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Analog Devices Inc. LT1933HDCB#TRPBF
- Part No.:
- LT1933HDCB#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 6-WFDFN Exposed Pad
- Datasheet:
-
LT1933HDCB#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 600MA 6DFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,018
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Product details
Overview
LT1933HDCB#TRPBF 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, housed in a thermally enhanced 6-lead (2mm × 3mm × 0.75mm) DFN 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 automotive battery regulation and industrial control supplies.
For engineers reviewing the LT1933HDCB#TRPBF datasheet, LT1933HDCB#TRPBF pinout, LT1933HDCB#TRPBF application, or LT1933HDCB#TRPBF equivalent, key selection criteria include its guaranteed –40°C to 150°C junction temperature range, fixed 500kHz switching frequency, 1.245V feedback reference, BOOST pin voltage headroom requirement (>2.3V above SW), and DFN thermal performance (θJC = 12°C/W).
Technical Context
The LT1933HDCB#TRPBF implements constant-frequency current-mode control using an internal 500kHz oscillator and slope-compensated current sensing. Its VC node is servoed by an error amplifier referenced to 1.245V at FB, with active clamping enabling precise current limiting and soft-start via SHDN pin voltage ramping.
It employs a bipolar NPN switch driven from either VIN or the BOOST pin, requiring an external boost capacitor and diode to generate a gate drive voltage >2.3V above SW. Frequency foldback activates below ~55kHz when FB voltage drops, improving overload and startup behavior without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V - supports unregulated wall adapters, 24V industrial rails, and automotive batteries with cold-crank margin. |
| Switch Current Limit | 0.75A typical - sets maximum continuous load capability and short-circuit protection threshold. |
| Feedback Reference | 1.245V ±20mV - enables precise output voltage setting via resistor divider; determines VOUT = 1.245V × (1 + R1/R2). |
| Switching Frequency | 500kHz ±100kHz - allows use of small 22–33μH inductors and ceramic capacitors while maintaining EMI manageability. |
| Shutdown Current | <2μA - ensures true output disconnect and ultra-low quiescent power in battery-powered sleep modes. |
| Operating Temperature | –40°C to 150°C junction - qualified for under-hood automotive and high-ambient industrial environments. |
| Package Thermal Resistance | θJC = 12°C/W - enables high-power dissipation via exposed pad soldered to PCB ground plane. |
Pinout & Package
LT1933HDCB#TRPBF uses a 6-lead plastic DFN package (2mm × 3mm × 0.75mm) with exposed thermal pad (Pin 7, GND). The package is RoHS-compliant, lead-free, and optimized for high-density layouts and thermal performance in space-constrained applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST (Pin 1) | Bootstrap drive supply | Must be ≥2.3V above SW to fully saturate internal NPN switch; requires external 0.1μF capacitor + fast diode (e.g., 1N4148). |
| GND (Pin 2 & Exposed Pad) | Power and signal reference | Primary return path for switch current, feedback divider, and internal regulator; exposed pad must be soldered to PCB ground plane for thermal and electrical integrity. |
| FB (Pin 3) | Output voltage sense | Regulated to 1.245V; connects to resistor divider tap - sets output voltage and closes control loop. |
| SHDN (Pin 4) | Enable/soft-start control | Logic-high (≥2.3V) enables operation; logic-low disables switcher and reduces IQ to <2μA; RC network on this pin provides programmable soft-start. |
| VIN (Pin 5) | Main power input | Supplies internal regulator and switch driver; must be bypassed with ≥2.2μF X7R/X5R ceramic capacitor placed adjacent to pin. |
| SW (Pin 6) | Switch node | Connects to inductor, catch diode cathode, and boost capacitor anode - carries high di/dt pulsed current; layout critical for EMI and efficiency. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated current-mode control | Eliminates need for external compensation components; stable with low-ESR ceramic output capacitors down to 22μF. |
| Cycle-by-cycle current limit | Provides robust short-circuit and overload protection without external sensing; slope compensation prevents subharmonic oscillation. |
| Fixed 500kHz switching frequency | Enables predictable EMI filtering and consistent inductor/capacitor sizing across designs; foldback to 55kHz aids startup into heavy loads. |
| Soft-start via SHDN pin | RC-filtered SHDN voltage ramp limits inrush current during power-up - prevents input rail sag and avoids overstressing input capacitors. |
| Low 1.245V feedback reference | Supports accurate 3.3V/5V outputs with standard 1% resistors; enables adjustable outputs down to 1.25V with minimal divider error. |
Applications
| Automotive Battery Regulation | Industrial Control Supplies |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V or 5V for microcontrollers, sensors, and CAN transceivers in engine control units or ADAS modules. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, efficient, and thermally robust local power domain with cold-crank tolerance (down to 3.6V). Use Value: Guaranteed operation to 150°C junction enables placement near heat sources; 36V absolute max rating withstands load-dump transients up to 33V. |
Use Scenario: Powering PLC I/O modules, fieldbus interfaces, and analog front-ends from 24V industrial rails in factory automation systems. IC Role / Device Role / Timing Role: Compact, self-contained DC/DC stage delivering regulated 5V/600mA with minimal external components and no heatsink required. Use Value: DFN package and internal compensation reduce BOM count and PCB area; <2μA shutdown supports remote wake-on-event functionality. |
| Wall Transformer Regulation | Battery-Powered Equipment |
Use Scenario: Converting unregulated 9–24V AC/DC wall adapter outputs to stable 3.3V for embedded networking devices or IoT gateways. IC Role / Device Role / Timing Role: Input-flexible step-down regulator accepting wide-input, low-cost transformers while rejecting line ripple via 500kHz switching. Use Value: 3.6V UVLO prevents erratic operation during brownouts; high-frequency operation minimizes audible noise and filter size. |
Use Scenario: Supplying 3.3V to portable medical monitors, handheld test equipment, or wireless sensors powered by Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: High-efficiency buck converter with ultra-low shutdown IQ and soft-start to extend battery life and prevent inrush damage. Use Value: <2μA shutdown current preserves battery charge during multi-week standby; 500kHz operation allows tiny 22μH inductors for compact form factor. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3605EDE#TRPBF | 4MHz synchronous buck, 600mA, 2.5–5.5V input, 3mm × 3mm DFN | Requires lower input voltage; better suited for post-regulation from 3.3V/5V rails rather than direct 24V conversion | Select for higher efficiency at light loads and smaller inductors where input voltage ≤5.5V. |
| MP2451DT-LF-Z | 3.3–36V input, 600mA, 500kHz, 8-pin SOIC, no BOOST pin, MOSFET-based | Lacks BOOST architecture - simpler layout but lower peak efficiency at high VIN/VOUT ratios; SOIC thermal performance inferior to DFN | Select for cost-sensitive industrial designs where 150°C operation is not required and board space permits SOIC footprint. |
Compared with LTC3605EDE#TRPBF and MP2451DT-LF-Z, the LT1933HDCB#TRPBF uniquely combines bipolar NPN switch architecture with BOOST-driven gate drive, enabling robust 36V operation and 150°C qualification in a 2mm × 3mm DFN - making it the only option among the three qualified for under-hood automotive use.
Availability
LT1933HDCB#TRPBF 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 and long product lifecycles.
Supply support for LT1933HDCB#TRPBF 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 specifically for high-input-voltage, high-temperature DC/DC conversion in automotive and industrial settings - emphasizing ruggedness, minimal external components, and guaranteed performance over –40°C to 150°C.
FAQ
What is the maximum input voltage rating for LT1933HDCB#TRPBF?
The absolute maximum input voltage (VIN) for LT1933HDCB#TRPBF is 36V. Exceeding this may cause permanent damage. While transient spikes up to the absolute max ratings are tolerated, sustained operation should remain within 3.6V to 36V per specifications. The BOOST pin has a separate 43V absolute max rating, and its voltage relative to SW must stay ≤20V.
Does LT1933HDCB#TRPBF require an external catch diode?
Yes, LT1933HDCB#TRPBF requires an external Schottky catch diode (e.g., MBRM140 or MBR0540) connected between SW and GND. The IC contains no synchronous rectifier; the diode provides the return path for inductor current during switch-off cycles and directly impacts efficiency and thermal performance.
Can LT1933HDCB#TRPBF operate at 3.3V output from a 4.5V input?
Yes - LT1933HDCB#TRPBF supports 3.3V at 500mA from inputs as low as 4.5V to 36V, per its published application data. This is enabled by its 88% maximum duty cycle and low dropout characteristics, though minimum input depends on load, inductor value, and boost circuit configuration.
What is the purpose of the BOOST pin on LT1933HDCB#TRPBF?
The BOOST pin on LT1933HDCB#TRPBF supplies elevated gate drive voltage to the internal bipolar NPN switch. It must be ≥2.3V above the SW pin voltage to ensure full saturation and low conduction loss. An external 0.1μF capacitor and fast diode (e.g., 1N4148) generate this boosted voltage from the SW node.
Is LT1933HDCB#TRPBF pin-compatible with other LT1933 variants?
Yes - LT1933HDCB#TRPBF shares identical pinout and footprint with all LT1933 DFN variants (e.g., LT1933IDCB#TRPBF, LT1933EDCB#PBF), differing only in temperature grade and lead finish. All DCB-package LT1933 parts use the same 6-lead (2mm × 3mm) DFN layout and pin assignment.
LT1933HDCB#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 6-WFDFN Exposed Pad
- 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:
- -40°C ~ 150°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-DFN (2x3)
LT1933HDCB#TRPBF FAQ
1.How can I place an order for LT1933HDCB#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1933HDCB#TRPBF 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 LT1933HDCB#TRPBF reliable?
The price and inventory of LT1933HDCB#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1933HDCB#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1933HDCB#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1933HDCB#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1933HDCB#TRPBF?
LT1933HDCB#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1933HDCB#TRPBF 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 LT1933HDCB#TRPBF?
For technical support, including LT1933HDCB#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1933HDCB#TRPBF requirements.
6.How does Aetrix verify that LT1933HDCB#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1933HDCB#TRPBF 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 LT1933HDCB#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1933HDCB#TRPBF?
All LT1933HDCB#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1933HDCB#TRPBF, 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 LT1933HDCB#TRPBF part is unused and in its original packaging.
Return procedure for LT1933HDCB#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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