My Inquiry
My Account
Texas Instruments LM2621MMX
- Part No.:
- LM2621MMX
- Manufacturer:
- Texas Instruments
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM2621MMX.pdf
- Description:
- IC REG BST SEPIC ADJ 8VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,453
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2621MMX from Texas Instruments is a high-efficiency, low-input-voltage step-up DC-DC converter IC with an internal 0.17-Ω N-channel MOSFET switch, adjustable 1.24 V to 14 V output, and operation down to 0.65 V input. It delivers up to 1 A load current with up to 90% efficiency and supports switching frequencies up to 2 MHz for compact inductor/capacitor selection. It is used in battery-powered handheld devices requiring minimal board area and ultra-low quiescent current.
For engineers reviewing the LM2621MMX datasheet, LM2621MMX pinout, LM2621MMX application, or LM2621MMX equivalent, key selection criteria include its gated-oscillator topology for wide-load-range efficiency, 80 µA typical operating current, <2.5 µA shutdown current, VSSOP-8 package footprint (3.0 mm × 3.0 mm), and bootstrapped VDD operation capability.
Technical Context
The LM2621MMX implements a constant-duty-cycle gated oscillator control scheme with 70% fixed on-time, using hysteresis-based regulation (30 mV FB window) to achieve ultra-low quiescent current and high light-load efficiency. Its internal power switch and integrated current limit (2.85 A typical) eliminate external FETs and simplify design.
It supports bootstrapped VDD operation when VOUT is 2.5–5.0 V, enabling self-powered operation from the regulated output. The FREQ pin allows resistor-programmable switching frequency from 300 kHz to 2 MHz, directly determining external passive size while maintaining stable regulation across 1.2–14 V input and 1.24–14 V output ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.2 V to 14 V - supports single-cell Li-ion, two/three alkaline/NiMH, and wide industrial supply rails. |
| Output Voltage Range | 1.24 V to 14 V - adjustable via external resistive divider; FB pin reference is precisely 1.24 V. |
| Switching Frequency | Up to 2 MHz - enables use of sub-10 µH shielded inductors and small ceramic/tantalum capacitors. |
| Peak Switch Current Limit | 2.85 A typical - protects against overload and short-circuit without external sensing components. |
| Operating Quiescent Current | 80 µA typical - extends battery life in standby mode for portable electronics. |
| Shutdown Supply Current | <2.5 µA - reduces system leakage during deep sleep or power-off states. |
| Efficiency | Up to 90% - achieved at 3.6 VIN/5 VOUT/500 mA and 2.5 VIN/3.3 VOUT/200 mA loads. |
| Start-Up Input Voltage | 1.1 V minimum - enables cold-start from nearly depleted batteries. |
Pinout & Package
VSSOP-8 (DGK) package: 3.00 mm × 3.00 mm body, 1.09 mm height, 0.65 mm lead pitch - occupies half the PCB area of standard SOIC-8 and suits ultra-thin portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PGND (Pin 1) | Power Ground | Low-impedance return path for high-current switch node; must be routed separately from SGND to avoid noise coupling. |
| EN (Pin 2) | Active-Low Shutdown Input | Logic-controlled enable: pulled below 0.15×VDD to enter shutdown (<2.5 µA IQ); above 0.7×VDD for normal operation. |
| FREQ (Pin 3) | Frequency Adjustment | Resistor-connected to VDD sets oscillator frequency (300 kHz–2 MHz); determines inductor/capacitor sizing and EMI profile. |
| FB (Pin 4) | Feedback Input | Monitors output voltage via resistive divider; 1.24 V reference with ±30 mV hysteresis enables gated-oscillator regulation. |
| SGND (Pin 5) | Signal Ground | Reference ground for FB, EN, and FREQ pins; isolated from PGND to prevent switching noise from corrupting feedback. |
| VDD (Pin 6) | Internal Circuit Power | Supplies bias for control circuitry; can be bootstrapped from VOUT (2.5–5.0 V) or supplied externally (2.5–5.0 V). |
| BOOT (Pin 7) | Bootstrap Supply | Provides gate drive voltage for internal N-MOSFET; must remain ≤10 V; tied to SW through external capacitor. |
| SW (Pin 8) | Switch Node | Drain of internal N-MOSFET; connects to inductor and output diode; carries high di/dt and requires tight layout. |
Key Features
| Feature | Design Value |
|---|---|
| Gated Oscillator Topology | Delivers 80 µA quiescent current and >87% efficiency at light loads by disabling switching entirely between hysteresis thresholds. |
| Integrated 0.17-Ω N-Channel MOSFET | Eliminates external high-side switch and associated gate-drive complexity; reduces BOM count and layout area. |
| Bootstrappable VDD Operation | Enables self-powered operation from regulated output (2.5–5.0 V), removing need for auxiliary bias supply in many applications. |
| Programmable 300 kHz–2 MHz Switching | Allows trade-off between component size (higher fSW) and efficiency/EMI (lower fSW) using one external resistor. |
| Thermal Protection & Cycle-by-Cycle Current Limit | Shuts down internal switch if junction temperature exceeds ~160°C or peak inductor current exceeds ~2.85 A, preventing damage. |
| VSSOP-8 Package Footprint | 3.0 mm × 3.0 mm area and 1.09 mm height enable integration into space-constrained PDAs, memory cards, and GPS modules. |
Applications
| Handheld GPS Receivers | PCMCIA / Memory Card Power |
|---|---|
|
Use Scenario: Boosting single-cell Li-ion (3.0–4.2 V) or dual-alkaline (1.8–3.0 V) to stable 3.3 V or 5.0 V for RF front-end and baseband ICs. IC Role / Device Role / Timing Role: Primary step-up regulator supplying clean, regulated power to GPS chipset and flash memory interface. Use Value: 80 µA quiescent current extends battery runtime during satellite acquisition; 2-MHz switching enables miniature 6.8 µH inductor placement near antenna module. |
Use Scenario: Generating 3.3 V or 5.0 V from 1.2–3.3 V host bus supplies in PCMCIA slots or SD/microSD card adapters. IC Role / Device Role / Timing Role: Compact, low-profile boost converter powering card controller and NAND flash during read/write cycles. Use Value: VSSOP-8 package fits within 2-mm height envelope; <2.5 µA shutdown current meets PCMCIA hot-swap and card-detect power budgets. |
| TFT-LCD Backlight Driver Support | Flash Memory Programming Supply |
|
Use Scenario: Providing 5.0–12 V bias for white LED strings in small-format TFT displays powered by 1.8–3.3 V logic rails. IC Role / Device Role / Timing Role: High-efficiency boost stage feeding current-mode LED driver IC or discrete transistor array. Use Value: Adjustable 1.24–14 V output covers common LED forward voltages; 1 A capability supports multi-string configurations. |
Use Scenario: Generating precise 12 V programming voltage from 3.3 V system rail for NOR/NAND flash erase/write operations. IC Role / Device Role / Timing Role: Dedicated, low-noise boost converter activated only during flash programming sequences. Use Value: Gated-oscillator architecture minimizes ripple-induced bit errors; EN pin enables precise timing control synchronized to flash command cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61022DRVR | Higher 2.5-A switch current limit; 0.9-V start-up; integrated soft-start; 2.5-MHz max fSW; WSON-10 package (2.5 mm × 2.5 mm). | Better suited for higher-current loads (>700 mA) and ultra-low-input systems (e.g., coin cells); lacks bootstrappable VDD. | Select TPS61022DRVR when higher peak current or lower start-up voltage is required; verify thermal performance under full load. |
| MAX77818EWL+ | PMIC with dual buck + boost; 1.2-A boost switch; I2C programmability; 1.8-V min input; 1.57-mm WLP package. | Targets multi-rail SoC power in wearables; adds system-level control but increases design complexity and cost. | Select MAX77818EWL+ only when integrating multiple regulators is justified; LM2621MMX remains optimal for standalone boost simplicity. |
Compared with TPS61022DRVR and MAX77818EWL+, the LM2621MMX offers superior integration of bootstrapped VDD operation and ultra-low 80 µA quiescent current in a proven, low-cost VSSOP-8 package-making it ideal for cost-sensitive, battery-life-critical handheld applications where single-output boost suffices.
Availability
LM2621MMX is available at Aetrix Electronics and suitable for handheld GPS receivers, PCMCIA/memory card interfaces, TFT-LCD backlight support, and flash memory programming circuits requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for LM2621MMX 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 digital signal technologies, with decades of expertise in power management ICs for portable and industrial systems.
The LM2621 product line was designed specifically for ultra-compact, high-efficiency step-up conversion in battery-powered consumer electronics-emphasizing low quiescent current, minimal external component count, and robust thermal/current protection.
FAQ
What is the minimum input voltage required to start up the LM2621MMX?
The LM2621MMX starts up from a minimum input voltage of 1.1 V at room temperature, as specified in the Electrical Characteristics table. This enables operation from nearly depleted single-cell batteries. Once started, it continues regulating down to 0.65 V input due to bootstrapped VDD operation, making LM2621MMX especially valuable in energy-constrained portable systems.
How does the gated oscillator topology in the LM2621MMX improve efficiency at light loads?
The LM2621MMX uses a hysteresis-based gated oscillator that stops switching entirely when output voltage reaches the upper threshold (1.24 V + 30 mV), reducing quiescent current to just 80 µA. When voltage drops to the lower threshold, it resumes fixed 70% duty-cycle switching. This eliminates switching losses at light loads-unlike PWM topologies-so LM2621MMX maintains >85% efficiency even below 10 mA output current.
Can the LM2621MMX operate without an external bias supply for VDD?
Yes-the LM2621MMX supports bootstrapped VDD operation when the output voltage is between 2.5 V and 5.0 V. In this mode, Pin 6 (VDD) is connected directly to VOUT, eliminating the need for a separate bias rail. For outputs outside this range, an external 2.5–5.0 V supply must be provided to VDD. This flexibility simplifies power architecture in designs using LM2621MMX.
What is the function of the FREQ pin on the LM2621MMX, and how is it configured?
The FREQ pin (Pin 3) sets the LM2621MMX switching frequency by connecting an external resistor between FREQ and VDD. Resistor values from 10 kΩ to 100 kΩ yield frequencies from ~2 MHz down to ~300 kHz, as shown in Figure 9 of the datasheet. This resistor selection directly determines inductor and capacitor sizes-enabling optimization for either minimal footprint (high fSW) or peak efficiency (moderate fSW) in each LM2621MMX application.
Does the LM2621MMX include built-in protection features, and what are they?
Yes-the LM2621MMX integrates cycle-by-cycle peak current limiting (2.85 A typical) and thermal shutdown (~160°C junction). When current exceeds the limit or temperature rises beyond threshold, the internal MOSFET disables until conditions normalize. These protections operate autonomously without external components, safeguarding both the LM2621MMX and downstream circuitry during fault conditions such as output short or excessive ambient temperature.
LM2621MMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Boost, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.2V
- Voltage - Input (Max):
- 14V
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 14V
- Current - Output:
- 2.85A (Switch)
- Frequency - Switching:
- 300kHz ~ 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-VSSOP
LM2621MMX FAQ
1.How can I place an order for LM2621MMX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2621MMX 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 LM2621MMX reliable?
The price and inventory of LM2621MMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2621MMX is usually 5 days.
3.What payment methods are accepted for LM2621MMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2621MMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2621MMX?
LM2621MMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2621MMX 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 LM2621MMX?
For technical support, including LM2621MMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2621MMX requirements.
6.How does Aetrix verify that LM2621MMX is sourced from the original manufacturer or authorized distributors?
All LM2621MMX 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 LM2621MMX meets industry standards.
7.What is the process for return or replacement of LM2621MMX?
All LM2621MMX units undergo pre-shipment inspection (PSI). If there is an issue with LM2621MMX, 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 LM2621MMX part is unused and in its original packaging.
Return procedure for LM2621MMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2621MMX Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
