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Analog Devices Inc. LTC1437ACG#PBF
- Part No.:
- LTC1437ACG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1437ACG#PBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,472
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Product details
Overview
LTC1437ACG#PBF from Analog Devices (formerly Linear Technology) is a phase-lockable, fixed-frequency synchronous step-down switching regulator controller driving external N-channel MOSFETs. It supports 3.5V–36V input, delivers up to 5A output via adaptive dual-stage gate drive (TGL/BG + TGS), maintains constant frequency down to ~1% load, and integrates a 0.5A auxiliary linear regulator for low-noise CPU I/O or audio supplies - used in notebook power subsystems and portable instrumentation.
For engineers reviewing the LTC1437ACG#PBF datasheet, LTC1437ACG#PBF pinout, LTC1437ACG#PBF application, or LTC1437ACG#PBF equivalent, key selection criteria include its PLL-synchronizable 112–240kHz oscillator, ≤300ns minimum on-time, 99% dropout duty cycle, remote sense capability, and dual-mode low-load operation (Adaptive Power™ vs Burst Mode®).
Technical Context
The LTC1437ACG#PBF implements a current-mode, constant-frequency buck architecture with an error amplifier (ITH-controlled), dual N-MOSFET synchronous drive (TGL/BG for high-current, TGS for low-current Adaptive Power mode), and secondary feedback (SFB) for isolated winding regulation. Its phase-locked loop accepts external synchronization via PLLIN and modulates oscillator frequency over 0–2.4V at PLL LPF.
It integrates a 5V internal LDO (INTVCC), EXTVCC switchover at 4.7V, programmable soft-start (RUN/SS), built-in POR timer (65536 cycles), low-battery comparator (LBI/LBO), and foldback current limiting. The auxiliary regulator uses AUXON/AUXFB/AUXDR to control an external PNP for 12V or adjustable outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3.5V to 36V - supports wide-input industrial and battery-powered systems including 24V rails and 12V automotive inputs. |
| Oscillator Frequency | 112–240kHz (PLL-enabled) - enables EMI reduction via external sync and avoids critical noise bands. |
| Min On-Time | ≤300ns - allows high-frequency, low-duty-cycle operation (e.g., 3.3V out from 24V in at 400kHz). |
| Duty Cycle Max | 99% - ensures ultra-low dropout regulation near input voltage, critical for battery end-of-life operation. |
| Aux Regulator Output | 0.5A linear regulator - provides low-noise, low-ripple bias for sensitive analog circuits or CPU I/O without added LDO IC. |
| Shutdown IQ | <25µA - enables micropower hold modes in portable devices during sleep states. |
| Output Voltage Range | 1.19V to 9V - selectable via VPROG pin or external divider, covering core logic, memory, and interface rails. |
Pinout & Package
Package: 24-Lead Narrow SSOP (GN), 150-mil body, θJA = 95°C/W. RoHS-compliant, lead-free (Pb-free) finish per #PBF suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply rail | Accepts 3.5V–36V; powers internal circuitry and drives high-side gate driver via BOOST path. |
| INTVCC | Internal 5V regulator output | Supplies control logic, error amp, and drivers; requires ≥2.2µF local decoupling to PGND. |
| BOOST | Floating top-side driver supply | Connected to bootstrap capacitor; enables high-side N-MOSFET drive with voltage swing up to VIN + INTVCC. |
| SW | Switch node | Connects to inductor; swings from ~–0.4V (Schottky drop) to VIN - defines switching waveform and EMI profile. |
| TGL | High-current top-gate driver | Drives large N-MOSFET (e.g., Si4412DY); active in continuous/high-load mode. |
| TGS | Low-current top-gate driver | Drives small N-MOSFET (e.g., IRLML2803); enables Adaptive Power™ mode below ~1% load. |
| BG | Bottom-gate driver | Drives synchronous rectifier; voltage swing 0V to INTVCC - eliminates diode loss and improves light-load efficiency. |
| SENSE+, SENSE− | Current sense differential inputs | Measure RSENSE voltage drop; set peak inductor current threshold (130–180mV range). |
| VOSENSE | Remote output voltage feedback | Accepts feedback from output or external divider; enables precision regulation with PCB trace IR compensation. |
| VPROG | Output voltage programming | Selects 1.19V (open), 3.3V (0V), or 5V (INTVCC); determines internal reference routing and VOSENSE connection point. |
| RUN/SS | Soft-start and enable control | Pull low to shut down (IQ < 25µA); capacitor to ground sets ramp time (~0.5s/µF). |
| PLLIN, PLL LPF | Phase-locked loop interface | PLLIN accepts external clock; PLL LPF sets oscillator frequency (0–2.4V = ±30% fOSC) - only on LTC1437A variant. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Power™ Dual-Stage Drive | Automatically switches between TGL/BG (high-current) and TGS-only (low-current) to sustain constant-frequency operation down to ~1% load - avoids audible noise and EMI spikes of Burst Mode®. |
| PLL-Synchronizable Oscillator | Accepts external clock on PLLIN and adjusts fOSC via PLL LPF voltage (0–2.4V), enabling deterministic timing alignment across multiple converters in dense power systems. |
| Integrated Auxiliary Linear Regulator | Controls external PNP pass device for 0.5A low-noise output; auto-selects 12V internal divider when AUXDR > 9.5V - simplifies dual-rail (e.g., 5V main + 12V VPP) designs. |
| Programmable Soft Start & POR | RUN/SS capacitor sets controlled ramp; POR asserts open-drain signal after 65536 oscillator cycles once VOUT reaches –5% regulation - ensures clean system boot sequencing. |
| True Remote Sense with Foldback | VOSENSE + SFB pins support Kelvin sensing and secondary-winding regulation; foldback current limit (optional) protects against sustained overload without thermal runaway. |
Applications
| Portable Computing Power | Industrial DC Distribution |
|---|---|
Use Scenario: Notebook motherboard VRM supplying CPU core and I/O rails from single 19V adapter. IC Role / Device Role / Timing Role: Primary buck controller managing 5A main rail (e.g., 1.2V/1.8V) and auxiliary 12V VPP for display backlight or USB-PD negotiation. Use Value: Adaptive Power™ eliminates light-load efficiency cliff; remote sense compensates for PCB voltage drop; PLL sync reduces beat frequencies across multi-phase systems. | Use Scenario: DIN-rail mounted 24V-to-5V/3.3V converter powering PLC I/O modules and sensors. IC Role / Device Role / Timing Role: High-reliability step-down controller with wide VIN tolerance, integrated POR for brown-out recovery, and foldback protection against field wiring faults. Use Value: 36V absolute max rating withstands 48V transients; 99% duty cycle sustains regulation during 24V battery sag; EXTVCC switchover enables self-powered efficiency boost. |
| Battery-Powered Test Equipment | Wireless Modem Power Management |
Use Scenario: Handheld oscilloscope or multimeter requiring ultra-low-noise analog supplies and long runtime. IC Role / Device Role / Timing Role: Dual-output controller generating 3.3V digital rail and 12V analog rail (via AUX regulator) from Li-ion battery (3.0–4.2V). Use Value: Integrated 0.5A linear regulator eliminates discrete LDO noise; shutdown IQ < 25µA extends battery life; low-minimum-on-time enables direct 3.3V conversion from single-cell input. | Use Scenario: LTE/5G modem module needing fast transient response and EMI-constrained power delivery. IC Role / Device Role / Timing Role: Synchronized buck controller operating at 200kHz (PLL-locked to baseband clock) to avoid interference with RF receive bands. Use Value: PLL lock ensures deterministic switching edge placement; <300ns min on-time supports 3.8V→3.3V conversion at high frequency; TGS-driven Adaptive Power™ maintains clean spectrum at idle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1436ACGN#PBF | No PLL circuitry; fixed-frequency only (112–138kHz); same pinout and package but lacks PLLIN/PLL LPF pins. | Suitable where EMI control via sync is unnecessary; lower BOM cost and simpler layout. | Select LTC1436ACGN#PBF if external clock sync is not required and cost sensitivity outweighs frequency flexibility. |
| LT8610EMS#PBF | Monolithic 3.5A buck (integrated MOSFETs); higher integration, lower quiescent current (2.5µA), but no auxiliary regulator or PLL sync. | Better for space-constrained designs; unsuitable where external high-current FETs or 12V auxiliary rail are needed. | Choose LT8610EMS#PBF for compact, low-IQ applications without auxiliary regulation or multi-controller synchronization. |
Compared with LTC1436ACGN#PBF, LTC1437ACG#PBF adds PLL synchronization for EMI-sensitive systems; versus LT8610EMS#PBF, it trades monolithic simplicity for design flexibility, higher current scalability, and integrated auxiliary bias generation - making LTC1437ACG#PBF optimal for multi-rail, high-reliability, or synchronized power architectures.
Availability
LTC1437ACG#PBF is available at Aetrix Electronics and suitable for notebook computing power subsystems, industrial DC distribution units, and battery-operated test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC1437ACG#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 LTC1437A belongs to Linear's high-efficiency synchronous buck controller product line, designed specifically for demanding portable and distributed power applications requiring wide input range, precise regulation, and advanced features like PLL sync and auxiliary bias generation.
FAQ
What is the maximum input voltage rating for the LTC1437ACG#PBF?
The LTC1437ACG#PBF has an absolute maximum input voltage rating of 36V on the VIN pin. Continuous operation is specified from 3.5V to 30V, with transient tolerance up to 36V. Exceeding 36V risks permanent damage. This rating enables use with 24V industrial buses and 12V/24V battery systems including automotive cold-crank scenarios.
Does the LTC1437ACG#PBF support remote output voltage sensing?
Yes, the LTC1437ACG#PBF supports true remote sensing via the VOSENSE pin, which accepts feedback directly from the load point to compensate for PCB trace resistance. When combined with the VPROG pin configuration, this enables accurate regulation independent of board-level IR drops - critical for high-current, low-voltage rails like 1.2V CPU cores.
How does the Adaptive Power™ mode in the LTC1437ACG#PBF differ from Burst Mode®?
Adaptive Power™ mode in the LTC1437ACG#PBF uses the TGS pin to drive a small N-MOSFET at full switching frequency down to ~1% load, maintaining constant frequency and low EMI. Burst Mode® (activated by leaving TGS open) pulses full-power switching intermittently, causing variable frequency and potential acoustic noise - making Adaptive Power™ preferable for noise-sensitive applications.
Can the LTC1437ACG#PBF generate a 12V auxiliary output?
Yes, the LTC1437ACG#PBF can generate a 12V auxiliary output using its integrated auxiliary regulator block. When the AUXDR pin voltage exceeds 9.5V, the device automatically connects an internal resistive divider to AUXFB, setting the regulated output to 12V - simplifying implementation of VPP supplies for displays or flash memory without external feedback components.
What is the purpose of the SFB pin on the LTC1437ACG#PBF?
The SFB (Secondary Feedback) pin on the LTC1437ACG#PBF enables regulation of an isolated secondary winding in flyback or forward converters. By connecting SFB to a resistive divider from the secondary output, the controller forces continuous conduction mode regardless of main output loading - ensuring stable regulation across varying primary-side loads and improving cross-regulation in multi-output designs.
LTC1437ACG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 3.5V ~ 30V
- Frequency - Switching:
- Up to 400kHz
- Duty Cycle (Max):
- 99%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power on Reset, Soft Start
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC1437ACG#PBF FAQ
1.How can I place an order for LTC1437ACG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1437ACG#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 LTC1437ACG#PBF reliable?
The price and inventory of LTC1437ACG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1437ACG#PBF is usually 5 days.
3.What payment methods are accepted for LTC1437ACG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1437ACG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1437ACG#PBF?
LTC1437ACG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1437ACG#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 LTC1437ACG#PBF?
For technical support, including LTC1437ACG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1437ACG#PBF requirements.
6.How does Aetrix verify that LTC1437ACG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1437ACG#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 LTC1437ACG#PBF meets industry standards.
7.What is the process for return or replacement of LTC1437ACG#PBF?
All LTC1437ACG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1437ACG#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 LTC1437ACG#PBF part is unused and in its original packaging.
Return procedure for LTC1437ACG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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