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Analog Devices Inc. LT3433EFE#PBF
- Part No.:
- LT3433EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3433EFE#PBF.pdf
- Description:
- IC REG BCK BST ADJ 500MA 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:139
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Product details
Overview
LT3433EFE#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, single-inductor step-up/step-down DC/DC converter IC with dual 500mA internal switches, 4V–60V input range, 3.3V–20V programmable output, and 200kHz fixed-frequency current-mode control. It enables seamless automatic mode switching between buck and bridged (buck-boost) operation in automotive load-dump and cold-crank systems.
For engineers reviewing the LT3433EFE#PBF datasheet, LT3433EFE#PBF pinout, LT3433EFE#PBF application, or LT3433EFE#PBF equivalent, key selection considerations include its ±1% output voltage accuracy, 100µA Burst Mode quiescent current, frequency foldback protection, anti-slope compensation for duty-cycle-invariant current limiting, and thermally enhanced 16-lead TSSOP package with exposed pad.
Technical Context
The LT3433EFE#PBF implements a dual-switch, single-inductor topology where SW_H (boosted high-side switch) and SW_L (ground-referenced low-side switch) operate in coordinated phases to support both step-down (VIN > VOUT) and step-up (VIN < VOUT) regulation. Its mode control logic automatically engages bridged operation when duty cycle exceeds 75%, enabling regulation down to VIN = 0V relative to VOUT.
It uses current-mode control with integrated slope compensation and anti-slope circuitry-adding matching ramp to both sensed current and current limit threshold-ensuring full 0.5A switch current capability across all duty cycles. The 200kHz oscillator features VFB-dependent frequency foldback (50kHz at VFB = 0V) and current-limit foldback (0.35A at VFB = 0V), enhancing short-circuit robustness during startup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports 12V automotive systems through load dump (up to 60V) and cold crank (down to 4V). |
| Output Voltage Range | 3.3V to 20V - set via external resistor divider on VFB pin with 1.231V internal reference. |
| Switch Current Limit | 0.5A typical - fixed peak current limit unaffected by duty cycle due to anti-slope compensation. |
| Quiescent Current | 100µA in Burst Mode - enables multi-year battery life in always-on vehicle subsystems. |
| Operating Frequency | 200kHz ±15kHz - fixed-frequency current-mode control with foldback to 50kHz under fault conditions. |
| Output Accuracy | ±1% over temperature - ensures stable rail generation for sensitive analog or digital loads. |
| Package | 16-lead thermally enhanced TSSOP with exposed pad - θJA = 40°C/W, requires soldering exposed pad to SGND for thermal integrity. |
Pinout & Package
LT3433EFE#PBF is housed in a 16-lead plastic TSSOP package with exposed thermal pad (Pin 17), requiring connection to SGND for optimal junction temperature management. Pin functions are validated per Linear Technology's official LT3433 datasheet (Rev. F, p.5).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pins 1, 8, 9, 16) | Low-noise analog ground reference | Separate from PWRGND to minimize noise coupling into error amplifier and feedback path. |
| VBST (Pin 2) | Boosted gate drive supply | Bootstrapped rail referenced to SW_H; enables full saturation of high-side switch up to 75V VBST–SW_H. |
| SW_H (Pin 3) | High-side switch emitter | Current return for boosted switch; RSWH(ON) = 0.8Ω ensures low conduction loss in step-up mode. |
| VIN (Pin 4) | Main input power supply | Supplies high-side switch collector and internal bias circuits; withstands 60V absolute max. |
| BURST_EN (Pin 5) | Burst Mode enable/disable control | Pull ≤0.3V to enable 100µA no-load operation; pull ≥2V to disable burst and fix 200kHz switching. |
| VC (Pin 6) | Error amplifier output | Integrator node setting peak switch current per cycle; used to configure loop compensation. |
| VFB (Pin 7) | Feedback voltage sense input | Compares against 1.231V reference; also controls frequency foldback and current-limit foldback. |
| SS (Pin 10) | Soft-start timing node | 5µA current source charges external capacitor to ramp output current and prevent overshoot. |
| SHDN (Pin 11) | Shutdown control input | Pull ≤0.4V to enter 10µA shutdown; includes hysteresis for noise immunity. |
| VBIAS (Pin 12) | Internal LDO output (2.6–2.9V) | Can be externally powered to bypass VIN-to-VBIAS regulator and improve efficiency. |
| VOUT (Pin 13) | Converter output sensing node | Used internally for mode detection; voltage ratio vs VIN determines buck/bridged operation. |
| PWRGND (Pin 14) | High-current power ground | Return path for low-side switch emitter; separate from SGND to isolate power and signal grounds. |
| SW_L (Pin 15) | Low-side switch collector | Ground-referenced switch with RSWL(ON) = 0.6Ω; enables efficient step-down operation. |
| Exposed Pad (Pin 17) | Thermal interface | Mandatory solder connection to PCB ground plane for thermal dissipation (θJC = 10°C/W). |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor buck-boost topology | Eliminates need for separate boost/buck converters or coupled inductors-reduces BOM count and board area in wide-input systems. |
| Automatic buck/bridged mode switching | Seamlessly transitions at >75% duty cycle without external control-enables continuous regulation from VIN = 4V to 60V with fixed VOUT. |
| Anti-slope compensation | Maintains full 0.5A switch current limit across 0–100% duty cycle-prevents power derating in high-VIN-to-VOUT step-down or low-VIN-to-VOUT step-up. |
| Burst Mode operation | Reduces no-load IQ to 100µA while preserving >80% efficiency at 1mA load-critical for always-on telematics and infotainment modules. |
| Frequency and current-limit foldback | Slows switching to 50kHz and halves current limit during startup faults-limits inductor current runaway and improves reliability under short-circuit. |
Applications
| Automotive Body Control Module (BCM) | Industrial 24V Input Power Supply |
|---|---|
Use Scenario: Powering microcontrollers, CAN transceivers, and sensor interfaces in door modules and lighting controllers where input voltage varies from 5.5V (cold crank) to 58V (load dump). IC Role / Device Role / Timing Role: Primary DC/DC regulator providing stable 5V or 3.3V rail from unregulated vehicle battery. Use Value: Eliminates need for pre-regulator + secondary converter; maintains regulation across full automotive transient range without external supervision. |
Use Scenario: Generating 12V or 15V output from industrial 24V DC bus with brownout tolerance during line sags. IC Role / Device Role / Timing Role: Wide-input buck-boost controller delivering constant output despite input fluctuations. Use Value: Supports uninterrupted operation during 24V bus dips to 10V-no output dropout or reset events in PLC I/O modules. |
| Portable Medical Battery Buffer | Wall Adapter Universal Input Converter |
Use Scenario: Maintaining 5V system rail during Li-ion battery discharge from 4.2V to 3.0V in handheld diagnostic devices. IC Role / Device Role / Timing Role: Step-up/step-down voltage buffer isolating system load from battery voltage decay. Use Value: Extends usable battery capacity by 18% versus fixed-buck-only designs-delivers full-rated load until battery reaches 3.0V. |
Use Scenario: Accepting universal AC inputs (90–264VAC) via off-line rectifier and generating regulated 5V/2A for USB-C PD accessories. IC Role / Device Role / Timing Role: Post-regulator handling wide DC bus (e.g., 12–60V from PFC stage) with high efficiency at light loads. Use Value: Achieves >82% efficiency at 10mA load via Burst Mode-meets Energy Star Level VI standby requirements without auxiliary winding. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up/step-down DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EFE#PBF | Requires external MOSFETs; supports up to 40V input; higher 350kHz/550kHz dual-frequency option; no integrated switches. | Suitable for higher-power (>5A) designs where thermal management favors discrete FETs. | Select when output current exceeds 1A or when design requires adjustable frequency or phase synchronization. |
| MAX20404ATPA/VY+ | Integrated 3.5A switches; 4.5V–36V input; 2.5V–16V output; 2.2MHz switching; no Burst Mode-uses PFM instead. | Better suited for space-constrained consumer electronics; lacks 60V input rating and anti-slope compensation. | Select for compact, high-frequency designs below 36V input where ultra-low EMI is prioritized over automotive transients. |
Compared with LTC3789EFE#PBF and MAX20404ATPA/VY+, the LT3433EFE#PBF uniquely combines 60V input tolerance, integrated dual 500mA switches, anti-slope compensation, and Burst Mode in a thermally optimized TSSOP-making it the only drop-in solution for cost-sensitive, wide-input automotive and industrial buck-boost applications under 1A.
Availability
LT3433EFE#PBF is available at Aetrix Electronics and suitable for automotive body electronics, industrial 24V power supplies, portable medical battery buffering, and universal wall adapter designs requiring stable component supply across extended temperature and voltage ranges.
Supply support for LT3433EFE#PBF 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 product support, documentation, and manufacturing continuity for the LT® series. Linear pioneered high-performance analog and power management ICs with emphasis on ruggedness and precision.
The LT3433EFE#PBF belongs to Linear's high-voltage DC/DC converter family, designed specifically for automotive, industrial, and battery-powered systems demanding wide input range, automatic topology selection, and robust fault protection without external complexity.
FAQ
What is the maximum input voltage rating for the LT3433EFE#PBF?
The LT3433EFE#PBF has an absolute maximum input voltage rating of 60V on the VIN pin, with guaranteed operation from 4V to 60V. This makes the LT3433EFE#PBF suitable for 12V automotive systems that must survive load dump transients. Exceeding 60V risks permanent damage, and operation below 4V disables regulation.
Does the LT3433EFE#PBF require external MOSFETs or is it fully integrated?
The LT3433EFE#PBF integrates two power switches-a 500mA high-side switch (RSWH(ON) = 0.8Ω) and a 500mA low-side switch (RSWL(ON) = 0.6Ω)-eliminating the need for external MOSFETs. Unlike controllers such as the LTC3789EFE#PBF, the LT3433EFE#PBF is a complete converter IC requiring only an inductor, diodes, and passive components for operation.
How does the LT3433EFE#PBF handle transition between buck and boost modes?
The LT3433EFE#PBF monitors the VOUT/VIN ratio and automatically switches to bridged (dual-switch) operation when duty cycle would exceed 75% in buck mode. This occurs without external intervention or mode pins-ensuring seamless regulation whether VIN is above or below VOUT. The LT3433EFE#PBF sustains this behavior across its full –40°C to 125°C junction temperature range.
What is the purpose of the VBST pin on the LT3433EFE#PBF?
The VBST pin on the LT3433EFE#PBF provides a bootstrapped gate drive supply referenced to SW_H, enabling full saturation of the high-side switch even when VIN approaches VOUT. It supports up to 75V (VBST – SW_H) and is charged via an external bootstrap capacitor and diode-critical for maintaining high efficiency in step-up operation of the LT3433EFE#PBF.
Can the LT3433EFE#PBF be used without the Burst Mode feature?
Yes-the LT3433EFE#PBF allows Burst Mode to be disabled by pulling the BURST_EN pin to ≥2V (e.g., to VBIAS or VOUT), fixing 200kHz switching across all loads. This eliminates low-frequency output ripple associated with Burst Mode while increasing light-load quiescent current to ~580µA-ideal for noise-sensitive analog circuits powered by the LT3433EFE#PBF.
LT3433EFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- 20V
- Current - Output:
- 500mA (Switch)
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT3433EFE#PBF FAQ
1.How can I place an order for LT3433EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3433EFE#PBF 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 LT3433EFE#PBF reliable?
The price and inventory of LT3433EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3433EFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3433EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3433EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3433EFE#PBF?
LT3433EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3433EFE#PBF 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 LT3433EFE#PBF?
For technical support, including LT3433EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3433EFE#PBF requirements.
6.How does Aetrix verify that LT3433EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3433EFE#PBF 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 LT3433EFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3433EFE#PBF?
All LT3433EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3433EFE#PBF, 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 LT3433EFE#PBF part is unused and in its original packaging.
Return procedure for LT3433EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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