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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Texas Instruments LM3311SQ/NOPB

Name: LM3311SQ/NOPB
Brand: Texas Instruments
SKU: LM3311SQ/NOPB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LM3311SQ/NOPB

Manufacturer:: Texas Instruments

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 24-WFQFN Exposed Pad

Datasheet:: LM3311SQ/NOPB.pdf

Description:: IC REG BOOST ADJ 2A 24WQFN

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Product details

Overview

LM3311SQ/NOPB from Texas Instruments is a highly integrated step-up DC/DC converter with co-located LDO regulator, rail-to-rail operational amplifier (135mA sink/source), and gate pulse modulation (GPM) switch for TFT LCD bias generation. It features a 2A, 0.18Ω internal NMOS switch, adjustable boost output up to 20V, and dual switching frequencies (660kHz/1.28MHz). Used in portable TFT-LCD power supplies where compact multi-rail generation is critical.

For engineers reviewing the LM3311SQ/NOPB datasheet, LM3311SQ/NOPB pinout, LM3311SQ/NOPB application, or LM3311SQ/NOPB equivalent, key selection considerations include its integrated GPM timing control interface (VFLK/VDPM), LDO output adjustability via ADJ pin, soft-start programmability via SS pin, and thermal/UVLO protection behavior under transient load conditions.

Technical Context

The LM3311SQ/NOPB implements a current-mode PWM boost controller with internal compensation (VC pin), selectable fixed-frequency operation (FREQ pin), and duty-cycle-limited regulation up to 91% at 660kHz. Its GPM block accepts VFLK timing signals and modulates VGHM output using external RE/CE components to drive TFT gate drivers.

The integrated op-amp operates from AVIN (4–14V), delivers ±135mA typical output current, and supports unity-gain stable operation with ceramic capacitors. The LDO accepts LVIN (2.5–7V), regulates to user-set VOUT via ADJ feedback, and maintains <409mV dropout at 350mA - all while sharing thermal and ground domains with the boost stage.

Key Specifications

Parameter	Value and Actual Design Meaning
Boost Switch Current Limit	2.0A min - ensures reliable inductor charging under peak load without cycle-by-cycle foldback.
Feedback Voltage (FB / ADJ)	1.263V typ - sets precise output voltage for both boost and LDO via resistor divider ratio.
Switching Frequency	660kHz or 1.28MHz - selected by FREQ pin; enables trade-off between efficiency and external component size.
LDO Dropout Voltage	409mV max at 350mA - allows stable 2.8V output from 3.3V LVIN input with minimal headroom loss.
Op-Amp Output Current	±135mA typ - sufficient to directly drive gate driver inputs or small-signal loads without external buffers.
GPM VGH Input Range	5V to 30V - accommodates standard TFT panel VGH supply rails while enabling high-side PMOS control.
Operating Input Voltage	2.5V to 7V - supports single-cell Li-ion (3.0–4.2V) and dual-cell alkaline (3.0–3.6V) battery inputs.

Pinout & Package

LM3311SQ/NOPB is housed in a thermally enhanced 24-pin WQFN package (4mm × 4mm, 0.5mm pitch) with exposed die attach pad (DAP) tied internally to AGND/PGND. Thermal resistance θ_JA = 37°C/W on 2-layer board per RTW0024A package drawing.

Pin	Circuit Role	Design Meaning
1	NC	No internal connection - must be left floating or grounded per layout best practice.
2	VGHM	GPM output driving gate driver supply - sourced from internal PMOS; requires external RE/CE timing network.
3	VFLK	TFT frame latch signal input - controls GPM on/off timing synchronized to display controller.
4	VDPM	GPM enable/disable control - high = active; used for power sequencing during panel initialization.
5	VDD	GPM reference input - sets lower VGHM clamp level; connect to VIN if GPM unused.
6	AVIN	Op-amp analog supply - independent of boost/LDO rails; supports 4–14V range.
7	OUT	Op-amp output - capable of sourcing/sinking 135mA; rail-to-rail swing with 50V/µs slew rate.
8	NEG	Inverting input of op-amp - high-impedance node; requires low-noise routing near POS.
9	POS	Non-inverting input of op-amp - high-impedance node; used for precision sensing or buffer configuration.
10	AGND	Analog ground for boost, LDO, and op-amp - must connect directly to DAP and PGND beneath device.
11	ADJ	LDO feedback input - senses VOUT via resistor divider; 1.263V reference enables accurate output setting.
12	VOUT	LDO regulated output - adjustable from ~1.3V to LVIN − V_DO; stable with ≥2.2µF ceramic capacitor.
13	LVIN	LDO input supply - accepts 2.5–7V; shares input path with boost VIN but decoupled internally.
14	SS	Soft-start control - external capacitor sets ramp time; ISS = 11µA typical charges CSS to 1.24V.
15	VC	Boost error amplifier output - connects to compensation network; critical for loop stability tuning.
16	FREQ	Frequency select - AGND = 660kHz, VIN = 1.28MHz; determines minimum off-time and inductor sizing.
17	VIN	Primary boost input - powers boost controller, GPM, and SHDN logic; 2.5–7V operating range.
18	SW	Boost switch node - connects to inductor and catch diode; handles 2A pulsed current with 0.18Ω R_DS(ON).
19	SHDN	Active-low shutdown - pulls internal regulators and GPM offline; threshold = 0.4V (low), 1.4V (high).
20	FB	Boost feedback input - senses VOUT via resistor divider; identical 1.263V reference as ADJ pin.
21	PGND	Power ground - return path for boost switch and GPM circuits; tie directly to DAP and AGND.
22	CE	GPM timing capacitor - forms RC network with RE to set VGHM rise/fall time; CE current = 57µA typ.
23	RE	GPM timing resistor - sets VGHM discharge rate with CE; VGHM-RE resistance = 27–55Ω at 30V.
24	VGH	GPM high-voltage supply - powers internal PMOS switches; 5–30V range supports wide TFT panel compatibility.

Key Features

Feature	Design Value
Integrated GPM block	Eliminates external gate driver ICs by generating timed VGHM pulses synchronized to VFLK/VDPM signals.
Adjustable soft-start	Programmable startup ramp via external SS capacitor prevents inrush current damage to input capacitors and inductors.
Dual-frequency selection	660kHz/1.28MHz switching enables optimization for efficiency (lower f_SW) or miniaturization (higher f_SW).
LDO with ceramic stability	Stable with ≥2.2µF X5R/X7R ceramic output caps - reduces BOM count and PCB area vs. electrolytic solutions.
Thermal shutdown with hysteresis	Shuts down at 145°C and re-enables at ~125°C - protects against sustained overload or poor heatsinking.
Input UVLO with hysteresis	Enables only above 2.4V and disables below 2.1V - prevents erratic operation during battery brownout or cold start.

Applications

TFT LCD Panel Bias Supply	Portable Medical Display Power
Use Scenario: Generating VGH (15–25V), VGL (−5–−10V), and AVDD (2.8–3.3V) rails for active-matrix TFT panels in handheld ultrasound or patient monitors. IC Role / Device Role / Timing Role: LM3311SQ/NOPB serves as primary power hub - boost stage sets VGH, LDO provides AVDD, op-amp buffers timing signals, and GPM synchronizes gate pulses to VFLK. Use Value: Single-chip solution replaces 3–4 discrete ICs, reducing footprint by >40% and eliminating inter-rail timing skew in compact enclosures.	Use Scenario: Powering high-resolution color displays in battery-operated diagnostic tools requiring low-noise, fast-transient response. IC Role / Device Role / Timing Role: LM3311SQ/NOPB delivers regulated AVDD and VGH with simultaneous soft-start and GPM sequencing to prevent display artifacts during power-on. Use Value: Integrated UVLO and thermal shutdown ensure safe operation during intermittent battery contact or ambient temperature excursions up to 60°C.
Industrial HMI Display Module	Automotive Infotainment Test Fixture
Use Scenario: Providing stable bias rails for 7–10 inch industrial HMIs operating across −40°C to +85°C ambient range. IC Role / Device Role / Timing Role: LM3311SQ/NOPB's LDO and op-amp operate independently of boost stage, enabling clean AVDD even during VGH load transients. Use Value: 125°C junction rating and guaranteed performance over full temp range allow direct mounting on display PCB without derating.	Use Scenario: Simulating TFT panel power behavior in automotive infotainment validation rigs with programmable VFLK/VDPM timing. IC Role / Device Role / Timing Role: LM3311SQ/NOPB acts as programmable reference supply - GPM block replicates real panel timing sequences for ECU interoperability testing. Use Value: External RE/CE network allows precise adjustment of VGHM edge rates to match production panel specs within ±5ns.

TFT LCD Panel Bias Supply

Portable Medical Display Power

Use Scenario: Generating VGH (15–25V), VGL (−5–−10V), and AVDD (2.8–3.3V) rails for active-matrix TFT panels in handheld ultrasound or patient monitors.

IC Role / Device Role / Timing Role: LM3311SQ/NOPB serves as primary power hub - boost stage sets VGH, LDO provides AVDD, op-amp buffers timing signals, and GPM synchronizes gate pulses to VFLK.

Use Value: Single-chip solution replaces 3–4 discrete ICs, reducing footprint by >40% and eliminating inter-rail timing skew in compact enclosures.

Use Scenario: Powering high-resolution color displays in battery-operated diagnostic tools requiring low-noise, fast-transient response.

IC Role / Device Role / Timing Role: LM3311SQ/NOPB delivers regulated AVDD and VGH with simultaneous soft-start and GPM sequencing to prevent display artifacts during power-on.

Use Value: Integrated UVLO and thermal shutdown ensure safe operation during intermittent battery contact or ambient temperature excursions up to 60°C.

Industrial HMI Display Module

Automotive Infotainment Test Fixture

Use Scenario: Providing stable bias rails for 7–10 inch industrial HMIs operating across −40°C to +85°C ambient range.

IC Role / Device Role / Timing Role: LM3311SQ/NOPB's LDO and op-amp operate independently of boost stage, enabling clean AVDD even during VGH load transients.

Use Value: 125°C junction rating and guaranteed performance over full temp range allow direct mounting on display PCB without derating.

Use Scenario: Simulating TFT panel power behavior in automotive infotainment validation rigs with programmable VFLK/VDPM timing.

IC Role / Device Role / Timing Role: LM3311SQ/NOPB acts as programmable reference supply - GPM block replicates real panel timing sequences for ECU interoperability testing.

Use Value: External RE/CE network allows precise adjustment of VGHM edge rates to match production panel specs within ±5ns.

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-rail TFT bias supply applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS65136QRGER	Dual-output (VPOS/VNEG) charge pump + LDO; no integrated op-amp or GPM; 1.2MHz fixed frequency.	Lacks VFLK/VDPM timing interface and rail-to-rail op-amp - requires external circuitry for gate pulse control and signal conditioning.	Select when only dual-rail bias is needed and GPM timing is handled externally; smaller solution size but less integration.
MAX17105ATI+	Triple-output (boost + dual LDO) + op-amp + GPM; 2.5A boost switch; supports 2.7–5.5V input only.	Higher boost current and wider VGH range (up to 36V); same GPM architecture but different pinout and timing parameter thresholds.	Select for higher-current panels (>2A VGH load) or wider VGH requirements; not drop-in due to different FB/ADJ reference (1.25V vs. 1.263V).

Compared with TPS65136QRGER and MAX17105ATI+, the LM3311SQ/NOPB uniquely combines GPM timing control, op-amp buffering, and LDO regulation in one 24-pin WQFN - enabling full TFT bias generation without supplemental ICs while maintaining design flexibility through programmable soft-start and frequency selection.

Availability

LM3311SQ/NOPB is available at Aetrix Electronics and suitable for TFT LCD bias supplies, portable medical displays, industrial HMI modules, and automotive test fixtures requiring stable component supply with full production traceability.

Supply support for LM3311SQ/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 50 years of innovation in high-reliability power conversion ICs.

The LM3311SQ/NOPB belongs to TI's display power management portfolio, designed specifically for single-chip TFT-LCD bias generation in space-constrained portable and industrial applications.

FAQ

What is the maximum output voltage achievable with the LM3311SQ/NOPB boost converter?

The LM3311SQ/NOPB boost converter supports an adjustable output voltage up to 20V, set via the FB pin and external resistor divider. This is confirmed in the datasheet's "Features" section and validated by the absolute maximum SW voltage rating of 21V and typical application circuits targeting 8.5V–10.5V outputs. The 20V limit ensures safe operation within the internal switch's voltage handling capability.

How does the GPM function in the LM3311SQ/NOPB interact with VFLK and VDPM pins?

The GPM block in the LM3311SQ/NOPB uses VFLK as the frame latch timing input and VDPM as the enable/disable control. When VDPM is high, VGHM output is modulated in sync with VFLK edges to drive TFT gate drivers; pulling VDPM low disables GPM entirely. This behavior is explicitly defined in the Pin Descriptions and verified in Figures 52–55 of the SNVS320G datasheet.

Can the LM3311SQ/NOPB's op-amp drive capacitive loads directly, and what is its slew rate?

Yes, the LM3311SQ/NOPB's op-amp is specified for 50V/µs slew rate with CL = 10pF and remains stable with ≥2.2µF ceramic output capacitors per the Electrical Characteristics table and Typical Performance Characteristics (Figure 40–41). It delivers ±135mA typical output current, enabling direct drive of moderate capacitive loads like gate drivers without external buffers.

What thermal protection mechanisms are implemented in the LM3311SQ/NOPB?

The LM3311SQ/NOPB incorporates thermal shutdown that disables all functional blocks (boost, LDO, op-amp, GPM) when junction temperature reaches 145°C, with ~20°C hysteresis (re-enable at ~125°C). This is documented in the "THERMAL SHUTDOWN" section of the datasheet and verified by the Absolute Maximum Ratings table listing 150°C max junction temperature.

Is the LM3311SQ/NOPB compatible with ceramic output capacitors for both the boost and LDO stages?

Yes, the LM3311SQ/NOPB is explicitly designed for ceramic output capacitors: the LDO requires ≥2.2µF X5R/X7R ceramics (per "LINEAR REGULATOR (LDO)" section), and the boost stage is stable with standard ceramic COUT values (e.g., 20µF in Figure 45). This eliminates need for bulkier electrolytic or tantalum capacitors in space-sensitive designs.

LM3311SQ/NOPB Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 24-WFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Step-Up

Output Configuration:: Positive

Topology:: Boost

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 2.5V

Voltage - Input (Max):: 7V

Voltage - Output (Min/Fixed):: 1.263V

Voltage - Output (Max):: 20V

Current - Output:: 2A (Switch)

Frequency - Switching:: 660kHz, 1.28MHz

Synchronous Rectifier:: No

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-WQFN (4x4)

LM3311SQ/NOPB FAQ

1.How can I place an order for LM3311SQ/NOPB through Aetrix?

Please submit a Request for Quotation (RFQ) for LM3311SQ/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 LM3311SQ/NOPB reliable?

The price and inventory of LM3311SQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3311SQ/NOPB is usually 5 days.

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We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3311SQ/NOPB transactions.

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LM3311SQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LM3311SQ/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 LM3311SQ/NOPB?

For technical support, including LM3311SQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3311SQ/NOPB requirements.

6.How does Aetrix verify that LM3311SQ/NOPB is sourced from the original manufacturer or authorized distributors?

All LM3311SQ/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 LM3311SQ/NOPB meets industry standards.

7.What is the process for return or replacement of LM3311SQ/NOPB?

All LM3311SQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3311SQ/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 LM3311SQ/NOPB part is unused and in its original packaging.

Return procedure for LM3311SQ/NOPB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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