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LMX2411 の電気的特性と機能

LMX2411のメーカーはNational Semiconductorです、この部品の機能は「Baseband Processor」です。


製品の詳細 ( Datasheet PDF )

部品番号 LMX2411
部品説明 Baseband Processor
メーカ National Semiconductor
ロゴ National Semiconductor ロゴ 




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LMX2411 Datasheet, LMX2411 PDF,ピン配置, 機能
www.DataSheet4U.com
PRELIMINARY
September 1993
LMX2411
Baseband Processor for Radio Communications
General Description
The LMX2411 is a monolithic integrated baseband proces-
sor suitable for use in Digital European Cordless Telecom-
munications (DECT) systems as well as other mobile teleph-
ony and wireless communications applications It is fabricat-
ed using National’s ABiC IV BiCMOS process (fT e
15 GHz)
The LMX2411 contains both transmit and receive functions
The transmitter utilizes a low power high speed digital-to-
analog converter (DAC) and a mask programmable Read
Only Memory (ROM) to generate a Gaussian filter pulse
shape The receiver includes a high speed low power volt-
age comparator for making hard decisions on incoming data
and a CMOS switch coupled with a sample and hold circuit
for DC compensation Supply voltage can range from 2 85V
to 3 6V The LMX2411 features very low current consump-
tion of 2 5 mA transmit and 5 mA receive (steady state) It
also has separate power down pins for transmit and receive
functions to further reduce power consumption
The LMX2411 can be used with the LMX2216B LNA Mixer
the LMX2240 IF Receiver and the LMX2320 Phase-Locked
Loop to form a complete RF front end solution These chips
form the major blocks of an RF front end solution for DECT
The LMX2411 is available in a 16-pin JEDEC surface mount
plastic package
Features
Y High speed voltage comparator (40 ns settling time)
Y Generates Gaussian filtered modulating signal for a di-
rect VCO modulator
Y Bit rates to 1 152 Mb s (DECT)
Y Supports 10 368 13 824 and 18 432 MHz system
clocks through pin selection
Y On-chip DC compensation circuit
Y Average current consumption 0 6 mA for DECT handset
(burst mode operation)
Y Power down mode for extended battery life
Y Compatible with Sierra SC14400 and Philips PCD5040
DECT Burst Mode Controllers
Applications
Y Digital European Cordless Telecommunications (DECT)
Y Portable wireless communications (PCS PCN cordless)
Y Wireless local area networks (WLANs)
Y Other wireless communications systems
This data sheet contains the design specifications for product development
Specifications may change in any manner without notice
Functional Block Diagram
TRI-STATE is a registered trademark of National Semiconductor Corporation
C1995 National Semiconductor Corporation TL W 11911
TL W 11911 – 1
RRD-B30M115 Printed in U S A

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LMX2411 pdf, ピン配列
Absolute Maximum Ratings
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Power Supply Voltage (VCC)
Storage Temperature Range (TS)
Lead Temperature (TI)
(Soldering 10 Seconds)
6 5V
b65 C to a150 C
a260 C
Recommended Operating
Conditions
Supply Range (VCC)
Operating Temperature (TA)
2 85V to 3 6V
b10 C to a70 C
DC Electrical Characteristics
The following specifications are guaranteed over the recommended operating conditions
Symbol
Parameter
Conditions
Min Typ Max Unit
DIGITAL INTERFACE SECTION (Note 1)
VOH
VOL
VIH
VIL
IIN
High Level Output Voltage
Low Level Output Voltage
High Level Input Voltage
Low Level Input Voltage
Input Current
IOH e b1 0 mA
IOL e 1 0 mA
GND k VIN k VCC
VCC b 0 4
VCC b 0 8
b1 0
V
04 V
V
08 V
1 0 mA
Note 1 DC Electrical Characteristics for the digital section apply to all digital input and output pins This includes Tx Data Tx PD Rx PD Comp Out ROM Sel1
ROM Sel2 and S-Field
Electrical Characteristics The following specifications are guaranteed over recommended operating condi-
tions and oscillator (Sys Clk) frequency of 10 368 MHz unless otherwise specified
Symbol
Parameter
IRx Rx Mode Current Consumption (Note 1)
ITx Tx Mode Current Consumption (Note 2)
IPD Standby Current (Power Down)
SYSTEM CLK INPUT
VOSC
Oscillator Sensitivity
fOSC
Maximum Oscillator Frequency
VOFF
Oscillator DC Offset
IOSC
Oscillator Input Current
TRANSMIT ROM FILTER
tS DAC Voltage Settling Time to within
LSB
ROUT
VOUT
Output Impedance (Pin 6)
Output Voltage Swing (Pin 6) (Note 3)
DAC Midband Voltage
Gaussian Filter Pulse Response
Accuracy (Note 4)
ISI from Gaussian Filter (Note 5)
DC COMPENSATION SAMPLE AND HOLD CIRCUIT
VOS
VI O
RSH
DV
Input Offset Voltage
Input Output Voltage Swing
Sample and Hold Resistor
Threshold Input Voltage Droop
Condition
Tx Mode Off
Rx Mode Off
Tx and Rx Mode Off
Sys Clk Input
40% k Duty Cycle k 60%
GND k VIN k VCC
CLOAD e 3 pF
All 0’s to all 1’s
Measured from 0V
DAC Code e 10000000
Bb T e 0 5 Filter
Centered at 1 5V
CHOLD e 2700 pF (Pin 2)
Min
05
19
29
0 95
479
2240
Typ
6
35
50
15
g30
100
11
1
1
Max
7
5
100
g50
41
1 05
529
g0 5
3
3360
10
Unit
mA
mA
mA
VPP
MHz
V
mA
ns
kX
V
mV
%
%
mV
VPP
X
mV ms
3


3Pages


LMX2411 電子部品, 半導体
Functional Description
OVERVIEW
The LMX2411 is a 3V integrated circuit designed to be ca-
pable of regenerating received GMSK data and generating
GMSK transmitter drive signals to meet the specifications of
the Digital European Cordless Telecommunications (DECT)
standard
The transmit portion of the LMX2411 functions as a pulse
shaper for incoming serial data delivering a filtered data
stream capable of modulating a VCO The ROM and sup-
porting logic is designed to create Gaussian filter pulse re-
sponses The output of the LPF ROM and DAC is the modu-
lating baseband drive signal that is fed to a VCO
The receiver section of the LMX2411 processes the filtered
data stream produced by a demodulator (e g the
LMX2240) The data stream is compared against a thresh-
old voltage determined by the DC compensation circuit This
DC compensation circuit allows control over DC drift due to
temperature frequency drift component tolerance and
aging
THE TRANSMIT ROM FILTER
The LMX2411 uses a mask-programmable Read-Only
Memory (ROM) look-up table to construct pulse responses
of a Gaussian filter shape For DECT this filter is half the
bandwidth of the bit rate (Bb T e 0 5) The output of the
ROM addresses a (voltage mode output) digital-to-analog
converter (DAC) The LMX2411 ROM Filter supports three
different system clocks selected by two external pins
These pins (ROM Sel1 and ROM Sel2) choose the proper
oversampling clock When the 12x or 16x clock is chosen a
divide by 2 flip flop is enabled to give the ROM a 6x or 8x
clock from which to operate However when the 9x over-
sampling clock (10 368 MHz) is chosen the divide by 2 cir-
cuit is not enabled The Tx Data is synchronized with the
Sys Clk in the following manner When Tx PD is taken LOW
the first edge (rising or falling) of Tx Data initializes an inter-
nal counter so that the data bits are sampled near their
center The power up state of the three bit memory in the
ROM filter depends on the state of Tx Data during power
down If Tx Data is LOW when the Tx PD pin is HIGH the
ROM filter register will be set to 010 If Tx Data is HIGH
when the Tx PD pin is HIGH the ROM filter register will be
set to 101 This allows the filter to be set for either base
station or handset operation
THE COMPARATOR AND ANALOG DC COMPENSATION
CIRCUIT
The high speed comparator’s threshold can be set either by
an external voltage or by using the internal DC compensa-
tion circuit When using the internal DC compensation loop
the received demodulated signal is input both to the com-
parator ‘‘a’’ input and to the sample-and-hold (S H) buffer
amplifier The S H buffer allows a single RC filter to aver-
age the DC value of the received signal without distorting it
This DC value is connected to the ‘‘b’’ input of the compar-
ator When the signal S-Field is used (named after the syn-
chronization field in DECT) this circuit can acquire the DC
voltage during the preamble and then hold it (with the exter-
nal capacitor) for the duration of the burst This solution
avoids the problem of long strings of 1’s and 0’s that con-
ventional continuous averaging circuits have while still re-
acting quickly to acquire the proper DC average at the be-
ginning of a burst
6

6 Page



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部品番号部品説明メーカ
LMX2411

Baseband Processor

National Semiconductor
National Semiconductor


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