Texas Instruments LP3917RL-M/NOPB

Overview

LP3917RL-M/NOPB from Texas Instruments is a highly integrated Power Management Unit (PMU) for CDMA cellular handsets, featuring two synchronous buck regulators (800 mA and 600 mA), nine low-noise LDOs (35 µV typ noise), USB 2.0 transceiver (12 Mbps), battery voltage monitor, and thermal shutdown with early warning alarm - all in a 3.5×3.5 mm DSBGA-49 package.

For engineers reviewing the LP3917RL-M/NOPB datasheet, LP3917RL-M/NOPB pinout, LP3917RL-M/NOPB application, or LP3917RL-M/NOPB equivalent, key selection considerations include LDO noise performance for RF supply, PFM/PWM auto-mode efficiency at light load, interrupt-driven status reporting to baseband processor, and compact micro SMD footprint for space-constrained handset designs.

Technical Context

The LP3917RL-M/NOPB integrates dual DC/DC buck converters with automatic PFM/PWM mode switching and nine independently controllable LDOs optimized for RF (2.85 V @ 150 mA), memory (1.875 V @ 300 mA), and peripheral domains. Its serial interface supports dynamic voltage programming and real-time status readback via I²C-compatible SDA/SCL pins.

Two comparators enable accessory detection (e.g., earplug insertion), while the USB transceiver complies with USB 2.0 full-speed signaling (12 Mbps) and includes SUSPEND, RCV, VP/VM differential receivers, and D+/D− I/Os. Thermal monitoring triggers early-warning IRQ_N before shutdown.

Key Specifications

Pinout & Package

LP3917RL-M/NOPB uses a 49-bump DSBGA (Die Size Ball Grid Array) package with 0.5 mm pitch and 3.5×3.5 mm body size. Pin assignment follows TI's YPG drawing, with dedicated power domains (VIN_BUCK, VIN1, VIN2, VBATT), analog ground (GNDA), digital ground (GNDD), and serial control (SDA, SCL).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power management unit applications.

Compared with TPS65023RSBR and MAX1587AETD+, the LP3917RL-M/NOPB uniquely combines USB 2.0 transceiver, dual comparators, and 9-LDO flexibility in a micro SMD package - making it optimal for space-constrained CDMA handsets requiring minimal external components and interrupt-driven system responsiveness.

Availability

LP3917RL-M/NOPB is available at Aetrix Electronics and suitable for CDMA handset design, RF front-end power systems, and USB-enabled portable electronics requiring stable component supply and long-term lifecycle support.

Supply support for LP3917RL-M/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of experience in mobile communications ICs.

The LP3917RL-M/NOPB belongs to TI's legacy cellular PMU product line, engineered specifically for CDMA handset power architecture - integrating buck, LDO, USB, and monitoring functions into a single die to minimize footprint and system-level complexity.

FAQ

What is the primary application domain for the LP3917RL-M/NOPB?

The LP3917RL-M/NOPB is purpose-built for CDMA cellular handsets, delivering tightly regulated, low-noise power to baseband processors, RF sections (synthesizers, TCXO, PA), memory, peripherals, and USB interfaces. Its integrated features - including USB 2.0 transceiver, dual comparators, and interrupt-driven status reporting - align precisely with the system-level power architecture requirements of mid-2000s CDMA mobile platforms. The LP3917RL-M/NOPB replaces multiple discrete regulators and interface ICs in these designs.

Does the LP3917RL-M/NOPB support automatic PFM/PWM mode switching in its buck regulators?

Yes, the LP3917RL-M/NOPB buck regulators feature automatic PFM/PWM mode switching based on load current. At light loads, they operate in high-efficiency PFM mode to maintain >90% efficiency down to ~10 µA; at higher loads, they seamlessly transition to PWM mode for tighter voltage regulation. This behavior is fully internal - no external control signals or configuration are required to enable the LP3917RL-M/NOPB's adaptive mode operation.

What is the significance of the 35 µV typical LDO output noise specification for the LP3917RL-M/NOPB?

The 35 µV typical RMS noise rating for LP3917RL-M/NOPB LDOs reflects their suitability for powering noise-sensitive RF circuitry such as CDMA RX synthesizers and TCXOs. This low noise level prevents phase noise degradation and maintains EVM compliance in 1.9 GHz band transmission. The LP3917RL-M/NOPB achieves this through optimized internal reference and error amplifier design - eliminating the need for external ferrite beads or LC filters in most RF supply paths.

How does the LP3917RL-M/NOPB handle thermal protection, and what role does IRQ_N play?

The LP3917RL-M/NOPB implements thermal shutdown with an early-warning alarm function. When die temperature approaches the shutdown threshold, it asserts the open-drain IRQ_N pin before triggering full thermal shutdown - giving the baseband processor time to reduce power or initiate cooling actions. This two-stage thermal response is integral to the LP3917RL-M/NOPB's safety architecture and is documented in the SNVS425A datasheet as a key reliability feature.

Can the LP3917RL-M/NOPB's LDO output voltages be programmed dynamically during operation?

Yes, the LP3917RL-M/NOPB supports dynamic LDO voltage programming via its I²C-compatible serial interface (SDA/SCL pins). All nine LDOs can have their output voltages selected from predefined options (e.g., 1.8 V, 2.6 V, 2.85 V) and enabled/disabled individually in real time. This capability is used in CDMA handsets for adaptive power scaling - for example, lowering LDO voltage during sleep mode or adjusting RF bias per transmission mode - and is a core function of the LP3917RL-M/NOPB's control architecture.