|
|
PDF LMV242 Data sheet ( Hoja de datos )
| Número de pieza | LMV242 | |
| Descripción | Quad-Band GSM/GPRS Power Amplifier Controller | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LMV242 (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
July 2004
LMV242
Dual Output, Quad-Band GSM/GPRS Power Amplifier
Controller
General Description
The LMV242 is a power amplifier (PA) controller intended for
use within an RF transmit power control loop in GSM/GPRS
mobile phones. The LMV242 supports all single-supply PA’s
including InGaP, HBT and bipolar power amplifiers. The
device operates with a single supply from 2.6V to 5.5V.
Included in the PA controller are an RF detector, a ramp filter
and two selectable output drivers that function as error am-
plifiers for two different bands. The LMV242 input interface
consists two analog and two digital inputs. The analog inputs
are the RF input, Ramp voltage input. The digital inputs
perform the function of “Band Select” and “Shutdown/
Transmit Enable” respectively. The “Band Select” function
enables either of two outputs, namely OUT1 when BS =
High, or output OUT2 when BS = Low. The output that is not
enabled is pulled low to the minimum output voltage. The
LMV242 is active in the case TX_EN = High. When TX_EN
= Low the device is in a low power consumption shutdown
mode. During shutdown both outputs will be pulled low to the
minimum output voltage. Individual PA characteristics are
accommodated by a user selectable external RC combina-
tion.
The LMV242 is offered in fully tested die form as well as in a
10-lead LLP package and is therefore especially suitable for
small footprint PA module solutions.
Features
n Support of InGaP HBT, bipolar technology
n Quad-band operation
n Shutdown mode for power save in RX slot
n Integrated ramp filter
n 50 dB RF detector
n GPRS compliant
n External loop compensation option
n Accurate temperature compensation
n LLP package 3x3 mm and fully tested die sales
Applications
n GSM/GPRS/TDMA/TD_SCDMA mobile phone
n Pulse RF control
n Wireless LAN
n GSM/GPRS power amplifier module
n Transmit module
Typical Application
VIP® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS200795
20079501
www.national.com
1 page  
Bond Pad mechanical Dimensions
Signal Name
Out 1
Out 2
Comp2
VDD
RFIN
VRAMP
TX_EN
BS
Comp1
GND
Pad Number
1
2
3
4
5
6
7
8
9
10
X/Y Coordinates
XY
−281
617
−281
490
−281
363
−281
236
−281
−617
281 −617
281 −360
281 −118
281 20
281 187
Pad Size
X
92
92
92
92
92
92
92
92
92
92
Note: Dimensions of the bond pad coordinates are in µm Origin of the coordinates: center of the die Coordinates refer to the center of the bond pad
Y
92
92
92
92
92
92
92
92
92
92
Pin Descriptions
Power Supply
Digital Inputs
Pin
4
10
7
8
Analog Inputs
5
6
Compensation
9
Output
3
1
2
Name
VDD
GND
TX_EN
BS
RFIN
VRAMP
Comp1
Comp2
Out1
Out2
Description
Positive Supply Voltage
Power Ground
Schmitt-triggered logic input. A LOW shuts down the whole
chip for battery saving purposes. A HIGH enables the chip.
Schmitt-triggered Band Select pin. When BS = H, channel 1
(OUT1) is selected, when BS = L, channel 2 (OUT2) is
selected.
RF Input connected to the Coupler output with optional
attenuation to measure the Power Amplifier (PA) / Antenna
RF power levels.
Sets the RF output power level. The useful input voltage
range is from 0.2V to 1.8V, although voltages from 0V to VDD
are allowed.
Connects an external RC network between the Comp1 pin
and the Comp2 pin for an overall loop compensation and to
control the closed loop frequency response. Conventional
loop stability techniques can be used in selecting this
network, such as Bode plots. A good starting value for the
RC combination will be C = 68 pF and R = 0Ω.
Frequency compensation pin. The BS signal switches this pin
either to OUT1 or to OUT2.
This pin is connected to the PA of either channel 1 or
channel 2.
Note: 1. All inputs and outputs are referenced to GND (pin 10).
2. For the digital inputs, a LOW is < 0.8V and a HIGH is > 1.8V.
3. RF power detection is performed internally in the LMV242 and only an RF power coupler with optional extra attenuation has to be used.
5 www.national.com
5 Page 
Application Section
POWER CONTROL PRINCIPLES
The LMV242 is a member of the power loop controller family
of National Semiconductor, for quad-band TDMA/GSM solu-
tions. The typical application diagram demonstrates a basic
approach for implementing the quad-band solution around
an RF Power Amplifier (PA). The LMV242 contains a 50 dB
Logamp detector and interfaces directly with the directional
coupler.
The LMV242 Base Band (control-) interface consists of 3
signals: TX_EN to enable the device, BS to select either
output 1 or output 2 and VRAMP to set the RF output power to
the specified level. The LMV242 gives maximum flexibility to
meet GSM frequency- and time mask criteria for many dif-
ferent single supply Power Amplifier types like HBT or Mes-
FET in GaAs, SiGe or Si technology. This is accomplished by
the programmable Ramp characteristic from the Base Band
and the TX_EN signal along with the external compensation
capacitor.
POWER AMPLIFIER CONTROLLED LOOP
This section gives a general overview and understanding of
how a typical Power Amplifier control loop works and how to
solve the most common problems confronted in the design.
General Overview
The key benefit of a PA control loop circuit is its immunity to
changes in the PA gain control function. When a PA control-
ler is used, the relationship between gain and gain control
voltage (VAPC) of the PA is of no consequence to the overall
transfer function. It is a function of the controller’s VRAMP
voltage. Based upon the value of VRAMP, the PA controller
will set the gain control voltage of the PA to a level that is
necessary to produce the desired output level. Any tempera-
ture dependency in the PA gain control function will be
eliminated. Also, non-linearity’s in the gain transfer function
of the PA do not appear in the overall transfer function (POUT
vs. VRAMP). The only requirement is that the gain control
function of the PA has to be monotonic. To achieve this, it is
crucial, that the LMV242’s detector is temperature stable.
Typical PA Closed Loop Control Setup
A typical setup of PA control loop is depicted in Figure 1.
Beginning at the output of the Power Amplifier (PA), this
signal is fed, usually via a directional coupler, to a detector.
The error between the detector output current IDET and the
ramp current IRAMP, representing the selected power setting,
drives the inverting input of an op amp, configured as an
integrator. A reference voltage drives the non-inverting input
of the op amp. Finally the output of the integrator op amp
drives the gain control input of the power amplifier, which
sets the output power. The loop is stabilized when IDET is
equal to IRAMP . Lets examine how this circuit works in detail.
FIGURE 1. PA Control Loop
11
20079528
www.national.com
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet LMV242.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LMV242 | LMV242 Dual Output Quad-Band GSM/GPRS Power Amplifier Controller (Rev. C) |  Texas Instruments |
| LMV242 | Quad-Band GSM/GPRS Power Amplifier Controller | National Semiconductor |
| LMV243 | LMV243 Single-ChannelQuad-B GSM Pwr Controller in DSBGA (Rev. C) | Texas Instruments |
| LMV243 | Single-Channel / Quad-Band GSM Power Controller in micro SMD | National Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |