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Analog Devices Inc. LT3973HMSE-5#TRPBF
- Part No.:
- LT3973HMSE-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3973HMSE-5#TRPBF.pdf
- Description:
- IC REG BUCK 5V 750MA 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,851
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Product details
Overview
LT3973HMSE-5#TRPBF from Analog Devices (formerly Linear Technology) is a 42V, 750mA monolithic step-down regulator with integrated boost and catch Schottky diodes, 2.5µA quiescent current, and fixed 5V output. It operates from 4.2V to 42V input, maintains regulation down to 530mV dropout, and delivers low-ripple Burst Mode® operation for automotive cold-crank and always-on industrial power rails.
For engineers reviewing the LT3973HMSE-5#TRPBF datasheet, LT3973HMSE-5#TRPBF pinout, LT3973HMSE-5#TRPBF application, or LT3973HMSE-5#TRPBF equivalent, key selection criteria include its H-grade (–40°C to 150°C) junction temperature rating, MSOP-10 thermally enhanced package, programmable UVLO, power-good flag, and integrated diode architecture eliminating external components in space-constrained 5V bias supplies.
Technical Context
The LT3973HMSE-5#TRPBF implements constant-frequency current-mode control with adjustable switching frequency (200kHz–2.2MHz) via RT pin resistor. Its bipolar NPN internal switch is driven by a charge-pump boosted gate voltage, enabling full saturation even at high duty cycles during automotive dropout conditions.
Burst Mode® operation reduces quiescent current to 1.8µA at light loads while maintaining <10mVP-P output ripple; the integrated catch diode current limit (1.15A typ.) and thermal shutdown provide fault protection without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0V ±1.2% over –40°C to 150°C; eliminates need for external feedback resistors. |
| Input Voltage Range | 4.2V to 42V continuous; supports 12V/24V/36V automotive and industrial bus inputs. |
| Quiescent Current | 2.5µA at 12VIN/5VOUT; enables >10-year battery life in always-on sensor nodes. |
| Max Output Current | 750mA continuous; limited by thermal design and 1.15A catch diode valley current threshold. |
| Dropout Voltage | 530mV minimum; sustains regulation during automotive cold-crank (e.g., 5.5VIN → 5VOUT). |
| Switching Frequency | Programmable 200kHz–2.2MHz via RT pin; balances inductor size, efficiency, and EMI in compact layouts. |
| Power Good Flag | Open-drain PG asserts when VOUT reaches 90% of 5V; provides system reset timing without external monitoring. |
Pinout & Package
LT3973HMSE-5#TRPBF uses a thermally enhanced 10-lead MSOP package with exposed pad (Pin 11 = GND), rated for –40°C to 150°C junction temperature. The exposed pad must be soldered to PCB for thermal performance (θJA = 45°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Fixed-output voltage reference | Internally regulated to 5.0V; connects directly to output capacitor-no external divider required. |
| OUT (Pin 2) | Dropout regulation node | Tied to VOUT to enforce ≥530mV dropout; critical for cold-crank operation. |
| EN/UVLO (Pin 3) | Enable & undervoltage lockout input | 1.19V rising threshold with 30mV hysteresis; enables programmable brown-in/brown-out behavior. |
| VIN (Pin 4) | Main power input | Supplies internal circuitry and switch; requires local 4.7µF ceramic bypass. |
| GND (Pin 5 & 11) | Signal and power ground | Exposed pad (Pin 11) is mandatory GND connection for thermal and electrical integrity. |
| SW (Pin 6) | Switch node | Connects to inductor; carries high di/dt; requires tight layout to minimize EMI. |
| BOOST (Pin 7) | Charge-pump drive | Drives external boost capacitor to enable full NPN switch saturation at high duty cycles. |
| BD (Pin 8) | Bias diode anode | Accepts external bias (≥3.2V) to improve efficiency; also powers internal regulator. |
| PG (Pin 9) | Power good open-drain output | Sinks 350µA max; pulled high externally to signal valid 5V rail for microcontroller reset. |
| RT (Pin 10) | Frequency programming | Resistor-to-ground sets switching frequency; 215kΩ yields 600kHz per datasheet Table 1. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost and catch Schottky diodes | Eliminates two external diodes, reducing BOM count, board area, and forward-drop losses in 5V bias rails. |
| Low-ripple Burst Mode® operation | Maintains <10mVP-P output ripple at light loads while achieving 1.8µA IQ, critical for battery-powered IoT sensors. |
| H-grade temperature rating (–40°C to 150°C) | Validated for under-hood automotive and high-ambient industrial environments without derating. |
| Accurate programmable UVLO | EN/UVLO threshold tolerance (±30mV) enables precise system-level brownout detection aligned with MCU requirements. |
| Internal catch diode current limit | 1.15A valley current limit protects against short-circuit faults without external sensing, simplifying fault-tolerant designs. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC I/O Power |
|---|---|
Use Scenario: Powering microcontrollers, CAN transceivers, and sensor interfaces in engine bay-mounted BCMs subject to cold-crank (5.5VIN) and load-dump transients. IC Role / Device Role / Timing Role: Primary 5V bias regulator delivering stable rail despite wide VIN swing and high ambient temperature. Use Value: 530mV dropout and 150°C rating ensure uninterrupted operation during cold-crank; integrated diodes reduce component count in vibration-prone assemblies. | Use Scenario: Providing isolated 5V supply for digital I/O modules in factory-floor PLCs exposed to 24VDC field wiring and ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: Compact, high-reliability DC-DC converter replacing discrete buck solutions with external diodes. Use Value: 2.5µA quiescent current minimizes standby loss; PG flag synchronizes I/O initialization with power stabilization. |
| Portable Medical Diagnostic Device | Smart Building Sensor Node |
Use Scenario: Battery-powered handheld ultrasound or glucose meter requiring long shelf life and reliable 5V rail for ADCs and displays. IC Role / Device Role / Timing Role: Always-on power management IC managing battery-to-5V conversion with ultra-low IQ. Use Value: 1.8µA Burst Mode current extends 2000mAh Li-ion battery life to >10 years in sleep mode; fixed 5V output ensures consistent ADC reference. | Use Scenario: Wireless Zigbee/Z-Wave temperature/humidity sensor node powered by coin-cell or energy harvesting, needing regulated 5V for RF SoC and precision analog front-end. IC Role / Device Role / Timing Role: High-efficiency, low-noise step-down regulator enabling multi-year operation on small batteries. Use Value: <10mVP-P ripple prevents RF interference; programmable UVLO disables regulator below battery EOL voltage, preventing deep discharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE-5#TRPBF | Same manufacturer, 42V input, but 150mA output; no integrated catch diode; requires external Schottky. | Lower current capability; suited for ultra-low-power logic rails, not 750mA loads. | Select only if load current ≤150mA and board space allows external diode placement. |
| TPS54340DDAR | 42V input, 3.5A output, but 4.5µA IQ; external diodes required; no PG flag or programmable UVLO. | Higher current, lower integration; lacks power-good signaling and precise UVLO hysteresis. | Choose when higher output current is needed and system can accommodate external diodes and discrete monitoring. |
Compared with LTC3631EMSE-5#TRPBF and TPS54340DDAR, LT3973HMSE-5#TRPBF uniquely combines 750mA output, integrated diodes, 2.5µA IQ, PG flag, and H-grade rating in a single MSOP-10 package-making it optimal for space-constrained, high-reliability 5V bias applications where thermal margin and feature completeness are critical.
Availability
LT3973HMSE-5#TRPBF is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC I/O power supplies, and portable medical diagnostic devices requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3973HMSE-5#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 continues its legacy of high-performance analog and power management ICs for demanding industrial, automotive, and aerospace applications.
The LT3973 product line was designed specifically for high-input-voltage, low-quiescent-current step-down regulation in harsh environments-emphasizing integrated diodes, robust thermal performance, and precise fault protection for mission-critical 5V and 3.3V bias rails.
FAQ
What is the guaranteed operating temperature range for LT3973HMSE-5#TRPBF?
The LT3973HMSE-5#TRPBF is specified for –40°C to 150°C junction temperature, validated as an H-grade device. This rating ensures reliable operation in under-hood automotive locations and high-ambient industrial enclosures without thermal derating, unlike E- or I-grade variants limited to 125°C.
Does LT3973HMSE-5#TRPBF require external feedback resistors to set the 5V output?
No. LT3973HMSE-5#TRPBF is a fixed-output variant: Pin 1 is labeled VOUT and internally regulated to 5.0V ±1.2% across temperature. External resistors are unnecessary-unlike the adjustable LT3973 version which uses the FB pin with a resistor divider.
How does the LT3973HMSE-5#TRPBF maintain regulation during automotive cold-crank events?
The LT3973HMSE-5#TRPBF sustains regulation down to a 530mV minimum dropout voltage by tying the OUT pin to VOUT. During cold-crank (e.g., VIN drops to 5.5V), this architecture enforces VOUT ≥ VIN – 530mV, allowing stable 5V output even at marginal input voltages.
What is the purpose of the BD pin on LT3973HMSE-5#TRPBF, and how should it be connected?
The BD pin on LT3973HMSE-5#TRPBF accepts an external bias voltage ≥3.2V (e.g., from VOUT) to power the internal regulator, improving efficiency by reducing VIN current draw. If unused, BD may be left unconnected-but connecting it to VOUT lowers total system quiescent current.
Can LT3973HMSE-5#TRPBF be used with a 36V input and 5V/750mA output without thermal issues?
Yes-when properly heatsinked via the exposed pad. At 36VIN/5VOUT/750mA, power dissipation is ~2.3W. With θJA = 45°C/W and 25°C ambient, junction temperature reaches ~129°C-within the 150°C H-grade limit. Use ≥2cm² copper pour under the exposed pad for safe operation.
LT3973HMSE-5#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.2V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 750mA
- Frequency - Switching:
- 195kHz ~ 2.15MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3973HMSE-5#TRPBF FAQ
1.How can I place an order for LT3973HMSE-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3973HMSE-5#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 LT3973HMSE-5#TRPBF reliable?
The price and inventory of LT3973HMSE-5#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3973HMSE-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3973HMSE-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3973HMSE-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3973HMSE-5#TRPBF?
LT3973HMSE-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3973HMSE-5#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 LT3973HMSE-5#TRPBF?
For technical support, including LT3973HMSE-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3973HMSE-5#TRPBF requirements.
6.How does Aetrix verify that LT3973HMSE-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3973HMSE-5#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 LT3973HMSE-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3973HMSE-5#TRPBF?
All LT3973HMSE-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3973HMSE-5#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 LT3973HMSE-5#TRPBF part is unused and in its original packaging.
Return procedure for LT3973HMSE-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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