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Texas Instruments LM2650MX-ADJ
- Part No.:
- LM2650MX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LM2650MX-ADJ.pdf
- Description:
- IC REG BUCK ADJ 3A 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,010
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Product details
Overview
LM2650MX-ADJ from Texas Instruments is a synchronous step-down DC/DC converter IC designed for high-efficiency power conversion in battery-powered systems. It delivers up to 3A output current, supports adjustable output voltage from 1.5V to 16V, operates across 4.5V–18V input range, and achieves ≥94% efficiency at 1A load-enabling long runtime in portable instruments and GPS devices.
For engineers reviewing the LM2650MX-ADJ datasheet, LM2650MX-ADJ pinout, LM2650MX-ADJ application, or LM2650MX-ADJ equivalent, key selection criteria include its dual-mode PWM/sleep operation, programmable soft-start, logic-controlled shutdown (≤25 µA), frequency adjustability up to 300 kHz, and thermal shutdown protection.
Technical Context
The LM2650MX-ADJ implements fixed-frequency voltage-mode PWM control with synchronous NMOS power switches (RDS(on) HS = 130 mΩ typ, RDS(on) LS = 125 mΩ typ) and an automatic hysteretic sleep mode activated below user-programmable load thresholds. Its internal 4V VDD regulator powers signal circuitry, while bootstrapped gate drive enables high-side NMOS switching.
It features dual feedback paths: one for PWM regulation via COMP/EAPIN and FB, another for sleep-mode hysteresis centered at 1.25V with 30 mV typical hysteresis. Frequency synchronization (SYNC pin), external frequency adjustment (FREQ ADJ), and independent SLEEP LOGIC control allow flexible system-level power management integration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 18V - supports 3–4-cell Li-ion, 8–12-cell NiCd/NiMH, and 6-cell lead-acid battery stacks. |
| Output Voltage Range | 1.5V to 16V - set externally via resistor divider on FB pin; reference voltage is 1.25V ±1.2%. |
| Max Output Current | 3A - sustained delivery enabled by low RDS(on) power FETs and thermal shutdown at 170°C. |
| Efficiency @ 1A | ≥94% - achieved via synchronous rectification and optimized gate drive, minimizing conduction and switching losses. |
| Quiescent Current (PWM) | 4.0 mA - total PVIN+VIN supply current during active regulation, enabling stable light-load performance. |
| Sleep Mode IQ | 850 µA - reduces power draw during standby without disabling regulation, extending battery life in low-duty-cycle applications. |
| Shutdown Current | 9 µA - ensures near-zero power consumption when disabled via SD pin, critical for emergency cutoff or deep-sleep states. |
| Switching Frequency | 90 kHz nominal, adjustable to 300 kHz - lower frequencies reduce core loss for high-inductance designs; higher frequencies shrink passive size. |
Pinout & Package
LM2650MX-ADJ is housed in a 24-lead SOIC package (DW0024B), with exposed substrate pins (1, 12) requiring connection to a large copper ground plane for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 12 (SUB) | Die substrate connection | Must be grounded to same thermal plane as PGND for effective heat dissipation and EMI reduction. |
| 2 (SLEEP LOGIC) | Mode selection input | Low = forced PWM; high = forced sleep; open = automatic transition between modes based on load. |
| 3, 4, 9, 10 (PGND) | Power ground return | Carries high-current switch node return path; requires low-impedance, wide copper pour to minimize noise and voltage drop. |
| 5, 8 (SW) | Power switch node | Connects to inductor and catch diode/capacitor; must be routed short and away from sensitive signals to limit EMI. |
| 6, 7 (PVIN) | High-side power rail | Supplies gate drivers and power FETs; bypassed locally with 0.1 µF low-ESR/ESL capacitor to PGND. |
| 11 (BOOT) | Bootstrap supply | Connected to SW via 0.1 µF capacitor; generates ~9V above PVIN to fully enhance high-side NMOS gate. |
| 13 (FB) | Feedback input | Monitors output via resistive divider; sets regulated voltage using internal 1.25V reference. |
| 14 (VDD) | Internal 4V rail output | Supplies analog/digital circuitry; requires 0.2 µF local bypass to GND for stability. |
| 15 (COMP) | Error amplifier inverting input | Used for loop compensation (RC/CC network); connects to EA OUT to close voltage control loop. |
| 16 (EA OUT) | Error amplifier output | Drives modulator comparator; compensation components placed between COMP and EA OUT define loop bandwidth. |
| 17 (SS) | Soft-start timing node | Capacitor to GND controls startup ramp rate, limiting inrush current and enabling power sequencing. |
| 18 (GND) | Signal ground | Reference for internal regulators and error amplifier; separate from PGND but tied at single point. |
| 19 (VIN) | VDD regulator input | Bypassed with 0.1 µF capacitor to GND; supplies internal 4V LDO that powers control circuitry. |
| 20 (FREQ ADJ) | Oscillator frequency adjust | Resistor to GND scales switching frequency from 90 kHz up to 300 kHz; not usable above 250 kHz in sleep mode. |
| 21 (SYNC) | External clock input | Accepts TTL/CMOS clock for synchronization; grounded if unused to prevent noise coupling. |
| 22 (SD) | Shutdown control | Pull low for normal operation; pull high to disable converter and reduce supply current to ≤25 µA. |
| 23 (SOA) | Sleep-out threshold adjust | Resistor to GND programs load level at which device exits sleep mode into PWM operation. |
| 24 (SIA) | Sleep-in threshold adjust | Resistor to GND programs load level at which device enters sleep mode from PWM operation. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous NMOS switching | Eliminates external Schottky diode, reducing conduction loss and improving efficiency across full 0.12–3A load range. |
| Automatic PWM/sleep mode transition | Maintains >85% efficiency down to milliamp loads by dynamically selecting optimal regulation topology without external intervention. |
| Programmable soft-start | Prevents input surge and enables controlled power-up sequencing of multiple rails using a single external capacitor. |
| Logic-controlled micropower shutdown | Reduces total input current to ≤25 µA, supporting zero-power standby in battery-backed real-time clocks or sensor nodes. |
| Thermal shutdown with hysteresis | Protects against overheating by disabling switching at 170°C junction temperature and re-enabling only after cooldown. |
| Frequency synchronization capability | Enables noise-sensitive systems (e.g., RF receivers) to align switching harmonics outside critical bands via external clock injection. |
Applications
| Portable Instruments | Global Positioning Devices (GPSs) |
|---|---|
Use Scenario: Handheld multimeters and portable oscilloscopes powered by 4-cell Li-ion batteries requiring stable 3.3V/5V rails under variable load. IC Role / Device Role / Timing Role: Primary step-down regulator delivering regulated output with <120 mV ripple in hysteretic mode during display/idle periods. Use Value: Extends battery life beyond 10 hours by maintaining >90% efficiency from 10 mA to 3 A, enabled by automatic sleep/PWM transition. | Use Scenario: GPS modules in asset trackers operating from 3.7V Li-ion cells with intermittent RF transmission bursts. IC Role / Device Role / Timing Role: Supplies clean 3.3V to GNSS receiver and baseband processor; soft-start prevents brownout during cold start. Use Value: Achieves 94% efficiency at 1A continuous load and drops to 850 µA quiescent in sleep-critical for multi-day field deployment. |
| Notebook and Palmtop PCs | Battery-Powered Digital Devices |
Use Scenario: Sub-regulator in legacy palmtop computers converting 12V main rail to 5V for USB peripherals and I/O controllers. IC Role / Device Role / Timing Role: High-current DC/DC converter with programmable frequency (90–300 kHz) to avoid audible noise in compact enclosures. Use Value: Enables use of smaller magnetics at 200 kHz while retaining >89% efficiency at full 3A load, reducing board area by 35%. | Use Scenario: Power management in ruggedized handheld data terminals used in warehouse logistics with 8–12 cell NiMH packs. IC Role / Device Role / Timing Role: Adjustable-output (1.5–16V) regulator supporting multiple subsystem voltages via FB divider reconfiguration. Use Value: Single BOM variant replaces three fixed-output parts, simplifying inventory and enabling field voltage reprogramming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2678-ADJ | Higher 5A output rating, 150 kHz fixed frequency, no sleep mode, larger SOIC-20 package. | Targets heavier loads where efficiency at <100 mA is less critical; lacks automatic light-load optimization. | Select LM2678-ADJ when peak current exceeds 3A and thermal headroom allows higher RDS(on). |
| TPS5430-ADJ | 3A output, 500 kHz max frequency, integrated compensation, no external sleep threshold programming. | Optimized for compact designs with fast transient response; sleep behavior is fixed and non-adjustable. | Choose TPS5430-ADJ for space-constrained layouts needing higher switching frequency and simplified layout. |
Compared with LM2650MX-ADJ, LM2678-ADJ trades light-load efficiency for higher current capability and simpler biasing, while TPS5430-ADJ sacrifices programmable sleep thresholds for faster regulation and smaller passives-making LM2650MX-ADJ optimal for battery life–sensitive, medium-power portable systems.
Availability
LM2650MX-ADJ is available at Aetrix Electronics and suitable for portable instruments, GPS devices, notebook PCs, and battery-powered digital devices requiring stable component supply with long-term manufacturability.
Supply support for LM2650MX-ADJ 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 50 years of innovation in energy-efficient power conversion.
The LM2650MX-ADJ belongs to TI's high-efficiency synchronous buck converter product line, engineered specifically for battery-operated equipment demanding extended runtime, dynamic load adaptation, and robust thermal management.
FAQ
What is the maximum input voltage rating for the LM2650MX-ADJ?
The LM2650MX-ADJ has an absolute maximum DC input voltage rating of 20V on PVIN and VIN pins. Its recommended operating range is 4.5V to 18V, making it compatible with 4-cell Li-ion (up to 16.8V), 12-cell NiMH (up to 18V), and 6-cell lead-acid (up to 13.8V) battery configurations. Exceeding 18V during operation risks violating the specified operating ratings and may trigger thermal shutdown.
How does the LM2650MX-ADJ achieve high efficiency at light loads?
The LM2650MX-ADJ achieves high light-load efficiency through its automatic hysteretic "sleep" mode, which disables the PWM modulator and uses a simpler, lower-bias control loop. With quiescent current reduced to 850 µA and switching frequency dropping to a few Hz under ultra-light loads, the LM2650MX-ADJ maintains >85% efficiency down to 10 mA-critical for standby operation in portable instruments and GPS receivers.
Can the LM2650MX-ADJ be synchronized to an external clock?
Yes, the LM2650MX-ADJ supports external clock synchronization via the SYNC pin (pin 21). A TTL- or CMOS-compatible clock signal applied to this pin overrides the internal oscillator and locks the switching frequency to the external source. When not used, SYNC must be grounded to prevent noise coupling; floating the pin is not permitted per the datasheet.
What is the purpose of the SUB pins (1 and 12) on the LM2650MX-ADJ?
Pins 1 and 12 on the LM2650MX-ADJ are substrate connections that electrically contact the silicon die's backside. They must be soldered to a large, uninterrupted copper ground plane-ideally shared with PGND-to provide a low-thermal-resistance path for heat dissipation and reduce EMI. Leaving them unconnected degrades thermal performance and may cause premature thermal shutdown under 3A load.
Does the LM2650MX-ADJ require external compensation components?
Yes, the LM2650MX-ADJ requires external compensation components connected between COMP (pin 15) and EA OUT (pin 16) to stabilize the voltage control loop. Typical networks include a series RC (e.g., 37.4 kΩ + 4.7 nF) and optional C10 (5.6 nF) for phase margin tuning. The exact values depend on output capacitance, inductance, and desired transient response-TI provides design tables for 90 kHz and 200 kHz configurations in the datasheet.
LM2650MX-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 18V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- 16V
- Current - Output:
- 3A
- Frequency - Switching:
- 90kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
LM2650MX-ADJ FAQ
1.How can I place an order for LM2650MX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2650MX-ADJ 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 LM2650MX-ADJ reliable?
The price and inventory of LM2650MX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2650MX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2650MX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2650MX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2650MX-ADJ?
LM2650MX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2650MX-ADJ 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 LM2650MX-ADJ?
For technical support, including LM2650MX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2650MX-ADJ requirements.
6.How does Aetrix verify that LM2650MX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2650MX-ADJ 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 LM2650MX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2650MX-ADJ?
All LM2650MX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2650MX-ADJ, 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 LM2650MX-ADJ part is unused and in its original packaging.
Return procedure for LM2650MX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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