My Inquiry
My Account
Analog Devices Inc. LT3667HUDD#PBF
- Part No.:
- LT3667HUDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LT3667HUDD#PBF.pdf
- Description:
- IC REG TRIPLE BUCK/LINEAR 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,542
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3667HUDD#PBF from Analog Devices (formerly Linear Technology) is a monolithic triple-output power management IC integrating a 400mA buck switching regulator and two 200mA fault-protected LDOs in a single 24-pin 3mm × 5mm QFN package. It operates from 4.3V–40V input, delivers regulated 5V/3.3V/2.5V outputs with <15mVP-P ripple in Burst Mode, and supports automotive battery regulation with ±45V fault protection on LDO inputs.
For engineers reviewing the LT3667HUDD#PBF datasheet, LT3667HUDD#PBF pinout, LT3667HUDD#PBF application, or LT3667HUDD#PBF equivalent, key selection considerations include its triple-output architecture, programmable current-limited LDOs, thermal grade (–40°C to 150°C), exposed-pad QFN thermal performance, and dual fault-protected LDO inputs enabling robust sensor supply design.
Technical Context
The LT3667HUDD#PBF implements current-mode control for fast transient response and stable loop behavior in its 400mA buck stage, with adjustable switching frequency (250kHz–2.2MHz) via RT resistor and external synchronization capability. Its dual LDOs feature accurate 0.8V feedback references, programmable current limits via EN2/ILIM2 and EN3/ILIM3 pins, and ±45V fault tolerance on IN2/IN3 inputs.
Internal protection includes reverse-battery protection, thermal shutdown, current limiting, reverse-current blocking, and undervoltage lockout (UVLO1 threshold = 1V). The QFN package integrates PG1/PG2/PG3 open-drain power-good indicators per output and exposes GND on pin 25 for low-θJA (46°C/W) thermal management.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input voltage range (buck) | 4.3V to 40V continuous; 60V max transient - supports wide automotive and industrial input rails |
| Buck output current | 400mA with internal switch - eliminates need for external MOSFET in compact designs |
| LDO output current | 200mA per LDO with programmable current limit - enables precise overcurrent protection for sensitive loads |
| LDO dropout voltage | 340mV at 200mA - ensures regulation down to low VIN–VOUT differentials |
| Switching frequency range | 250kHz to 2.2MHz (adjustable via RT) - allows EMI optimization and small external component selection |
| Operating temperature | –40°C to +150°C junction - qualified for under-hood automotive and high-temp industrial use |
| Output ripple (Burst Mode) | <15mVP-P typical - maintains low noise for analog/RF subsystems without sacrificing light-load efficiency |
Pinout & Package
The LT3667HUDD#PBF is housed in a thermally enhanced 24-lead (3mm × 5mm) plastic QFN package with exposed pad (pin 25 = GND), offering θJA = 46°C/W. Pin assignment is validated per Linear Technology's official LT3667 datasheet (Rev. FB, pp. 11–12).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (24) | Buck switch node | Connects to inductor, catch diode anode (DA), and boost capacitor - critical high-dI/dt path requiring tight layout |
| BOOST (1) | Boost drive voltage source | Supplies >VIN gate drive to internal NPN switch; requires 0.22µF capacitor to SW |
| EN (3) | Global enable input | Active-high logic control; ≥1V enables all regulators; ≤0.3V disables entire device |
| RT (4) | Oscillator frequency set | Resistor-to-GND sets switching frequency (250kHz–2.2MHz); enables EMI tuning |
| BD (5) | Boost diode anode / bias supply | Connects to internal Schottky anode; supplies internal regulator when >3.2V - improves efficiency |
| OUT3 (7), OUT2 (14) | LDO regulated outputs | Each delivers up to 200mA; require ≥2.2µF ceramic output capacitors for stability |
| FB3 (8), FB2 (13) | LDO feedback reference | Regulated to 0.8V; used with resistor dividers to set VOUT2/3; bias current ±40nA |
| FB1 (10) | Buck feedback reference | Regulated to 1.2V; sets buck output voltage; line regulation 0.005%/V |
| PG1 (9), PG2 (11), PG3 (12) | Per-output power-good flags | Open-drain outputs active-low until respective FB pin is within ±10% of target - enables sequenced system startup |
| EN2/ILIM2 (16), EN3/ILIM3 (17) | LDO enable & current limit | Resistor-to-GND programs current limit (e.g., 31.6k = 10mA); >1.2V disables LDO |
| IN1 (20) | Buck input supply | Main input for buck stage; must be locally bypassed; supports 4.3V–40V |
| DA (23) | Catch diode anode sense | Monitors catch diode current for foldback frequency reduction during overload |
| GND (25) | Power and signal ground | Exposed thermal pad - must be soldered to PCB plane for thermal and electrical integrity |
| UVLO1 (19) | Precision undervoltage lockout | 1.0V ±5% threshold; controls buck operation only - LDOs remain functional below UVLO |
| SYNC (2) | External clock input | Accepts 300kHz–2.2MHz external clock; synchronizes switching to avoid beat frequencies |
Key Features
| Feature | Design Value |
|---|---|
| Fault-protected LDO inputs | Withstands ±45V on IN2/IN3 - enables direct connection to unregulated automotive battery with transient suppression |
| Low-ripple Burst Mode | Maintains <15mVP-P output ripple at light loads while achieving 50µA no-load quiescent current - ideal for always-on systems |
| Triple independent power-good signals | PG1/PG2/PG3 provide per-rail status - simplifies FPGA/CPU power sequencing without external supervisors |
| Programmable LDO current limit | Resistor-programmed thresholds (e.g., 1.54kΩ = 176mA) - replaces discrete current-limit circuits and enables load-specific protection |
| Thermally enhanced QFN | 3mm × 5mm footprint with exposed GND pad (θJA = 46°C/W) - supports 150°C operation in space-constrained layouts |
Applications
| Automotive Battery Regulation | Industrial Sensor Power Supply |
|---|---|
Use Scenario: Powering infotainment head-unit microcontrollers and CAN transceivers from a 12V vehicle battery subject to load dump (60V transients) and cold-crank (3V dips). IC Role / Device Role / Timing Role: Triple-output PMIC providing isolated, fault-protected 5V (MCU core), 3.3V (peripherals), and 2.5V (ADC reference) rails with independent power-good signaling. Use Value: Eliminates need for three discrete regulators and external fault protection; ±45V LDO input rating withstands battery reversal and jump-start conditions. | Use Scenario: Powering precision analog sensors (e.g., pressure, temperature) in factory automation PLC modules where ESD and field-wiring faults are common. IC Role / Device Role / Timing Role: Dual LDOs deliver clean, low-noise 3.3V and 5V sensor excitation and signal-chain bias, while buck powers digital interface logic. Use Value: Fault protection on IN2/IN3 prevents damage from miswired 24V field cables; 0.8V FB reference enables accurate low-voltage sensing. |
| Portable Instrumentation | High-Temperature Industrial Control |
Use Scenario: Battery-powered handheld test equipment requiring long runtime and stable analog front-end performance across temperature. IC Role / Device Role / Timing Role: Buck powers main processor; LDOs supply ultra-low-noise 3.3V for ADC/DAC and 1.8V for RF front-end, all from single Li-ion or 2-cell pack. Use Value: 50µA no-load IQ extends battery life; <15mVP-P Burst Mode ripple avoids digitization errors in 16-bit+ data converters. | Use Scenario: Motor drive control boards operating near heat sinks or in enclosed enclosures where ambient exceeds 105°C. IC Role / Device Role / Timing Role: Primary power source for gate drivers, isolation logic, and current-sense amplifiers in harsh thermal environments. Use Value: H-grade (–40°C to +150°C) qualification ensures reliable operation without derating; exposed-pad QFN sustains thermal stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-output power management applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3372EFE#PBF | Octal 150mA LDOs with buck controller (no integrated switch); 40V max input; no ±45V LDO fault protection | Targeted at multi-rail digital systems needing fine-grained LDO count; lacks integrated buck switch and LDO fault tolerance | Select when flexible LDO count and external FET control outweigh need for integrated switch and fault hardening |
| TPS65218D0RSLR | Integrated 3A buck + 4x LDOs; 5.5V max input; no LDO fault protection; lower temp grade (–40°C to 105°C) | Optimized for low-voltage portable processors (AM335x, Sitara); incompatible with automotive/high-VIN systems | Select for cost-sensitive consumer electronics with sub-6V inputs and no fault exposure requirements |
Compared with LTC3372EFE#PBF and TPS65218D0RSLR, the LT3667HUDD#PBF uniquely combines integrated 400mA buck switching, dual fault-protected 200mA LDOs, and H-grade thermal rating - making it the only option qualified for automotive battery-fed sensor and control applications demanding ±45V input resilience and 150°C operation.
Availability
LT3667HUDD#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial sensor power supply, portable instrumentation, and high-temperature industrial control applications requiring stable component supply across extended temperature ranges and fault-prone environments.
Supply support for LT3667HUDD#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3667 product line was designed specifically for ruggedized triple-output power conversion in automotive and industrial systems - emphasizing fault tolerance, wide input range, and extended temperature operation without external protection components.
FAQ
What is the maximum input voltage rating for the buck regulator in LT3667HUDD#PBF?
The LT3667HUDD#PBF buck regulator supports a continuous input voltage range of 4.3V to 40V, with an absolute maximum rating of 60V for nonrepetitive 1-second transients. This makes LT3667HUDD#PBF suitable for automotive applications where load dump events occur. The 40V upper limit applies during normal operation, and exceeding it continuously risks permanent damage.
How does the LT3667HUDD#PBF achieve fault protection on its LDO inputs?
The LT3667HUDD#PBF provides ±45V fault protection on both IN2 and IN3 pins, meaning it can withstand reverse battery connections and field-wiring transients up to ±45V without damage. This protection is implemented internally using robust junction isolation and clamping structures - no external TVS diodes are required. The specification is verified per Absolute Maximum Ratings table in the official datasheet.
Can the LT3667HUDD#PBF operate with only the LDOs enabled while the buck regulator is disabled?
Yes, the LT3667HUDD#PBF allows independent control: pulling EN low disables the buck regulator but leaves the LDOs operational if their respective EN2/ILIM2 and EN3/ILIM3 pins are held above 1.2V. Each LDO can be enabled or disabled separately, and the buck stage remains inactive until EN rises above 1.1V. This enables flexible power sequencing in complex systems.
What is the purpose of the BD pin on the LT3667HUDD#PBF, and how should it be connected?
The BD pin on the LT3667HUDD#PBF connects to the anode of the internal boost Schottky diode and also serves as an auxiliary bias supply input. When BD is held above 3.2V (e.g., tied to a regulated LDO output), the IC draws internal bias current from BD instead of IN1 - improving overall efficiency. If unused, BD must be connected to IN3 (as shown in QFN pinout) and not left floating.
Does the LT3667HUDD#PBF support synchronous rectification, and what is the role of the DA pin?
No, the LT3667HUDD#PBF does not support synchronous rectification; it uses an external Schottky catch diode. The DA pin senses current through that diode to implement frequency foldback during overload - reducing switching frequency when catch diode current exceeds ~500mA, thereby limiting output current and thermal stress. DA must be connected directly to the cathode of the external catch diode.
LT3667HUDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Topology:
- Step-Down (Buck) (1), Linear (LDO) (2)
- Number of Outputs:
- 3
- Frequency - Switching:
- 243kHz ~ 2.2MHz
- Voltage/Current - Output 1:
- 1.2V ~ 38.6V, 400mA
- Voltage/Current - Output 2:
- 0.8V ~ 38.6V, 200mA
- Voltage/Current - Output 3:
- 0.8V ~ 38.6V, 200mA
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- No
- Voltage - Supply:
- 1.6V ~ 45V
- Operating Temperature:
- -40°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-QFN (3x5)
LT3667HUDD#PBF FAQ
1.How can I place an order for LT3667HUDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3667HUDD#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 LT3667HUDD#PBF reliable?
The price and inventory of LT3667HUDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3667HUDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3667HUDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3667HUDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3667HUDD#PBF?
LT3667HUDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3667HUDD#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 LT3667HUDD#PBF?
For technical support, including LT3667HUDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3667HUDD#PBF requirements.
6.How does Aetrix verify that LT3667HUDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3667HUDD#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 LT3667HUDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3667HUDD#PBF?
All LT3667HUDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3667HUDD#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 LT3667HUDD#PBF part is unused and in its original packaging.
Return procedure for LT3667HUDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3667HUDD#PBF Tags
-
TPS6521905RHBR
Texas Instruments
-
MIC3385YHL-TR
Microchip Technology
-
A4402ELPTR-T
Allegro MicroSystems
-
LM26480SQ-AA/NOPB
Texas Instruments
-
A4402KLPTR-T
Allegro MicroSystems
-
BD71847AMWV-E2
ROHM Semiconductor
-
ADP5040ACPZ-1-R7
Analog Devices Inc.
-
LT3048IDC#TRPBF
Analog Devices Inc.
-
ADP5037ACPZ-R7
Analog Devices Inc.
-
XRP7714ILB-F
MaxLinear, Inc.
-
LTC3260EDE#TRPBF
Analog Devices Inc.
-
LTC3260EMSE#PBF
Analog Devices Inc.
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
