Texas Instruments LM2775DSGR

Overview

LM2775DSGR from Texas Instruments is a regulated switched-capacitor voltage doubler IC that generates a stable 5-V output from 2.7-V to 5.5-V input, delivers up to 200 mA, operates at 2 MHz, and features PFM mode for light-load efficiency in USB OTG and HDMI power rails.

For engineers reviewing the LM2775DSGR datasheet, LM2775DSGR pinout, LM2775DSGR application, or LM2775DSGR equivalent, key selection considerations include its inductorless architecture, thermal shutdown behavior, OUTDIS-controlled shutdown discharge, input current limit (600 mA), and WSON-8 package thermal performance under 125°C junction conditions.

Technical Context

The LM2775DSGR implements pre-regulation before charge-pumping: internal current control of VIN-connected switches regulates voltage prior to doubling, minimizing input current ripple. Its two-phase non-overlapping clock drives external flying capacitor C1 (1 µF) between C1+ and C1− terminals to achieve voltage gain.

Functional modes are controlled via three digital inputs: EN enables/disables operation, PFM selects pulse-frequency modulation (light load) or fixed 2-MHz PWM mode, and OUTDIS configures active discharge (450 µA) or high-impedance hold during shutdown. Thermal shutdown triggers at 150°C (typical) with hysteresis to 130°C.

Key Specifications

Pinout & Package

LM2775DSGR uses an 8-pin WSON package (2.00 mm × 2.00 mm) with exposed thermal pad soldered to PCB ground for optimal heat dissipation (R_θJB = 41.5°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switched-capacitor boost converter applications.

Compared with TPS60403DBVR and MAX680ESA+, the LM2775DSGR uniquely combines 200-mA capability, PFM efficiency optimization, configurable shutdown discharge, and WSON thermal performance - making it the only option qualified for USB OTG and HDMI power delivery in compact portable systems.

Availability

LM2775DSGR is available at Aetrix Electronics and suitable for USB OTG power supplies, HDMI sink rails, and portable medical sensor hubs requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for LM2775DSGR 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 ICs, with decades of expertise in high-efficiency DC/DC conversion and precision regulation.

The LM2775DSGR belongs to TI's switched-capacitor power converter family, designed specifically for inductorless 5-V rail generation in space-constrained portable electronics where EMI, size, and input ripple are critical constraints.

FAQ

What is the minimum input voltage required for the LM2775DSGR to regulate 5 V at full 200 mA?

The LM2775DSGR requires a minimum input voltage of 3.1 V to sustain 200 mA output while maintaining 5-V regulation. Below 3.1 V - down to 2.7 V - maximum output current drops to 125 mA due to reduced pre-regulator headroom. This behavior is confirmed in the Load Current vs. Input Voltage plot (Figure D017) and Section 8.2.2.1 of the SNVSA57 datasheet. The LM2775DSGR remains functional but derated at lower VIN.

Can the LM2775DSGR be used without the OUTDIS pin connected?

Yes - the OUTDIS pin of the LM2775DSGR has an internal pull-down, so leaving it unconnected defaults to logic low (high-impedance shutdown mode). In this state, the output remains near its last regulated voltage during shutdown with only ~1.6 µA leakage. This is safe for applications like USB OTG where the 5-V rail may be shared with other sources. However, for guaranteed behavior, TI recommends explicitly tying OUTDIS to GND if high-Z hold is intended.

What ceramic capacitor characteristics are mandatory for reliable LM2775DSGR operation?

The LM2775DSGR requires X7R or X5R dielectric ceramic capacitors for CIN, COUT, and C1 - specifically rated ≥10 V for COUT and ≥VIN(max) for others. Y5V/Z5U types are prohibited due to severe DC-bias capacitance loss (up to 80%) and temperature drift. Per Section 8.2.2.4, 0402-case, 2.2-µF/6.3-V X7R input/output caps and 1-µF/10-V X7R flying cap meet all stability, ESR (<15 mΩ), and bias requirements across −40°C to +85°C.

Does the LM2775DSGR support automatic transition between PFM and PWM modes?

No - the LM2775DSGR does not auto-switch between PFM and PWM. The PFM pin is a static digital control: logic high enables PFM burst mode (variable frequency, low I_Q), and logic low forces fixed 2-MHz PWM (constant frequency, higher I_Q). There is no internal hysteresis or load-threshold detection. System firmware or external logic must assert the PFM pin level based on measured load current or application state - e.g., set PFM=1 during standby, PFM=0 during active data transfer.

How does thermal performance of the LM2775DSGR compare between PCB layouts with and without thermal pad connection?

Thermal pad connection is mandatory for rated LM2775DSGR performance. With the thermal pad properly soldered to a 1-in² copper pour (2 oz), R_θJB = 41.5°C/W enables full 200-mA operation at +85°C ambient. Without thermal pad connection, junction temperature rise exceeds 125°C within seconds at >100 mA - triggering thermal shutdown cycling. TI's layout guidelines (Section 10.2) require ≥4 thermal vias (0.3-mm diameter) under the pad connected to inner-layer ground planes to achieve specified thermal resistance.