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PDF LTC1757A-2EMS Data sheet ( Hoja de datos )
| Número de pieza | LTC1757A-2EMS | |
| Descripción | Single/Dual Band RF Power Controllers | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
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Final Electrical Specifications
LTC1757A-1/LTC1757A-2
Single/Dual Band
RF Power Controllers
FEATURES
DESCRIPTIO
April 2000
s Dual Band RF Power Amplifier Control (LTC1757A-2)
s Improved Internal Schottky Diode Detector
s Wide Input Frequency Range: 850MHz to 2GHz
s Autozero Cancels Initial Offsets and Temperature
Dependent Offset Errors
s Wide VIN Range of 2.7V to 6V Allows
Direct Connection to Battery
s RF Output Power Set by External DAC
s Fast Acquire After Transmit Enable
s Internal Frequency Compensation
s Rail-to-Rail Power Control Outputs
s RF PA Supply Current Limiting
s Battery Overvoltage Protection
s Power Control Signal Overvoltage Protection
s Low Operating Current: 1mA
s Very Low Shutdown Current: < 1µA
s Available in a 8-Pin MSOP Package (LTC1757A-1)
and 10-Pin MSOP (LTC1757A-2)
U
APPLICATIO S
s Single and Dual Band GSM Cellular Telephones
s PCS Devices
s Wireless Data Modems
s TDMA Cellular Telephones
, LTC and LT are registered trademarks of Linear Technology Corporation.
The LTC®1757A-2 is a dual band RF power controller for
RF power amplifiers operating in the 850MHz to 2GHz
range. The LTC1757A is pin compatible with the LTC1757
but has improved RF detection range. The input voltage
range is optimized for operation from a single lithium-ion
cell or 3× NiMH. Several functions required for RF power
control and protection are integrated in one small 10-pin
MSOP package, thereby minimizing PCB area.
The LTC1757A-1 is a single output RF power controller
that is identical in performance to the LTC1757A-2 except
that one output (VPCA) is provided. The LTC1757A-1 can
be used to drive a single RF channel or dual channel
module with integral multiplexer. This part is available in
an 8-pin MSOP package.
RF power is controlled by driving the RF amplifier power
control pins and sensing the resultant RF output power
via a directional coupler. The RF sense voltage is peak
detected using an on-chip Schottky diode. This detected
voltage is compared to the DAC voltage at the PCTL pin
to control the output power. The RF power amplifier is
protected against high supply voltage and current and
high power control pin voltages.
Internal and external offsets are cancelled over tempera-
ture by an autozero control loop, allowing accurate low
power programming. The shutdown feature disables the
part and reduces the supply current to < 1µA.
TYPICAL APPLICATIO
LTC1757A-2 Dual Band Cellular Telephone Transmitter
68Ω
VIN 33pF
LTC1757A-2
1 10
VIN VCC
Li-Ion
2
RF
9
VPCA
38
SHDN
SHDN
VPCB
47
BSEL
BSEL
TXEN
TXEN
5
GND
6
PCTL
900MHz
RF PA
DIRECTIONAL
COUPLER
DIPLEXER
DAC
1.8GHz /1.9GHz
RF PA
50Ω
1757A TA01
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
1
1 page  
BLOCK DIAGRA (LTC1757A-2)
LTC1757A-1/LTC1757A-2
DIPLEXER
900MHz
RF PA
Li-Ion
68Ω
33pF
10
VCC
0.02Ω
RSENSE
0.05Ω
METAL
1
VIN
0.02Ω
100Ω
METAL
RF
2
–
CS
+
OFFSET
TRIM
VIN
175Ω
OVERCURRENT
GAIN
TRIM
gm
600mV
42k
22pF
42k
GND
5
60µA
60µA
+
RFDET
–
AUTOZERO
–
AZ
+
50mV
–+
6pF
ICL
33k
16.7k 33k
BG1
THERMAL
SHUTDOWN
BG1
1.2V BANDGAP
1.2V
600mV
TSDB
OPERATE SHDN
150k
XMT AUTOZERO
150k
SHDN
3
TXEN
7
33k
PCTL
6
RF PA
1.8GHz
50Ω
TXENB
+– ADJ
PA
VPCA
9
+
CAMP
–
PB
CC 400µA
VPC
gm
140k
110k
VPCB
8
OVP
gm
TSDB
TXENI
150k
PB
MUX
CONTROL
PA
BSEL
4
1.2V
173k
54.5k
VIN
12Ω
100Ω
12Ω
100Ω
1757A BD
5
5 Page 
LTC1757A-1/LTC1757A-2
PACKAGE DESCRIPTIO
Dimensions in inches (millimeters) unless otherwise noted.
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.118 ± 0.004*
(3.00 ± 0.102)
8 76 5
0.193 ± 0.006
(4.90 ± 0.15)
0.118 ± 0.004**
(3.00 ± 0.102)
1 234
0.007
(0.18)
0° – 6° TYP
0.021 ± 0.006
(0.53 ± 0.015)
0.040 ± 0.006
(1.02 ± 0.15)
SEATING
PLANE
0.012
(0.30)
REF
0.0256
(0.65)
BSC
0.034 ± 0.004
(0.86 ± 0.102)
0.006 ± 0.004
(0.15 ± 0.102)
MSOP (MS8) 1098
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
MS10 Package
10-Lead Plastic MSOP
(LTC DWG # 05-08-1661)
0.118 ± 0.004*
(3.00 ± 0.102)
10 9 8 7 6
0.193 ± 0.006
(4.90 ± 0.15)
0.118 ± 0.004**
(3.00 ± 0.102)
12345
0.007
(0.18)
0° – 6° TYP
0.021 ± 0.006
(0.53 ± 0.015)
0.040 ± 0.006
(1.02 ± 0.15)
SEATING
PLANE 0.009
(0.228)
REF
0.0197
(0.50)
BSC
0.034 ± 0.004
(0.86 ± 0.102)
0.006 ± 0.004
(0.15 ± 0.102)
MSOP (MS10) 1098
* DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
11
11 Page | ||
| Páginas | Total 12 Páginas | |
| PDF Descargar | [ Datasheet LTC1757A-2EMS.PDF ] | |
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