824MM-2.0 ,Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM OutputGeneral Description Key Specificationsn Ultra low insertion loss (0.003Ω)The LM3824 Current Gauge p ..
LM382N ,40 V, 20 mA, low noise dual preamplifierFeatures
I Low noise - 0.8 MV total equivalent input noise
I High gain - 100 dB open loop
I ..
LMV7219M5 ,7 nsec, 2.7V to 5V Comparator with Rail-to- Rail OutputFeaturesThe LMV7219 is a low-power, high-speed comparator with (V =5V,T = 25˚C, Typical values unle ..
LMV7219M5X ,7 nsec, 2.7V to 5V Comparator with Rail-to- Rail OutputFeatures List 1• Changed Operating Temperature to Ambient Temperature ........ 4• Added Junction Te ..
LMV7219M5X ,7 nsec, 2.7V to 5V Comparator with Rail-to- Rail OutputApplicationsn Portable and battery-powered systemsn Scannersn Set top boxesn High speed differentia ..
LMV7219M5X ,7 nsec, 2.7V to 5V Comparator with Rail-to- Rail OutputFeaturesThe LMV7219 is a low-power, high-speed comparator with (V =5V,T = 25˚C, Typical values unle ..
LMV7219M5X/NOPB ,7 nsec, 2.7V to 5V Comparator with Rail-to- Rail Output 5-SOT-23 -40 to 85Maximum Ratings(1)(2)over operating free-air temperature range (unless otherwise noted)MIN MAX UNIT ..
LMV7219M7 ,7 nsec, 2.7V to 5V Comparator with Rail-to- Rail OutputLMV7219 7 nsec, 2.7V to 5V Comparator with Rail-to-Rail OutputNovember 2004LMV72197 nsec, 2.7V to 5 ..
LM3820N
AM RADIO SYSTEM
National .
Semiconductor
LM3820 AM Radio System
General Description
The LM3820 is a 3-stage AM radio IC consisting of an RF
amplifier, oscillator, mixer, IF amplifier, AGC detector, and
zener regulator.
The device was originally designed for use in slug-tuned
auto radio applications, but is also suitable for capacitor-
tuned portable radios.
The LM3820 is an improved replacement for the LM1820.
Features
I! Input protection diodes
II Good control on sensitivity
n Improved S/N and tweet
II Versatile building-block approach
I: Gain-controlled RF stage
II Cascode IF amplifier
I: Regulated supply
I: Pin compatible with LM1820
Connection Diagram
Dual-In-Llne Package
mxm INPUT -
oscuLATnn TANK -
tt' -,..'..
MIXER BYPASS -
Mt DRIVE .2.
- MIXER OUTPUT
- RF 00"!"
- RF INPUT
- RF BYPASS
JSI ncc CAPMITtrtt
w ouwur - - RF cnouno
IF INPUT - - so BSTRATE Mitt
w Anm snouun
TL/H/7967-1
Order Number LM3820N
See NS Package Number N14A
Circuit Schematic
l" 01201 Tu 02 0| 3 Os
05 son
m 5.5x 2
" . R16
tt R11
o-4 3.3x
TL/H/7967-2
0388““
LM3820
Absolute Maximum Ratings
If Mllltary/Aerospace apeeltied. devices are required, Currentinto Supply Terminal(Pin 3) 35 mA
please contact the National Semiconductor Sales
Operating Temperature Range - 25''C to + 85''C
P''"..!."'."..""'? for availability and specifications. St or a g e T emp er atur e R an g e _ 65°C t o +1500
Power Dissipation (Note 1) 1200 mW Lead Temperature (Soldering, 10 sec.) 26tt'C
Supply Voltage 16V
Electrical Characteristics (Figure 1, TA = 25"C, vs = 6V unless noted)
Symbol Parameter Condltlons Mln Typ Max Units
ls Supply Current No RF Input 12 18 24 mA
Vz Internal Zener Voltage 7.0 7.5 8.0 V
Input Sensitivity f = 1 MHz, 30% Mod 400 Hz
Measure RF Input Level for
10 mV Audio Output with 15 35 70 'si/
Tuning Peaked
Signal to Noise Ratio f -- 1 MHz, 30% Mod 1 kHz
(S + N)/N at Audio Output 22 28 - dB
with 100 WV RF Input
Overload Distortion f == 1 MHz, 90% Mod1 kHz
THD at Audio Output - 6 10 %
with 30 mV RF Input
Note 1: Above TA = 25''C, derate based on Tum“) --- 150°C and OM = 100 °C/W.
Typical Applications
SIMULAYES
LOGISTICK
AMTEINA' Is
IINPUT t ovs
150p! !
I I ttN "
" " "ll"
I .. i",-",,iif-i,--r--r,-"la,.-, ---.-..1. I"
. J, J, a.‘ 0.05 u’
tls,.rtiir-i
____ ___I‘O‘A'__.__—__—J
‘1 t ' a
tit " AUDIO
ll cum:
- - 7 516
'Ct"'' "
'100 ptV RF INPUT is equivalent to approx. 1 mV/meter field strength. See Applications Information tor coil specifications. TL/H/7t?67-3
FIGURE 1. Capacltor-Tuned Test Fixture
Applications Information
The circuit shown in Figure , is recommended as a starting
point for portable radio designs. Loopstick antenna L1 is
used in place of LO, and the RF amplifier is used with a
resistor load to drive the mixer. A double tuned circuit at the
output of the mixer provides selectivity, while the remainder
of the gain is provided by the IF section, which is matched to
the diode through a unity turns ratio transformer. RAGC may
be used in place of CAGC to bypass the internal AGC detec-
tor and provide more recovered audio.
An AM automobile radio design is shown in Figure 2. Tuning
of both the input and the output of the RF amplifier and the
mixer is accomplished with variable inductors. Better selec-
tivity is obtained through the use of double tuned interstage
transformers. Input circuits are inductively tuned to prevent
microphonics and provide a linear tuning motion to facilitate
push-button operation.
Coil specifications for Figure 1 are as follows:
AM PVC AM ANT AM OSC
VC L1 L0, L2
525 kH1-1650 kHz 980 kHz-2105 Hi!
It =o .
CA c. II F um ll
IWIImm" L-o S" :: III
CA: uo pF ll
c3: so pF L s 360 m
L= 650 .4" the ‘10
AMIMIF AM 2nd IF AM 3rd IF
T1 T2 "
455 kHz 455 ete 455 kHz
. --O-- .
MT -..t. II II '".-l- "
o- " tm II " o- " m
111 II " in II
o-, - - - - o-4
C=1BOpF Cul'IpF 0:1pr
tbu=14tt Ousl20 Ou=tlo
PCB Layout for Figure , Circult
TL/H/7987-4
- AUDIO
OUTPUY
COMPONENT SIDE
.1 TL/ H/7987 - 5
0388"“
LM3820
Applications Information (Continued)
ll firm» b ll
'il" l
:1 Ir.?""" "
7 T. 0.02 " y '
o,....,...,,.--...-..,,." "
tth-TCI., m
kttxEtl
d -ttt
u . I Mus TRANSFORMERS
-50 Yl.t" T1: C - 130 pF primary & secondary
Mmary to secondary tap ratitr-aty.1
t II too tt ttN a " 60
INPUT tEVEL Wm”) coupling-critical
FIGURE 2. Slug-Tuned Auto Radlo
T2: C -- 130 pF primary & secondary
primary tap ratio-NM
secondary tap ratio-65:1
O = 60
etsuplirtg-mitieal
TL/H/ 7867 -6
tl',',','',',',',',,",', Toko. Part Number
LO, L2 RWO-6A6255
T1 RRC-3A6426N
" RRG3A6427A
T3 nzc.1As425A
'Toko America
1250 Feehanville Drive
Mount Prospect, IL 60056
(312) 297.0070
FIGURE 3. Representative Part Numbers
for the Cells of Figure 1
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:
LM3820 - product/Im3820?HQS=T|—nu|l-nu|I-dscataIog-df-pf-null-wwe
LM3820N - product/Im3820n?HQS=T|-nu|I-nu|I-dscatalog-df-pf-null-wwe
LM3820N - product/Im3820n?HQS=T|-nu|I-nu|I-dscatalog-df—pf-nuIl-wwe
LM3820 - product/Im3820?HQS=T|—nu|I-null-dscatalog-df—pf—nuII-wwe
LM3820N - product/lm3820n?HQS=TI-nu|I-nu|I-dscatalog-df-pf-null-wwe
LM3820 - product/Im3820?HQS=T|-nu|I-null-dscatalog-df—pf—nulI-wwe
