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Analog Devices Inc. LTC1438IG-ADJ#TRPBF
- Part No.:
- LTC1438IG-ADJ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1438IG-ADJ#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,205
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Product details
Overview
LTC1438IG-ADJ#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 adjustable 1.19V–9V outputs, supports 3.5V–30V input, maintains constant frequency down to ~1% load via Adaptive Power™ mode, and integrates a 0.5A low-noise linear regulator - used in portable instrumentation requiring high efficiency and remote sensing.
For engineers reviewing the LTC1438IG-ADJ#TRPBF datasheet, LTC1438IG-ADJ#TRPBF pinout, LTC1438IG-ADJ#TRPBF application, or LTC1438IG-ADJ#TRPBF equivalent, key selection criteria include programmable output voltage (via VPROG2/VOSENSE2), secondary feedback control (SFB1), dual-channel soft-start (RUN/SS1/RUN/SS2), and 28-pin SSOP package compatibility with thermal design for industrial ambient range (–40°C to 85°C).
Technical Context
The LTC1438IG-ADJ#TRPBF implements a current-mode, constant-frequency step-down architecture with independent error amplifiers per channel, where ITH1/ITH2 set peak inductor current via sensed voltage across external RSENSE resistors. Its Adaptive Power™ stage dynamically switches between TGL/BG (high-current synchronous drive) and TGS (low-current diode-assisted drive) to sustain 400kHz operation down to light loads.
It features dual independent control loops: Controller 1 is adjustable-only with remote sense (VOSENSE1), while Controller 2 supports 3.3V/5V/adjustable outputs via VPROG2; both support PLL synchronization (LTC1439 only), but LTC1438IG-ADJ#TRPBF excludes PLLIN and PLL LPF pins per its G-package variant. The auxiliary linear regulator uses AUXON/AUXFB/AUXDR for 12V or low-noise 1.19V–12.5V outputs.
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–28V portable systems. |
| Output Voltage Range | 1.19V to 9V (adjustable via VOSENSE2/VPROG2); supports custom rail generation without fixed-resistor dividers on Channel 2. |
| Switching Frequency | Up to 400kHz (COSC-programmable); balances efficiency vs. size - higher fSW allows smaller L/C but increases gate loss. |
| Operating Temp Range | –40°C to +85°C (Industrial grade); validated for embedded instrumentation and battery-powered equipment. |
| Quiescent Current | 320µA typical (normal mode); ensures minimal standby drain in always-on subsystems. |
| Shutdown Current | <30µA (IQ < 30µA); meets micropower requirements for long-life battery applications. |
| Current Sense Threshold | 150mV typical (∆VSENSE(MAX)); sets overcurrent trip point with ±30mV tolerance - defines RSENSE selection for 3.5A+ designs. |
Pinout & Package
Package: 28-Lead Plastic SSOP (G package), 5.6mm × 10.2mm body, 0.635mm pitch, exposed pad not specified - suitable for thermally constrained PCB layouts in portable devices.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE+ 1 / SENSE– 1 | Current sense differential inputs (Channel 1) | Connect across RSENSE1 to set peak current limit; SENSE– 1 internally tied to VOUT1 in non-ADJ versions, but LTC1438IG-ADJ#TRPBF enables true remote sensing via VOSENSE1. |
| VPROG1 / VPROG2 | Output voltage programming inputs | VPROG1 open = adjustable Channel 1; VPROG2 open = adjustable Channel 2 via VOSENSE2 - enables precise custom regulation without fixed taps. |
| VOSENSE1 / VOSENSE2 | Remote output voltage feedback inputs | VOSENSE1 present only on -ADJ variants; allows Kelvin sensing of Channel 1 output - critical for low-dropout stability under load transients. |
| RUN/SS1 / RUN/SS2 | Soft-start and enable control | Capacitor-to-ground sets ramp time (~0.5s/µF); pulling below 1.3V disables respective channel - supports staggered power-up sequencing. |
| SFB1 | Secondary winding feedback input | Forces continuous operation on Channel 1 when pulled below 1.19V - ensures regulation integrity in multi-winding transformer topologies. |
| AUXON / AUXFB / AUXDR | Auxiliary linear regulator interface | AUXON enables 0.5A PNP-based supply; AUXFB senses output; AUXDR drives PNP base - delivers low-noise bias for audio or ADC references. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Power™ Mode | Automatically selects TGS (low-ILOAD) or TGL/BG (high-ILOAD) drive paths - sustains 400kHz operation down to ~1% rated load without efficiency collapse. |
| Dual Independent Soft-Start | RUN/SS1 and RUN/SS2 accept separate timing capacitors - enables controlled, non-simultaneous ramp-up of two power rails to avoid inrush current stacking. |
| Remote Output Sensing (Channel 1) | VOSENSE1 pin available only on -ADJ variants - eliminates IR drop errors in high-current PCB traces, improving regulation accuracy to ±0.8% under full load. |
| Integrated Power-On Reset (POR2) | Generates 300ms-delayed active-low signal after VOUT2 reaches ±5% - provides deterministic system reset timing without external RC networks. |
| Low-Battery Detection (LBI/LBO) | Comparator with 1.19V internal reference and 20mV hysteresis - detects battery sag before brownout, enabling graceful shutdown in handheld devices. |
Applications
| Portable Instrumentation | Battery-Powered Test Equipment |
|---|---|
Use Scenario: Handheld multimeter with dual analog front-end rails (±5V, +3.3V) and low-noise ADC reference. IC Role / Device Role / Timing Role: LTC1438IG-ADJ#TRPBF regulates precision analog supplies while its auxiliary linear regulator powers the 12-bit DAC reference with <10µV ripple. Use Value: Remote sensing on Channel 1 eliminates trace resistance error; Adaptive Power™ maintains stable 400kHz switching during battery discharge from 4.2V to 3.5V. | Use Scenario: Portable oscilloscope with FPGA core (1.2V), memory (1.8V), and display backlight (5V). IC Role / Device Role / Timing Role: LTC1438IG-ADJ#TRPBF generates 1.2V (adjustable) and 5V rails; RUN/SS2 delays 5V startup until FPGA config completes. Use Value: Dual soft-start prevents simultaneous inrush; 320µA quiescent current extends battery life beyond 8 hours at 100mA avg load. |
| Industrial Data Acquisition | Medical Point-of-Care Devices |
Use Scenario: Isolated sensor node with 24-bit sigma-delta ADC requiring ultra-low-noise 5V and 3.3V supplies. IC Role / Device Role / Timing Role: LTC1438IG-ADJ#TRPBF's auxiliary linear regulator supplies ADC reference; SFB1 enforces continuous mode for clean spectral performance. Use Value: Auxiliary regulator PSRR >60dB at 1kHz suppresses switching noise; SFB1 forcing eliminates burst-mode jitter in FFT measurements. | Use Scenario: Battery-operated pulse oximeter needing regulated 3.3V for MCU and 1.8V for optical sensor driver. IC Role / Device Role / Timing Role: LTC1438IG-ADJ#TRPBF configures Channel 2 as 1.8V adjustable output; LBI monitors Li-ion cell voltage for end-of-life warning. Use Value: LBI comparator with 1.19V threshold triggers alert at 3.0V/cell; shutdown IQ <30µA preserves standby time over 72 hours. |
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 |
|---|---|---|---|
| LTC1439IGW#TRPBF | 36-pin SSOP; includes PLLIN/PLL LPF pins; supports external clock synchronization; no VOSENSE1 pin. | Used where multi-controller phase alignment is required (e.g., parallel power stages); lacks Channel 1 remote sensing. | Select when clock sync is mandatory and Channel 1 adjustability is sufficient without remote sense. |
| MP2491DS-LF-Z | Single-channel, integrated MOSFETs; 4.5–18V input; fixed 3.3V/5V options; no auxiliary LDO or SFB1. | Targeted at cost-sensitive single-rail apps; no secondary feedback or linear regulator - requires external components for noise-sensitive rails. | Choose for simplified BOM in non-critical, single-output systems where remote sensing and low-noise aux supply are unnecessary. |
Compared with LTC1438IG-ADJ#TRPBF, LTC1439IGW#TRPBF adds PLL synchronization but removes VOSENSE1, limiting remote sensing capability on Channel 1; MP2491DS-LF-Z reduces component count via integrated FETs but sacrifices dual-channel flexibility, auxiliary regulation, and precision sensing - making it unsuitable for medical or test equipment demanding rail independence and noise immunity.
Availability
LTC1438IG-ADJ#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered test equipment, and industrial data acquisition systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC1438IG-ADJ#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 acquired Linear Technology in 2017 and maintains its high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LTC1438 series targets dual-rail, battery-fed applications demanding efficiency across wide load ranges - designed specifically for portable instrumentation, medical devices, and test equipment where remote sensing, low IQ, and adaptive light-load operation are critical.
FAQ
What is the maximum input voltage rating for the LTC1438IG-ADJ#TRPBF?
The LTC1438IG-ADJ#TRPBF has an absolute maximum input voltage (VIN) rating of 36V, with recommended continuous operation from 3.5V to 30V. Exceeding 36V risks permanent damage to internal circuitry, including the INTVCC regulator and gate drivers. This rating enables direct connection to 24V industrial buses or stacked Li-ion batteries while maintaining margin for transient spikes.
Does the LTC1438IG-ADJ#TRPBF support remote voltage sensing on both output channels?
No - remote sensing is supported only on Channel 1 via the VOSENSE1 pin, which is exclusive to the -ADJ variant. Channel 2 uses VOSENSE2 for remote sensing, but Channel 1's VOSENSE1 enables true Kelvin connection for high-accuracy regulation. Non-ADJ versions (e.g., LTC1438IG) lack VOSENSE1 and tie SENSE–1 internally to VOUT1, limiting sensing accuracy in high-current layouts.
How does the Adaptive Power™ mode in the LTC1438IG-ADJ#TRPBF improve light-load efficiency?
The LTC1438IG-ADJ#TRPBF's Adaptive Power™ mode reduces switching losses at light loads by routing gate drive to the smaller TGS1/TGS2 MOSFETs instead of the high-current TGL1/TGL2 paths. This avoids large gate charge penalties while sustaining fixed 400kHz operation down to ~1% of full load - extending usable efficiency range beyond Burst Mode, which typically activates at ~10% load in non-Adaptive controllers.
Can the auxiliary linear regulator in the LTC1438IG-ADJ#TRPBF be used as a low-battery comparator?
Yes - the AUX block can operate as a comparator by connecting AUXFB to a resistive divider from the battery and leaving AUXON high. The internal 1.19V reference serves as the threshold; when battery voltage drops below the divider-set point, AUXDR pulls low. This dual-use capability eliminates need for a separate supervisor IC in space-constrained designs using the LTC1438IG-ADJ#TRPBF.
What is the purpose of the SFB1 pin on the LTC1438IG-ADJ#TRPBF?
The SFB1 pin on the LTC1438IG-ADJ#TRPBF forces continuous synchronous operation on Channel 1 when pulled below 1.19V - overriding Adaptive Power™ or Burst Mode behavior. This ensures stable regulation in transformer-coupled topologies where secondary winding feedback must remain active regardless of primary-side load, preventing dropout-induced instability in isolated DC/DC converters.
LTC1438IG-ADJ#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-ADJ#TRPBF FAQ
1.How can I place an order for LTC1438IG-ADJ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1438IG-ADJ#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-ADJ#TRPBF reliable?
The price and inventory of LTC1438IG-ADJ#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-ADJ#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1438IG-ADJ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1438IG-ADJ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1438IG-ADJ#TRPBF?
LTC1438IG-ADJ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1438IG-ADJ#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-ADJ#TRPBF?
For technical support, including LTC1438IG-ADJ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1438IG-ADJ#TRPBF requirements.
6.How does Aetrix verify that LTC1438IG-ADJ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1438IG-ADJ#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-ADJ#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1438IG-ADJ#TRPBF?
All LTC1438IG-ADJ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1438IG-ADJ#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-ADJ#TRPBF part is unused and in its original packaging.
Return procedure for LTC1438IG-ADJ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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