My Inquiry
My Account
Analog Devices Inc. LT1977IFE#PBF
- Part No.:
- LT1977IFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT1977IFE#PBF.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:638
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT1977IFE#PBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode synchronous step-down switching regulator IC designed for automotive and industrial power systems. It operates from 3.3V to 60V input, delivers up to 1.5A peak switch current with 0.2Ω on-resistance, features 500kHz fixed-frequency operation, Burst Mode® for 100µA quiescent current, and programmable Power Good flag - enabling robust 14V/42V automotive DC-DC conversion.
For engineers reviewing the LT1977IFE#PBF datasheet, LT1977IFE#PBF pinout, LT1977IFE#PBF application, or LT1977IFE#PBF equivalent, key selection considerations include its 16-pin TSSOP thermally enhanced package, load-dump tolerance to 60V, soft-start via CSS pin, BIAS pin efficiency optimization, and compatibility with external synchronization up to 700kHz.
Technical Context
The LT1977IFE#PBF implements constant-frequency current-mode control using an internal 500kHz oscillator and dual feedback loops: one for output voltage regulation via the error amplifier (VC pin), and another for cycle-by-cycle peak current limiting (SW pin sensing). This architecture ensures fast transient response and stable loop compensation across wide input/output conditions.
It integrates a high-voltage NPN power switch with BOOST pin-driven saturation (enabling 0.2Ω effective RDS(on)), supports Burst Mode® at light loads to maintain 100µA IQ, and includes programmable Power Good delay via CT capacitor timing - all within a single monolithic die in thermally optimized TSSOP-16EP package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 60V - supports direct connection to 42V automotive battery rails and industrial 24V/48V systems without pre-regulation. |
| Switch Current Limit | 1.5A peak - sustains full output current capability across full duty cycle range, verified per U.S. Pat. 6498466/6531909. |
| Quiescent Current | 100µA in Burst Mode® - enables >10-year battery life in always-on vehicle modules (e.g., telematics, CAN gateways). |
| Switching Frequency | 425–575kHz (typ. 500kHz) - allows compact 10µH inductors and reduces EMI fundamental frequency vs. 200kHz alternatives like LT1976. |
| Feedback Reference | 1.25V ±2.5% (1.225–1.275V) - sets precise output voltage via resistor divider; low 75–200nA FB bias current minimizes divider power loss. |
| Power Good Threshold | Programmable at 88–92% of VREF - enables accurate output voltage monitoring with adjustable delay via external CT capacitor. |
| Thermal Range | –40°C to +125°C junction - fully specified and tested for under-hood automotive applications. |
| Package Thermal Resistance | θJA = 45°C/W, θJC(PAD) = 10°C/W - exposed pad soldered to PCB ground plane enables high-power operation without heatsink. |
Pinout & Package
LT1977IFE#PBF is housed in a 16-lead plastic TSSOP package with exposed thermal pad (Pin 17), requiring soldering to PCB ground plane for thermal management. The package footprint matches JEDEC MO-153, with 0.65mm lead pitch and 5mm × 4.4mm body size.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (2) | Emiter of integrated NPN power switch | Connects to inductor; swings from –0.8V (clamped) to VIN during switching; requires catch diode or synchronous rectifier. |
| VIN (4) | Collector of NPN switch & primary supply input | Accepts 3.3–60V; powers internal circuitry when BIAS pin is unconnected; high di/dt node requiring short, low-inductance path to input cap. |
| BOOST (6) | Bootstrap drive voltage source | Enables full saturation of NPN switch via external capacitor/diode; minimum 1.8V boost voltage required for 0.2Ω RON. |
| GND (8,17) | Signal reference & thermal ground | Pins 8 and 17 are internally connected; exposed pad (17) must be soldered to PCB ground plane for thermal performance (θJC = 10°C/W). |
| CSS (9) | Soft-start ramp control input | Sinks current proportional to FB voltage; capacitor to VOUT sets controlled dV/dt at startup; disabled above 0.9V FB. |
| BIAS (10) | Efficiency-optimized auxiliary supply | When tied to regulated output ≥3V, shifts internal bias current from VIN to BIAS, improving efficiency at high VIN/light load. |
| VC (11) | Error amplifier output & current limit threshold | Direct access to control loop; used for compensation, current clamping, or override; ranges from ~0.45V (light load) to 2.2V (full load). |
| FB (12) | Output voltage sense input | Compares divided output to 1.25V reference; also triggers frequency foldback (<0.4V) and soft-start activation (<0.9V). |
| PGFB (13) | Power Good comparator input | Resistive divider from VOUT or VIN sets PG threshold; rising edge initiates programmable PG delay via CT pin. |
| SYNC (14) | External clock synchronization input | Logic-level compatible (30–70% duty); accepts 575–700kHz signals; disabled during frequency foldback or FB <0.9V. |
| SHDN (15) | Enable/disable control | Active-high; 1.15–1.45V threshold; pulls VIN supply current <2µA in shutdown; 5–20µA input leakage. |
| PG (16) | Open-drain Power Good output | Active-low when output is in regulation; high-impedance after programmable delay; sinks 200µA typical when asserted. |
Key Features
| Feature | Design Value |
|---|---|
| Load Dump Protection | Withstands 60V transients per ISO 7637-2 Pulse 5a - eliminates need for external TVS in 14V/42V automotive designs. |
| Burst Mode® Operation | Maintains 100µA no-load IQ while preserving fast transient response - critical for always-on vehicle ECUs. |
| Thermally Enhanced TSSOP | Exposed pad reduces θJA to 45°C/W - enables 1.5A continuous output in compact 5mm × 4.4mm footprint without heatsink. |
| Programmable Power Good | Adjustable threshold (88–92% of 1.25V) and delay (via CT capacitor) - supports system-level sequencing and fault detection. |
| BIAS Pin Efficiency Boost | Redirects internal bias current from VIN to regulated output ≥3V - increases efficiency by up to 5% at VIN = 48V / VOUT = 5V / IOUT = 100mA. |
| Current-Mode Control | Provides inherent cycle-by-cycle current limiting and simplified loop compensation - improves stability with ceramic output capacitors. |
Applications
| Automotive Infotainment Power Supply | Industrial PLC I/O Module |
|---|---|
Use Scenario: Powering 3.3V/5V logic rails in head units exposed to 14V/42V battery transients and cold-crank conditions. IC Role / Device Role / Timing Role: Primary buck regulator converting battery voltage to stable low-voltage rails; handles load dump, cold crank (4.5V min), and EMI-sensitive audio subsystems. Use Value: 60V absolute max rating and Burst Mode® enable direct battery connection without pre-regulator; 100µA IQ extends backup battery life in memory retention circuits. | Use Scenario: Generating isolated 5V/12V supplies for analog sensor interfaces and digital I/O in factory automation controllers. IC Role / Device Role / Timing Role: High-efficiency DC-DC converter powering isolated ADCs, DACs, and microcontrollers in DIN-rail mounted PLCs. Use Value: Wide 3.3–60V input accommodates 24V/48V industrial buses; programmable PG flag enables safe power-up sequencing of isolated domains. |
| Telematics Control Unit (TCU) | Distributed Battery Management System |
Use Scenario: Always-on power for LTE/GNSS modules requiring ultra-low standby current and robust start-stop operation. IC Role / Device Role / Timing Role: Main system regulator delivering 3.3V to cellular modem and GPS receiver; manages brown-out recovery and wake-on-CAN events. Use Value: 100µA Burst Mode® IQ enables >10-year battery backup life; frequency foldback protects against short-circuit faults during antenna disconnect events. | Use Scenario: Local voltage regulation for cell monitoring ICs and isolation drivers in multi-cell EV battery packs. IC Role / Device Role / Timing Role: Point-of-load regulator converting 48V–60V pack voltage to 5V/3.3V for analog front-ends and SPI isolators. Use Value: 60V input rating supports direct connection to 13S–16S Li-ion stacks; thermal pad design sustains 1.5A continuous load in confined module space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3639EMSE#PBF | 40V max input, 1.5A, 3MHz sync capability, integrated MOSFETs, 2.5µA IQ in sleep mode | Better suited for space-constrained, lower-input-voltage apps; lacks 60V load dump tolerance and BIAS pin efficiency boost | Select LTC3639 for compact 24V systems needing higher frequency and lower IQ; avoid for 42V automotive or high-VIN industrial use. |
| LT1976IFE#PBF | Same family, 200kHz switching, wider continuous-duty input range, larger inductor requirement, lower EMI | Preferred for high-current, low-EMI applications where board space allows larger magnetics and efficiency at light loads is less critical | Choose LT1976 for 48V telecom or industrial supplies where EMI filtering is prioritized over size; LT1977IFE#PBF saves board area with 2.5× smaller inductor. |
Compared with LTC3639EMSE#PBF, LT1977IFE#PBF offers superior 60V transient handling and BIAS-driven efficiency at high VIN, but trades off higher EMI and larger magnetics than the 3MHz part. Against LT1976IFE#PBF, it delivers 2.5× smaller inductors and faster transient response at the cost of narrower continuous conduction range above 30V input.
Availability
LT1977IFE#PBF is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC I/O modules, and telematics control units requiring stable component supply with guaranteed long-term availability and automotive-grade qualification.
Supply support for LT1977IFE#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT1977IFE#PBF belongs to ADI's high-voltage power conversion product line, engineered specifically for demanding automotive and industrial environments where input transients, wide VIN range, and ultra-low quiescent current are critical design requirements.
FAQ
What is the maximum input voltage the LT1977IFE#PBF can withstand during load dump events?
The LT1977IFE#PBF is rated for absolute maximum input voltage of 60V and explicitly designed for load dump protection in 14V and 42V automotive systems. Per datasheet Absolute Maximum Ratings and Applications Information, it withstands ISO 7637-2 Pulse 5a transients up to 60V without external TVS diodes - making it suitable for direct battery connection in engine control and infotainment modules.
How does the BIAS pin improve efficiency in the LT1977IFE#PBF?
The BIAS pin on the LT1977IFE#PBF allows routing the internal bias current from VIN to the regulated output (≥3V), reducing input supply current draw. When BIAS is connected to VOUT, efficiency improves by up to 5% at high input voltages (e.g., 48V→5V), as confirmed in Electrical Characteristics and Applications Information sections - particularly beneficial in industrial 48V systems and automotive 42V architectures.
Can the LT1977IFE#PBF be synchronized to an external clock, and what is its sync range?
Yes, the LT1977IFE#PBF supports external synchronization via the SYNC pin (Pin 14), accepting logic-level inputs with 30–70% duty cycle. Its sync range spans 575kHz to 700kHz, extending beyond its native 425–575kHz oscillator frequency. Synchronization is disabled when FB voltage falls below 0.9V (e.g., during startup or fault conditions), ensuring reliable operation per datasheet Electrical Characteristics and Applications Information.
What thermal management is required for the LT1977IFE#PBF in 1.5A continuous operation?
The LT1977IFE#PBF requires soldering of its exposed thermal pad (Pin 17) to a PCB ground plane to achieve θJC = 10°C/W. With proper copper pour (≥2 cm²), it sustains 1.5A continuous output at +125°C ambient in standard 4-layer boards. Datasheet specifies θJA = 45°C/W with JEDEC 2S2P test board - insufficient for full-load operation without thermal pad connection.
Does the LT1977IFE#PBF support programmable Power Good delay, and how is it implemented?
Yes, the LT1977IFE#PBF implements programmable Power Good delay via the CT pin (Pin 7) and external capacitor. When PGFB exceeds its 88–92% VREF threshold, current (2–5.5µA) sources into the CT capacitor until voltage reaches 1.16–1.26V clamp level; delay time t = CCT × VCT/ICT. This enables precise power sequencing in multi-rail systems, as detailed in Pin Functions and Applications Information sections.
LT1977IFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 55.2V
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 500kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP-EP
LT1977IFE#PBF FAQ
1.How can I place an order for LT1977IFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1977IFE#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 LT1977IFE#PBF reliable?
The price and inventory of LT1977IFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1977IFE#PBF is usually 5 days.
3.What payment methods are accepted for LT1977IFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1977IFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1977IFE#PBF?
LT1977IFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1977IFE#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 LT1977IFE#PBF?
For technical support, including LT1977IFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1977IFE#PBF requirements.
6.How does Aetrix verify that LT1977IFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT1977IFE#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 LT1977IFE#PBF meets industry standards.
7.What is the process for return or replacement of LT1977IFE#PBF?
All LT1977IFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1977IFE#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 LT1977IFE#PBF part is unused and in its original packaging.
Return procedure for LT1977IFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT1977IFE#PBF Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
