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Analog Devices Inc. LT1572CS#PBF
- Part No.:
- LT1572CS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1572CS#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 1.25A 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,885
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Product details
Overview
LT1572CS#PBF from Analog Devices (formerly Linear Technology) is a monolithic 100kHz current-mode switching regulator with integrated 1.25A NPN switch and on-die 1A Schottky catch diode in a 16-lead SOIC package. It supports boost, buck, SEPIC, flyback, inverting, and Cuk topologies, delivers up to 15W output power, operates from 3V to 30V input, and achieves >80% efficiency at 12V/0.25A boost conversion.
For engineers reviewing the LT1572CS#PBF datasheet, LT1572CS#PBF pinout, LT1572CS#PBF application, or LT1572CS#PBF equivalent, key selection considerations include its integrated catch diode, adaptive anti-saturation switch drive, 50µA shutdown current, external synchronization capability (120–160kHz), and dual-emitter (E1/E2) current limit adjustment.
Technical Context
The LT1572CS#PBF implements current-mode control with pulse-by-pulse current limiting, where switch duty cycle is directly set by sensed switch current rather than output voltage feedback alone. Its internal 100kHz oscillator drives an adaptive anti-saturation driver that dynamically adjusts base drive to minimize saturation loss and enable fast turn-off.
It features two independent error amplifiers (normal mode and isolated flyback mode), selectable via FB pin voltage threshold (0.45V), and a VC pin serving four functions: compensation node, current limit control, soft-start interface, and shutdown activation (≤0.15V). The E1/E2 emitter pins allow 2:1 current limit scaling while doubling switch RON.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Current Limit | 1.25A typical at 50% duty cycle; adjustable via VC pin clamp or E2 disconnection |
| Input Voltage Range | 3V to 30V continuous; absolute max 40V - enables wide-input industrial and battery-powered designs |
| Quiescent Supply Current | 6mA typical - supports low-power standby operation without external LDO |
| Shutdown Current | 50µA typical - reduces system idle power in battery-backed applications |
| Switching Frequency | 100kHz nominal (88–112kHz); externally synchronizable to 120–160kHz for EMI reduction |
| Reference Voltage | 1.244V ±20mV - sets output voltage accuracy in standard boost/buck configurations |
| Catch Diode VF | 0.55V at 1A - minimizes conduction loss in high-current boost paths |
Pinout & Package
LT1572CS#PBF is housed in a 16-lead plastic SOIC (S package) with exposed thermal pad not connected internally. Pin assignments are validated per Linear Technology's official SO16 top view diagram and thermal management documentation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 16 | NC | No connect - must remain unconnected per datasheet |
| 2, 15 | Anode | Cathode-side connection of integrated Schottky diode - both pins must be tied together and to output node |
| 3, 14 | Cathode | Anode-side connection of integrated Schottky diode - both pins must be tied together and to ground or return path |
| 4, 5, 6, 7, 8 | GND | Power and signal ground reference - all five pins must be soldered to PCB ground plane |
| 9 | E2 | Secondary emitter - disconnecting E2 halves current limit but doubles switch RON |
| 10 | VIN | Main input supply - accepts 3V–30V; decoupling capacitor required at pin |
| 11 | VSW | Switch collector output - connects to inductor in boost/buck; requires snubber in flyback |
| 12 | E1 | Primary emitter - must always be connected to GND; defines baseline current limit |
| 13 | FB | Feedback input - senses output voltage divider; also selects flyback mode when pulled below 0.45V |
| 14 | VC | Error amplifier output - used for compensation, current limit setting, soft-start, and shutdown |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Schottky catch diode | Eliminates external diode BOM cost and layout area; rated 1A average / 2A peak forward current |
| Adaptive anti-saturation switch drive | Maintains high efficiency across 0.1A–1.25A load range without external compensation |
| Dual-emitter current limit scaling | E2 disconnection reduces switch current limit to 0.625A while increasing RON - enables precise overload protection |
| External frequency synchronization | Accepts 120–160kHz sync pulses on VC pin - allows EMI spread-spectrum alignment in multi-rail systems |
| Flyback topology support | Dedicated flyback error amplifier and blanking delay network enable transformer-isolated regulation without optocoupler |
Applications
| 5V-to-12V Boost Converter | Negative-to-Positive Converter |
|---|---|
Use Scenario: Generating stable 12V rail from a 5V USB or logic supply in portable instrumentation. IC Role / Device Role / Timing Role: Primary DC/DC controller implementing boost topology with internal switch and diode; regulates output via FB voltage divider. Use Value: Reduces component count by eliminating external diode and simplifies loop compensation due to current-mode architecture. | Use Scenario: Converting –12V or –5V rail to +3.3V for mixed-signal interfaces in telecom line cards. IC Role / Device Role / Timing Role: Inverting regulator controlling energy transfer through coupled inductor; uses E1/E2 pins to match negative input current limits. Use Value: Achieves high efficiency (>75%) without external P-channel switch or level-shifting gate drivers. |
| SEPIC Converter | Battery Charger |
Use Scenario: Powering 5V microcontroller from variable 3.0–4.2V Li-ion battery during full discharge cycle. IC Role / Device Role / Timing Role: Non-inverting buck-boost controller maintaining regulated output as input drops below or rises above VOUT. Use Value: Enables single-cell battery operation without voltage sag-induced brownouts or overvoltage damage. | Use Scenario: Constant-current/constant-voltage charging of 3.7V Li-ion cells from 5V wall adapter. IC Role / Device Role / Timing Role: Adjustable current-limited boost converter with FB-based voltage termination; VC pin used for CC/CV transition control. Use Value: Delivers precise 4.2V termination and programmable charge current using only resistive feedback and VC clamp. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1172CS#PBF | No integrated catch diode; requires external Schottky; same pinout except missing ANODE/CATHODE pins | Suitable where board space allows discrete diode placement and higher thermal budget exists | Select LT1172CS#PBF only if diode thermal management is handled externally or higher reverse voltage (>20V) is needed |
| LTC1574CGN#PBF | Step-down only; integrated 1A Schottky; 500kHz switching; different pinout and control architecture | Optimized for 5V→3.3V/2.5V point-of-load conversion, not boost or isolated topologies | Choose LTC1574CGN#PBF for high-efficiency buck applications requiring smaller magnetics and lower output ripple |
Compared with LT1172CS#PBF, LT1572CS#PBF saves board area and design time via integrated diode but trades off maximum diode reverse voltage (20V vs unlimited). Versus LTC1574CGN#PBF, it supports broader topology flexibility at lower frequency, making it preferable for cost-sensitive boost and flyback designs.
Availability
LT1572CS#PBF is available at Aetrix Electronics and suitable for 5V-to-12V boost converters, negative-to-positive power supplies, SEPIC battery interfaces, and isolated flyback converters requiring stable component supply and long-term industrial availability.
Supply support for LT1572CS#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 acquired Linear Technology in 2017 and maintains full technical and manufacturing continuity for legacy Linear products including the LT1572 series.
The LT1572CS#PBF belongs to Linear's monolithic switching regulator product line, designed specifically for compact, high-reliability DC/DC conversion in space-constrained industrial, test equipment, and telecom applications where integration and topology flexibility are critical.
FAQ
What is the maximum output voltage achievable with LT1572CS#PBF in boost configuration?
The LT1572CS#PBF catch diode has a peak repetitive reverse voltage rating of 20V. In boost topology, diode reverse voltage equals output voltage; therefore, maximum regulated output is 20V. Exceeding this risks diode breakdown. For higher outputs, use LT1172CS#PBF with external diode rated ≥30V.
Can LT1572CS#PBF operate in flyback mode with primary-side regulation?
Yes. The LT1572CS#PBF includes a dedicated flyback error amplifier and leading-edge blanking circuit. When FB pin voltage drops below 0.45V, it switches to flyback mode and regulates the amplitude of the reflected flyback pulse - enabling true primary-side regulation without optocoupler or secondary sensing.
How does disconnecting E2 affect LT1572CS#PBF performance?
Disconnecting E2 on LT1572CS#PBF halves the switch current limit (to ~0.625A) and doubles the switch "on" resistance (to ~2Ω). This increases conduction loss above 300mA but improves overload protection margin. E1 must remain grounded; both anode and cathode pins must still be fully connected.
What is the minimum input voltage required for LT1572CS#PBF to start regulation?
The LT1572CS#PBF requires a minimum input voltage of 2.6V (typical) to initiate regulation. Below this, internal biasing fails and the device remains inactive. Startup is guaranteed down to 3.0V across temperature; operation below 3V is not characterized and may result in erratic behavior or no switching.
Does LT1572CS#PBF support external clock synchronization, and what is the valid frequency range?
Yes. The LT1572CS#PBF supports external synchronization via short pulses (<0.3µs width) applied to the VC pin. Valid sync frequency range is 120kHz to 160kHz. Pulses must pull VC below 200mV to trigger; exceeding 0.3µs width disturbs internal error amplifier DC operating point and degrades regulation accuracy.
LT1572CS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost, Cuk, Flyback, Forward Converter, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.244V
- Voltage - Output (Max):
- 60V (Switch)
- Current - Output:
- 1.25A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LT1572CS#PBF FAQ
1.How can I place an order for LT1572CS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1572CS#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 LT1572CS#PBF reliable?
The price and inventory of LT1572CS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1572CS#PBF is usually 5 days.
3.What payment methods are accepted for LT1572CS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1572CS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1572CS#PBF?
LT1572CS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1572CS#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 LT1572CS#PBF?
For technical support, including LT1572CS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1572CS#PBF requirements.
6.How does Aetrix verify that LT1572CS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1572CS#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 LT1572CS#PBF meets industry standards.
7.What is the process for return or replacement of LT1572CS#PBF?
All LT1572CS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1572CS#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 LT1572CS#PBF part is unused and in its original packaging.
Return procedure for LT1572CS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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