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Analog Devices Inc. LT3570IFE#TRPBF
- Part No.:
- LT3570IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Regulators - Linear + Switching
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3570IFE#TRPBF.pdf
- Description:
- IC REG TRPL BUCK/BST/LNR 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,908
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Product details
Overview
LT3570IFE#TRPBF from Analog Devices (formerly Linear Technology) is a triple-output power management IC integrating a 1.5A buck converter, a 1.5A boost converter, and an LDO controller with external NPN transistor drive. It operates from 2.5V to 36V input, supports up to 2.1MHz switching frequency via RT pin, delivers regulated outputs down to 0.8V, and features independent soft-start and separate VIN supplies per channel. It is used in telecom systems for multi-rail bias generation and "dying gasp" backup power sequencing.
For engineers reviewing the LT3570IFE#TRPBF datasheet, LT3570IFE#TRPBF pinout, LT3570IFE#TRPBF application, or LT3570IFE#TRPBF equivalent, key selection criteria include its 20-lead TSSOP package with exposed pad, independent shutdown control per regulator (SHDN1/2/3), FB voltage of 788 mV, 1.5 A switch current limit per converter, and compatibility with external synchronization up to 2.75 MHz.
Technical Context
The LT3570IFE#TRPBF implements constant-frequency current-mode control for both buck and boost converters, each with dedicated error amplifiers (A1/A2), VC compensation pins, and programmable soft-start (SS1/SS2). Its LDO controller drives an external NPN transistor via NPN_DRV with up to 10 mA base current, referenced to VIN3 and controlled by FB3.
Switching frequency is set by an external resistor on RT (500 kHz–2.1 MHz) and can be synchronized externally up to 2.75 MHz via SYNC. The device uses internal bipolar NPN switches - SW1 (collector-driven boost) and SW2 (emitter-driven buck) - with VCE(SAT) ≤ 240 mV at 1 A and current-limit thresholds decreasing linearly from 1.5 A (low duty) to 1.2 A (80% duty).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5 V to 36 V - supports wide industrial and automotive supply rails without pre-regulation. |
| Switch Current Limit | 1.5 A (min) - sets maximum deliverable load current per converter before foldback. |
| Feedback Reference Voltage | 788 mV - determines output voltage accuracy and stability across temperature (±16 mV over –40°C to 125°C). |
| Switching Frequency Range | 500 kHz to 2.1 MHz - enables compact magnetics and noise avoidance in sensitive RF or audio subsystems. |
| Soft-Start Control | Independent SS1/SS2 pins - prevents inrush current and output overshoot during power-up of each converter. |
| LDO Controller Output | Up to 10 mA base drive - sufficient to bias external NPN transistors for low-noise, high-current linear regulation. |
| Shutdown Threshold | SHDN1/2: 1.4 V min; SHDN3: 1.5 V min - ensures clean, noise-immune enable/disable sequencing across mixed-voltage domains. |
Pinout & Package
LT3570IFE#TRPBF is housed in a 20-lead plastic TSSOP package (FE) with exposed thermal pad (Pin 21) that must be soldered to PCB ground for thermal and electrical integrity. θJA = 38°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1, FB2, FB3 | Feedback reference input | Each regulates to 788 mV; sets output voltage via resistor divider; shared reference accuracy enables tight multi-rail tracking. |
| SW1, SW2 | Internal NPN switch nodes | SW1 (boost collector), SW2 (buck emitter); require external diode/inductor; VCE(SAT) ≤ 240 mV ensures low conduction loss. |
| SHDN1, SHDN2, SHDN3 | Independent enable inputs | Allow staggered startup/shutdown of boost, buck, and LDO sections - critical for power sequencing in telecom and set-top boxes. |
| NPN_DRV | External NPN base driver | Sinks up to 10 mA from VIN3; enables high-efficiency linear post-regulation with low dropout and minimal noise. |
| RT, SYNC | Oscillator timing interface | RT sets base frequency (500 kHz–2.1 MHz); SYNC accepts external clock up to 2.75 MHz for EMI reduction or system-level timing alignment. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent regulators | Buck (1.5 A), boost (1.5 A), and LDO controller (10 mA NPN drive) co-integrated - eliminates need for three discrete PMICs and simplifies BOM. |
| Separate VIN supplies | VIN1 (boost only), VIN2 (buck + IC bias), VIN3 (LDO controller) - enables optimal source selection per rail (e.g., battery vs. main supply). |
| Programmable soft-start per converter | SS1/SS2 pins charge to 2 V with 4.5 µA current - allows independent ramp rates to prevent cross-talk and ensure monotonic startup. |
| High-frequency operation | Up to 2.1 MHz switching - reduces inductor size (e.g., 3.3 µH typical) and eases EMI filtering in space-constrained designs. |
| Thermal-enhanced TSSOP | Exposed pad (Pin 21) tied to GND - improves thermal resistance by >30% vs. standard TSSOP, enabling 125°C continuous operation. |
Applications
| Cable and Satellite Set-Top Boxes | Automotive Systems |
|---|---|
Use Scenario: Powering multiple analog front-end ICs (tuner, demodulator, DAC) requiring isolated 3.3 V, 5 V, and 12 V rails with strict sequencing. IC Role / Device Role / Timing Role: LT3570IFE#TRPBF acts as primary multi-rail DC/DC manager - generating all required voltages from a single 12 V vehicle bus while enforcing startup order via SHDN1/2/3. Use Value: Eliminates discrete buck/boost/LDO combinations; reduces board area by 40% and improves efficiency over linear solutions at 1 A loads. | Use Scenario: Providing backup power for telematics modules during ignition-off "dying gasp" events using supercapacitor or small battery storage. IC Role / Device Role / Timing Role: LT3570IFE#TRPBF's boost converter charges storage elements from low-voltage sources (e.g., 3.3 V MCU rail), while its LDO controller maintains stable 2.5 V for real-time clock and memory retention. Use Value: Enables >10 s hold-up time with <5 mm² footprint; independent shutdown prevents leakage during sleep mode. |
| Telecom Systems | TFT LCD Displays |
Use Scenario: Generating bias voltages (AVDD, VGH, VGL) for optical transceivers and line cards operating from 48 V PoE-derived rails. IC Role / Device Role / Timing Role: LT3570IFE#TRPBF serves as compact auxiliary power supply - boosting 5 V to 12 V for laser drivers and bucking 12 V to 3.3 V for control logic, with SYNC aligned to system clock. Use Value: Achieves >85% efficiency at 1 A loads across 40–85°C ambient; RT-programmable frequency avoids interference with Ethernet PHY clocks. | Use Scenario: Supplying gate driver (18 V), source driver (15 V), and logic (3.3 V) rails for portable LCD panels powered from single-cell Li-ion (2.7–4.2 V). IC Role / Device Role / Timing Role: LT3570IFE#TRPBF functions as integrated display power manager - using VIN1 for boost (to 18 V), VIN2 for buck (to 3.3 V), and VIN3+LDO for precision 15 V generation. Use Value: Supports full brightness at minimum battery voltage; soft-start prevents panel flicker during wake-up from deep sleep. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multi-output DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EFE#PBF | Single synchronous buck controller (no boost/LDO); supports up to 60 V input; requires external MOSFETs. | Not suitable for boost or LDO functions; better for high-current (>5 A), high-efficiency buck-only designs. | Select when only high-power buck regulation is needed and board space allows discrete FET layout. |
| TPS65136RGTR | Dual-output (boost + LDO) only; no buck; fixed 1.2 MHz frequency; max 400 mA boost output. | Lacks buck converter and independent shutdown; limited to smaller displays or low-power interfaces. | Choose for cost-sensitive, low-complexity LCD bias where 12 V boost and 3.3 V LDO suffice. |
Compared with LTC3891EFE#PBF and TPS65136RGTR, the LT3570IFE#TRPBF uniquely integrates buck, boost, and LDO controller in one 20-pin TSSOP - enabling complete multi-rail power management without external switches or additional controllers, while supporting higher current (1.5 A) and wider input (2.5–36 V).
Availability
LT3570IFE#TRPBF is available at Aetrix Electronics and suitable for cable set-top boxes, automotive "dying gasp" systems, and telecom line cards requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant packaging.
Supply support for LT3570IFE#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 technical and manufacturing continuity for legacy Linear power products.
The LT3570IFE#TRPBF belongs to Linear's high-voltage monolithic DC/DC controller family, designed specifically for multi-rail power management in space-constrained, wide-input industrial and telecom equipment where integration, sequencing, and thermal performance are critical.
FAQ
What is the maximum supported switching frequency for LT3570IFE#TRPBF?
The LT3570IFE#TRPBF supports an internal switching frequency range of 500 kHz to 2.1 MHz, set by the RT resistor. It can also synchronize to an external clock up to 2.75 MHz via the SYNC pin - useful for EMI reduction and system-level timing alignment in dense PCB layouts.
Does LT3570IFE#TRPBF require external MOSFETs or bipolar transistors?
The LT3570IFE#TRPBF integrates internal bipolar NPN power switches for both buck (SW2) and boost (SW1) channels, so no external switching transistors are needed for those functions. However, its LDO controller requires an external NPN transistor driven by the NPN_DRV pin - enabling flexible, low-noise linear regulation tailored to load requirements.
What is the purpose of the BIAS pin on LT3570IFE#TRPBF?
The BIAS pin is not present on the LT3570IFE#TRPBF - it exists only on the QFN (UF) package variant (e.g., LT3570IUF#TRPBF). The TSSOP (FE) package does not include this pin; internal circuitry is powered solely from VIN2. This simplifies layout but increases quiescent dissipation when VIN2 is significantly higher than required.
Can LT3570IFE#TRPBF generate negative output voltages?
No, the LT3570IFE#TRPBF cannot generate negative outputs. Its boost converter is configured for positive voltage step-up only (e.g., 5 V to 12 V), and its buck and LDO controller sections are strictly positive-rail regulators. For negative rails, an external inverting topology or dedicated inverting controller would be required.
How is output voltage accuracy maintained across temperature for LT3570IFE#TRPBF?
The LT3570IFE#TRPBF maintains output voltage accuracy via a tightly regulated 788 mV feedback reference (±16 mV over –40°C to 125°C), implemented with on-chip bandgap and trimming. This reference feeds all three error amplifiers (for buck, boost, and LDO), ensuring consistent regulation across temperature without external calibration.
LT3570IFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Topology:
- Step-Down (Buck) (1), Step-Up (Boost) (1), Linear (LDO) (1)
- Number of Outputs:
- 3
- Frequency - Switching:
- 500kHz ~ 2.1MHz
- Voltage/Current - Output 1:
- Adj to 0.8V, 1.5A
- Voltage/Current - Output 2:
- Adj to 0.8V, 1.5A
- Voltage/Current - Output 3:
- Controller
- w/LED Driver:
- No
- w/Supervisor:
- No
- w/Sequencer:
- No
- Voltage - Supply:
- 2.5V ~ 36V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LT3570IFE#TRPBF FAQ
1.How can I place an order for LT3570IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3570IFE#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 LT3570IFE#TRPBF reliable?
The price and inventory of LT3570IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3570IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3570IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3570IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3570IFE#TRPBF?
LT3570IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3570IFE#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 LT3570IFE#TRPBF?
For technical support, including LT3570IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3570IFE#TRPBF requirements.
6.How does Aetrix verify that LT3570IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3570IFE#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 LT3570IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3570IFE#TRPBF?
All LT3570IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3570IFE#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 LT3570IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3570IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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