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Analog Devices Inc. LT1933ES6#TRMPBF
- Part No.:
- LT1933ES6#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LT1933ES6#TRMPBF.pdf
- Description:
- IC REG BUCK ADJ 600MA TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:6,621
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Product details
Overview
LT1933ES6#TRMPBF from Analog Devices (formerly Linear Technology) is a 500kHz, current-mode PWM step-down DC/DC converter with an integrated 0.75A bipolar NPN power switch in a 6-lead TSOT-23 package. It operates from 3.6V to 36V input, delivers up to 600mA at 3.3V or 5V output, and features internal compensation, soft-start, and <2μA shutdown current - ideal for space-constrained industrial and automotive power rails.
For engineers reviewing the LT1933ES6#TRMPBF datasheet, LT1933ES6#TRMPBF pinout, LT1933ES6#TRMPBF application, or LT1933ES6#TRMPBF equivalent, key selection criteria include its 500kHz fixed switching frequency, 1.245V feedback reference, 88% maximum duty cycle, BOOST pin voltage headroom requirement, and SOT-23 thermal performance (θJA = 165°C/W).
Technical Context
The LT1933ES6#TRMPBF implements constant-frequency current-mode control with slope-compensated PWM, where the internal error amplifier regulates the VC node to maintain 1.245V at FB. Its oscillator includes frequency foldback below ~55kHz when FB voltage drops, improving overload behavior during startup.
Power delivery relies on external BOOST capacitor and diode to generate >VIN drive voltage for the internal bipolar switch; minimum BOOST-to-SW differential must exceed 1.9V for full saturation. Undervoltage lockout (~3.35V) disables switching until VIN exceeds threshold, and SHDN pin doubles as soft-start control via external RC ramp.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V - supports unregulated wall adapters, 24V industrial buses, and automotive battery inputs with transient tolerance up to 36V. |
| Switching Frequency | 500kHz (typical), 400–600kHz (min–max) - enables use of compact 22μH inductors and ceramic output capacitors without ESR dependency. |
| Feedback Reference | 1.245V (±20mV over temp) - sets output voltage via resistor divider; allows adjustable outputs down to 1.25V with stable regulation. |
| Max Output Current | 600mA at 3.3V/5V - achievable with appropriate inductor (e.g., 22μH), catch diode (MBRM140), and thermal layout in TSOT-23 package. |
| Shutdown Current | <2μA - ensures true output disconnect and ultra-low quiescent power in battery-powered systems during sleep mode. |
| Max Duty Cycle | 88% - limits minimum input voltage required for regulation; e.g., ≥4.5V input needed for 3.3V output under full load. |
| Operating Temp | –40°C to +85°C - specified for commercial/industrial environments; junction temperature limited to 125°C. |
Pinout & Package
LT1933ES6#TRMPBF uses the 6-lead TSOT-23 (ThinSOT™) package: 2.9mm × 1.6mm × 1.0mm profile, exposed pad not present (unlike DFN variants), θJA = 165°C/W. Pin 1 is BOOST, Pin 2 is GND, Pin 3 is FB, Pin 4 is SHDN, Pin 5 is VIN, Pin 6 is SW - confirmed by Linear Technology datasheet Figure 1 (S6 PACKAGE top view).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST (Pin 1) | Charge pump drive node | Must be ≥1.9V above SW to fully saturate internal bipolar switch; requires external 0.1μF capacitor + fast diode (e.g., 1N4148). |
| GND (Pin 2) | Power and signal reference | Primary ground return for internal regulator, error amp, and feedback divider; must connect to low-impedance local ground plane. |
| FB (Pin 3) | Output voltage sense input | Regulated to 1.245V; connects to resistor divider tap; bias current ≤120nA minimizes divider error. |
| SHDN (Pin 4) | Enable/soft-start control | Logic-high (≥2.3V) enables operation; grounded disables converter; external RC creates controlled start-up ramp. |
| VIN (Pin 5) | Main power input | Supplies internal regulator and switch driver; requires local 2.2μF X7R/X5R ceramic bypass within 3mm of pin. |
| SW (Pin 6) | Switch node output | Connects to inductor, catch diode cathode, and BOOST capacitor; carries high di/dt pulsed current - critical for EMI layout. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated | Eliminates need for external compensation components - simplifies design and reduces BOM count for standard 3.3V/5V outputs. |
| Cycle-by-cycle current limit | Protects against shorted outputs using sensed switch current; limit threshold is 0.75A (typ), reduced at high duty cycles due to slope compensation. |
| Fixed 500kHz operation | Enables predictable EMI filtering and consistent inductor sizing; avoids subharmonic oscillation with L ≥ 3(VOUT + 0.4V) μH. |
| Low-profile TSOT-23 package | 1.0mm height and 2.9mm × 1.6mm footprint - suitable for ultra-thin industrial HMI, portable test equipment, and space-limited PCBs. |
| Soft-start via SHDN pin | External RC network on SHDN controls rise time of internal VC node - prevents input surge and output overshoot during power-up. |
Applications
| Automotive Battery Regulation | Industrial Control Supply |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to stable 3.3V for microcontroller and CAN transceiver logic. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, ripple-controlled power domain with UVLO protection against cranking dips. Use Value: Withstands 36V transients and operates down to 3.6V input - maintains function during cold-crank events while delivering 600mA continuous load. |
Use Scenario: Powering PLC I/O modules and sensor interfaces from 24V factory bus with minimal heatsinking. IC Role / Device Role / Timing Role: Compact, self-contained step-down regulator replacing discrete switcher designs in DIN-rail mounted controllers. Use Value: 500kHz switching enables small 22μH inductor and 22μF ceramic output cap - reduces board area by >40% vs. lower-frequency alternatives. |
| Wall Transformer Regulation | Battery-Powered Equipment |
Use Scenario: Converting unregulated 9–24V AC/DC adapter output to clean 5V for USB peripherals or embedded gateways. IC Role / Device Role / Timing Role: Input-tolerant buck converter absorbing line regulation variation and providing low-noise downstream power. Use Value: Wide 3.6–36V input range accepts legacy wall adapters without redesign; <2μA shutdown extends standby time in always-on devices. |
Use Scenario: Supplying 3.3V to portable medical monitors or handheld test tools powered by Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: High-efficiency, low-quiescent buck regulator enabling >100-hour runtime in sleep mode. Use Value: 95% peak efficiency at 500mA (12V→3.3V) and <2μA shutdown current minimize battery drain - critical for long-life portable applications. |
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 |
|---|---|---|---|
| LT3975EMSE#PBF | 42V input, 1.2A switch, 2.5MHz sync rectifier, MSOP-10 package; requires external compensation. | Higher current, higher frequency, synchronous rectification - better for >1A loads or tighter EMI constraints. | Choose LT3975EMSE#PBF only if 1.2A output or 2.5MHz operation is required; not pin-compatible and needs layout revision. |
| TPS54331DR | 28V input, 3A switch, 570kHz, SOIC-8; integrated MOSFETs, adjustable soft-start, 0.8V ref. | Higher current capability and lower RDS(on) - suited for thermally demanding 3A applications with less stringent size limits. | TPS54331DR offers higher output current but larger SOIC-8 footprint and different pinout - requires PCB redesign and new compensation. |
Compared with LT1933ES6#TRMPBF, LT3975EMSE#PBF provides higher frequency and current but demands more complex layout and external compensation, while TPS54331DR delivers triple the current in a larger package with different thermal and control characteristics - neither is drop-in replaceable.
Availability
LT1933ES6#TRMPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial control supplies, and wall transformer regulation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1933ES6#TRMPBF 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
Analog Devices acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear power products including the LT1933 family.
The LT1933 product line was designed for high-input-voltage, space-constrained buck conversion in automotive, industrial, and instrumentation applications - emphasizing robustness, wide VIN range, and minimal external component count.
FAQ
What is the absolute maximum input voltage rating for the LT1933ES6#TRMPBF?
The LT1933ES6#TRMPBF has an absolute maximum input voltage (VIN) rating of 36V. Exceeding this voltage - even momentarily - risks permanent damage. The BOOST pin has a separate 43V absolute maximum rating, and its voltage relative to SW must not exceed 20V. These limits are defined in the Absolute Maximum Ratings table of the official datasheet.
Can the LT1933ES6#TRMPBF operate with a 3.3V input to produce a 3.3V output?
No, the LT1933ES6#TRMPBF cannot regulate a 3.3V output from a 3.3V input. Its minimum operating input voltage is ~3.35V due to undervoltage lockout, and practical regulation requires VIN ≥ (VOUT + VD) / DCMAX + VSW – VD, where DCMAX = 88%. For 3.3V output, minimum VIN is ~4.5V under typical conditions - confirmed by Figure 3a in the datasheet.
What is the purpose of the BOOST pin on the LT1933ES6#TRMPBF, and what external components does it require?
The BOOST pin on the LT1933ES6#TRMPBF supplies elevated gate drive voltage to fully saturate the internal bipolar NPN switch. It requires an external 0.1μF ceramic capacitor and fast-switching diode (e.g., 1N4148) connected between VIN and BOOST, with the diode anode tied to VIN and cathode to BOOST. The BOOST-to-SW voltage must remain ≥1.9V for optimal efficiency.
Does the LT1933ES6#TRMPBF require external compensation components?
No, the LT1933ES6#TRMPBF is internally compensated. Its control loop is optimized for standard ceramic output capacitors (e.g., 22μF X7R) and recommended inductor values (e.g., 22μH). No external compensation network is needed for basic 3.3V or 5V configurations - verified by the "Internally Compensated" feature and typical application circuits in the datasheet.
How does the LT1933ES6#TRMPBF implement soft-start, and can it be disabled?
The LT1933ES6#TRMPBF implements soft-start by tying an external RC network to the SHDN pin, which ramps the internal VC node voltage. To disable soft-start, connect SHDN directly to VIN (for enable) or leave it unconnected only if unused - but note that direct tie-to-VIN eliminates the soft-start function and results in full-current startup. The datasheet Figure 4b shows the enabled soft-start waveform.
LT1933ES6#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- SOT-23-6 Thin, TSOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 1.245V
- Voltage - Output (Max):
- 33.84V
- Current - Output:
- 600mA
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-6
LT1933ES6#TRMPBF FAQ
1.How can I place an order for LT1933ES6#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1933ES6#TRMPBF 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 LT1933ES6#TRMPBF reliable?
The price and inventory of LT1933ES6#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1933ES6#TRMPBF is usually 5 days.
3.What payment methods are accepted for LT1933ES6#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1933ES6#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1933ES6#TRMPBF?
LT1933ES6#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1933ES6#TRMPBF 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 LT1933ES6#TRMPBF?
For technical support, including LT1933ES6#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1933ES6#TRMPBF requirements.
6.How does Aetrix verify that LT1933ES6#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LT1933ES6#TRMPBF 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 LT1933ES6#TRMPBF meets industry standards.
7.What is the process for return or replacement of LT1933ES6#TRMPBF?
All LT1933ES6#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1933ES6#TRMPBF, 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 LT1933ES6#TRMPBF part is unused and in its original packaging.
Return procedure for LT1933ES6#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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