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RF PLL： 16/17/20/21 or 32/33/36/37
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IF PLL： 8/9 or 16/17
Advanced Sigma-Δ fraction compensation
- 12-bit or 22-bit decimal mode is available
- Up to 4th order programmable Δ-σ modulator
Features to improve lock-on time and programming
- Fastlock/weekly hop reduction
- Integrated timeout counter
- One word is written to change the frequency with Fastlock
Wide operating voltage range
- LMX2487E RF PLL: 3.0 GHz to 7.5 GHz
Practical functions
- Digital lock detection output
- Hardware and software power-down control
- The reference frequency of the on-chip crystal is doubled.
- RF frequencies are up to 50 MHz
- 2.5 to 3.6 volts operate with I CC = 8.5 mA 3.0 V
illustrate
The LMX2487E is a low-power, high-performance Δ-Sigma decimal N division PLL with an auxiliary integer N PLL. It uses an advanced process manufactured by National Semiconductor Corporation of the United States.
With the delta-sigma architecture, the fractional spurs with lower offset frequencies are pushed to frequencies with higher external loop bandwidth. The ability to push at the promoted and phase noise energy approaching higher frequencies is the modulator's command indication function. With analog compensation, digital feedback technology is used in LMX2487E to have a high resistance to temperature changes and wafer processing variations. The LMX2487EΔ-Σ modulator is programmable to the fourth order, which allows designers to select the best modulator to accommodate phase noise, spur, and lock in system time requirements.
For programming LMX2487E serial data transmission via a three-wire high-speed (20 MHz) MICROWIRE Interface. The LMX2487E offers fine frequency resolution, low spurs, fast programming speed, and a single word to change the frequency. This makes N counters ideal for direct and information modulation in direct digital modulation applications. The LMX2487E is available in 24 leads 4.0 × 4.0 x 0.8 mm LLP encapsulation.
apply
- Mobile phones and base stations
- Direct digital modulation applications
- Satellite and cable TV tuners
- Wireless LAN standards
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