LTC5507 - 100kHz to 1GHz RF Power Detector

LTC5507
100kHz to 1GHz
RF Power Detector
U
FEATURES
■
■
■
■
■
■
■
■
DESCRIPTIO
Temperature Compensated Internal Schottky
Diode RF Detector
Wide Input Power Range: –34dBm to 14dBm
Ultra Wide Input Frequency Range: 100kHz to
1000MHz
Buffered Output
Wide VCC Range of 2.7V to 6V
Low Operating Current: 550µA
Low Shutdown Current: <2µA
Low Profile (1mm) ThinSOTTM Package
U
APPLICATIO S
■
■
■
The RF input voltage is peak detected using an on-chip
Schottky diode and external capacitor. The detected voltage is buffered and supplied to the VOUT pin. A power
saving shutdown mode reduces supply current to less
than 2µA.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation
Wireless Transceivers
Wireless and Cable Infrastructure
RF Power Alarm
Envelope Detector
U
■
The LTC®5507 is an RF power detector for applications
operating from 100kHz to 1000MHz. The input frequency
range is determined by an external capacitor. A temperature-compensated Schottky diode peak detector and buffer
amplifier are combined in a small 6-pin ThinSOT package.
TYPICAL APPLICATIO
Typical Detector Characteristics
at 100kHz, 100MHz and 1000MHz
4
VBAT
2.7V TO 6V
C2
5
C1
RF
INPUT
6
LTC5507
VCC
VOUT
PCAP
GND
RFIN
SHDN
3
2
1
VOUT
DETECTED
VOLTAGE
TA = 25°C
VCC = 2.7V TO 6V
VOUT OUTPUT VOLTAGE (mV)
10000
1000
DISABLE ENABLE
5507 TA01
Figure 1. 100kHz to 1000MHz RF Power Detector
100kHz, 100MHz
1000MHz
100
–34
–26
–18
–10
–2
6
RF INPUT POWER (dBm)
14
5507 TA01b
5507f
1
LTC5507
U
W W
W
ABSOLUTE
AXI U RATI GS
U
W
U
PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
NUMBER
VCC, VOUT to GND .................................... –0.3V to 6.5V
RFIN Voltage to GND ......................... (VCC ± 1.8V) to 7V
SHDN Voltage to GND ................ –0.3V to (VCC + 0.3V)
PCAP Voltage to GND ........................(VCC – 1.8V) to 7V
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
LTC5507ES6
SHDN 1
6 RFIN
GND 2
5 PCAP
VOUT 3
4 VCC
S6 PART
MARKING
S6 PACKAGE
6-LEAD PLASTIC SOT-23
TJMAX = 125°C, θJA = 250°C/W
LTZX
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, RF Input Signal is Off, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
VCC Operating Voltage
●
IVCC Shutdown Current
SHDN = 0V
●
IVCC Operating Current
SHDN = VCC, IVOUT = 0mA
●
VOUT VOL (No RF Input)
RLOAD = 2k, SHDN = VCC, Enabled
SHDN = 0V, Disabled
VOUT Output Current
VOUT = 1.75V, VCC = 2.7V to 6V, ∆VOUT = 10mV
●
VOUT Enable Time
SHDN = VCC, CLOAD = 33pF, RLOAD = 2k
●
VOUT Load Capacitance
(Note 4)
●
VOUT Noise
VCC = 3V, Noise BW = 1.5MHz, 50Ω RF Input Termination
2.7
MAX
VCC = 2.7V to 6V
●
SHDN Voltage, Chip Enabled
VCC = 2.7V to 6V
●
SHDN Input Current
SHDN = 3.6V
●
UNITS
6
V
2
µA
0.55
0.85
mA
130
250
1
370
mV
mV
1
2
7
mA
20
µs
33
pF
2
SHDN Voltage, Chip Disabled
RFIN Input Frequency Range
TYP
mVP-P
0.35
1.4
V
V
24
40
µA
0.1– 1000
MHz
Max RFIN Input Power
(Note 3)
14
dBm
RFIN AC Input Resistance
F = 10MHz, RF Input = –10dBm
F = 1000MHz, RF Input = –10dBm
130
95
Ω
Ω
1.7
pF
RFIN Input Shunt Capacitance
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: RF performance is tested at: 80MHz, –4dBm
Note 4: Guaranteed by design.
5507f
2
LTC5507
U W
TYPICAL PERFOR A CE CHARACTERISTICS
LTC5507 Typical Detector
Characteristics, 100kHz,
VCC = 2.7V TO 6V
10000
LTC5507 Typical Detector
Characteristics, 100MHz
VCC = 2.7V TO 6V
10000
C1 = 1000pF
C2 = 1000pF
VOUT OUTPUT VOLTAGE (mV)
VOUT OUTPUT VOLTAGE (mV)
C1 = 0.47µF
C2 = 0.47µF
1000
1000
TA = –40°C
TA = 85°C
TA = –40°C
TA = 85°C
TA = 25°C
100
–34 –28 –22 –16 –10 –4
2
RF INPUT POWER (dBm)
8
TA = 25°C
100
–34 –28 –22 –16 –10 –4
2
RF INPUT POWER (dBm)
14
5507 G01
Positive VOUT Slew Rate vs C2
Capacitance
1000
10.0
POSITIVE VOUT SLEW RATE (V/µs)
C1 = 33pF
C2 = 33pF
VOUT OUTPUT VOLTAGE (mV)
14
5507 G02
LTC5507 Typical Detector
Characteristics, 1000MHz
VCC = 2.7V TO 6V
10000
8
1.0
0.10
TA = –40°C
TA = 85°C
TA = 25°C
100
–34 –28 –22 –16 –10 –4
2
RF INPUT POWER (dBm)
0.01
8
33
14
330
3300
33000
C2 CAPACITANCE (pF)
5507 G03
5507 G04
Negative VOUT Slew Rate vs C2
Capacitance
VOUT BW vs C2 Capacitance
10000
10.000
1.000
1000
VOUT BW (kHz)
NEGATIVE VOUT SLEW RATE (V/µs)
330000
0.100
0.010
100
10
0.001
0
33
330
3300
33000
C2 CAPACITANCE (pF)
330000
5507 G05
1
33
330
3300
33000
C2 CAPACITANCE (pF)
330000
5507 G06
5507f
3
LTC5507
U
U
U
PI FU CTIO S
SHDN (Pin 1): Shutdown Input. A logic low or no-connect
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 enable driver is in a tri-state condition.
VCC (Pin 4): Power Supply Voltage, 2.7V to 6V. VCC should
be bypassed with 0.1µF and 100pF ceramic capacitors.
GND (Pin 2): System Ground.
RFIN (Pin 6): RF Input Voltage. Referenced to VCC. A
coupling capacitor must be used to connect to the RF
signal source. This pin has an internal 250Ω termination
and an internal Schottky diode detector.
PCAP (Pin 5): Peak Detector Hold Capacitor. Capacitor
value is dependent on RF frequency. Capacitor must be
connected between PCAP and VCC.
VOUT (Pin 3): Buffered and Level Shifted Detector Output
Voltage.
W
BLOCK DIAGRA
VCC
4
GAIN
COMPRESSION
+
BUFFER
C1
250Ω
RFSOURCE
VOUT
–
6
SHDN
RFIN
30k
30k
C2
VCC
3
100Ω
+
5
PCAP
RF DET
–
60µA
60µA
150k
BIAS
GND 2
1
C1 = C2
C2 (µF) ≥
1
, f = LOWEST RF INPUT FREQUENCY (MHz)
30f
5507 BD
SHDN
Figure 2.
5507f
4
LTC5507
U
W
U
U
APPLICATIO S I FOR ATIO
Operation
Applications
The LTC5507 integrates several functions to provide RF
power detection over frequencies up to 1000MHz. These
functions include an internally compensated buffer amplifier, an RF Schottky diode peak detector and level shift
amplifier to convert the RF 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.
The LTC5507 can be used as a self-standing signal strength
measuring receiver for a wide range of input signals from
–34dBm to 14dBm for frequencies up to 1000MHz.
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 VCC – 0.1V.
RF Detector
The internal RF Schottky diode peak detector and level
shift amplifier converts the RF input signal to a low
frequency signal. The frequency range of the RF pin is
typically up to 1000MHz. The detector demonstrates excellent operation over a wide range of input power. The
Schottky detector is biased at about 70µA. The hold
capacitor is external.
The LTC5507 can be used as a demodulator for AM and
ASK modulated signals with data rates up to 1.5MHz.
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.
C1, C2 Capacitor Selection (Refer to Figure 3)
C1 couples the RF input signal to the detector input RFIN
which is referenced to VCC. C2 is the peak detector
capacitor connected between PCAP and VCC. The value of
C2 will affect the slew rate and bandwidth. Typically C1 can
equal C2. Ceramic capacitors are recommended for C1
and C2. The values for C1 and C2 are dependent on the
operating RF frequency. The capacitive reactance should
be less than 5Ω to minimize ripple on C2.
C2(µF) ≥ 1/(30 • f) where f is the lowest RF input
frequency (MHz)
C1 = C2
Gain Compression
The gain compression circuit changes the feedback ratio
as the RF peak-detected input voltage increases above
60mV. Below 60mV, the DC voltage gain from the peak
detector to the buffer output is 4. Above 140mV, the DC
voltage gain is reduced to 0.75. The compression expands
the low power detector range due to higher gain.
In general, select C1 and C2 large enough to pass the
lowest expected RF signal frequency, as described by the
above formulas. But optimize C1 and C2, subject to this
constraint, to improve output slew rate and bandwidth,
and to enable good AC performance for the highest
expected RF signal frequency.
Modes of Operation
MODE
SHDN
OPERATION
Shutdown
Low
Disabled
Enable
High
Power Detect
5507f
5
LTC5507
U
U
W
U
APPLICATIO S I FOR ATIO
SHDN
E4
R3*
22k
R4*
1
JP1
2
VOUT
GND
E2
E3
J1
RFIN
VCC
SHDN R2*
68Ω
C5*
3
LTC5507
SHDN
RFIN
GND
PCAP
VOUT
VCC
C1
6
5
4
C2
C4*
0.1µF
VCC
E1
VCC
C3*
100pF
5507 F03
* OPTIONAL COMPONENTS
R2 AND C5 FORM AN OPTIONAL OUTPUT LOWPASS FILTER.
R3 IS USED FOR DEMO PURPOSES ONLY, AND IS NOT USED IN ACTUAL PRODUCT IMPLEMENTATION.
R4 CAN BE USED FOR INPUT POWER LIMITING OR BROADBAND IMPEDANCE MATCHING.
C3 AND C4 ARE OPTIONAL POWER SUPPLY FILTERS.
Figure 3. Evaluation Demo Board Schematic
5507f
6
LTC5507
U
PACKAGE DESCRIPTIO
S6 Package
6-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1636)
0.62
MAX
2.90 BSC
(NOTE 4)
0.95
REF
1.22 REF
3.85 MAX 2.62 REF
1.4 MIN
2.80 BSC
1.50 – 1.75
(NOTE 4)
PIN ONE ID
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
0.30 – 0.45
6 PLCS (NOTE 3)
0.95 BSC
0.80 – 0.90
0.20 BSC
0.01 – 0.10
1.00 MAX
DATUM ‘A’
0.30 – 0.50 REF
0.09 – 0.20
(NOTE 3)
1.90 BSC
S6 TSOT-23 0302
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
5507f
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.
7
LTC5507
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
RF Power Controllers
LTC1757A
RF Power Controller
Multiband GSM/DCS/GPRS Mobile Phones
LTC1758
RF Power Controller
Multiband GSM/DCS/GPRS Mobile Phones
LTC1957
RF Power Controller
Multiband GSM/DCS/GPRS Mobile Phones
LTC4400
ThinSOT RF PA Controller
Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 450kHz Loop BW
LTC4401
ThinSOT RF PA Controller
Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 250kHz Loop BW
LTC4403
Multiband RF Power Controllers for EDGE/TDMA
Supports EDGE/TDMA Applications
LT5504
800MHz to 2.7GHz RF Measuring Receivers
80dB Dynamic Range, Temperature Compensated, 2.7V to 5.5V Supply
LTC5505
300MHz to 3.5GHz RF Power Detector
>40dB Dynamic Range, Temperature Compensated, 2.7V to 6V Supply
LTC5508
300MHz to 7GHz RF Power Detector
>40dB Dynamic Range, SC-70 Package
Other Related Parts
LT5500
1.8GHz to 2.7GHz, Receiver Front End
Dual LNA gain Setting +13.5dB/–14dB at 2.5GHz, Double-Balanced Mixer,
1.8V to 5.25V Supply
LT5502
400MHz Quadrature Demodulator with RSSI
1.8V to 5.25V Supply, 70MHz to 400MHz IF, 84dB Limiting Gain, 90dB RSSI Range
LT5503
1.2GHz to 2.7GHz Direct IQ Modulator and
Up Converting Mixer
1.8V to 5.25V Supply, Four-Step RF Power Control, 120MHz Modulation Bandwidth
LT5506
500MHz Quadrature IF Demodulator with VGA
1.8V to 5.25V Supply, 40MHz to 500MHz IF, –4dB to 57dB Linear Power Gain
LT5511
High Signal Level Upconverting Mixer
10MHz to 3000MHz RF Output Range, Integrated LO Buffer, 17dBm IIP3
LT5512
High Signal Level Down Converting Mixer
DC-3GHz, 20dBm IIP3, Integrated LO Buffer
5507f
8
Linear Technology Corporation
LT/TP 0103 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