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LG Electronics U250 service manual Vctcxo X100 DSA321SCE-19.2M, Front-End Module U500 D5011

Models: U250

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3. TECHNICAL BRIEF

3.5.2 VCTCXO (X100 : DSA321SCE-19.2M)

The Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO) provides the reference frequency for all RFIC synthesizers as well as clock generation functions within the MSM6245 IC. The oscillator frequency is controlled by the MSM6245 IC.

TRK_LO_ADJ pulse density modulated signal in the same manner as the transmit gain control TX_AGC_ADJ. A two-pole RC lowpass filter is recommended on this control line.

The PM6650 IC controls the handset power-up sequence, including a special VCTCXO warm-up interval before other circuits are turned on. This warm-up interval (as well as other TCXO controller functions) is enabled by the MSM TCXO_EN line . The PM6650 IC VREG_TCXO regulated output voltage is used to power the VCTCXO and is enabled before most other regulated outputs.

Any GSM mode power control circuits within the MSM6245 IC require a reference voltage for proper operation and sufficient accuracy. Connecting the PM6650 IC REF_OUT directly to the MSM6245 IC GSM_PA_PWR_CTL_REF provides this reference. This sensitive analog signal needs a 0.1 •ÏF low frequency filter near to MSM side, and isolate from digital logic and clock traces with ground on both sides, plus ground above and below if routed on internal layers.

3.5.3 Front-End Module (U500 : D5011)

This equipment uses a single antenna to support all handset operating modes, with an antenna switch module select the operating frequency and band. UMTS operation requires simultaneous reception and transmission, so the UMTS Rx/Tx connection is routed to a duplexer that separates receive and transmit signals. The active connection is MSM-selected by three control lines (GPIO[9], GPIO[10]). Two GPIO are programmed to be ANT_SEL0_N, ANT_SEL1_N) respectively.

GSM 1800 / GSM1900 RX

GSM 900 RX

GSM 900 TX / WCDMA

GSM 1800 / GSM 1900 TX

[Table 1.2] Front End Module control logic

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LG Electronics U250 service manual Vctcxo X100 DSA321SCE-19.2M, Front-End Module U500 D5011, Front End Module control logic
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U250 specifications

The LG Electronics U250 is a distinguished device known for its cutting-edge features and innovative technologies within the mobile phone sector. Launched as part of LG's effort to cater to a growing demand for functional yet stylish smartphones, the U250 boasts an array of characteristics that appeal to a savvy clientele.

One of the primary features of the U250 is its impressive display. Sporting a vibrant screen that offers excellent color reproduction and clarity, it enhances the user experience for gaming and multimedia consumption. The responsive touchscreen interface allows for seamless navigation, making it user-friendly for all age groups.

The U250 is powered by a robust processor that ensures smooth performance, whether multitasking between applications or running demanding games. With ample RAM, it minimizes lag and enhances the overall operating experience, allowing users to switch effortlessly between tasks.

Photography enthusiasts will appreciate the U250's advanced camera system. It is equipped with a high-resolution primary camera that captures stunning images in various lighting conditions. The inclusion of features like autofocus and image stabilization significantly elevates the quality of photos and videos. Additionally, the front-facing camera is designed for high-quality selfies and video calls, ensuring that users can always stay connected.

The device supports a range of connectivity options, including 4G LTE, Bluetooth, and Wi-Fi, ensuring users can remain connected to the world around them. The integration of NFC technology also enables quick and convenient transactions, particularly useful in a cashless society.

Battery life is another standout characteristic of the U250. With a durable battery, it offers extended usage time, allowing users to go through their day without the constant worry of recharging. Coupled with fast-charging capabilities, it reduces downtime significantly.

The LG U250 runs on an intuitive operating system that provides easy access to a plethora of apps on the platform. Customization options are abundant, allowing users to tailor their device's appearance and functionality to suit their preferences.

In conclusion, the LG Electronics U250 combines striking design with versatile functionality, making it a formidable entry in the smartphone market. With its impressive display, powerful performance, advanced camera features, and strong battery life, the U250 is poised to meet the needs of modern users seeking both style and substance in a mobile device. Whether for work or leisure, this smartphone is designed to enhance everyday life.