RF2512 RF Micro Devices, RF2512 Datasheet
RF2512
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RF2512 Summary of contents
Page 1
... Single- or Dual-Channel LO Source • FM/FSK Transmitter • Wireless Data Transmitters Product Description The RF2512 is a monolithic integrated circuit intended for use as a low-cost frequency synthesizer and transmitter. The device is provided pin SSOP package and is designed to provide a phased locked frequency source for use in local oscillator or transmitter applications ...
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... RF2512 Absolute Maximum Ratings Parameter Supply Voltage Power Down Voltage ( Operating Ambient Temperature Storage Temperature Parameter Overall Frequency Range Modulation Modulation Frequency Maximum FM Deviation PLL and Prescaler Prescaler Divide Ratio PLL Lock TIme PLL Phase Noise Reference Frequency Max Crystal R ...
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... VREF P Bias voltage reference pin for bypassing the prescaler and phase detector. The bypass capacitor should be of appropriate size to provide filtering of the reference crystal frequency and be connected directly to this pin. Rev B9 010509 RF2512 Interface Schematic OSC B1 OSC B2 OSC E See pin 1. See pin 1. ...
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... RF2512 Pin Function Description 14 MOD CTRL This pin is used to select the prescaler modulus. A logic “high” selects 64 or 128 for the prescaler divisor. A logic “low” selects 65 or 129 for the prescaler divisor. 15 DIV CTRL This pin is used to select the desired prescaler divisor. A logic “high” ...
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... A PLL consists of a reference oscillator, a phase detec- tor, a loop filter, a voltage controlled oscillator (VCO), and a programmable divider in the feedback path. The RF2512 includes all of these internally except for the loop filter and the reference oscillator's crystal and two feedback capacitors. The reference oscillators are Colpitts type oscillators. ...
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... During transmission the transmitter is enabled and the impedance of the output pin, pin 8 (TX OUT), is low. When the transmitter is not enabled, the impedance becomes high. The RF2512 contains onboard band gap reference voltage circuitry which provides a stable DC bias over varying temperature and supply voltages. Designing with the RF2512 The reference oscillator is built around the onboard transistor at pins 1, 2 and 3 ...
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... The frequency at which unity gain occurs is given by This is also the loop bandwidth. If the phase margin (PM) and the loop bandwidth ( ) are known possible to calculate the time LBW constants. These are found using the equations sec PM ------------------------------------------------- - = 1 RF2512 VCO Loop Filter ...
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... In order to perform these calculations, one will need to know the value of two constants, K calculated by dividing the charge pump current For the RF2512, the charge pump current best found empirically as it will change with VCO frequency and board parasitics. By briefly connecting pin 23 (LOOP FLT) to VCC and then to ground, the fre- quency tuning range of the VCO can be seen ...
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... OSC OSC SEL OSC LOOP FLT OSC PLL ENABL 4 21 GND3 GND1 5 20 RESNTR+ VCC3 LVL ADJ 7 18 RESNTR- TX OUT 8 17 VCC2 GND2 9 16 MOD IN VCC1 10 15 DIV CTRL TX ENABL 11 14 MOD CTRL 12 13 VREF P RF2512 11 11-19 ...
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... RF2512 H (915MHz) and M (868MHz) Boards AUDIO R7* R5* R6 D3* D2* X2* C3 100 pF C2* 100 pF PLL ON VCC LVL ADJ C18 0 8 strip J1 RF OUT VCC C9 C10 PRESC OUT R3* TBD 11 11-20 Evaluation Board Schematic (Download Bill of Materials from www ...
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... Charge Pump C15 Gain Control Prescaler C11 *Denotes optional. These parts are not normally populated. 0.1 F 2512400A RF2512 P3 P4 P3-1 AUDIO 1 P4-1 1 DIV 64 2 GND 2 GND P3-3 3 OSCSLT P4-3 3 MOD CTL 4 GND CON3 P3-5 VCC 5 CON5 OSC SEL ...
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... RF2512 Evaluation Board Layout 433MHz Evaluation Board Layout 868MHz 11 Evaluation Board Layout 915MHz 11-22 Board Size 1.5” x 1.5” Board Size 1.5” x 1.5” Board Size 1.5” x 1.5” Rev B9 010509 ...
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... TX Power versus V CC Level Adjust = V , 915 MHZ CC 11.0 -40°C -15°C 10.0 +10°C +35°C 9.0 +60°C +85°C 8.0 7.0 6.0 5.0 4.0 3.0 2.0 2.5 3.0 3.5 4.0 V (V) CC Rev B9 010509 Level Adjust = V 45.0 -40°C -15°C +10°C +35°C 40.0 +60°C +85°C 35.0 30.0 25.0 20.0 15.0 4.5 5.0 2.5 3.0 RF2512 I versus 915 MHz CC 3.5 4.0 4.5 5.0 V (V) CC 11-23 11 ...
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... RF2512 11 11-24 Rev B9 010509 ...