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Analog Devices Inc. LTC1574CS-3.3#PBF
- Part No.:
- LTC1574CS-3.3#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1574CS-3.3#PBF.pdf
- Description:
- IC REG BCK 3.3V 340MA/600MA 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,849
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Product details
Overview
LTC1574CS-3.3#PBF from Analog Devices (formerly Linear Technology) is a monolithic step-down DC/DC converter with integrated P-channel MOSFET switch and Schottky diode, delivering 3.3V at up to 425mA output current. It operates from 4V to 12.5V input, achieves up to 94% efficiency, and features pin-selectable 340mA/600mA current limiting for optimized performance in portable power rails.
For engineers reviewing the LTC1574CS-3.3#PBF datasheet, LTC1574CS-3.3#PBF pinout, LTC1574CS-3.3#PBF application, or LTC1574CS-3.3#PBF equivalent, key selection criteria include its fixed 3.3V output, low 130µA no-load quiescent current, internal low-drop Schottky diode (0.45V typ), micropower shutdown (2µA), and built-in low-battery detection comparator.
Technical Context
The LTC1574CS-3.3#PBF uses constant off-time current-mode control with 4µs fixed tOFF, enabling frequency variation (≈111kHz at VIN=9V, VOUT=3.3V) while maintaining stable regulation. Its internal 0.9Ω P-MOSFET switch and integrated Schottky diode eliminate external power components beyond inductor and capacitors.
It integrates a precision 1.25V reference, feedback comparator, and low-battery detector with 1.25V trip threshold and 7.5–30mV hysteresis. Current limit is set via IPGM pin: 340mA (IPGM = 0V) or 600mA (IPGM = VIN), directly determining peak inductor current and thermal performance under load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±4.6% (3.14V to 3.46V), internally trimmed for stable rail generation without external resistors. |
| Input Voltage Range | 4V to 12.5V operating range; absolute max 18.5V - supports 4×NiCd, Li-ion, or regulated 5V/9V supplies. |
| Max Output Current | 425mA continuous (LTC1574CS-3.3#PBF design example); limited by 340mA/600mA selectable peak switch current. |
| Efficiency | Up to 94% at mid-load (e.g., VIN=5V, IOUT=100mA, L=50µH), enabling minimal thermal rise in compact layouts. |
| Quiescent Current | 130µA in active no-load mode; drops to 2µA in shutdown - critical for battery runtime extension. |
| Low-Battery Detection | Comparator with 1.25V reference and 7.5–30mV hysteresis; LBIN/LBOUT pins enable system-level battery monitoring. |
| Switch RDS(ON) | 0.9Ω typical (VIN < 11V), defining conduction loss and thermal dissipation under full load. |
Pinout & Package
16-lead plastic SO (narrow, 0.150") package, 110°C/W θJA, rated for 0°C to 70°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 5) | Input supply voltage input | Accepts 4V–12.5V; must be decoupled locally to GND (Pins 2,4,13,15) to suppress switching noise. |
| SW (Pins 3,14) | Switch node | Drain of internal P-MOSFET and cathode of integrated Schottky diode - connects to inductor and output capacitor. |
| VOUT (Pin 10) | Regulated output / feedback sense | Fixed 3.3V output; internal resistive divider sets voltage - no external resistor required for LTC1574CS-3.3#PBF. |
| IPGM (Pin 6) | Current limit programming | Logic-level select: 0V → 340mA limit; VIN → 600mA limit - determines inductor sizing and thermal margin. |
| SHDN (Pin 7) | Active-low shutdown control | Pull to GND to enter 2µA shutdown; VIH ≥1.2V required for operation - enables system-level power sequencing. |
| LBIN (Pin 12) | Low-battery comparator inverting input | Connects to external resistor divider from VIN; trips when divided voltage falls below 1.25V reference. |
| LBOUT (Pin 11) | Open-drain low-battery indicator | Sinks up to 1.5mA when LBIN < 1.25V - drives LED or microcontroller interrupt without pull-up. |
| GND (Pins 2,4,13,15) | Power and signal ground | Four dedicated ground pins minimize ground impedance and improve EMI performance in high-current switching paths. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Schottky Diode | 0.45V forward drop at 200mA eliminates external diode, reduces BOM count, and improves light-load efficiency. |
| Three-Component Solution | Only inductor, input capacitor, and output capacitor required - simplifies layout and accelerates prototyping. |
| Pin-Selectable Current Limit | 340mA/600mA options allow matching inductor saturation current and optimizing efficiency across load ranges. |
| Burst Mode™ Operation | Maintains regulation at light loads with discontinuous conduction, reducing no-load current to 130µA. |
| Short-Circuit Protection | Internal current limiting + extended off-time prevents thermal runaway during output faults - no external circuitry needed. |
Applications
| Portable Medical Sensors | Industrial Data Loggers |
|---|---|
Use Scenario: Battery-powered handheld glucose meter with LCD display and Bluetooth LE radio. IC Role / Device Role / Timing Role: Primary 3.3V power rail generator for MCU, sensor interface, and RF transceiver. Use Value: 130µA no-load current extends AA battery life to >12 months; integrated Schottky avoids diode thermal derating in sealed enclosure. | Use Scenario: Remote environmental monitor using 4×AA alkaline cells and SD card storage. IC Role / Device Role / Timing Role: Main 3.3V supply for ARM Cortex-M0+ MCU, ADC, and SPI flash memory. Use Value: Low-battery detection (LBIN/LBOUT) triggers firmware alert before brownout; 4V min input supports full battery discharge down to 1.0V/cell. |
| Wireless Sensor Nodes | Embedded Point-of-Sale Terminals |
Use Scenario: Zigbee-enabled temperature/humidity node powered by CR2032 coin cell with energy harvesting supplement. IC Role / Device Role / Timing Role: Efficient 3.3V conversion from variable 2.5–5.5V harvested source or backup battery. Use Value: 94% peak efficiency minimizes heat in ultra-thin housing; 2µA shutdown enables multi-year shelf life. | Use Scenario: Compact credit card reader with touch interface and USB-C power delivery negotiation. IC Role / Device Role / Timing Role: Secondary 3.3V rail derived from 5V USB PD bus for secure element and display driver. Use Value: Wide 4–12.5V input accommodates USB PD negotiation states; 0.9Ω RDS(ON) ensures <100mV dropout at 300mA load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1174CS-3.3 | SO-8 package, 0.5A peak current, Burst Mode™ only (no constant-frequency option), 2.7–18V input. | Lower pin count and smaller footprint; lacks LBIN/LBOUT and IPGM pins - no low-battery monitoring or current limit selection. | Select when board space is constrained and battery monitoring is handled externally. |
| LT1376-3.3 | SO-8, 1.5A switch, 500kHz fixed frequency, external diode required, higher IQ (1.5mA active). | Higher output current capability but requires external Schottky diode and larger input capacitor due to higher ripple. | Select when >500mA load is needed and layout allows extra component placement. |
Compared with LTC1174CS-3.3 and LT1376-3.3, the LTC1574CS-3.3#PBF uniquely combines integrated diode, low-quiescent current, and system-level battery monitoring in a 16-pin SO package - making it optimal for cost-sensitive, battery-critical portable designs where reliability and feature integration outweigh footprint savings.
Availability
LTC1574CS-3.3#PBF is available at Aetrix Electronics and suitable for portable medical sensors, industrial data loggers, wireless sensor nodes, and embedded point-of-sale terminals requiring stable component supply and long-term lifecycle support.
Supply support for LTC1574CS-3.3#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 power products.
The LTC1574 family was designed specifically for high-efficiency, low-noise, battery-operated step-down conversion in space-constrained portable equipment - emphasizing integration, micropower operation, and system-level monitoring features.
FAQ
What is the maximum recommended output current for LTC1574CS-3.3#PBF in continuous operation?
The LTC1574CS-3.3#PBF supports up to 425mA continuous output current in typical design examples (e.g., TA05 schematic). This assumes IPGM = VIN (600mA peak switch current), 50µH inductor, and proper thermal layout. Derating is required above 70°C ambient or with poor PCB copper area.
Does LTC1574CS-3.3#PBF require external feedback resistors to set the output voltage?
No. The LTC1574CS-3.3#PBF is the fixed-output variant with internal resistive divider - VOUT (Pin 10) delivers 3.3V without any external resistors. Only the adjustable LTC1574 version requires R1/R2 on the VFB pin.
How does the low-battery detection function work on LTC1574CS-3.3#PBF?
The LTC1574CS-3.3#PBF uses LBIN (Pin 12) as the inverting input to a comparator referenced to 1.25V. An external resistor divider from VIN to GND sets the trip point (e.g., 5.5V with 162k/4.7k). When LBIN falls below 1.25V, LBOUT (Pin 11) sinks current to signal low battery.
Can LTC1574CS-3.3#PBF operate with an input voltage lower than 4V?
No. The absolute minimum operating input voltage for LTC1574CS-3.3#PBF is 4V per the Electrical Characteristics table. Operation below 4V may cause regulation loss or undefined behavior; the device is not characterized or guaranteed below this threshold.
What is the purpose of the IPGM pin on LTC1574CS-3.3#PBF?
The IPGM pin (Pin 6) selects the peak switch current limit: 0V sets 340mA, and VIN sets 600mA. This adjusts inductor saturation requirements and optimizes efficiency across light-to-moderate loads - critical for balancing size, cost, and thermal performance.
LTC1574CS-3.3#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-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 18.5V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 340mA, 600mA
- Frequency - Switching:
- Up to 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LTC1574CS-3.3#PBF FAQ
1.How can I place an order for LTC1574CS-3.3#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1574CS-3.3#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 LTC1574CS-3.3#PBF reliable?
The price and inventory of LTC1574CS-3.3#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1574CS-3.3#PBF is usually 5 days.
3.What payment methods are accepted for LTC1574CS-3.3#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1574CS-3.3#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1574CS-3.3#PBF?
LTC1574CS-3.3#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1574CS-3.3#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 LTC1574CS-3.3#PBF?
For technical support, including LTC1574CS-3.3#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1574CS-3.3#PBF requirements.
6.How does Aetrix verify that LTC1574CS-3.3#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1574CS-3.3#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 LTC1574CS-3.3#PBF meets industry standards.
7.What is the process for return or replacement of LTC1574CS-3.3#PBF?
All LTC1574CS-3.3#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1574CS-3.3#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 LTC1574CS-3.3#PBF part is unused and in its original packaging.
Return procedure for LTC1574CS-3.3#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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