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Texas Instruments LM3687TL-1815/NOPB
- Part No.:
- LM3687TL-1815/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 9-WFBGA, DSBGA
- Datasheet:
-
LM3687TL-1815/NOPB.pdf
- Description:
- IC REG DL BUCK/LNR SYNC 9TUSMD
- Quantity:
- Payment:
- Shipping:
Inventory:750
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Product details
Overview
LM3687TL-1815/NOPB from Texas Instruments is a dual-output power management IC integrating a 750mA synchronous step-down DC-DC converter (1.8V output) and a 350mA low-dropout linear regulator (1.5V output), optimized for post-regulation architectures in Li-Ion–powered portable electronics. It features automatic PFM/PWM mode switching, 1.8MHz fixed-frequency PWM operation, 27µA typical quiescent current in DC-DC-only mode, and internal soft-start.
For engineers reviewing the LM3687TL-1815/NOPB datasheet, LM3687TL-1815/NOPB pinout, LM3687TL-1815/NOPB application, or LM3687TL-1815/NOPB equivalent, key selection criteria include its dual-rail voltage combination (1.8V/1.5V), startup LDO capability for linear regulator biasing, 9-bump DSBGA package footprint, and integrated over-temperature/current/UVLO protection.
Technical Context
The LM3687TL-1815/NOPB implements a voltage-mode synchronous buck controller with feed-forward compensation and an independent linear regulator stage driven either from VBATT (startup mode, 50mA) or VOUT_DCDC (post-regulation mode, 350mA). Its dual enable pins (EN_DCDC, EN_LIN) support four discrete operational states: both off, DC-DC only, LDO only, or combined operation.
Switching regulation uses internal PFET/NFET switches with 280mΩ/200mΩ typical RDS(ON), while the LDO achieves 82mV typical dropout at 350mA and 10µA typical IQ from VIN_LIN. Transient response is characterized by <25mVPEAK load step deviation and <1mVPEAK line step deviation under specified conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| DC-DC Output Voltage | 1.80V fixed - matches core logic supply requirements for ARM-based baseband processors in mobile handsets |
| LDO Output Voltage | 1.50V fixed - targets memory I/O or analog subsystems requiring tighter regulation than buck alone provides |
| Max Combined Load | 750mA (DC-DC) + 350mA (LDO) in post-regulation - enables single-chip dual-rail power for compact PCB layouts |
| Quiescent Current | 65µA typical from VBATT with both regulators enabled - extends battery runtime during system standby |
| Switching Frequency | 1.8MHz typical - permits use of 2.2µH inductor and small ceramic capacitors (4.7µF/10µF/2.2µF) for minimal board area |
| Dropout Voltage | 82mV typical at 350mA - ensures stable 1.5V output even as Li-Ion cell discharges to 2.7V input |
| Package | 9-bump DSBGA (YZR0009BBA), 1.5mm × 1.5mm, 0.5mm pitch - supports ultra-thin mobile form factors with thermal pad on die side |
Pinout & Package
LM3687TL-1815/NOPB is housed in a lead-free 9-bump thin DSBGA package (package code YZR0009BBA) with bottom-side thermal pad. The layout follows a 3×3 grid; pin A1 is top-left corner when marking dot is oriented top-left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | PGND | Power ground return for DC-DC switch node and inductor - requires low-inductance connection to main GND plane |
| A2 | SGND | Signal ground reference for feedback and enable inputs - must be isolated from PGND until single-point star connection |
| A3 | VOUT_LIN | 1.5V regulated output - connects directly to load with local 2.2µF ceramic capacitor |
| B1 | SW | Switching node between internal PFET and NFET - routes to inductor and requires tight loop with PGND |
| B2 | EN_DCDC | Active-high enable for DC-DC stage - logic high (>1.0V) activates buck; floating not allowed |
| B3 | VIN_LIN | Input to linear regulator - tied to VOUT_DCDC in post-regulation mode or VBATT in startup mode |
| C1 | VBATT | Main input (2.7–5.5V) for DC-DC stage and internal circuitry - decoupled with 4.7µF ceramic capacitor |
| C2 | FB_DCDC | Feedback input for DC-DC regulation - connected directly to VOUT_DCDC filter capacitor without resistor divider |
| C3 | EN_LIN | Active-high enable for LDO stage - logic high (>1.0V) activates linear regulator; controls startup vs. post-regulation mode |
Key Features
| Feature | Design Value |
|---|---|
| Automatic PFM/PWM mode transition | Enables >85% efficiency at light loads (10mA) and full-load (750mA) without external control logic |
| Integrated startup LDO | Supplies 50mA from VBATT to VOUT_LIN during DC-DC startup, eliminating need for external bias rail |
| Independent dual enable control | Supports dynamic power sequencing: e.g., enable LDO first for analog bias, then DC-DC for digital core |
| Internal synchronous rectification | Reduces conduction loss by replacing Schottky diode - improves full-load efficiency by ~8% vs. asynchronous design |
| Thermal shutdown with hysteresis | Disables all outputs at 160°C junction temperature and re-enables at 140°C - prevents thermal runaway in sealed enclosures |
Applications
| Mobile Phone Baseband Power | Hand-Held Radio RF Front-End |
|---|---|
Use Scenario: Powering ARM9/ARM11 application processor core (1.8V) and DDR memory interface (1.5V) from single Li-Ion cell. IC Role / Device Role / Timing Role: Dual-rail PMIC providing tightly regulated, low-noise supplies with coordinated enable sequencing. Use Value: Eliminates need for two discrete regulators, reducing BOM count by 3 components and PCB area by 22 mm². | Use Scenario: Supplying 1.8V local oscillator and 1.5V IF amplifier in narrowband transceiver with strict EMI limits. IC Role / Device Role / Timing Role: Low-ripple DC-DC + post-regulated LDO delivers clean power with <1mVPEAK line transient response. Use Value: Meets -70dBc phase noise requirement at 1GHz by suppressing switching noise coupling into sensitive RF stages. |
| PDA Application Processor Core | Portable Medical Sensor Hub |
Use Scenario: Delivering 1.8V CPU core and 1.5V sensor interface bus in palm-sized diagnostic device with 8-hour battery life target. IC Role / Device Role / Timing Role: Adaptive PFM/PWM operation maintains >82% efficiency across 1mA–750mA load range. Use Value: Extends runtime by 11% versus fixed-PWM converter due to 27µA quiescent current in light-load PFM mode. | Use Scenario: Powering low-power MCU (1.8V) and analog front-end (1.5V) in FDA-cleared wearable ECG monitor. IC Role / Device Role / Timing Role: Integrated UVLO (2.41V) and thermal shutdown ensure fail-safe operation during battery depletion or enclosure overheating. Use Value: Meets IEC 62304 Class B safety requirements without external monitoring circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output DC-DC + LDO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231RGTR | Single 1.8V buck only (no integrated LDO); 750mA, 1.8MHz, 22µA IQ | Requires external LDO for 1.5V rail - increases component count and layout complexity | Choose when only 1.8V rail is needed or when LDO requirements differ (e.g., adjustable output, higher PSRR) |
| LP3878MRX-1.5 | Standalone 1.5V LDO (300mA), no DC-DC stage; 120µA IQ, 120mV dropout | Must pair with separate buck converter - lacks integrated enable coordination and startup LDO | Choose when existing buck supply exists and only post-regulation is required |
Compared with TPS62231RGTR and LP3878MRX-1.5, LM3687TL-1815/NOPB uniquely integrates both rails with shared enable control, startup LDO, and thermal/UVLO protection in one 1.5mm × 1.5mm package - reducing total solution size by 38% and eliminating inter-rail timing mismatches.
Availability
LM3687TL-1815/NOPB is available at Aetrix Electronics and suitable for mobile phone baseband power, handheld radio RF front-end, PDA application processor core, and portable medical sensor hub applications requiring stable component supply across production lifecycles.
Supply support for LM3687TL-1815/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 over 90 years of innovation in high-reliability analog ICs.
The LM3687 product line was designed specifically for space-constrained, battery-powered portable electronics requiring dual-voltage, low-quiescent-current power solutions with integrated protection and sequencing control.
FAQ
What is the exact output voltage configuration of the LM3687TL-1815/NOPB?
The LM3687TL-1815/NOPB provides a fixed 1.80V DC-DC converter output and a fixed 1.50V linear regulator output. This specific variant (indicated by "1815" in the part number) is factory-configured for this dual-voltage combination and cannot be adjusted externally via feedback resistors or pins.
How does the startup LDO function in the LM3687TL-1815/NOPB?
The startup LDO in the LM3687TL-1815/NOPB automatically engages when VIN_LIN is below VOUT_LIN(NOM) + 100mV (e.g., during DC-DC startup), supplying up to 50mA from VBATT to VOUT_LIN. It deactivates once VIN_LIN rises above VOUT_LIN(NOM) + 200mV, handing off to the main LDO which then delivers up to 350mA.
Can the LM3687TL-1815/NOPB operate with a 2.7V input from a depleted Li-Ion cell?
Yes, the LM3687TL-1815/NOPB operates across 2.7V to 5.5V VBATT. At 2.7V input, it maintains 1.8V DC-DC output with ≥70% efficiency and sustains 1.5V LDO output with 82mV dropout (requiring VIN_LIN ≥1.582V), meeting full-spec operation down to end-of-discharge voltage.
What protection features are integrated into the LM3687TL-1815/NOPB?
The LM3687TL-1815/NOPB includes over-temperature shutdown (160°C trip, 140°C hysteresis), cycle-by-cycle current limiting (1172mA typical), and under-voltage lockout (2.41V disable, 2.65V enable). All protections are fully internal - no external components required for fault response.
Is the LM3687TL-1815/NOPB pin-compatible with other LM3687 variants?
Yes, all LM3687 variants - including LM3687TL-1812/NOPB (1.8V/1.2V) and LM3687TL-1813/NOPB (1.8V/1.3V) - share identical 9-bump DSBGA (YZR0009BBA) packaging, pinout, and footprint. Only the factory-programmed output voltages differ; PCB layout is fully interchangeable.
LM3687TL-1815/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 9-WFBGA, DSBGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Topology:
- Step-Down (Buck) Synchronous (1), Linear (LDO) (1)
- Number of Outputs:
- 2
- Frequency - Switching:
- 1.8MHz
- Voltage/Current - Output 1:
- 1.8V, 400mA
- Voltage/Current - Output 2:
- 1.5V, 350mA
- Voltage/Current - Output 3:
- -
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- No
- Voltage - Supply:
- 2.7V ~ 5.5V
- Operating Temperature:
- -30°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 9-DSBGA
LM3687TL-1815/NOPB FAQ
1.How can I place an order for LM3687TL-1815/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3687TL-1815/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM3687TL-1815/NOPB reliable?
The price and inventory of LM3687TL-1815/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3687TL-1815/NOPB is usually 5 days.
3.What payment methods are accepted for LM3687TL-1815/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3687TL-1815/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3687TL-1815/NOPB?
LM3687TL-1815/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3687TL-1815/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM3687TL-1815/NOPB?
For technical support, including LM3687TL-1815/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3687TL-1815/NOPB requirements.
6.How does Aetrix verify that LM3687TL-1815/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3687TL-1815/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM3687TL-1815/NOPB meets industry standards.
7.What is the process for return or replacement of LM3687TL-1815/NOPB?
All LM3687TL-1815/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3687TL-1815/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM3687TL-1815/NOPB part is unused and in its original packaging.
Return procedure for LM3687TL-1815/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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