My Inquiry
My Account
Analog Devices Inc. LT3959EFE#TRPBF
- Part No.:
- LT3959EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3959EFE#TRPBF.pdf
- Description:
- IC REG BOOST CUK ADJ 6A 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,384
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3959EFE#TRPBF from Analog Devices (formerly Linear Technology) is a wide-input, current-mode DC/DC controller supporting boost, SEPIC, and inverting topologies with an integrated 6A/40V N-channel MOSFET. It operates from 1.6V to 40V input, regulates ±output voltages via a single FBX pin, and delivers up to 1.5A at VIN > 8V in SEPIC configuration-ideal for automotive 12V post-regulation and industrial power supplies.
For engineers reviewing the LT3959EFE#TRPBF datasheet, LT3959EFE#TRPBF pinout, LT3959EFE#TRPBF application, or LT3959EFE#TRPBF equivalent, key selection factors include its programmable 100kHz–1MHz switching frequency, PGOOD status reporting, soft-start control, internal INTVCC LDOs (3.75V/4.75V), and thermal shutdown with 125°C junction limit.
Technical Context
The LT3959EFE#TRPBF implements fixed-frequency current-mode control with dual error amplifiers-one for +1.6V regulation and one for –0.8V regulation-enabling seamless positive/negative output configuration using only the FBX pin. Its architecture includes slope compensation, frequency foldback during low-FBX conditions, and overvoltage protection with 7.5% hysteresis on both polarities.
It integrates two independent LDOs: a VIN-powered 3.75V regulator and a DRIVE-powered 4.75V regulator, automatically selecting the active source based on input conditions. The EN/UVLO pin supports accurate 1.22V falling threshold with externally programmable hysteresis, while SYNC enables external clock synchronization with 20% slower RT-set base frequency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.6V to 40V - supports direct connection to automotive battery (cold-crank down to 1.6V) and industrial 24V/36V rails. |
| Switch Rating | 6A/40V internal N-MOSFET - eliminates need for external high-current switch in most <15W applications. |
| Feedback Regulation | +1.6V or –0.8V FBX reference - enables single-pin programming of positive or negative output without topology change. |
| Switching Frequency | 100kHz to 1MHz (RT-programmable) - balances efficiency (lower fSW) vs. size (higher fSW); supports SYNC to external clock. |
| PGOOD Threshold Accuracy | ±5% window around FBX reference - provides reliable output voltage status for system sequencing and fault detection. |
| Shutdown Current | <1µA - meets ultra-low-power requirements for always-on automotive modules and battery-backed systems. |
| Operating Junction Temp | –40°C to 125°C - qualified for under-hood automotive and industrial environments without derating. |
Pinout & Package
LT3959EFE#TRPBF is packaged in a 38-lead plastic TSSOP with exposed pads: Pin 39 = SGND (soldered to signal ground plane), Pin 40 = SW (soldered to switch node copper). Thermal resistance θJA = 42°C/W, θJC = 3°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Primary supply input and VIN LDO input | Bypass with ≥1µF ceramic near pin; powers internal bias and enables 3.75V INTVCC when DRIVE is inactive. |
| DRIVE | Alternate LDO supply input | Connect to regulated rail (e.g., DC/DC output) to enable 4.75V INTVCC; reduces dropout losses vs. VIN-only operation. |
| SW | Drain of internal 6A/40V N-MOSFET | High-current switch node; requires low-inductance layout and direct soldering of exposed pad (Pin 40) to SW copper. |
| FBX | Unified feedback pin for ±VOUT regulation | Accepts resistor divider from VOUT to SGND; selects +1.6V or –0.8V reference automatically based on polarity. |
| PGOOD | Open-collector output status flag | Asserts low when INTVCC > 2.7V and FBX within ±5% of target - used for power-good sequencing and fault indication. |
| EN/UVLO | Enable and input undervoltage lockout | 1.22V nominal falling threshold with external hysteresis; resets soft-start on undervoltage event. |
| RT | Frequency programming input | Resistor to SGND sets switching frequency (100kHz–1MHz); open-circuit disables operation. |
| SS | Soft-start timing control | 10µA pull-up to 2.5V rail; external capacitor sets ramp time - limits inrush current and prevents inductor saturation. |
| VC | Error amplifier compensation node | Connect RC network (5k–50kΩ + 470pF–22nF) to SGND for loop stability; critical for transient response and phase margin. |
| INTVCC | Internally regulated supply rail | Must be bypassed with ≥4.7µF ceramic to SGND; powers gate driver and analog circuitry; UVLO threshold 2.15V rising. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-polarity output support | Single FBX pin configures +1.6V or –0.8V regulation - eliminates separate feedback networks and simplifies BOM for bipolar supplies. |
| Programmable frequency foldback | Reduces switching frequency when FBX approaches SGND - prevents peak current runaway during start-up or short-circuit recovery. |
| Auto-selecting dual LDOs | VIN and DRIVE inputs independently feed 3.75V/4.75V regulators - maximizes efficiency by choosing lowest-dropout path without external logic. |
| Accurate EN/UVLO with hysteresis | 1.22V falling threshold + user-defined rising hysteresis - enables precise brown-in/brown-out control for robust automotive power sequencing. |
| Thermal shutdown with latch-off | 165°C junction trip with automatic restart after cooldown - protects against sustained overload without requiring external thermal management. |
Applications
| Automotive Post-Regulator | Industrial Dual-Rail Supply |
|---|---|
|
Use Scenario: Regulating 12V battery to stable 12V output in vehicles with wide input variation (6V–16V during cranking/load dump). IC Role / Device Role / Timing Role: SEPIC controller maintaining regulation during cold-crank dips below 2.5V start-up threshold. Use Value: Eliminates need for pre-regulator stage; 6A switch handles peak loads up to 1.5A at >8V input without external FET. |
Use Scenario: Generating ±15V rails from 24V industrial bus for op-amp and ADC front-ends. IC Role / Device Role / Timing Role: Inverting converter topology with FBX tied to negative divider to regulate –15V output. Use Value: Single IC replaces dual converters; ±0.8V/±1.6V references ensure tight output matching across temperature. |
| LED Driver for High-Voltage Strings | Telecom Bias Supply |
|
Use Scenario: Driving 36V LED strings from 12V input in signage or emergency lighting. IC Role / Device Role / Timing Role: Boost controller with constant-current sense via external resistor and FBX feedback. Use Value: 40V switch rating supports >30V LED forward voltage; PGOOD confirms stable output before enabling LED PWM dimming. |
Use Scenario: Providing isolated –48V bias for telecom line interface circuits from +12V backplane. IC Role / Device Role / Timing Role: Inverting converter with SYNC locked to system clock for EMI reduction. Use Value: 100kHz–1MHz programmability allows EMI band avoidance; low shutdown IQ (<1µA) extends standby time. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3757AEMSE#TRPBF | Wider 2.8V–100V input range; no integrated switch; requires external MOSFET. | Better suited for >40V inputs (e.g., 48V telecom) but adds BOM cost and layout complexity. | Select when input exceeds 40V or higher output power (>25W) is required. |
| MAX17595ATP+T | 4.5V–60V input; 5A/75V internal switch; fixed 600kHz frequency; no negative output support. | Lacks dual-polarity capability and programmable frequency; optimized for high-efficiency boost only. | Choose for cost-sensitive, single-output boost applications where FBX polarity flexibility is unnecessary. |
Compared with LT3959EFE#TRPBF, LT3757AEMSE#TRPBF offers higher input voltage tolerance but demands external power components, while MAX17595ATP+T sacrifices output polarity flexibility for tighter integration in fixed-frequency boost designs.
Availability
LT3959EFE#TRPBF is available at Aetrix Electronics and suitable for automotive post-regulation, industrial dual-rail supplies, high-voltage LED drivers, and telecom bias generation requiring stable component supply across extended temperature ranges.
Supply support for LT3959EFE#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 maintains full product support, documentation, and manufacturing continuity for all Linear-branded parts including the LT3959 series.
The LT3959 product line was designed specifically for high-reliability, wide-input DC/DC conversion in automotive, industrial, and telecom applications where integrated 6A switching, dual-polarity output, and robust fault protection are essential.
FAQ
What is the minimum input voltage required to start up the LT3959EFE#TRPBF?
The LT3959EFE#TRPBF has a guaranteed start-up voltage of 2.5V at room temperature with RT = 27.4kΩ and FBX = 0V. It can operate continuously down to 1.6V once running, making it suitable for automotive cold-crank scenarios. Below 2.5V, startup may not occur reliably, though the device remains functional if already enabled.
Can the LT3959EFE#TRPBF generate both positive and negative outputs simultaneously?
No-the LT3959EFE#TRPBF supports either positive or negative output regulation per configuration, not both simultaneously. The FBX pin selects one reference (+1.6V or –0.8V) based on the voltage divider polarity; dual-rail generation requires two separate LT3959EFE#TRPBF circuits or a different controller architecture.
How does the EN/UVLO pin provide hysteresis, and what resistor values are needed?
The EN/UVLO pin uses an internal 2.2µA pull-down current to generate rising hysteresis. With R3 between VIN and EN/UVLO and R4 between EN/UVLO and SGND, the falling threshold is 1.22V × (R3+R4)/R4, and rising threshold adds 2.2µA × R3. For example, R3 = 121kΩ and R4 = 15.8kΩ yields ~12V turn-on and ~12.27V turn-off.
What is the purpose of the two exposed pads (Pins 39 and 40) on the LT3959EFE#TRPBF TSSOP package?
Pin 39 is SGND and must be soldered directly to the signal ground plane for optimal noise immunity and thermal performance. Pin 40 is SW and must be soldered to the switch-node copper pour to minimize parasitic inductance and handle high di/dt currents safely-both are mandatory for reliable operation and thermal management.
Does the LT3959EFE#TRPBF support synchronization to an external clock, and what are the constraints?
Yes-the SYNC pin accepts a digital clock input to synchronize switching. To avoid instability, the RT resistor must be selected to set the free-running frequency at least 20% lower than the SYNC frequency. The SYNC pulse width must exceed 200ns, and synchronization is disabled during frequency foldback or when INTVCC falls below 2.7V.
LT3959EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Cuk, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.6V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 40V (Switch)
- Current - Output:
- 6A (Switch)
- Frequency - Switching:
- 100kHz ~ 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP-EP
LT3959EFE#TRPBF FAQ
1.How can I place an order for LT3959EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3959EFE#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 LT3959EFE#TRPBF reliable?
The price and inventory of LT3959EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3959EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3959EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3959EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3959EFE#TRPBF?
LT3959EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3959EFE#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 LT3959EFE#TRPBF?
For technical support, including LT3959EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3959EFE#TRPBF requirements.
6.How does Aetrix verify that LT3959EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3959EFE#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 LT3959EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3959EFE#TRPBF?
All LT3959EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3959EFE#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 LT3959EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3959EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3959EFE#TRPBF 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…
