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Analog Devices Inc. LTC1438XCG#TRPBF
- Part No.:
- LTC1438XCG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1438XCG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,731
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Product details
Overview
LTC1438XCG#TRPBF from Analog Devices (formerly Linear Technology) is a dual synchronous step-down switching regulator controller driving external N-channel MOSFETs in a fixed-frequency, phase-lockable architecture. It delivers two regulated outputs (selectable 3.3V/5V or adjustable), supports ultrahigh efficiency down to 1% load via Adaptive Power™ mode, maintains 99% duty cycle for ultra-low dropout, and operates from 3.5V to 30V input - ideal for notebook computers and portable instrumentation.
For engineers reviewing the LTC1438XCG#TRPBF datasheet, LTC1438XCG#TRPBF pinout, LTC1438XCG#TRPBF application, or LTC1438XCG#TRPBF equivalent, key selection criteria include its dual-channel current-mode control, programmable soft-start, remote output voltage sensing on Channel 2, integrated power-on reset timer (POR2), and compatibility with external PNP-based auxiliary linear regulators for low-noise VPP or audio supplies.
Technical Context
The LTC1438XCG#TRPBF implements a constant-frequency, current-mode control architecture with independent error amplifiers per channel, where ITH1/ITH2 pins set peak current thresholds via voltage-controlled comparators. Its Adaptive Power™ stage dynamically routes gate drive between large (TGL/BG) and small (TGS) top-side MOSFETs based on load current and SENSE– voltage hysteresis, enabling continuous 125kHz operation down to ~35mA (1% of 3.5A rating).
It features dual independent RUN/SS pins for per-channel enable/soft-start, SFB1 feedback forcing continuous conduction on Channel 1, and internal resistive dividers for pin-selectable 3.3V/5V outputs - with Channel 1 fixed to 3.3V or 5V (not adjustable) and Channel 2 supporting adjustable output via VOSENSE2 and VPROG2. POR2 is disabled on this variant, distinguishing it from LTC1439 and LTC1438-ADJ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 30V (absolute max 36V); enables direct battery-input operation in 5V–24V systems without pre-regulation. |
| Switching Frequency | 125kHz typical (COSC = 100pF); fixed-frequency operation ensures predictable EMI profile and simplifies filter design. |
| Output Voltage Options | Channel 1: 3.3V or 5.0V only (pin-selectable); Channel 2: 1.19V–9V adjustable via VOSENSE2 and external divider. |
| Efficiency Mode | Adaptive Power™ mode sustains fixed frequency down to ~1% load; eliminates burst-mode noise in sensitive analog/audio rails. |
| Quiescent Current | 320µA typical in normal operation; <30µA in logic-controlled shutdown - critical for battery runtime in portable devices. |
| Operating Temp Range | 0°C to 70°C (Commercial grade); validated for notebook, PDA, and industrial portable instrument ambient conditions. |
| Duty Cycle Max | 99%; supports ultra-low dropout regulation (e.g., 5V out from 5.1V in), essential for post-regulation in tight-voltage-margin systems. |
Pinout & Package
Package: 28-Lead Plastic SSOP (G package), RoHS-compliant, moisture-sensitive level 3. Thermal resistance θJA = 95°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE+ 1 / SENSE– 1 | Current sense differential inputs (Channel 1) | Measure inductor current via external RSENSE; SENSE– 1 internally tied to VOUT1 for non-adjustable configurations. |
| VPROG1 | Output voltage programming select (Channel 1) | DC voltage level sets 3.3V (0V) or 5.0V (INTVCC) output; open-circuit not supported on LTC1438XCG. |
| ITH1 | Error amplifier compensation node (Channel 1) | Controls peak current threshold; voltage increase raises current limit - used for loop compensation and current limiting. |
| RUN/SS1 | Channel 1 enable + soft-start timing input | Pull below 1.3V disables Channel 1; capacitor to ground sets soft-start ramp time (~0.5s/µF). |
| VOSENSE2 | Remote feedback input (Channel 2) | Accepts voltage from external resistor divider; enables precise regulation at point-of-load, critical for high-current digital rails. |
| VPROG2 | Output voltage programming select (Channel 2) | Open = adjustable mode; INTVCC = 5V; 0V = 3.3V - provides flexible configuration without external DAC. |
| SGND / PGND | Signal ground / power ground | Separate return paths prevent noise coupling from high di/dt switch-node currents into control circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent current-mode controllers | Enables simultaneous regulation of CPU core (5V) and I/O (3.3V) rails with separate soft-start, fault response, and enable control. |
| Adaptive Power™ gate drive architecture | Automatically switches between high-current (TGL/BG) and low-current (TGS) top-FET drivers - maintains fixed frequency and low noise at light loads. |
| Remote output voltage sensing (Channel 2) | Compensates for PCB trace IR drop up to ±150mV, ensuring stable 3.3V/5V delivery at FPGA or ASIC VCC pins. |
| Logic-controlled micropower shutdown | IQ < 30µA with both RUN/SS pins low - extends battery life in sleep modes without external disconnect circuitry. |
| Integrated 5V internal LDO (INTVCC) | Self-powered driver supply; EXTVCC switchover at 4.7V allows efficient sourcing from main output, reducing system component count. |
Applications
| Notebook Power Management | Portable Instrumentation |
|---|---|
Use Scenario: Dual-rail power for Intel Pentium-class CPU (5V) and peripheral logic (3.3V) in clamshell-form factor notebooks. IC Role / Device Role / Timing Role: Primary DC/DC controller managing synchronous buck conversion, adaptive light-load efficiency, and coordinated soft-start sequencing. Use Value: Eliminates burst-mode EMI during low-power states while maintaining <1% output voltage deviation across 0–3.5A load range. | Use Scenario: Precision analog front-end and microcontroller supply in handheld multimeters and oscilloscopes. IC Role / Device Role / Timing Role: Dual-output regulator delivering clean 3.3V for ADC/DAC and 5V for display backlight drivers with independent enable control. Use Value: Remote sensing on Channel 2 ensures ±0.5% regulation accuracy at measurement circuitry, directly improving DC voltage measurement fidelity. |
| Battery-Operated Medical Devices | DC Power Distribution Systems |
Use Scenario: Powering low-noise analog signal chains and wireless transceivers in portable ECG monitors. IC Role / Device Role / Timing Role: Main regulator supplying 3.3V rail; auxiliary linear regulator (via AUXON/AUXFB) generates ultra-low-noise 12V VPP for op-amp biasing. Use Value: Adaptive Power™ mode prevents audible coil whine during standby, meeting IEC 60601-1 acoustic emission requirements. | Use Scenario: Distributed 5V/3.3V generation across modular industrial I/O cards with shared 24V backplane input. IC Role / Device Role / Timing Role: Local point-of-load controller with SFB1-driven secondary winding feedback for cross-regulation between adjacent slots. Use Value: SFB1 pin forces continuous conduction on Channel 1, guaranteeing stable 5V output even when Channel 2 load varies widely - critical for deterministic bus timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1439CG#TRPBF | Includes PLLIN/PLL LPF pins and functional POR2 output; supports external clock synchronization and power-good signaling on Channel 2. | Required where system-level clock alignment or sequenced power-good assertion is mandatory (e.g., multi-processor SoM). | Select LTC1439CG#TRPBF if phase-locking to master clock or POR2 monitoring is needed; LTC1438XCG#TRPBF omits these functions to reduce pin count and cost. |
| TPS54290RGTT | Single-channel, integrated FET (no external MOSFETs); 4.5–20V input; 0.76–14V adjustable output; no auxiliary linear regulator support. | Suitable for space-constrained single-rail designs but lacks dual independent control, remote sensing, and PNP-based auxiliary supply capability. | Choose TPS54290RGTT only for cost-sensitive, single-output applications where external MOSFET flexibility and auxiliary VPP generation are unnecessary. |
Compared with LTC1439CG#TRPBF, LTC1438XCG#TRPBF removes PLL and POR2 functionality - reducing complexity and BOM count for fixed-frequency, non-sequenced dual-rail systems. Versus TPS54290RGTT, LTC1438XCG#TRPBF offers true dual-channel independence, external FET scalability, and integrated auxiliary linear regulator control - essential for high-efficiency, multi-rail portable power architectures.
Availability
LTC1438XCG#TRPBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, and battery-operated medical devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC1438XCG#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC1438XCG#TRPBF belongs to Linear's legacy high-efficiency DC/DC controller product line, engineered specifically for portable computing and instrumentation where light-load efficiency, low EMI, and dual-rail flexibility are critical design constraints.
FAQ
What is the maximum output current capability of the LTC1438XCG#TRPBF?
The LTC1438XCG#TRPBF is a controller IC and does not integrate power MOSFETs; its output current is determined by external components. Reference designs using Si4412ADY MOSFETs and 10µH inductors achieve 3.5A per channel. Peak gate drive capability is 2A (TGL/TGS) and 250mA (TGS), supporting robust high-current designs when paired with appropriately rated external FETs and magnetics.
Does the LTC1438XCG#TRPBF support adjustable output voltage on both channels?
No. The LTC1438XCG#TRPBF supports fixed 3.3V or 5.0V output on Channel 1 (selected via VPROG1), while Channel 2 supports adjustable output from 1.19V to 9V via VOSENSE2 and an external resistive divider. This is confirmed in Table 1 of the datasheet and distinguishes LTC1438XCG#TRPBF from the LTC1438-ADJ (adjustable Channel 1) and LTC1439 (full adjustability plus PLL).
Is the POR2 power-on reset function available on the LTC1438XCG#TRPBF?
No. The POR2 output is explicitly disabled on the LTC1438XCG#TRPBF variant, as stated in the Pin Functions section: "POR2 Output - This pin is not functional on the LTC1438X." Designers requiring power-good signaling must select LTC1439CG#TRPBF or implement external supervision circuitry when using LTC1438XCG#TRPBF.
Can the LTC1438XCG#TRPBF drive an external PNP transistor for auxiliary voltage generation?
Yes. The LTC1438XCG#TRPBF includes dedicated AUXON, AUXFB, and AUXDR pins to control an external PNP pass device, enabling low-noise, low-dropout linear regulation - for example, generating 12V VPP or clean 3.3V audio supplies. This function remains fully operational despite the absence of POR2 and PLL features.
What is the purpose of the SFB1 pin on the LTC1438XCG#TRPBF?
The SFB1 pin on the LTC1438XCG#TRPBF provides secondary winding feedback for Channel 1. Pulling SFB1 below 1.19V forces continuous conduction mode regardless of load, ensuring regulation stability in flyback-derived auxiliary supplies or cross-regulated multi-output systems - a key feature for maintaining timing integrity in DC power distribution applications.
LTC1438XCG#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:
- 2
- 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
LTC1438XCG#TRPBF FAQ
1.How can I place an order for LTC1438XCG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1438XCG#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 LTC1438XCG#TRPBF reliable?
The price and inventory of LTC1438XCG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1438XCG#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1438XCG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1438XCG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1438XCG#TRPBF?
LTC1438XCG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1438XCG#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 LTC1438XCG#TRPBF?
For technical support, including LTC1438XCG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1438XCG#TRPBF requirements.
6.How does Aetrix verify that LTC1438XCG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1438XCG#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 LTC1438XCG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1438XCG#TRPBF?
All LTC1438XCG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1438XCG#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 LTC1438XCG#TRPBF part is unused and in its original packaging.
Return procedure for LTC1438XCG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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