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Analog Devices Inc. LTC7138EMSE#PBF
- Part No.:
- LTC7138EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Datasheet:
-
LTC7138EMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 400MA 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,863
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Product details
Overview
LTC7138EMSE#PBF from Analog Devices is a high-efficiency, 140V input, 400mA synchronous step-down DC/DC regulator with integrated P-channel MOSFET, 12µA quiescent current in Burst Mode®, programmable peak current limit (140–610mA), and 0.8V ±1% feedback reference. It operates across 4V–140V input and supports adjustable or fixed 1.8V/3.3V/5V outputs-ideal for industrial power supplies where wide VIN and low IQ are critical.
For engineers reviewing the LTC7138EMSE#PBF datasheet, LTC7138EMSE#PBF pinout, LTC7138EMSE#PBF application, or LTC7138EMSE#PBF equivalent, key selection factors include its 140V absolute max input rating, thermally enhanced MSE-16 package with exposed pad, programmable OVLO/RUN thresholds, internal soft-start, and parallel operation capability via FBO pin for higher current designs.
Technical Context
The LTC7138EMSE#PBF uses Burst Mode® control with hysteretic feedback to achieve ultra-low 12µA no-load supply current while maintaining regulation. Its P-channel internal switch enables 100% duty-cycle dropout operation down to VOUT, and the valley-current–tracking architecture provides inherent short-circuit protection without external sensing.
Peak inductor current is set by a resistor on ISET (5µA source), scaling linearly from 140mA to 610mA; valley current is fixed at 50–60% of peak. Output voltage is selected via VPRG1/VPRG2 logic states-ground, SS, or floating-to configure 0.8V-adjustable, 1.8V, 3.3V, or 5V fixed modes without external resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 140V - supports direct regulation from unregulated HV rails (e.g., 48V telecom, 120V AC-derived, or battery stacks) without pre-regulation. |
| Max Output Current | 400mA average - determined by 610mA peak / 140mA min peak current setting and 75% duty factor; scalable via parallel FBO connection. |
| Quiescent Current | 12µA typical in Burst Mode® - enables multi-year battery life in always-on industrial sensors or remote monitoring nodes. |
| Feedback Reference | 0.800V ±1% - precise threshold enables accurate output regulation across temperature; fixed outputs use internal dividers (no external R network needed). |
| Switch On-Resistance | 1.8Ω typical - low RDS(on) minimizes conduction loss at high input voltages and moderate load currents. |
| Soft-Start Time | 1ms internal default - prevents inrush current and input droop during cold start; externally adjustable via SS-to-GND capacitor. |
| Operating Temp Range | –40°C to +125°C - qualified for extended industrial and automotive under-hood environments (E-grade). |
Pinout & Package
Package: 16-lead plastic MSOP (MSE-16) with four missing pins (pins 2, 4, 13, 15 omitted); thermally enhanced with exposed GND pad (Pin 17) requiring PCB soldering for rated thermal performance (θJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (1) | Switch Node | Drain of internal P-MOSFET; connects to inductor and cathode of external catch diode-critical for EMI layout and thermal path. |
| VIN (3) | Main Input Supply | High-voltage input rail (up to 140V); requires local 1µF/250V ceramic bypass to GND for stability and transient suppression. |
| FBO (5) | Feedback Comparator Output | Open-drain output enabling master-slave parallel operation; pulls up ~20µA, pulls down ~70Ω-synchronizes multiple LTC7138EMSE#PBF units. |
| VPRG1/VPRG2 (6,7) | Output Voltage Selection | Logic inputs defining fixed output: both GND = adjustable; VPRG1=SS/VPRG2=GND = 5V; VPRG1=GND/VPRG2=SS = 3.3V; both SS = 1.8V. |
| GND (8,17) | Ground Reference | Pins 8 and 17 (exposed pad) are common GND; pad must be soldered to PCB ground plane for electrical integrity and thermal dissipation. |
| VFB (9) | Feedback Input | Compares divided output against 0.8V reference; for fixed outputs, connect directly to VOUT; for adjustable, use external resistor divider. |
| SS (10) | Soft-Start Control | Capacitor-to-GND sets ramp time (1ms per 6.25nF); internal 5µA current source enables controlled VOUT rise and avoids input sag. |
| ISET (11) | Peak Current Programming | Resistor-to-GND sets peak inductor current (140–610mA); 5µA internal source defines threshold-directly scales max output current and ripple. |
| OVLO (12) | Overvoltage Lockout | Resistor-divider input disabling switching above 1.21V; ensures safe shutdown during input transients-resets via soft-start on recovery. |
| RUN (14) | Enable/UVLO Control | Resistor-divider input enabling operation above 1.21V; disables below 1.10V hysteresis-configurable undervoltage lockout for system sequencing. |
| ANODE (16) | Catch Diode Anode Sense | Senses anode voltage of external Schottky diode; internal sense resistor enables accurate valley-current detection for cycle control. |
Key Features
| Feature | Design Value |
|---|---|
| Burst Mode® Operation | Reduces no-load IQ to 12µA while maintaining regulation-enables energy harvesting and battery-powered applications with multi-year runtime. |
| Programmable Peak Current Limit | Adjusts max output from 100mA to 400mA via single ISET resistor-optimizes inductor size, efficiency, and output ripple for specific load requirements. |
| Fixed Output Voltage Options | 1.8V/3.3V/5V selectable via VPRG1/VPRG2 logic-eliminates external feedback resistors, reduces BOM count, and improves noise immunity on VFB node. |
| Parallel Operation Support | FBO pin enables seamless current sharing across multiple LTC7138EMSE#PBF regulators-scales output to 800mA+ without external current-sharing circuitry. |
| Thermally Enhanced High-Voltage Package | MSE-16 with soldered exposed pad delivers θJC = 10°C/W-supports continuous 400mA operation at 125°C ambient with proper PCB copper area. |
Applications
| Industrial Control Power | Avionics Power Conversion |
|---|---|
|
Use Scenario: Regulating 28V or 115VAC-derived 140V DC bus to 5V/3.3V for PLC I/O modules, motor controllers, and fieldbus gateways operating in harsh factory environments. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator providing stable, low-noise bias for microcontrollers, ADCs, and isolated gate drivers. Use Value: 140V input range eliminates need for front-end pre-regulators; 12µA IQ reduces standby power in always-on systems; AEC-Q100–qualified E-grade ensures reliability over –40°C to 125°C. |
Use Scenario: Converting 270VDC aircraft distribution bus or 28V primary bus to 5V/3.3V for flight control computers, sensor interfaces, and cockpit displays. IC Role / Device Role / Timing Role: High-reliability point-of-load regulator with programmable OVLO/RUN for fault-tolerant power sequencing and transient ride-through. Use Value: Absolute max 140V rating accommodates 270V bus derating; precise RUN threshold enables controlled startup after power-up; exposed-pad thermal design sustains full load at elevated cabin temperatures. |
| Medical Diagnostic Equipment | Portable Test Instruments |
|
Use Scenario: Powering FPGA-based imaging subsystems (ultrasound, MRI front-end) from battery or AC adapter with strict low-noise and low-power constraints. IC Role / Device Role / Timing Role: Efficient, low-EMI buck converter delivering clean 1.8V/3.3V to high-speed digital logic and analog signal chains. Use Value: Adjustable output and 0.8V reference enable precision voltage scaling; Burst Mode® maintains regulation during deep sleep states; no compensation required simplifies layout. |
Use Scenario: Battery-operated handheld multimeters, oscilloscopes, and spectrum analyzers requiring long runtime and stable 5V/3.3V rails from Li-ion or alkaline packs. IC Role / Device Role / Timing Role: Main system regulator managing dynamic load transitions (e.g., backlight, ADC sampling, wireless transmission) with minimal voltage droop. Use Value: 100% duty-cycle dropout extends usable battery range; programmable ISET optimizes efficiency across 10mA–400mA loads; soft-start prevents brownout during wake-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-input-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3639EMSE#PBF | Lower max input (60V), lower IQ (4µA), same MSE-16 package, but no programmable peak current or FBO parallel support. | Best for ≤60V systems prioritizing ultra-low IQ over HV capability or scalability. | Select LTC3639EMSE#PBF only if input stays below 60V and parallel operation is unnecessary. |
| MAX5033BASA+ | 100V max input, 125mA max output, no programmable current limit, no FBO, SO-8 package, higher IQ (100µA). | Suitable for cost-sensitive, lower-current industrial sensors where footprint and simplicity outweigh HV headroom. | Choose MAX5033BASA+ when output current ≤125mA and 140V margin is not required. |
Compared with LTC3639EMSE#PBF and MAX5033BASA+, the LTC7138EMSE#PBF uniquely combines 140V input, 400mA output, programmable current limiting, and FBO-enabled parallel operation-making it the only option for scalable, high-voltage, medium-current industrial and avionics power designs.
Availability
LTC7138EMSE#PBF is available at Aetrix Electronics and suitable for industrial control supplies, avionics power conversion, and portable test instruments requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for LTC7138EMSE#PBF 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 is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets with precision, reliability, and innovation.
The LTC7138EMSE#PBF belongs to Analog Devices' Power by Linear™ high-voltage DC/DC regulator family, designed specifically for robust, efficient power conversion in demanding environments where wide input range, low quiescent current, and thermal resilience are essential.
FAQ
What is the maximum input voltage rating for the LTC7138EMSE#PBF?
The LTC7138EMSE#PBF has an absolute maximum input voltage rating of 140V on the VIN pin, with a functional operating range from 4V to 140V. This allows direct regulation from high-voltage sources such as 48V telecom lines, 120V AC-derived DC buses, or stacked battery packs without external pre-regulation stages.
How does the LTC7138EMSE#PBF achieve ultra-low quiescent current?
The LTC7138EMSE#PBF achieves 12µA typical quiescent current using Burst Mode® operation: during light loads, it enters sleep cycles where the internal power switch and comparators are disabled, drawing only bias current. Short burst cycles resume only when output voltage droop triggers the feedback comparator-preserving regulation while minimizing average IQ.
Can the LTC7138EMSE#PBF be used in parallel for higher output current?
Yes-the LTC7138EMSE#PBF supports parallel operation via its FBO (Feedback Comparator Output) pin. Connecting the FBO of a master LTC7138EMSE#PBF to the VFB pins of slave units forces current sharing, enabling scalable output up to 400mA × N. No external current-sense resistors or complex control ICs are required.
What output voltage options does the LTC7138EMSE#PBF support?
The LTC7138EMSE#PBF supports both adjustable and fixed outputs: grounding VPRG1 and VPRG2 yields 0.8V–VIN adjustable mode; tying VPRG1 to SS and VPRG2 to GND selects 5V; VPRG1 to GND and VPRG2 to SS selects 3.3V; both tied to SS selects 1.8V-all using internal feedback dividers, eliminating external resistors.
Is the LTC7138EMSE#PBF thermally optimized for high-power operation?
Yes-the LTC7138EMSE#PBF uses a thermally enhanced MSE-16 package with an exposed GND pad (Pin 17) that must be soldered to the PCB ground plane. This achieves θJC = 10°C/W and θJA = 40°C/W, enabling continuous 400mA operation at 125°C ambient when implemented with adequate copper area and thermal vias.
LTC7138EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width), 12 Leads, Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable (Programmable)
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 140V
- Voltage - Output (Min/Fixed):
- 0.8V (1.8V, 3.3V, 5V)
- Voltage - Output (Max):
- 140V
- Current - Output:
- 400mA
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LTC7138EMSE#PBF FAQ
1.How can I place an order for LTC7138EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC7138EMSE#PBF 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 LTC7138EMSE#PBF reliable?
The price and inventory of LTC7138EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC7138EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LTC7138EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC7138EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC7138EMSE#PBF?
LTC7138EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC7138EMSE#PBF 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 LTC7138EMSE#PBF?
For technical support, including LTC7138EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC7138EMSE#PBF requirements.
6.How does Aetrix verify that LTC7138EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LTC7138EMSE#PBF 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 LTC7138EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LTC7138EMSE#PBF?
All LTC7138EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC7138EMSE#PBF, 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 LTC7138EMSE#PBF part is unused and in its original packaging.
Return procedure for LTC7138EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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