Datasheet LMV242 Datasheet (National Semiconductor)

查询LMV242供应商

LMV242
Dual Output, Quad-Band GSM/GPRS Power Amplifier
Controller

LMV242 Dual Output, Quad-Band GSM/GPRS Power Controller

July 2004

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 am­plifiers 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 combina­tion.

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.

Typical Application

Features

n Support of InGaP HBT, bipolar technology
n Quad-band operation
n Shutdown mode for power save in R
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

slot

X

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

20079501

VIP®is a registered trademark of National Semiconductor Corporation.

© 2004 National Semiconductor Corporation DS200795 www.national.com

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

LMV242

please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage

- GND 6.5V Max

V

DD

ESD Tolerance (Note 2)

Human Body Model 2 kV

Machine Model 200V

Storage Temperature Range −65˚C to 150˚C

Junction Temperature (Note 6) 150˚C Max

Mounting Temperature

Infrared or convection (20 sec) 235˚C

Operating Ratings (Note 1)

Supply Voltage 2.6V to 5.5V

Operating Temperature
Range −40˚C to +85˚C

V

Voltage Range 0V to 2V

RAMP

RF Frequency Range 450 MHz to 2 GHz

2.6V Electrical Characteristics Unless otherwise specified, all limits are guaranteed to T

= 2.6V. Boldface limits apply at temperature extremes (Note 4).

V

DD

= 25˚C.

J

Symbol Parameter Condition Min Typ Max Units

I

DD

Supply Current V

=(VDD- GND)/2 6.9 9

OUT

mA

12

0.2 30 µA

V

HIGH

V

LOW

T

ON

I

EN,IBS

In Shutdown (TX_EN = 0V)

=(VDD- GND)/2

V

OUT

Logic Level to Enable Power (Note 7) 1.8 V

Logic Level to Disable Power (Note 7) 0.8 V

Turn-on-Time from Shutdown 3.6 6 µs

Current into TX_EN and BS Pin 0.03 5 µA

RAMP Amplifier

V

RD

1/R

RAMP

I

OUT RAMP

V

Deadband 155 206 265 mV

RAMP

Transconductance (Note 8) 70 96 120 µA/V

Ramp Amplifier Output Current V

=2V 100 162 µA

RAMP

RF Input

P

IN

RF Input Power Range (Note 5) 20 kΩ // 68 pF between

COMP1

and V

COMP2

V

−50
0

−63

dBm

dBV

−13

@

Logarithmic Slope (Note 9)

Logarithmic Intercept (Note 9)

R

IN

DC Resistance (Note 8) 55.7 Ω

900 MHz, 20 kΩ // 68 pF

between V

@

1800 MHz, 20 kΩ // 68 pF

between V

@

1900 MHz, 20 kΩ // 68 pF

between V

@

2000 MHz, 20 kΩ // 68 pF

between V

@

900 MHz, 20 kΩ // 68 pF

between V

@

1800 MHz, 20 kΩ // 68 if

between V

@

1900 MHz, 20 kΩ // 68 pF

between V

@

2000 MHz, 20 kΩ // 68 pF

between V

COMP1

COMP1

COMP1

COMP1

COMP1

COMP1

COMP1

COMP1

and V

and V

and V

and V

and V

and V

and V

and V

COMP2

COMP2

COMP2

COMP2

COMP2

COMP2

COMP2

COMP2

−1.74

−1.62

−1.60

−1.59

–50.4

–52.3

–51.9

–52.3

µA/dB

dBm

Error Amplifier

GBW Gain-Bandwidth Product (Note 8) 5.1 MHz

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LMV242

2.6V Electrical Characteristics Unless otherwise specified, all limits are guaranteed to T

= 2.6V. Boldface limits apply at temperature extremes (Note 4). (Continued)

V

DD

= 25˚C.

J

Symbol Parameter Condition Min Typ Max Units

V

O

Output Swing from Rail From Positive Rail, Sourcing,

=7mA

I

O

From Negative Rail Sinking,

=−7mA

I

O

I

O

e

n

Output Short Circuit Current
(Note 3)

Output Referred Noise f

Sourcing, VO= 2.4V 10 29.5

Sinking, V

MEASURE

= 0.2V 10 27.1

O.

= 10 KHz,

47 90

115

52 90

115

700 nV/

mV

mA

RF Input = 1800 MHz, -10
dBm, 20 kΩ // 68 pF between

COMP1

and V

COMP2,VOUT

, (Note 8)

RAMP

V
=1.4V, set by V

SR Slew Rate 2.1 4.4 V/µs

5.0V Electrical Characteristics Unless otherwise specified, all limits are guaranteed to T

= 5.0V. Boldface limits apply at temperature extremes (Note 4).

V

DD

= 25˚C.

J

Symbol Parameter Condition Min Typ Max Units

I

DD

Supply Current V

=(VDD- GND)/2 7.8 12

OUT

mA

15

0.4 30 µA

V

HIGH

V

LOW

T

ON

I

EN,IBS

In Shutdown (TX_EN = 0V)

=(VDD- GND)/2

V

OUT

Logic Level to Enable Power (Note 7) 1.8 V

Logic Level to Disable Power (Note 7) 0.8 V

Turn-on-Time from Shutdown 1.5 6 µs

Current into TX_EN and BS Pin 0.03 5 µA

RAMP Amplifier

V

RD

1/R

RAMP

I

OUT RAMP

V

Deadband 155 206 265 mV

RAMP

Transconductance (Note 8) 70 96 120 µA/V

Ramp Amplifier Output Current V

=2V 100 168 µA

RAMP

RF Input

P

IN

R

IN

RF Input Power Range
(Note 5)

Logarithmic Slope
(Note 9)

Logarithmic Intercept
(Note 9)

20 kΩ // 68 pF between
V

@

between V

@

between V

@

between V

@

between V

@

between V

@

between V

@

between V

@

between V

and V

COMP1

COMP2

900 MHz, 20 kΩ // 68 pF

and V

COMP1

1800 MHz, 20 kΩ // 68 pF

and V

COMP1

1900 MHz, 20 kΩ // 68 pF

and V

COMP1

2000 MHz, 20 kΩ // 68 pF

and V

COMP1

900 MHz, 20 kΩ // 68 pF

and V

COMP1

1800 MHz, 20 kΩ // 68 pF

and V

COMP1

1900 MHz, 20 kΩ // 68 pF

and V

COMP1

2000 MHz, 20 kΩ // 68 pF

and V

COMP1

COMP2

COMP2

COMP2

COMP2

COMP2

COMP2

COMP2

COMP2

−50
0

−63

−13

−1.79

–1.69

−1.67

–1.65

–50.2

–52.5

–52.5

–52.9

dBm

dBV

µA/dB

dBm

DC Resistance (Note 8) 55.7 Ω

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5.0V Electrical Characteristics Unless otherwise specified, all limits are guaranteed to T

= 5.0V. Boldface limits apply at temperature extremes (Note 4). (Continued)

V

DD

LMV242

= 25˚C.

J

Symbol Parameter Condition Min Typ Max Units

Error Amplifier

GBW Gain-Bandwidth Product (Note 8) 5.7 MHz

V

O

Output Swing from Rail From Positive Rail, Sourcing,

=7mA

I

O

From Negative Rail Sinking,
IO=−7mA

I

O

e

n

Output Short Circuit Current
(Note 3)

Output Referred Noise f

Sourcing, VO= 4.8V 15 31.5

Sinking, V

MEASURE

= 0.2V 15 31.5

O

= 10 kHz,

31 80

105

35 80

105

770 nV/

RF Input = 1800 MHz,

-10dBm, 20 kΩ // 68 pF
between V

= 1.4V, set by V

V

OUT

COMP1

and V

COMP2

RAMP

,

,

(Note 8)

SR Slew Rate 2.5 4.9 V/µs

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.

Note 2: Human body model: 1.5 kΩ in series with 100 pF.

Note 3: The output is not short circuit protected internally. External protection is necessary to prevent overheating and destruction or adverse reliability.

Note 4: Electrical Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of

the device such that T

Note 5: Power in dBV = dBm + 13 when the impedance is 50Ω.

Note 6: The maximum power dissipation is a function of T

(T

J(MAX)-TA

Note 7: All limits are guaranteed by design or statistical analysis.

Note 8: Typical values represent the most likely parametric norm.

Note 9: Slope and intercept are calculated from graphs "V

)/θJA. All numbers apply for packages soldered directly into a PC board.

. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where T

J=TA

, θJAand TA. The maximum allowable power dissipation at any ambient temperature is PD=

J(MAX)

vs. RF input power" where the current is obtained by division of the voltage by 20 kΩ.

OUT

mV

mA

J

>

TA.

Connection Diagrams

LLP-10 Bond Pad Layout

Top View

20079502

20079503

Top View

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Bond Pad mechanical Dimensions

X/Y Coordinates Pad Size

Signal Name Pad Number X Y X Y

Out 1 1 −281 617 92 92

Out 2 2 −281 490 92 92

Comp2 3 −281 363 92 92

V

RF

V

DD

IN

RAMP

4 −281 236 92 92

5 −281 −617 92 92

6 281 −617 92 92

TX_EN 7 281 −360 92 92

BS 8 281 −118 92 92

Comp1 9 281 20 92 92

GND 10 281 187 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

Pin Descriptions

Pin Name Description

Power Supply 4 V

DD

10 GND Power Ground

Digital Inputs 7 TX_EN Schmitt-triggered logic input. A LOW shuts down the whole

8 BS Schmitt-triggered Band Select pin. When BS = H, channel 1

Analog Inputs 5 RF

6V

IN

RAMP

Compensation 9 Comp1 Connects an external RC network between the Comp1 pin

3 Comp2 Frequency compensation pin. The BS signal switches this pin

Output 1 Out1 This pin is connected to the PA of either channel 1 or

2 Out2

Positive Supply Voltage

chip for battery saving purposes. A HIGH enables the chip.

(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 V
are allowed.

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 beC=68pFandR=0Ω.

either to OUT1 or to OUT2.

channel 2.

LMV242

DD

Note: 1. All inputs and outputs are referenced to GND (pin 10).

<

2. For the digital inputs, a LOW is

3. RF power detection is performed internally in the LMV242 and only an RF power coupler with optional extra attenuation has to be used.

0.8V and a HIGH is>1.8V.

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Ordering Information

LMV242

Package Part Number Package Marking Transport Media NSC Drawing

10-Pin LLP

Tested and Wafer

Form

Block Diagram

LMV242LD

LMV242LDX 4.5k Units tape and Reel

LMV242MDA

LMV242MWA 25 Wafer/Vial W008

242LD

No Mark

1k Units Tape and Reel

300 Units Waffle Pack DA0620035

LDA10A

20079504

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LMV242

Typical Performance Characteristics Unless otherwise specified, V

Supply Current vs. Supply Voltage V

20079505

V

and Log Conformance vs. RF Input Power

OUT

@

900 MHz

and Log Conformance vs. RF Input Power

OUT

V

and Log Conformance vs. RF Input Power

OUT

@

= +2.6V, TJ= 25˚C.

DD

1800 MHz

20079506

V

and Log Conformance vs. RF Input Power

OUT

@

1900 MHz

20079507 20079508

V

and Log Conformance vs. RF Input Power

OUT

20079514 20079515

@

2000 MHz

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Typical Performance Characteristics Unless otherwise specified, V

25˚C. (Continued)

LMV242

Logarithmic Slope vs. Frequency Logarithmic Intercept vs. Frequency

= +2.6V, TJ=

DD

20079516

RF Input Impedance vs. Frequency

@

Resistance and Reactance Gain and Phase vs. Frequency

20079518

I

COMP

vs. V

RAMP

PINvs. V

RAMP

20079517

20079519

20079520 20079521

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LMV242

Typical Performance Characteristics Unless otherwise specified, V

25˚C. (Continued)

Sourcing Current vs. Output Voltage Sinking Current vs. Output Voltage

20079510 20079511

Output Voltage vs. Sourcing Current Output Voltage vs. Sinking Current

= +2.6V, TJ=

DD

Closed Loop P

OUT

(PA) vs. V

RAMP

20079512

@

GSM 900 MHz Band

20079522 20079523

Closed Loop P

OUT

(PA) vs. V

Band

RAMP

20079513

@

DCS 1800 MHz

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Typical Performance Characteristics Unless otherwise specified, V

25˚C. (Continued)

LMV242

Closed Loop P

Closed Loop DCS-1800 MHz Band Closed Loop PCS-1900 MHz Band

OUT

(PA) vs. V

Band Closed Loop GSM- 900 MHz Band

RAMP

@

PCS 1900 MHz

20079524

= +2.6V, TJ=

DD

20079525

20079526 20079527

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Application Section

POWER CONTROL PRINCIPLES

The LMV242 is a member of the power loop controller family
of National Semiconductor, for quad-band TDMA/GSM solu­tions. 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 V
the specified level. The LMV242 gives maximum flexibility to
meet GSM frequency- and time mask criteria for many dif­ferent single supply Power Amplifier types like HBT or Mes­FET 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.

to set the RF output power to

RAMP

voltage (V
transfer function. It is a function of the controller’s V
voltage. Based upon the value of V

) of the PA is of no consequence to the overall

APC

, the PA controller

RAMP

RAMP

will set the gain control voltage of the PA to a level that is
necessary to produce the desired output level. Any tempera­ture 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 (P
vs. V

). The only requirement is that the gain control

RAMP

OUT

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 I
ramp current I

, representing the selected power setting,

RAMP

DET

and the

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 I
equal to I

. Lets examine how this circuit works in detail.

RAMP

DET

LMV242

is

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 control­ler is used, the relationship between gain and gain control

FIGURE 1. PA Control Loop

20079528

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Application Section (Continued)

We will assume initially that the output of the PA is at some

LMV242

low level and that the V
converter converts the V

. This current can only come from the integrator ca-

I

RAMP

pacitor C. Current flow from this direction increases the
output voltage of the integrator. The output voltage, which
drives the V

of the PA, increases the gain (we assume

APC

that the PA’s gain control input has a positive sense, that is,
increasing voltage increases gain). The gain will increase,
thereby increasing the amplifier’s output level until the de­tector output current equals the ramp current I
point, the current through the capacitor will decrease to zero
and the integrator output will be held constant, thereby set­tling the loop. If capacitor charge is lost over time, output
voltage will decrease. However, this leakage will quickly be
corrected by additional current from the detector. The loop
stabilizes to I
between the V

DET=IRAMP

set voltage and the PA output power,

RAMP

independent of the PA’s V

Power Control Over Wide Dynamic Range

The circuit as described so far, has been designed to pro­duce a temperature independent output power level. If the
detector has a high dynamic range, the circuit can precisely
set PA output levels over a wide power range. To set a PA
output power level, the reference voltage, V
To estimate the response of P
of the LMV242 should be known (P
as discussed is section 3).

The relation between P

IN

of 2 curves:

I

•

•

I

OUT

vs, V

COMP

V

OUT

RAMP

vs. RF Input Power (detection curve)

can be calculated by dividing the V
curve by the feedback resistor used for measuring. With the
knowledge that I
function P

IN

vs. V

COMP=IOUT

is shown in Figure 2. Extra attenua-

RAMP

tion should be inserted between PA output and LMV242’s

to match their dynamic ranges.

P

IN

voltage is at 1V. The V/I

RAMP

voltage to a sinking current

RAMP

thereby creating a direct relation

APC-POUT

and V

characteristics.

vs. V

OUT

RAMP,PIN

OUT=PIN

can be constructed out

RAMP

OUT

RAMP

of the detection

in a closed loop the resulting

. At that

RAMP

, is varied.

vs. V

RAMP

+ attenuation

Using a closed loop to control the PA has benefits over the
use of a directly controlled PA. Non-linearity’s and tempera­ture variations present in the PA transfer function do not
appear in the overall transfer function, P

OUT

vs. V

RAMP

The
response of a typical closed loop is given in Figure 3. The
shape of this curve is determined by the response of the
controller’s detector. Therefore the detector needs to be
accurate, temperature stable and preferably linear in dB to
achieve a accurately controlled output power. The only re­quirement for the control loop is that the gain control function
of the PA has to be monotonic. With a linear in dB detector,
the relation between V

and PA output power becomes

RAMP

linear in dB as well, which makes calibration of the system
easy.

20079522

FIGURE 3. Closed Loop Response

The response time of the loop can be controlled by varying
the RC time constant of the integrator. Setting this at a low
level will result in fast output settling but can result in ringing
in the output envelope. Setting the RC time constant to a
high value will give the loop good stability but will increase
settling time.

20079521

FIGURE 2. PINvs. V

www.national.com 12

RAMP

ATTENUATION BETWEEN COUPLER AND LMV242
DETECTOR

Figure 4 shows a practical RF power control loop realized by
using the National’s LMV242 with integrated RF detector.
The RF signal from the PA passes through a directional
coupler on its way to the antenna. Directional couplers are
characterized by their coupling factor, which is in the 10 dB
to 30 dB range, typical 20 dB. Because the coupled output
must in its own right deliver some power (in this case to the
detector), the coupling process takes some power from the
main output. This manifests itself as insertion loss, the inser­tion loss being higher for lower coupling factors.

It is very important to choose the right attenuation between
PA output and detector input to achieve power control over
the full output power range of the PA. A typical value for the
output power of the PA is +35.5 dBm for GSM and +30 dBm
for PCS/DCS. In order to accommodate these levels into the
LMV242 detection range the minimum required total attenu­ation is about 35 dBm (please refer to typical performance
characteristics in the datasheet and Figure 2). A typical
coupler factor is 20 dB. An extra attenuation of about 15 dB
should be inserted.

Application Section (Continued)

Extra attenuation Z between the coupler and the RF input of
the LMV242 can be achieved by 2 resistors R
according to Figure 3, where

Z = 20 LOG (R

/[RIN+RY])

IN

or

e.g. RY= 300Ω results in an attenuation of 16.9 dB.
To prevent reflection back to the coupler the impedance

seen by the coupler should be 50Ω (R
consists of R

in parallel with RY+RIN.RXcan be calculated

X

). The impedance

O

with the formula:

=[RO*(RY+RIN)]/R

R

X

Y

RX=50*[1+(50/RY)]

e.g. with R

= 300Ω,RIN=50Ω→RX=58Ω.

Y

X

and R

LMV242

about 206 mV, so offset voltages in the DAC or amplifier
supplying the R
output and increased power consumption.

Y

Transmit Enable

Power consumption requirements are supported by the
TX_EN function, which puts the entire chip into a power
saving mode to enable maximum standby and talk time while
ensuring the output does not glitch excessively during
Power-up and Power-down. The device will be active in the
case TX_EN = High, or otherwise go to a low power con­sumption shutdown mode. During shutdown the output is
pulled low to minimize the output voltage.

Band Select

The LMV242 is especially suitable for PA control loops with 2
PA’s. The 2 outputs to steer the V
controlled with the band select pin. When the band select is
LOW output2 is selected, while output1 is selected when
band select is HIGH. The not-selected output is pulled low.

Analog Output

The output is driven by a rail-to-rail amplifier capable of both
sourcing and sinking. Several curves are given in the “Typi­cal performance characteristics”-section regarding the out­put. The output voltage vs. sourcing/sinking current curves
show the typical voltage drop from the rail over temperature.
The sourcing/sinking current vs. output voltage characteris­tics show the typical charging/discharging current, which the
output is capable of delivering at a certain voltage. The
output is free from glitches when enabled by TX_EN. When
TX_EN is low, the selected output voltage is fixed or near
GND.

signal will not cause excess RF signal

AMP

of the PA’s can be

APCS

20079530

FIGURE 4. Simplified PA Control Loop with Extra

Attenuation

BASEBAND CONTROL OF THE LMV242

The LMV242 has 3 baseband-controlled inputs:

V

•

•

signal (Base band DAC ramp signal)

RAMP

TX_EN is a digital signal (performs the function
“Shutdown/Transmit Enable”).

Band Select (BS)

•

V

Signal

RAMP

The actual V

input value sets the RF output power. By

RAMP

applying a certain mask shape to the “Ramp in” pin, the
output voltage level of the LMV242 is adjusting the PA
control voltage to get a power level (P

/dBm) out of the

OUT

PA, which is proportional to the single ramp voltage steps.
The recommended V
trol is 0.2V to 2.0V. The V
from 0V to V

without malfunction or damage. The V

DD

voltage range for RF power con-

RAMP

input will tolerate voltages

RAMP

RAMP

input does not change the output level until the level reaches

FREQUENCY COMPENSATION

To compensate and prevent the closed loop arrangement
from oscillations and overshoots at the output of the RF
detector/error amplifier of the LMV242, the system can be
adjusted by means of external RC components connected
between Comp1 and Comp2. Exact values heavily depend
on PA characteristics. A good starting point isR=0Ω and
C = 68 pF. The vast combination of PA’s and couplers
available preclude a generalized formula for choosing these
components. Additional frequency compensation of the
closed loop system can be achieved by adding a resistor
(and if needed an inductor) between the LMV242’s output
and the V

input of the PA. Please contact National Semi-

APC

conductor for additional support.

TIMING DIAGRAM

In order to meet the timemask specifications for GSM, a
good timing between the control signals and the RF signal is
essential. According to the specifications the PA’s RF output
power needs to ramp within 28 µsec with minimum over­shoot. To achieve this, the output of the PA controller should
ramp at the same time as the RF signal from the Base Band.
The ramp signal sets the controllers output to the required
value, where the loop needs a certain time to set this output.
Therefore the ramp should be set high some time before the
output has to be high. How much time depends on the setup
and the PA used. If the controllers shutdown functionality is
used, the shutdown should be set high about 6 µsec before
the ramp is set high.

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Application Section (Continued)

The control loop can be configured by the following vari-

LMV242

ables:

Lead time TX_EN event vs. start GSM burst

•

Lead time V

•

Ramp profile

•

Loop compensation

•

vs. start GSM burst

RAMP

20079531

FIGURE 5. Timing V

vs. RF Signal

RAMP

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10-Pad Bare Die

LMV242

20079503

Die / Wafer Characteristics

Fabrication Attributes

Physical Die Identification LMV242A

Die Step A

Physical Attributes

Wafer Diameter 200 mm

Die Size (Drawn) 889 µm x 1562 µm

35.0 mils x 61.5 mils

Thickness 216 µm Nominal

Min Pitch 123 µm Nominal

General Die Information

Bond Pad Opening Size (min) 92 µm x 92µm

Bond Pad Metallization 0.5% Copper_Bal.

Aluminum

Passivation VOM Nitride

Back Side Metal Bare Back

Back Side Connection Floating

Note: Note: Actual die size is rounded to the nearest micron

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Physical Dimensions inches (millimeters)

unless otherwise noted

10-Pin LLP

NS Package Number LDA10A

LMV242 Dual Output, Quad-Band GSM/GPRS Power Controller

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