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Analog Devices Inc. LTC1437ACG#TRPBF
- Part No.:
- LTC1437ACG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1437ACG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,948
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Product details
Overview
LTC1437ACG#TRPBF 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-drive architecture (TGL/BG for high current, TGS for low-current mode), and integrates a 0.5A auxiliary linear regulator with 12V/1.2V selectable output - used in notebook CPU I/O and low-noise audio supplies.
For engineers reviewing the LTC1437ACG#TRPBF datasheet, LTC1437ACG#TRPBF pinout, LTC1437ACG#TRPBF application, or LTC1437ACG#TRPBF equivalent, key selection criteria include its programmable fixed frequency (112–240 kHz), ≤300 ns minimum on-time, 99% duty-cycle dropout capability, remote sense support, and PLL synchronization for EMI-sensitive multi-rail systems.
Technical Context
The LTC1437ACG#TRPBF implements a constant-frequency current-mode control loop with adaptive power staging: TGL/BG drive large N-MOSFETs for full-load efficiency, while TGS enables continuous low-current operation down to ~1% of rated load without Burst Mode. Its secondary feedback (SFB) pin forces continuous conduction regardless of auxiliary load, ensuring regulation stability in multi-output flyback-derived topologies.
Phase-locked loop functionality (PLLIN/PLL LPF pins) allows oscillator synchronization to external clocks (e.g., system master clock), reducing beat frequencies and EMI peaks. The internal 5V INTVCC regulator can be bypassed via EXTVCC ≥4.7V, enabling efficient self-powered operation when VOUT ≥5V or using a secondary winding supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V - supports wide industrial and automotive battery inputs, including 24V nominal systems with transients. |
| Switching Frequency | 112–240 kHz (PLL-locked) - programmable via COSC capacitor; enables EMI filtering and transformer sizing trade-offs. |
| Min On-Time | ≤300 ns - permits high-frequency, low-duty-cycle operation (e.g., 5V→1.2V conversion at 400 kHz). |
| Output Current Drive | TGL/BG: 2A peak (10 µs); TGS: 250 mA peak - enables discrete MOSFET selection for optimized thermal and conduction loss partitioning. |
| Auxiliary Regulator | 0.5A linear regulator with 12V/1.2V selectable output - provides low-noise bias for analog circuits or CPU I/O rails without added LDO. |
| Current Sense Threshold | 130–180 mV - sets peak inductor current limit; supports RSENSE ≥0.005Ω for accurate, temperature-stable current limiting. |
| Shutdown IQ | <25 µA - enables micropower hold mode in battery-backed systems with logic-controlled RUN/SS pin. |
Pinout & Package
Package: 24-Lead Narrow SSOP (GN), 150-mil body, RoHS-compliant, moisture-sensitive level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Supplies control circuitry and gate drivers; requires local 22µF/35V decoupling to PGND. |
| INTVCC | Internal 5V regulator output | Powers internal logic and drivers; must be decoupled with ≥2.2µF tantalum to PGND. |
| BOOST | Floating top-side driver supply | Connected to bootstrap capacitor; voltage swing = INTVCC superimposed on SW node. |
| SW | Switch node | Connects to inductor; voltage swings from Schottky drop below GND to VIN. |
| PGND | Power ground | Return path for bottom MOSFET source and CIN (–); separate from SGND to minimize noise coupling. |
| SGND | Small-signal ground | Reference for VOSENSE, SENSE+, SENSE–, ITH; routed separately to COUT (–) to avoid ground bounce. |
| TGL | Top gate driver (large MOSFET) | Floating output driving main high-side N-MOSFET; 2A peak capability for high-current phases. |
| TGS | Top gate driver (small MOSFET) | Floating output for auxiliary low-current N-MOSFET; open = Burst Mode fallback. |
| BG | Bottom gate driver | Ground-referenced output driving synchronous rectifier; 2A peak, 0–INTVCC swing. |
| VOSENSE | Remote output voltage sense | Feedback input for main regulator; connects to output or external divider; referenced to VPROG state. |
| VPROG | Output voltage select | DC voltage selects 1.19V (open), 3.3V (0V), or 5V (INTVCC); determines VOSENSE connection point. |
| RUN/SS | Enable + soft-start control | Pulled low = shutdown (<25 µA IQ); capacitor to GND sets ramp time (~0.5 s/µF). |
| ITH | Error amplifier compensation | Controls current comparator threshold; 0–2.5V range sets peak inductor current. |
| SENSE+ | Current sense (+) | High-side input to current comparator; used with SENSE– and RSENSE to set overcurrent trip. |
| SENSE– | Current sense (–) | Low-side input to current comparator; built-in offset enables accurate RSENSE-based current sensing. |
| SFB | Secondary feedback input | For flyback-derived auxiliary outputs; tie to GND to force continuous conduction, or to divider for regulation. |
| AUXON | Auxiliary regulator enable | Logic-high (>1.19V) activates 0.5A linear regulator; low disables AUX block completely. |
| AUXDR | Auxiliary driver output | Open-drain PNP base drive; >9.5V invokes internal 12V divider on AUXFB for standard 12V output. |
| AUXFB | Auxiliary feedback input | Connects to PNP collector (12V mode) or external divider (custom voltage); reference is 1.19V. |
| PLLIN | External sync input | 50kΩ internally pulled to SGND; accepts TTL/CMOS clock for PLL lock; open = min frequency. |
| PLL LPF | PLL filter/control node | Phase detector output and oscillator control; 0–2.4V range adjusts fOSC ±30%; RC filter required. |
| POR | Power-on reset output | Open-drain; asserts low when VOUT is >7.5% out-of-regulation; releases after 65536 fOSC cycles. |
| LBO/LBI | Low-battery detect I/O | LBI = comparator +in (1.19V ref); LBO = open-drain output asserting when LBI <1.19V. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Power™ dual-drive architecture | Enables continuous fixed-frequency operation down to ~1% load by switching between large (TGL/BG) and small (TGS) top MOSFETs - avoids efficiency cliff of Burst Mode. |
| Programmable fixed-frequency PLL lock | Allows synchronization to system clock (via PLLIN) to eliminate beat frequencies and reduce conducted/radiated EMI in multi-converter systems. |
| Integrated 0.5A auxiliary linear regulator | Eliminates need for external LDO in dual-rail designs; supports 12V (internal divider) or custom voltages (external divider) with single PNP pass device. |
| Remote output voltage sensing (VOSENSE) | Compensates for PCB trace IR drop in high-current applications, maintaining tight regulation at point-of-load. |
| Logic-controlled micropower shutdown | Reduces quiescent current to <25 µA during standby - critical for battery life in portable instruments and PDAs. |
| Secondary winding feedback (SFB) | Guarantees regulation of main output even under varying auxiliary load conditions, essential for isolated multi-output flyback derivatives. |
Applications
| Portable Computing Power | Industrial DC Distribution |
|---|---|
Use Scenario: Notebook motherboard requiring tightly regulated 3.3V/5V rails and low-noise 1.2V CPU I/O supply from 12V or 19V adapter input. IC Role / Device Role / Timing Role: Main step-down controller for primary rail + integrated auxiliary LDO for noise-sensitive I/O domain. Use Value: Adaptive Power maintains 92%+ efficiency at 100mA load (vs. 75% in Burst Mode), reducing thermal stress and audible coil whine. | Use Scenario: DIN-rail mounted 24V-to-5V/12V converter powering PLC I/O modules, sensors, and communication interfaces. IC Role / Device Role / Timing Role: High-voltage synchronous buck controller with robust fault protection (foldback, POR, LBO) and wide-temp operation. Use Value: 36V absolute max VIN and –40°C to 85°C rating ensure reliability in unregulated industrial environments with line surges. |
| Battery-Powered Test Equipment | Wireless Modem Power Management |
Use Scenario: Handheld oscilloscope or multimeter drawing variable load from Li-ion (3.0–4.2V) or 9V alkaline battery pack. IC Role / Device Role / Timing Role: Primary buck controller with ultra-low shutdown IQ and programmable soft-start to prevent inrush into capacitive loads. Use Value: <25 µA shutdown current extends battery runtime; 300ns min on-time supports 3.3V→1.8V conversion at 400 kHz for compact layout. | Use Scenario: LTE/Wi-Fi module requiring clean 3.3V digital rail and 1.2V RF core supply, synchronized to baseband clock to suppress switching noise. IC Role / Device Role / Timing Role: PLL-locked buck controller with auxiliary LDO for RF bias, minimizing spectral interference in sensitive receive bands. Use Value: PLL synchronization eliminates heterodyne tones between switching frequency and RF LO, improving receiver sensitivity by 3–5 dB. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610ACDE#TRPBF | Monolithic 3.5A buck (integrated MOSFETs); 35ns min on-time; 2.8–30V input; no auxiliary LDO or PLL sync. | Lower BOM count but lacks dual-rail support and external MOSFET flexibility; unsuitable for >5A or 12V auxiliary needs. | Select when board space is constrained and auxiliary rail is not required; verify thermal limits at full load. |
| TPS54360DGQR | 3.5A monolithic buck; 3.5–60V input; no PLL, no auxiliary regulator; integrated soft-start and current limit. | Higher VIN range but no adaptive low-load mode - defaults to Eco-mode (discontinuous conduction), less predictable light-load behavior. | Prefer for cost-sensitive 48V industrial inputs where auxiliary rail and EMI synchronization are unnecessary. |
Compared with LT8610ACDE#TRPBF and TPS54360DGQR, the LTC1437ACG#TRPBF uniquely combines external MOSFET control, PLL synchronization, and an integrated 0.5A auxiliary LDO - making it optimal for multi-rail, EMI-critical, or high-reliability applications where flexibility and noise performance outweigh monolithic integration benefits.
Availability
LTC1437ACG#TRPBF is available at Aetrix Electronics and suitable for notebook computing power, industrial DC distribution, and battery-operated test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC1437ACG#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC1437A belongs to Linear's high-efficiency synchronous buck controller family, designed specifically for multi-rail, low-noise, and EMI-sensitive applications in portable computing, telecom infrastructure, and industrial instrumentation.
FAQ
What is the operating temperature range for the LTC1437ACG#TRPBF?
The LTC1437ACG#TRPBF is specified for commercial temperature range: 0°C to 70°C. Its thermal resistance θJA is 95°C/W (24-lead SSOP package), enabling reliable operation in ambient temperatures up to 65°C with appropriate PCB copper area and airflow. Derating curves in the datasheet confirm stable performance across this range.
Does the LTC1437ACG#TRPBF support pin-selectable output voltages?
Yes, the LTC1437ACG#TRPBF supports three factory-configured output voltages via the VPROG pin: open-circuit = 1.19V (adjustable mode), 0V = 3.3V, and INTVCC = 5V. This eliminates external resistor dividers for common rails, simplifying design and improving accuracy - all configurations retain remote sensing via VOSENSE.
How does the Adaptive Power™ feature improve light-load efficiency in the LTC1437ACG#TRPBF?
The Adaptive Power™ feature in the LTC1437ACG#TRPBF switches gate drive from TGL/BG (large MOSFETs) to TGS (small MOSFET) below ~10% load, maintaining fixed-frequency operation and avoiding Burst Mode. This reduces switching losses and audible noise while sustaining >85% efficiency at 100mA - a 10–15% improvement over conventional controllers at light loads.
Can the LTC1437ACG#TRPBF be synchronized to an external clock?
Yes, the LTC1437ACG#TRPBF supports external synchronization via the PLLIN pin. When driven with a TTL/CMOS clock, the internal phase-locked loop locks the oscillator to the external source, aligning top-MOSFET turn-on edges. This eliminates beat frequencies and reduces EMI peaks - critical in multi-converter systems like base stations or multi-core processors.
What is the purpose of the SFB pin on the LTC1437ACG#TRPBF?
The SFB (Secondary Feedback) pin on the LTC1437ACG#TRPBF ensures main output regulation remains stable regardless of auxiliary load variations. When tied to a resistive divider from a flyback secondary winding, it forces continuous conduction mode - preventing output droop during transient loading on auxiliary rails, a key requirement in multi-output isolated supplies.
LTC1437ACG#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LTC1437ACG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1437ACG#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 LTC1437ACG#TRPBF reliable?
The price and inventory of LTC1437ACG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1437ACG#TRPBF is usually 5 days.
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We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1437ACG#TRPBF transactions.
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4.How is shipping managed for LTC1437ACG#TRPBF?
LTC1437ACG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1437ACG#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 LTC1437ACG#TRPBF?
For technical support, including LTC1437ACG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1437ACG#TRPBF requirements.
6.How does Aetrix verify that LTC1437ACG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1437ACG#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 LTC1437ACG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1437ACG#TRPBF?
All LTC1437ACG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1437ACG#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 LTC1437ACG#TRPBF part is unused and in its original packaging.
Return procedure for LTC1437ACG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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