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Analog Devices Inc. LTC1538IG-AUX#TRPBF
- Part No.:
- LTC1538IG-AUX#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
LTC1538IG-AUX#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,357
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Product details
Overview
LTC1538IG-AUX#TRPBF from Analog Devices (formerly Linear Technology) is a dual synchronous step-down switching regulator controller driving external N-channel MOSFETs in fixed-frequency, current-mode architecture. It delivers two independent regulated outputs (5V/3.3V or adjustable), supports 3.5V–36V input, achieves >95% efficiency at full load, and integrates adaptive power mode for ultralow-noise operation down to 1% rated load - used in notebook DC-DC power trees requiring high-density, low-RMS-noise regulation.
For engineers reviewing the LTC1538IG-AUX#TRPBF datasheet, LTC1538IG-AUX#TRPBF pinout, LTC1538IG-AUX#TRPBF application, or LTC1538IG-AUX#TRPBF equivalent, key selection criteria include dual-channel programmable output voltage (via VPROG1/VPROG2), remote sensing on Channel 2 (VOSENSE2), integrated 5V/20mA standby regulator with <200µA shutdown IQ, and phase-lockable oscillator (LTC1539 variant only).
Technical Context
The LTC1538IG-AUX#TRPBF implements a constant-frequency current-mode control loop per channel, with peak-current sensing via SENSE+/SENSE− inputs and error amplifier output ITH1/ITH2 controlling MOSFET on-time. Its Adaptive Power™ architecture dynamically selects between TGL/TGS gate drivers to maintain fixed-frequency operation down to ~35mA (1% of 3.5A rating), avoiding burst-mode noise.
It features dual independent RUN/SS pins enabling asymmetric enable/disable, internal 1.19V reference with ±0.5% accuracy over temperature, and dedicated auxiliary linear regulator block (AUXON/AUXDR/AUXFB) supporting 12V PNP-based VPP generation or comparator mode - all while retaining 5V INTVCC standby supply active during full shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 36V - supports wide-range industrial/battery inputs without external pre-regulation |
| Output Voltage Options | Channel 1: 3.3V or 5V only (VPROG1-controlled); Channel 2: 1.19V–9V adjustable (VPROG2 + VOSENSE2) |
| Max Output Current | 3.5A per channel - set by external RSENSE (0.03Ω typical), validated at 3.5A continuous with thermal derating |
| Oscillator Frequency | 125kHz typical (COSC = 56pF) - fixed-frequency operation ensures predictable EMI profile |
| Shutdown Quiescent Current | <200µA - enables ultra-low-power standby in portable systems with both controllers disabled |
| Operating Temperature | –40°C to +85°C - qualified for industrial and extended-temperature embedded applications |
| Package | 28-lead SSOP (G package) - surface-mount compatible with standard reflow profiles |
Pinout & Package
Package: 28-lead plastic SSOP (G package), 0.635mm pitch, JEDEC MS-012AC compliant. Thermal resistance θJA = 95°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| BOOST 1 / BOOST 2 | Floating top-side gate drive supply | Provides bias for TGL1/TGL2 drivers; requires bootstrap capacitor tied to SW1/SW2 |
| TGL1 / TGL2 | Main high-current top MOSFET gate driver | Drives large N-channel FETs (e.g., Si4412DY); active in continuous & Adaptive Power modes |
| BG1 / BG2 | Bottom N-MOSFET gate driver | Sinks up to 2A peak; directly drives source-connected low-side FETs |
| SENSE+ 1 / SENSE+ 2 | Current sense positive input | Paired with SENSE− to set peak inductor current threshold (ΔVSENSE = 150mV typ) |
| VOSENSE2 | Remote feedback input (Channel 2 only) | Enables true remote sensing for Channel 2; required for precision regulation under PCB trace drop |
| VPROG1 / VPROG2 | Output voltage programming select | VPROG1 sets Channel 1 to 3.3V/5V; VPROG2 leaves Channel 2 adjustable via VOSENSE2 divider |
| RUN/SS1 / RUN/SS2 | Enable + soft-start control | Capacitor-to-ground sets ramp time (~0.5s/µF); <1.3V disables respective channel |
| INTVCC/5V | Internal 5V LDO output | Supplies IC core logic and gate drivers; remains active in shutdown (IQ < 200µA) |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent current-mode controllers | Enables asymmetric output configurations (e.g., [email protected] + [email protected]) with separate enable, soft-start, and sensing |
| Adaptive Power™ gate drive selection | Automatically switches between TGL (high-current) and TGS (low-current) drivers to sustain fixed-frequency operation down to ~35mA |
| Integrated 5V/20mA standby regulator | Remains powered during full shutdown - supplies microcontrollers, RTCs, or wake-up circuitry without external LDO |
| Remote output voltage sensing (Channel 2) | VOSENSE2 pin allows Kelvin connection to load, eliminating PCB trace IR drop impact on regulation accuracy |
| Programmable output voltages | VPROG1/VPROG2 pins select fixed 3.3V/5V or enable external resistor divider for 1.19V–9V adjustment on Channel 2 |
Applications
| Notebook Computer Power Tree | Portable Instrument DC Supply |
|---|---|
Use Scenario: Dual-rail power for CPU core (3.3V) and I/O (5V) in space-constrained clamshell designs with battery backup. IC Role / Device Role / Timing Role: Primary dual-output DC-DC controller managing high-efficiency conversion from 12V/19V adapter or Li-ion battery pack. Use Value: Adaptive Power mode eliminates audible coil whine during light-load sleep states while maintaining tight 1% output regulation. | Use Scenario: Battery-powered handheld multimeter requiring clean 3.3V analog rail and 5V digital rail with <200µA shutdown current. IC Role / Device Role / Timing Role: Central power management IC delivering isolated, low-noise supplies with independent enable control per subsystem. Use Value: Integrated 5V standby regulator powers real-time clock and wake-on-interrupt logic without adding discrete LDO components. |
| Industrial PLC I/O Module | Medical Point-of-Care Device |
Use Scenario: DIN-rail mounted programmable logic controller needing robust 5V/3.3V rails tolerant of 36V field bus transients. IC Role / Device Role / Timing Role: Main DC-DC controller handling wide-input industrial supply with overvoltage lockout and thermal-safe current limiting. Use Value: 3.5A per channel capability supports multiple isolated RS-485 transceivers and ADC front-ends simultaneously. | Use Scenario: Portable ultrasound probe requiring ultra-low-noise 3.3V analog supply for RF front-end and 5V digital supply for FPGA processing. IC Role / Device Role / Timing Role: Dual-channel synchronous buck controller minimizing conducted EMI through fixed-frequency operation and remote sensing. Use Value: VOSENSE2 remote sensing ensures <±10mV load regulation at probe tip despite flex-cable voltage drop. |
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 |
|---|---|---|---|
| LTC1539IGW#TRPBF | 36-lead SSOP; adds PLLIN/PLL LPF/POR1/LBO/LBI pins; supports frequency synchronization and power-on reset | Required for systems needing synchronized switching (e.g., multi-phase or noise-sensitive audio) or battery low-voltage detection | Select LTC1539IGW when PLL locking or POR/LBO functionality is needed; not pin-compatible with LTC1538IG-AUX |
| TPS54290RGTT | Single-channel, integrated FETs; 4.5V–28V input; 2A max; no auxiliary linear regulator or standby LDO | Used where board area is critical and dual outputs can be implemented with two single-channel ICs | Choose TPS54290RGTT for cost-sensitive, lower-current designs without need for 5V standby or auxiliary regulation |
Compared with LTC1539IGW#TRPBF, LTC1538IG-AUX#TRPBF offers identical dual-controller core functionality in a smaller 28-pin package but omits PLL and battery-monitoring features; versus TPS54290RGTT, it provides higher current, dual independent channels, and integrated standby power - at the cost of external MOSFET complexity.
Availability
LTC1538IG-AUX#TRPBF is available at Aetrix Electronics and suitable for notebook computer power trees, portable instrumentation DC supplies, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC1538IG-AUX#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 strengthen its power management portfolio.
The LTC1538-AUX product line was designed specifically for high-efficiency, low-noise dual-output DC-DC conversion in portable and battery-operated systems - emphasizing adaptive gate drive, ultra-low shutdown IQ, and integrated standby regulation.
FAQ
What is the maximum input voltage rating for the LTC1538IG-AUX#TRPBF?
The LTC1538IG-AUX#TRPBF has an absolute maximum input voltage rating of 36V on the VIN pin. Continuous operation is specified from 3.5V to 30V, with transient tolerance up to 36V for short durations. Exceeding 36V risks permanent damage to internal circuitry including the INTVCC regulator and gate drivers.
Can the LTC1538IG-AUX#TRPBF support remote voltage sensing on both output channels?
No. The LTC1538IG-AUX#TRPBF supports remote sensing only on Channel 2 via the VOSENSE2 pin. Channel 1's SENSE−1 is internally connected to its output node, preventing true remote sensing - it is restricted to 3.3V or 5V fixed outputs selected by VPROG1. This architectural limitation is confirmed in the Pin Functions section and Table 1 of the datasheet.
Does the LTC1538IG-AUX#TRPBF include a phase-locked loop (PLL) for frequency synchronization?
No. The LTC1538IG-AUX#TRPBF does not include PLL functionality. Pins PLLIN and PLL LPF are absent in the 28-lead SSOP package and are exclusive to the LTC1539 variant (36-lead SSOP). Attempting to use external sync signals on LTC1538IG-AUX#TRPBF will have no effect, as those circuit blocks are unimplemented.
What is the purpose of the AUXON, AUXDR, and AUXFB pins on the LTC1538IG-AUX#TRPBF?
These pins implement an auxiliary linear regulator/comparator block. AUXON enables/disables the function (threshold = 1.19V); AUXDR is an open-drain output driving the base of an external PNP transistor for 12V VPP generation; AUXFB is the feedback input - internally configured as a 12V divider when AUXDR > 9.5V, or externally configurable for other voltages when AUXDR < 8.5V.
How does the Adaptive Power™ mode operate in the LTC1538IG-AUX#TRPBF?
Adaptive Power™ mode automatically switches gate drive from TGL (large FET) to TGS (small FET) when load current drops below ~35mA (1% of 3.5A rating), maintaining fixed-frequency operation and avoiding burst-mode noise. Transition occurs when current reversal is detected and RSENSE voltage stays below 20mV for one cycle - confirmed in the "Low Current Operation" section of the datasheet.
LTC1538IG-AUX#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
LTC1538IG-AUX#TRPBF FAQ
1.How can I place an order for LTC1538IG-AUX#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1538IG-AUX#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 LTC1538IG-AUX#TRPBF reliable?
The price and inventory of LTC1538IG-AUX#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1538IG-AUX#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1538IG-AUX#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1538IG-AUX#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1538IG-AUX#TRPBF?
LTC1538IG-AUX#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1538IG-AUX#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 LTC1538IG-AUX#TRPBF?
For technical support, including LTC1538IG-AUX#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1538IG-AUX#TRPBF requirements.
6.How does Aetrix verify that LTC1538IG-AUX#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1538IG-AUX#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 LTC1538IG-AUX#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1538IG-AUX#TRPBF?
All LTC1538IG-AUX#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1538IG-AUX#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 LTC1538IG-AUX#TRPBF part is unused and in its original packaging.
Return procedure for LTC1538IG-AUX#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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