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Analog Devices Inc. LTC1438CG#TRPBF
- Part No.:
- LTC1438CG#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1438CG#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,695
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Product details
Overview
LTC1438CG#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 regulated outputs (1.19V–9V), 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 for VPP or audio supply - used in notebook computers and portable instrumentation.
For engineers reviewing the LTC1438CG#TRPBF datasheet, LTC1438CG#TRPBF pinout, LTC1438CG#TRPBF application, or LTC1438CG#TRPBF equivalent, key selection criteria include dual-channel current-mode control, programmable output voltage via VPROG pins, remote sense capability on VOSENSE2, PLL synchronization support (LTC1439 only), and 28-lead SSOP packaging with verified thermal performance up to 85°C.
Technical Context
The LTC1438CG#TRPBF implements a constant-frequency, current-mode dual buck controller with independent error amplifiers, ITH1/ITH2 compensation nodes, and adaptive gate drive routing between TGL/TGS/BG outputs. Its main loop uses SENSE+/SENSE− differential current sensing with ∆VSENSE(MAX) = 150mV typical and supports foldback current limiting via external RSENSE.
It features an auxiliary linear regulator controlled by AUXON/AUXFB/AUXDR, delivering up to 0.5A with internal 12V or 1.19V reference selection based on AUXDR voltage threshold (7.5–9.5V). The device includes a built-in power-on reset timer (65536/fCLK ≈ 300ms), low-battery comparator (LBI/LBO), and secondary feedback input (SFB1) forcing continuous operation when pulled below 1.19V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 30V (absolute max 36V); enables direct integration into 5V–28V battery or DC distribution systems. |
| Output Voltage Range | 1.19V to 9V per channel; set via VPROG1/VPROG2 pin states or external resistive divider on VOSENSE2. |
| Switching Frequency | Programmable 112–138kHz (COSC = 100pF); supports PLL lockup on LTC1439 but not LTC1438CG#TRPBF. |
| Current Sense Threshold | 150mV typical (∆VSENSE(MAX)); defines peak inductor current limit with external RSENSE resistor. |
| Quiescent Current | 320µA typical in normal mode; drops to 30µA in shutdown (VRUN/SS1,2 = 0V). |
| Operating Temperature | 0°C to 70°C (Commercial grade); validated junction temperature up to 125°C with θJA = 95°C/W. |
| Package | 28-lead plastic SSOP (G package); footprint compatible with standard reflow and automated assembly. |
Pinout & Package
Package: 28-lead plastic SSOP (G package), 0.025" pitch, JEDEC MS-012AC compliant. Thermal resistance θJA = 95°C/W; suitable for convection-cooled PCB layouts in space-constrained portable designs.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS1, RUN/SS2 | Soft-start & enable inputs | Capacitor-to-ground sets ramp time (~0.5s/µF); <1.3V forces shutdown of respective channel. |
| SENSE+1, SENSE−1 / SENSE+2, SENSE−2 | Differential current sense inputs | Measure voltage across external RSENSE; define peak current limit (150mV typ) for each controller. |
| VPROG1, VPROG2 | Output voltage programming inputs | Select 3.3V/5V via voltage thresholds; open-circuit enables adjustable output using VOSENSE2 feedback. |
| VOSENSE2 | Remote output voltage sense input | Connects to external resistive divider for precise regulation of second output; not present on Controller 1 in LTC1438CG#TRPBF. |
| TGL1, TGL2 / BG1, BG2 / TGS1, TGS2 | Gate drive outputs | TGL/BG drive large N-MOSFETs; TGS drives small N-MOSFET for Adaptive Power™ low-load operation. |
| SFB1 | Secondary winding feedback input | Pulling below 1.19V forces continuous synchronous operation on Controller 1 - critical for transformer-coupled auxiliary rails. |
| AUXON, AUXFB, AUXDR | Auxiliary regulator control | AUXON enables 0.5A linear regulator; AUXFB senses output; AUXDR drives PNP base or serves as comparator output. |
| POR2, LBI, LBO | Power-good & battery monitor | POR2 asserts open-drain fault signal after 65536 cycles if VOUT2 deviates >7.5%; LBI/LBO form low-battery detector. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Power™ architecture | Automatically switches between high-current (TGL/BG) and low-current (TGS) gate drive paths to sustain fixed-frequency operation down to ~1% rated load. |
| Dual independent current-mode controllers | Each channel has dedicated ITH compensation node, SENSE+/− inputs, and RUN/SS control - enabling asymmetric output configurations (e.g., 5V/3.3V). |
| Integrated 0.5A auxiliary linear regulator | Generates low-noise, low-dropout supply (e.g., 12V VPP or audio bias) using external PNP pass device; enabled via logic-level AUXON pin. |
| Remote output voltage sensing | VOSENSE2 allows Kelvin connection to second output, eliminating IR drop errors in high-current PCB traces or connectors. |
| Programmable soft-start & shutdown | Individual RUN/SS pins provide per-channel sequencing; <30µA shutdown IQ supports battery longevity in always-on subsystems. |
Applications
| Notebook Power Management | Portable Instrumentation |
|---|---|
Use Scenario: Dual-rail CPU core (1.2V) and I/O (3.3V) supply in ultra-thin notebooks with tight thermal constraints. IC Role / Device Role / Timing Role: Dual synchronous buck controller managing independent current-mode loops, adaptive gate drive, and remote sensing for precision regulation. Use Value: Maintains >90% efficiency at light loads via Adaptive Power™, reducing heat buildup and extending battery runtime without burst-mode noise. | Use Scenario: Battery-powered handheld multimeter requiring clean analog supply (±5V, 12V VPP) and stable digital rail (3.3V). IC Role / Device Role / Timing Role: Primary buck controller for main 3.3V rail + auxiliary linear regulator generating low-noise 12V VPP for ADC reference and op-amp bias. Use Value: Integrated AUX regulator eliminates need for separate LDO, saving board area while meeting <10µV RMS noise spec for 6½-digit measurement accuracy. |
| DC Power Distribution | Battery-Operated Medical Devices |
Use Scenario: Centralized 24V-to-5V/3.3V conversion in industrial IoT gateway with multiple sensor modules. IC Role / Device Role / Timing Role: Dual-output DC/DC controller supporting remote sense on both outputs to compensate for PCB trace losses across modular backplane. Use Value: Pin-selectable voltages and independent RUN/SS pins allow flexible power sequencing across distributed subsystems without additional supervisors. | Use Scenario: Portable ECG monitor powered by single Li-ion cell (3.0–4.2V), requiring regulated 3.3V digital and 5V analog supplies. IC Role / Device Role / Timing Role: Step-down controller operating from low VIN (3.5V min), using SFB1 to force continuous mode during dynamic load transients for ECG signal integrity. Use Value: 99% duty cycle capability and 150mV current sense threshold enable stable regulation even at end-of-discharge battery voltage. |
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 PLL synchronization (PLLIN/PLL LPF pins) and full SFB1 functionality; same pinout and thermal specs. | Required for systems needing clock alignment across multiple converters (e.g., noise-sensitive RF subsystems). | Select when deterministic phase relationship between switching edges is mandatory; otherwise LTC1438CG#TRPBF offers cost-optimized feature set. |
| MP2491DS-LF-Z | Single-channel, integrated MOSFETs (no external FETs); 2.5–18V input; fixed 3.3V/5V options only; no auxiliary regulator or SFB1. | Suitable for simpler, lower-cost point-of-load designs where dual outputs and auxiliary functions are unnecessary. | Choose for compact, low-BOM-count applications lacking remote sense, adaptive drive, or linear regulator requirements. |
Compared with LTC1439CG#TRPBF, the LTC1438CG#TRPBF omits PLL circuitry and limits SFB1 use to forced-continuous operation - simplifying layout and reducing component count where synchronization isn't needed. Versus MP2491DS-LF-Z, it trades integration for flexibility: external MOSFETs enable higher current, wider VIN, and custom thermal management, while retaining auxiliary regulation and precision sensing.
Availability
LTC1438CG#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 guaranteed commercial-grade performance.
Supply support for LTC1438CG#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) acquired Linear Technology in 2017 and maintains its high-performance power management portfolio with rigorous automotive and industrial qualification standards.
The LTC1438CG#TRPBF belongs to Linear's Adaptive Power™ controller family, designed specifically for high-efficiency, low-noise dual-output DC/DC conversion in portable and battery-critical systems where light-load efficiency and output precision are paramount.
FAQ
What is the maximum input voltage rating for the LTC1438CG#TRPBF?
The LTC1438CG#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, especially the INTVCC regulator and gate drivers. Designers should include transient voltage suppression if operating near the 36V limit.
Does the LTC1438CG#TRPBF support remote voltage sensing on both outputs?
The LTC1438CG#TRPBF supports remote voltage sensing only on the second output via the VOSENSE2 pin. Controller 1 lacks VOSENSE1 (present only on LTC1438-ADJ variant), so its feedback must be taken locally at SENSE−1. This asymmetry is documented in Table 1 of the datasheet and confirmed in the pin function descriptions.
Can the LTC1438CG#TRPBF be used with the PLL synchronization feature?
No - the LTC1438CG#TRPBF does not include PLL circuitry. Pins PLLIN and PLL LPF are not bonded out and have no internal connection. Only the LTC1439 variants (e.g., LTC1439CG#TRPBF) implement the phase-locked loop for external clock synchronization. Using LTC1438CG#TRPBF in PLL-dependent systems will result in undefined oscillator behavior.
What is the purpose of the SFB1 pin on the LTC1438CG#TRPBF?
The SFB1 pin on the LTC1438CG#TRPBF provides secondary winding feedback for the first controller. Pulling SFB1 below 1.19V forces continuous synchronous operation - essential for maintaining regulation when powering auxiliary windings in flyback-derived topologies. It is not used for primary output regulation but ensures stability under light or dynamic loads on coupled inductors.
How does the Adaptive Power™ mode improve light-load efficiency in the LTC1438CG#TRPBF?
Adaptive Power™ mode in the LTC1438CG#TRPBF improves light-load efficiency by dynamically routing gate drive from high-current TGL/BG outputs to low-gate-charge TGS outputs when inductor current reversal is detected. This avoids large MOSFET switching losses while maintaining fixed-frequency operation down to ~1% of full load - unlike Burst Mode, which introduces audible noise and EMI.
LTC1438CG#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
LTC1438CG#TRPBF FAQ
1.How can I place an order for LTC1438CG#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1438CG#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 LTC1438CG#TRPBF reliable?
The price and inventory of LTC1438CG#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1438CG#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1438CG#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1438CG#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1438CG#TRPBF?
LTC1438CG#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1438CG#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 LTC1438CG#TRPBF?
For technical support, including LTC1438CG#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1438CG#TRPBF requirements.
6.How does Aetrix verify that LTC1438CG#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1438CG#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 LTC1438CG#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1438CG#TRPBF?
All LTC1438CG#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1438CG#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 LTC1438CG#TRPBF part is unused and in its original packaging.
Return procedure for LTC1438CG#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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