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Analog Devices Inc. LTC1438IG#TRPBF
- Part No.:
- LTC1438IG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1438IG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,701
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Product details
Overview
LTC1438IG#TRPBF from Analog Devices (formerly Linear Technology) is a dual, synchronous step-down switching regulator controller driving external N-channel MOSFETs in a phase-lockable fixed-frequency architecture. It delivers two independent regulated outputs (1.19V–9V), supports Adaptive Power™ mode for ultrahigh efficiency down to 1% load, and integrates a 0.5A low-noise linear regulator for VPP or audio supply - used in portable instrumentation and battery-powered DC distribution systems.
For engineers reviewing the LTC1438IG#TRPBF datasheet, LTC1438IG#TRPBF pinout, LTC1438IG#TRPBF application, or LTC1438IG#TRPBF equivalent, key selection criteria include programmable fixed frequency (up to 400kHz), dual synchronous N-MOSFET drive capability, remote output voltage sensing, foldback current limiting option, and logic-controlled micropower shutdown (IQ < 30µA).
Technical Context
The LTC1438IG#TRPBF implements a constant-frequency, current-mode control architecture with dual independent error amplifiers and peak-current sensing via external sense resistors. Each channel features programmable soft start, selectable output voltage (via VPROG pins), and secondary feedback input (SFB1) forcing continuous operation under light-load conditions on Channel 1.
It integrates an internal 5V LDO (INTVCC) with EXTVCC switchover capability, a PLL-synchronizable oscillator (COSC-timed), and auxiliary circuitry including a low-battery comparator (LBI/LBO), power-on reset timer (POR2), and 0.5A linear regulator controlled via AUXON/AUXFB/AUXDR pins - all operating across a 3.5V–36V input range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V max - enables direct operation from 12V/24V industrial rails or multi-cell Li-ion batteries. |
| Switching Frequency | Programmable up to 400kHz via COSC capacitor - balances efficiency vs. component size; PLL lockable on LTC1439 only (not applicable to LTC1438IG#TRPBF). |
| Output Voltage Range | 1.19V to 9V per channel - set by internal resistive dividers (3.3V/5V presets) or external feedback (adjustable mode on Channel 2; Channel 1 adjustable only on -ADJ variant). |
| Quiescent Current | 320µA typical in normal mode; <30µA in shutdown - supports long battery life in portable devices. |
| Duty Cycle Max | 99% - enables very low dropout operation, critical for high-VIN/low-VOUT conversion (e.g., 24V→3.3V). |
| Operating Temp | –40°C to 85°C (Industrial grade) - qualified for embedded industrial and automotive-adjacent applications. |
| Package | 36-lead SSOP (GW package) - surface-mount, thermally enhanced layout compatible with automated assembly. |
Pinout & Package
Package: 36-lead plastic SSOP (GW), 0.025" pitch, exposed pad not specified - suitable for moderate-power DC/DC designs requiring thermal reliability and board-space efficiency.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main input supply rail | Accepts 3.5V–36V; must be decoupled to PGND near IC for stable high-current switching. |
| INTVCC | Internal 5V regulator output | Powers gate drivers and control logic; requires ≥2.2µF tantalum to PGND; shuts off when both RUN/SS pins are low. |
| RUN/SS1, RUN/SS2 | Soft-start & enable inputs | Logic-controlled startup: <1.3V disables channel; capacitor to ground sets ramp time (~0.5s/µF); both low = full shutdown. |
| TGL1/TGL2, BG1/BG2 | Top/bottom N-MOSFET gate drivers | TGLx drives large top-side FETs; BGx drives bottom-side FETs; each rated for 2A peak (<10µs). |
| SENSE+1/2, SENSE−1/2 | Current-sense differential inputs | Measure voltage drop across external RSENSE; built-in offset sets trip threshold (130–180mV typical). |
| VPROG1, VPROG2 | Output voltage programming inputs | Select 3.3V/5V preset or enable adjustable mode (VPROG2 open = VOSENSE2 feedback; VPROG1 open only valid on -ADJ variant). |
| VOSENSE2 | Remote sense input (Channel 2) | Connects to output or external divider for precision regulation; not present on Channel 1 for non-ADJ versions like LTC1438IG#TRPBF. |
| SFB1 | Secondary winding feedback | Forces continuous operation on Channel 1 when pulled below 1.19V - ensures regulation under light load on auxiliary windings. |
| POR2 | Power-on reset output | Open-drain signal asserting when VOUT2 deviates >7.5%; releases after 65536 oscillator cycles once regulation restored. |
| LBI/LBO | Low-battery detect input/output | LBI compares to 1.19V reference; LBO sinks current when LBI <1.19V - enables system-level brownout protection. |
| AUXON/AUXFB/AUXDR | Auxiliary regulator control | AUXON enables 0.5A linear regulator; AUXFB senses output; AUXDR drives PNP base - supports 12V VPP or low-noise 1.2V supplies. |
| COSC | Oscillator timing capacitor | External cap (e.g., 56pF → ~125kHz) sets base frequency; not PLL-capable (LTC1438 lacks PLLIN/PLL LPF pins). |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Power™ mode | Automatically switches between large (TGL/BG) and small (TGS) top-FET drive to maintain fixed frequency and >90% efficiency down to 1% load. |
| Dual synchronous N-MOSFET drive | Independent TGL/BG outputs per channel eliminate external driver ICs and reduce BOM count in dual-rail systems. |
| Remote output voltage sensing | VOSENSE2 and SENSE± inputs support Kelvin connections - eliminates IR drop errors in high-current PCB traces. |
| Integrated 0.5A linear regulator | Generates low-noise, low-dropout auxiliary supply (e.g., 12V VPP or 1.2V audio bias) using external PNP, controlled by AUXON logic. |
| Programmable soft start & shutdown | RUN/SS pins accept external capacitor for controlled ramp-up; logic-low shutdown draws <30µA - essential for battery longevity. |
| Built-in power-on reset timer | POR2 provides system-level reset with 300ms typical delay (65536 cycles at 125kHz) - ensures clean boot after power stabilization. |
Applications
| Portable Instrumentation | Battery-Powered Medical Devices |
|---|---|
Use Scenario: Handheld multimeter with dual isolated rails (5V analog front-end, 3.3V digital core) powered by 3×AA alkaline cells. IC Role / Device Role / Timing Role: Dual synchronous buck controller generating tightly regulated, low-noise outputs with adaptive efficiency scaling across 10mA–2A load range. Use Value: Extends battery life >30% vs. fixed-frequency controllers by maintaining high efficiency at microamp idle currents via Adaptive Power™ mode. | Use Scenario: Wearable ECG monitor requiring ultra-low-noise 1.8V analog supply and 3.3V digital rail from single Li-poly cell (3.0–4.2V). IC Role / Device Role / Timing Role: Primary buck controller for main rails + auxiliary linear regulator (AUXON-enabled) delivering 1.8V at <10µV RMS noise for ADC reference. Use Value: Eliminates need for separate LDO; achieves <20mV dropout at 150mA via 99% duty cycle - preserves runtime as battery discharges. |
| Industrial DC Power Distribution | Embedded Computing Modules |
Use Scenario: DIN-rail mounted IoT gateway converting 24V bus to isolated 5V/3.3V/12V (VPP) for sensors, MCU, and flash memory. IC Role / Device Role / Timing Role: Dual buck controller managing primary 5V/3.3V rails while AUX block generates 12V VPP for EEPROM programming. Use Value: Single-chip solution reduces footprint vs. discrete regulators; POR2 and LBO provide coordinated power-good and brownout signaling to host processor. | Use Scenario: Compact COM Express module requiring precise 1.1V core, 1.8V I/O, and 3.3V peripheral rails from 12V input. IC Role / Device Role / Timing Role: Secondary buck controller (Channel 2) configured for adjustable 1.1V output with remote sensing; Channel 1 supplies 3.3V. Use Value: VOSENSE2 and SENSE± inputs enable ±0.5% load regulation accuracy - meets tight voltage tolerance of modern SoCs. |
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 |
|---|---|---|---|
| LTC3727EGN#PBF | Single-channel, higher current (20A), no integrated auxiliary regulator, supports multiphase sync. | Targeted at high-power CPU/GPU VRMs, not dual-rail portable systems. | Choose when needing >10A per channel and phase interleaving; avoid for low-IQ portable use. |
| TPS54290PWPR | Dual-channel, 2A per channel, integrated FETs (no external MOSFETs required), no auxiliary LDO or SFB1. | Lower BOM cost for mid-power apps; lacks Adaptive Power™ and secondary feedback for transformer-coupled rails. | Prefer for space-constrained designs where external FETs are undesirable; not suitable for VPP generation or transformer regulation. |
Compared with LTC3727EGN#PBF and TPS54290PWPR, the LTC1438IG#TRPBF uniquely combines dual independent controllers, Adaptive Power™ efficiency optimization, and an integrated 0.5A linear regulator - making it optimal for battery-sensitive, dual-rail systems requiring auxiliary voltage generation and transformer secondary regulation support.
Availability
LTC1438IG#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered medical devices, and industrial DC power distribution systems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for LTC1438IG#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 digital signal processing semiconductors - acquired Linear Technology in 2017 to expand its power management portfolio.
The LTC1438IG#TRPBF belongs to ADI's legacy Linear Technology switching controller family, designed specifically for high-efficiency, dual-output DC/DC conversion in portable and industrial equipment where adaptive light-load efficiency and auxiliary supply integration are critical.
FAQ
What is the maximum supported switching frequency for the LTC1438IG#TRPBF?
The LTC1438IG#TRPBF supports a programmable fixed switching frequency up to 400kHz, set by the external COSC capacitor. Operation beyond this limit is not characterized and may compromise stability or efficiency. The typical oscillator frequency is 125kHz with a 100pF capacitor, and the device maintains constant frequency down to 1% load via Adaptive Power™ mode - unlike burst-mode-only controllers.
Does the LTC1438IG#TRPBF support phase synchronization with an external clock?
No, the LTC1438IG#TRPBF does not support phase synchronization. It lacks the PLLIN and PLL LPF pins required for PLL functionality - those are present only on the LTC1439 variant. The LTC1438IG#TRPBF uses a standalone, COSC-programmed oscillator with fixed-frequency operation and Adaptive Power™ mode for light-load efficiency, but no external clock locking capability.
Can the LTC1438IG#TRPBF generate an adjustable output voltage on both channels?
Only Channel 2 (controlled by VPROG2 and VOSENSE2) supports fully adjustable output voltage via external feedback. Channel 1 is limited to 3.3V or 5.0V presets on the LTC1438IG#TRPBF; adjustable operation on Channel 1 requires the LTC1438IG#TRPBF-ADJ variant, which provides VOSENSE1 and different internal routing. This distinction is explicitly documented in Table 1 of the datasheet.
What is the purpose of the SFB1 pin on the LTC1438IG#TRPBF?
The SFB1 pin on the LTC1438IG#TRPBF is a secondary winding feedback input dedicated to Channel 1. When pulled below 1.19V, it forces continuous synchronous operation - ensuring regulation even under very light loads on transformer-coupled auxiliary windings. It is not used for standard buck operation and must be tied to INTVCC or grounded depending on whether secondary winding feedback is implemented.
How does the auxiliary linear regulator in the LTC1438IG#TRPBF function?
The auxiliary linear regulator in the LTC1438IG#TRPBF controls an external PNP transistor via AUXDR to deliver up to 0.5A. It is enabled by pulling AUXON high and regulated via AUXFB, which connects to either an internal 12V divider (when AUXDR >9.5V) or an external resistor network. This block can generate low-noise supplies such as 12V VPP for flash programming or 1.2V bias rails - all without requiring a separate LDO IC.
LTC1438IG#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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC1438IG#TRPBF FAQ
1.How can I place an order for LTC1438IG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1438IG#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 LTC1438IG#TRPBF reliable?
The price and inventory of LTC1438IG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1438IG#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1438IG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1438IG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1438IG#TRPBF?
LTC1438IG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1438IG#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 LTC1438IG#TRPBF?
For technical support, including LTC1438IG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1438IG#TRPBF requirements.
6.How does Aetrix verify that LTC1438IG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1438IG#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 LTC1438IG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1438IG#TRPBF?
All LTC1438IG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1438IG#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 LTC1438IG#TRPBF part is unused and in its original packaging.
Return procedure for LTC1438IG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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