LTC5505-1/LTC5505-2 - RF Power Detector with Buffered Output and >40dB Dynamic Range

LTC5505-1/LTC5505-2
RF Power Detector
with Buffered Output and >40dB
Dynamic Range
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DESCRIPTIO
FEATURES
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The LTC®5505-X is an RF power detector for RF applications operating in the 300MHz to 3.5GHz range. A temperature compensated Schottky diode peak detector and
buffer amplifier are combined in a small 5-pin ThinSOT
package. The supply voltage range is optimized for operation from a single lithium-ion cell or 3xNiMH.
Internal Schottky Diode RF Detector with Two Input
Power Ranges:
LTC5505-1, –28dBm to 18dBm
LTC5505-2, –32dBm to 12dBm
Wide Input Frequency Range: 300MHz to 3GHz
(LTC5505-1); 300MHz to 3.5GHz (LTC5505-2)
Temperature Compensated
Buffered Detector Output
Wide VCC Range of 2.7V to 6V
Low Operating Current: 0.5mA
Low Shutdown Current: <2µA
Low Profile (1mm) ThinSOTTM Package
The RF input voltage is peak detected using an on-chip
Schottky diode. The detected voltage is buffered and
supplied to the VOUT pin. A power saving shutdown mode
reduces supply current to less than 2µA.
The LTC5505-1 operates with input power levels from
–28dBm to 18dBm. The LTC5505-2 operates with input
power levels from –32dBm to 12dBm.
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APPLICATIO S
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Multimode Mobile Phone Products
PCS Devices
Wireless Data Modems
Wireless and Cable Infrastructure
RF Power Alarm
Envelope Detector
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, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation
TYPICAL APPLICATIO
Dual Band Mobile Phone Tx Power Control
R1
100Ω
RF
1
2
DISABLE ENABLE
3
LTC5505-X
VCC 5
RFIN
GND
SHDN
VOUT 4
MOBILE PHONE
DSP
C1
0.3pF
Tx PA MODULE
C2
0.1µF
Li-Ion
CELL BAND
DIPLEXER
PCS BAND
VPC
5505 TA01
BSE
5505f
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LTC5505-1/LTC5505-2
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ABSOLUTE
AXI U RATI GS
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PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
NUMBER
VCC, VOUT to GND .................................... –0.3V to 6.5V
RF Voltage
LTC5505-1 ................................... (VCC – 2.6V) to 7V
LTC5505-2 ................................... (VCC – 1.4V) to 7V
SHDN Voltage to GND ................ –0.3V to (VCC + 0.3V)
IVOUT ...................................................................... 5mA
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Maximum Junction Temperature ......................... 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
TOP VIEW
RFIN 1
LTC5505-1ES5
LTC5505-2ES5
5 VCC
GND 2
SHDN 3
4 VOUT
S5 PART
MARKING
S5 PACKAGE
5-LEAD PLASTIC SOT-23
TJMAX = 125°C, θJA = 250°C/W
LTXV
LTRW
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 3.6V, SHDN = VCC = HI, SHDN = 0V = LO, RF Input Signal is Off,
unless otherwise noted.
PARAMETER
CONDITIONS
VCC Operating Voltage
MIN
●
IVCC Shutdown Current
SHDN = LO
●
IVCC Operating Current
SHDN = HI, IVOUT = 0mA
●
VOUT VOL (No RF Input)
RLOAD = 2k, SHDN = HI, Enabled
SHDN = LOW, Disabled
TYP
2.7
MAX
UNITS
6
V
2
µA
0.5
0.75
mA
170
260
1
350
mV
mV
1
2
VOUT Output Current
VOUT = 1.75V, VCC = 2.7V, ∆VOUT = 10mV
●
VOUT Enable Time
SHDN = HI, CLOAD = 33pF, RLOAD = 2k
●
VOUT Bandwidth
CLOAD = 33pF, RLOAD = 2k (Note 4)
VOUT Load Capacitance
(Note 7)
VOUT Slew Rate
VRFIN = 2V Step, CLOAD = 33pF, RLOAD = 2k (Note 3)
10
V/µs
VOUT Noise
VCC = 3V, Noise BW = 1.5MHz, 50Ω RF Input Termination
1.4
mVP-P
8
mA
20
4
SHDN Voltage, Chip Disabled
VCC = 2.7V to 6V
●
SHDN Voltage, Chip Enabled
VCC = 2.7V to 6V
●
SHDN Input Current
SHDN = 3.6V
●
MHz
33
●
µs
0.35
1.4
pF
V
V
24
40
µA
5505f
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LTC5505-1/LTC5505-2
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 3.6V, SHDN = VCC = HI, SHDN = 0V = LO, RF Input Signal is Off,
unless otherwise noted.
PARAMETER
CONDITIONS
MIN
RFIN Input Frequency Range (LTC5505-1)
(LTC5505-2)
TYP
MAX
UNITS
300 to 3000
300 to 3500
MHz
MHz
RFIN Input Power Range (LTC5505-1)
RF Frequency = 900MHz (Note 5, 6, 7) VCC = 2.7V to 6V
RF Frequency = 1800MHz (Note 5, 6, 7)VCC = 2.7V to 6V
RF Frequency = 2400MHz (Note 5, 7)VCC = 2.7V to 6V
RF Frequency = 2700MHz (Note 5, 7)VCC = 2.7V to 6V
–28 to 18
–26 to 18
–24 to 16
–22 to 16
dBm
dBm
dBm
dBm
RFIN Input Power Range (LTC5505-2)
RF Frequency = 900MHz (Note 5)
RF Frequency = 1800MHz (Note 5)
RF Frequency = 2400MHz (Note 5)
RF Frequency = 2700MHz (Note 5)
–32 to 12
–32 to 12
–32 to 12
–30 to 12
dBm
dBm
dBm
dBm
RFIN AC Input Resistance (LTC5505-1)
F = 850MHz
F = 1850MHz
RFIN Input Shunt Capacitance (LTC5505-1)
RFIN AC Input Resistance (LTC5505-2)
F = 850MHz
F = 1850MHz
RFIN Input Shunt Capacitance (LTC5505-2)
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Specifications over the –40°C to 85°C operating temperature
range are assured by design, characterization and correlation with
statistical process controls.
Note 3: The rise time at VOUT is measured between 0.5V and 1.5V.
Note 4: Bandwidth is calculated using the 10% to 90% rise time equation:
BW = 0.35/rise time.
165
20
Ω
Ω
2
pF
165
59
Ω
Ω
1.3
pF
Note 5: RF performance is tested at:
1800MHz, 14dBm, –14dBm (LTC5505-1)
1800MHz, 12dBm, –14dBm (LTC5505-2)
Note 6: For input RF power levels >16dBm, VCC minimum is 3V and an RF
input series resistor of 20Ω is required to limit the input current.
Note 7: Guaranteed by design.
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LTC5505-1/LTC5505-2
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TYPICAL PERFOR A CE CHARACTERISTICS
10000
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
VOUT OUTPUT VOLTAGE (mV)
VOUT OUTPUT VOLTAGE (mV)
10000
LTC5505-1 Typical Detector
Characteristics, 2.45GHz
LTC5505-1 Typical Detector
Characteristics, 1.85GHz
10000
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
VOUT OUTPUT VOLTAGE (mV)
LTC5505-1 Typical Detector
Characteristics, 0.85GHz
1000
1000
100
0
6
–30 –24 –18 –12 –6
RF INPUT POWER (dBm)
12
1000
100
–30 –24
–18 –12 –6
0
6
RF INPUT POWER (dBm)
LTC5505-2 Typical Detector
Characteristics, 0.85GHz
100
0
6
–30 –24 –18 –12 –6
RF INPUT POWER (dBm)
12
5505 G03
LTC5505-2 Typical Detector
Characteristics, 1.85GHz
10000
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
VOUT OUTPUT VOLTAGE (mV)
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
VOUT OUTPUT VOLTAGE (mV)
12
5505 G02
5505 G01
10000
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
1000
1000
100
–32
–26
–20 –14 –8
–2
4
RF INPUT POWER (dBm)
100
–32
10
–26
–20 –14 –8
–2
4
RF INPUT POWER (dBm)
5505 G04
5505 G05
LTC5505-2 Typical Detector
Characteristics, 2.45GHz
LTC5505-2 Typical Detector
Characteristics, 3.5GHz
10000
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
VOUT OUTPUT VOLTAGE (mV)
VOUT OUTPUT VOLTAGE (mV)
10000
VCC = 2.7V TO 6V
0Ω SERIES TERMINATION
–40°C
25°C
85°C
1000
1000
100
–32
10
–26
–20 –14 –8
–2
4
RF INPUT POWER (dBm)
10
5505 G06
100
–32
–26
–20 –14 –8
–2
4
RF INPUT POWER (dBm)
10
5505 G07
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LTC5505-1/LTC5505-2
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PI FU CTIO S
RFIN (Pin 1): RF Input Voltage. Referenced to VCC. An
external coupling capacitor to the RF source is required.
The frequency range is 300MHz to 3GHz. This pin has an
internal 250Ω termination, an internal Schottky diode
detector and peak detector capacitor. (See Note 6 in the
Electrical Characteristics.)
GND (Pin 2): System Ground.
SHDN (Pin 3): Shutdown Input. A logic low on the SHDN
pin places the part in shutdown mode. A logic high enables
the part. SHDN has an internal 150k pull down resistor to
ensure that the part is in shutdown when the drivers are in
a tri-state condition.
VOUT (Pin 4): Buffered and Level Shifted Detector Output
Voltage.
VCC (Pin 5): Power Supply Voltage, 2.7V to 6V. VCC should
be bypassed appropriately with ceramic capacitors.
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BLOCK DIAGRA
VCC
5
GAIN
COMPRESSION
+
BUFFER
4
VOUT
–
SHDN
30k
250Ω
RFIN 1
30k
100Ω
100Ω
+
28pF
RF DET
130mV
–
60µA
22k
60µA
BIAS
150k
GND 2
3
5505 BD
SHDN
5505f
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LTC5505-1/LTC5505-2
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APPLICATIO S I FOR ATIO
Operation
The LTC5505-X RF detector integrates several functions to
provide RF power detection over frequencies ranging from
300MHz to 3.5GHz. These functions include an internally
compensated buffer amplifier, an RF Schottky diode peak
detector and level shift amplifier to convert the RF feedback
signal to DC, a delay circuit to avoid voltage transients at
VOUT when coming out of shutdown and a gain compression circuit to extend the detector dynamic range.
Buffer Amplifier
The buffer amplifier has a gain of two and is capable of
driving a 2mA load. The buffer amplifier typically has an
output voltage range of 0.25V to 1.75V.
RF Detector
The internal RF Schottky diode peak detector and level
shift amplifier converts the RF input signal to a low
frequency signal. The detector demonstrates excellent
efficiency and linearity over a wide range of input power.
The Schottky detector is biased at about 60µA and drives
a peak detector capacitor of 28pF.
Gain Compression
The gain compression circuit changes the feedback ratio
as the RF peak-detected input voltage increases above
100mV. Below 100mV, the voltage gain from the peak
detector to the buffer output is 1.5. Above 200mV, the
voltage gain is reduced to 0.7. The compression expands
the low power detector range due to higher gain.
Modes of Operation
MODE
SHDN
OPERATION
Shutdown
Low
Disabled
Enable
High
Power Detect
Applications
The LTC5505-1 and LTC5505-2 can be used as selfstanding signal strength measuring receivers for a wide
range of input signals from –32dBm to 18dBm for frequencies from 300MHz to 3.5GHz.
The LTC5505-1 and LTC5505-2 can be used as demodulators for AM and ASK modulated signals with data rates
up to 5MHz. Depending on specific application needs, the
RSSI output can be split into two branches, providing
AC-coupled data (or audio) output and DC-coupled, RSSI
output for signal strength measurements and AGC.
The LTC5505-1 and LTC5505-2 can be used for dual band
mobile phone transmitter power control (refer to Typical
Application schematic on first page). The circuit uses a
capacitive tap at the Tx PA outputs. For example, a 0.3pF
capacitor (C1) followed by a 100Ω resistor (R1) forms a
coupling circuit with about a 20dB loss at the cellular band
and 18dB loss at the PCS band, referenced to the LTC5505-2
IC RF input pin. For improved coupling accuracy, the C1
capacitor should be a high tolerance component (±0.05pF.)
Example of LTC5505-X GSM/DCS Power Control Timing Diagram
20µs
2µs
28µs
543µs
28µs
SHDN
VOUT
RF INPUT
POWER
5505 TD
t1
t2
t3
t4
t 1: PART COMES OUT OF SHUTDOWN 20µs MAXIMUM PRIOR TO BURST.
t 2: CIRCUITS POWER UP AND SETTLE.
t 3: BASEBAND CONTROLLER STARTS RF POWER RAMP UP AT 22µs AFTER SHDN IS ASSERTED HIGH.
t5
t6
t 4: BASEBAND CONTROLLER COMPLETES RAMP UP.
t 5: BASEBAND CONTROLLER STARTS RF POWER RAMP DOWN AT END OF BURST.
t 6: LTC5505-X RETURNS TO SHUTDOWN MODE BETWEEN BURSTS
5505f
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LTC5505-1/LTC5505-2
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TYPICAL APPLICATIO
Dual Band Mobile Phone Tx Power Control with Directional Coupler
0Ω TO 20Ω
33pF
1
2
3
DISABLE ENABLE
LTC5505-X
VCC 5
RFIN
0.1µF
GND
SHDN
VOUT 4
900MHz
INPUT
1.8GHz
INPUT
MOBILE PHONE
DSP
Li-Ion
BSEL
Tx PA MODULE
VPC
DIRECTIONAL
COUPLER
DIPLEXER
900MHz
OUTPUT
1.8GHz
OUTPUT
50Ω
5505 TA02
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PACKAGE DESCRIPTIO
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
2.90 BSC
(NOTE 4)
0.754
0.854 ± 0.127
3.254
2.80 BCS
1.50 – 1.75
(NOTE 4)
0.95 BSC
1.9 BSC
PIN ONE
RECOMMENDED SOLDER PAD LAYOUT
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.35 – 0.50 REF
0.09 – 0.20
(NOTE 3)
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
1.90 BSC
S5 TSOT-23 0801
5505f
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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LTC5505-1/LTC5505-2
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5505f
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Linear Technology Corporation
LT/TP 1102 2K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2001