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PDF MC33170 Data sheet ( Hoja de datos )
| Número de pieza | MC33170 | |
| Descripción | RF Amplifier Companion Chip for Dual-Band Cellular Subscriber Terminal | |
| Fabricantes | ON Semiconductor | |
| Logotipo |  |
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MC33170
RF Amplifier Companion Chip
for Dual-Band Cellular
Subscriber Terminal
The MC33170 is a complete solution for drain modulated
dual–band GSM 900MHz and DCS–1800MHz Power Amplifiers.
Thanks to its internal decoder, the MC33170 drastically simplifies the
interface between the PAs and the baseband logic section, providing
an immediate gain in part count but also in occupied copper area. The
device is also ready for 1V platforms since it accepts logic high control
signals down to 900mV@25°C.
A priority management system ensures the negative is present
before authorizing the power modulation, giving the necessary
ruggedness to the final design. This function can easily be disabled for
PAs not requiring a negative bias.
The device is able to directly drive an external P or N–channel with
the possibility to linearize the overall response via the internal
high–performance control amplifier and easily implement system
gain.
Finally, an LDO delivers a stable voltage, usable for external biasing
purposes.
• 1V platform compatible: ON voltage = 900mV, OFF voltage =
300mV max
• Priority management system prevents power modulation before
negative bias establishes
• High performance 4.5MHz gain–bandwidth product operational
amplifier
• Drives N or P–channel MOSFET
• 2.5V low–noise LDO
• Idle mode input for very low power consumption (standby mode)
http://onsemi.com
14
1
TSSOP–14
DTB SUFFIX
CASE 948G
PIN CONNECTIONS
Band Selection 1
Tx Enable 2
GSM-900 3
DCS-1800 4
PA Start-up 5
Gnd 6
Vbat 7
14 Common Enable
13
Negative
Regulator
12 Out
11 Vboost
10 INV
9 NINV
8 LDO
(Top View)
ORDERING INFORMATION
Device
Package
Shipping
MC33170DTB TSSOP–14 96 Units / Rail
MC33170DTBR2 TSSOP–14 2500 / Tape & Reel
LDO
Output 8
Shutdown
2.5 V
2.5 V
Low Dropout
2.5 V
Vbat
NINV Vboost Vbat (5.5 V Max)
9 11
7
Shutdown
Common
Enable 14
TX
Enable
Band
Selection
2
1
Open–Collector BG
Decoder BD
B′G
1 mA
Continuous
700 mA
Peak
50 mA
NEGOK?
3 4 Continuous 5
GSM–900 DCS–1800 PA Start–Up
Clip
to –5 V
+
-
13 10
Negative INV
Regulator
6
12
Out
© Semiconductor Components Industries, LLC, 2001
May, 2001 – Rev. 1
1
Publication Order Number:
MC33170/D
1 page  
MC33170
Characteristic
Pin # Symbol Min Typ Max Unit
PROTECTION AND STABILIZATION CIRCUIT
(For typical values TA = 25°C, for min/max values TA = –40°C to +85°C, Max TJ = 125°C unless otherwise noted)
Negative bias present
12
–4.2 V
No Negative protection disabled
12 2.5
V
Regulation level
12
–5.4 –5.0 –4.6
V
Sink current
12 5.0 MA
STEERING SWITCHES, SERIES RESISTANCE
(For typical values TA = 25°C, for min/max values TA = –40°C to +85°C, Max TJ = 125°C unless otherwise noted)
GSM–900 @ Id = 1mA, Vbat = 5.5V
3 60 160 W
DCS–1800 @ Id = 1mA, Vbat = 5.5V
Power Amplifier Startup @ Id = 50mA, Vbat = 5.5V
4
5
60 160 W
1.0 2.0 W
Lack of negative circuitry behavior:
The MC33170 hosts a circuitry that prevents the power
modulation startup if the negative bias is not established.
However, to accommodate with PAs that do make use of a
negative bias, it is possible to connect pin 13 to pin 7 and thus
invalidate the protection circuitry. The below sketch details
the available levels to fulfil this function
Vpin 13
OK
2.5V
NOT OK
0V
OK
–4.2V
–5V
MC33170 operating truth table, pin levels:
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁTxEN
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁX
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ0
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ1
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ1
Band Selection
X
X
0
1
Common Enable
0
1
1
1
GSM–900
High–impedance
High–impedance
VLDO–Io.RDS(ON)
High–impedance
DCS–1800
High–impedance
High–impedance
High–impedance
VLDO–Io.RDS(ON)
PA startup
High–impedance
High–impedance
VBAT–Io.RDS(ON)
VBAT–Io.RDS(ON)
Io is the current delivered by the considered pin, RDS(ON) is the switch series resistance as defined in the section Steering
Switches
http://onsemi.com
5
5 Page 
MC33170
MC33170 application hints
The MC33170 represents a major leap toward
miniaturization and compactness of Power Amplifiers (PAs)
systems. Prior to talk about the 33170 application circuits,
let us review how a classical dual–band transmission chain
is implemented. At the beginning of the chain, the power
ramping signal is delivered by the Baseband’s Digital to
Analog Converter (DAC). Because of the digitization, a
natural discontinuity appears between the various steps the
signal is made of. As a matter of fact, this sharp transitions
create undesirable effects and need to be smoothed by an
external circuitry (figure 13).
DAC staircase
Filter action
Figure 13. DAC’s signal can be smoothed by an appropriate circuitry
The filtering action can be implemented in a various way,
but usually a 3rd order Bessel filter represents a good choice.
Actual solutions require the use of an external operational
amplifier (OPAMP) dedicated to this function.
For drain–controlled PAs, the power is directly dependent
upon the supply delivered to the device. Several methods
exist but the preferred one stays the N or P channel
modulation. In this application, the N–channel is wired in a
source–follower configuration and therefore needs an
external voltage to ensure its adequate enhancement. This
upper voltage can be obtained from a step–up converter or
directly from ON Semiconductor PAs, as with the
MRFIC0919 or MRFIC1819. To quickly charge/discharge
the MOSFET Ciss capacitor, a dedicated driver is needed,
with a voltage swing high enough to bias the N–channel
toward its specified RDSON.
Radio–Frequency PAs need stable bias levels to keep their
operating point at the right place, despite supply variations.
A Low DropOut (LDO) regulator is the obvious choice for
this purpose. Unfortunately, to keep the quiescent power at
its minimum during the GSM/DCS time–frame pauses (e.g.
no power delivered), it is important to quickly remove the
bias from the PAs. Conversely, the LDO shall be fast enough
to bias the PAs at anytime, without hampering the overall
response time. Such a task is difficult for an off–the–shelf
regulator: a specific component has to be found.
Thanks to their innovative designs, ON Semiconductor
PAs, such as the aforementioned ones, do not require any
external negative sources. However, some synchronization
signals are needed to activate the internal circuitry and
provide them with a stable operating point. This is usually
done by using external low/high power switches.
Finally, a safety system needs to be implemented to
prevent the modulation start in case the negative bias is not
established.
Gathering all these information onto a final drawing gives
birth to figure 14.
Vboost
Digital
Analog
Converter
LDO for
Bias Point
Active
3rd Order
BESSEL Filter
MOSFET Driver
Level
Translation
Vbat
Shutdown
Shutdown
900 MHz
1.8 GHz
TX
Negative
Present?
Dual RF PA
Figure 14. Actual solution to drive a two–PA configuration
http://onsemi.com
11
Power Module
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet MC33170.PDF ] | |
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