Datasheet LTC5530 (Analog Devices) - 9
| Fabricante | Analog Devices |
| Descripción | Precision 300MHz to 7GHz RF Detector with Shutdown and Gain Adjustment |
| Páginas / Página | 12 / 9 — APPLICATIO S I FOR ATIO. Operation. Buffer Amplifier. RF Detector. … |
| Formato / tamaño de archivo | PDF / 320 Kb |
| Idioma del documento | Inglés |
APPLICATIO S I FOR ATIO. Operation. Buffer Amplifier. RF Detector. Shutdown. Demo Board Schematic
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LTC5530
U U W U APPLICATIO S I FOR ATIO Operation
MHz 4 RB = = The LTC5530 RF detector integrates several functions to BANDWIDTH MHz 4 • GAIN ( ) R ( + R ) provide RF power detection over frequencies ranging from A B 300MHz to 7GHz. These functions include an internal fre- A capacitor can be placed across the feedback resistor RA quency compensated buffer amplifier, an RF Schottky di- to shape the frequency response. In addition the amplifier ode peak detector and level shift amplifier to convert the RF can be used as a comparator. VM can be connected to a input signal to DC and a delay circuit to avoid voltage tran- reference voltage. When the internal detector voltage sients at VOUT when powering up. The LTC5530 has both (which is connected to the positive input of the buffer shutdown and gain setting capabilities. amplifier) exceeds the external voltage of VM, VOUT will switch high.
Buffer Amplifier RF Detector
The output buffer amplifier is capable of supplying typi- cally 4mA into a load. The negative terminal VM is brought The internal RF Schottky diode peak detector and level out to a pin for gain selection. External resistors connected shift amplifier converts the RF input signal to a low between VOUT and VM (RA) and VM to ground (RB) will set frequency signal. The detector demonstrates excellent the amplifier gain. efficiency and linearity over a wide range of input power. The Schottky diode is biased at about 55µA and drives a R 25pF internal peak detector capacitor. GAIN A = 1+ RB
Shutdown
The amplifier is unity gain stable; however a minimum gain The part is in shutdown mode when SHDN is low. The of two is recommended to improve low output voltage supply current is reduced to < 2µA and V accuracy. The amplifier bandwidth is 2MHz for a gain of 2. OUT is shorted to ground via a 280Ω resistor. When SHDN is asserted high, For increased gain applications, the bandwidth is reduced the part is enabled after about 8µs. according to the formula:
Demo Board Schematic
VCC 2.7V TO 6V C1 C4 LTC5530ES6 0.1µF RF 39pF IN C2 1 6 RF 100pF IN VCC R1 2 5 GND VOUT (OPT) VOUT C3 3 4 R3 R2 SHDN V (OPT) M 10k 22k VCC R4 SHDN 10k 5530 DB 5530f 9
U U W U APPLICATIO S I FOR ATIO Operation
MHz 4 RB = = The LTC5530 RF detector integrates several functions to BANDWIDTH MHz 4 • GAIN ( ) R ( + R ) provide RF power detection over frequencies ranging from A B 300MHz to 7GHz. These functions include an internal fre- A capacitor can be placed across the feedback resistor RA quency compensated buffer amplifier, an RF Schottky di- to shape the frequency response. In addition the amplifier ode peak detector and level shift amplifier to convert the RF can be used as a comparator. VM can be connected to a input signal to DC and a delay circuit to avoid voltage tran- reference voltage. When the internal detector voltage sients at VOUT when powering up. The LTC5530 has both (which is connected to the positive input of the buffer shutdown and gain setting capabilities. amplifier) exceeds the external voltage of VM, VOUT will switch high.
Buffer Amplifier RF Detector
The output buffer amplifier is capable of supplying typi- cally 4mA into a load. The negative terminal VM is brought The internal RF Schottky diode peak detector and level out to a pin for gain selection. External resistors connected shift amplifier converts the RF input signal to a low between VOUT and VM (RA) and VM to ground (RB) will set frequency signal. The detector demonstrates excellent the amplifier gain. efficiency and linearity over a wide range of input power. The Schottky diode is biased at about 55µA and drives a R 25pF internal peak detector capacitor. GAIN A = 1+ RB
Shutdown
The amplifier is unity gain stable; however a minimum gain The part is in shutdown mode when SHDN is low. The of two is recommended to improve low output voltage supply current is reduced to < 2µA and V accuracy. The amplifier bandwidth is 2MHz for a gain of 2. OUT is shorted to ground via a 280Ω resistor. When SHDN is asserted high, For increased gain applications, the bandwidth is reduced the part is enabled after about 8µs. according to the formula:
Demo Board Schematic
VCC 2.7V TO 6V C1 C4 LTC5530ES6 0.1µF RF 39pF IN C2 1 6 RF 100pF IN VCC R1 2 5 GND VOUT (OPT) VOUT C3 3 4 R3 R2 SHDN V (OPT) M 10k 22k VCC R4 SHDN 10k 5530 DB 5530f 9