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STMicroelectronics SG3525AN
- Part No.:
- SG3525AN
- Manufacturer:
- STMicroelectronics
- Category:
- DC DC Switching Controllers
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
SG3525AN.pdf
- Description:
- IC REG CTRLR BCK/PUSH-PULL 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,299
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Product details
Overview
SG3525AN from STMicroelectronics is a dual-output PWM controller IC designed for regulating switching power supplies, featuring an internal 5.1 V ±1% reference, oscillator frequency range of 100 Hz to 400 kHz, adjustable deadtime control via external resistor, and dual totem-pole output drivers capable of sourcing/sinking >200 mA. It supports push-pull, half-bridge, and full-bridge topologies in DC-DC converters and offline SMPS.
For engineers reviewing the SG3525AN datasheet, SG3525AN pinout, SG3525AN application, or SG3525AN equivalent, key selection considerations include its undervoltage lockout with 500 mV hysteresis, pulse-by-pulse shutdown capability, internal soft-start requiring only one external capacitor, latch-based PWM logic preventing multiple pulses per cycle, and NOR-output polarity (LOW = OFF state).
Technical Context
The SG3525AN integrates a precision error amplifier with rail-to-rail input common-mode range including the 5.1 V reference, eliminating external bias resistors. Its oscillator uses external RT/CT/RD components to set frequency and deadtime independently, with sync input enabling master-slave operation across multiple controllers.
A dedicated shutdown pin (Pin 10) controls both PWM latch reset and soft-start capacitor discharge at 150 µA, enabling either instantaneous turn-off (pulse-by-pulse limiting) or full soft-start recycle. The undervoltage lockout circuit holds outputs off and discharges soft-start capacitance below ~6.5 V with ~500 mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 8 V to 35 V - supports wide-input industrial and telecom power supplies without external regulators |
| Reference Voltage | 5.1 V ±1% - enables accurate feedback loop design without trimming resistors |
| Oscillator Frequency | 100 Hz to 400 kHz - covers low-noise audio-grade and high-efficiency high-frequency SMPS designs |
| Output Drive Capability | 200 mA sink/source per output - directly drives gate of MOSFETs up to 1 A peak current with fast rise/fall times |
| Deadtime Adjustment | Externally set via single resistor between CT and DISCHARGE pins - allows precise control of cross-conduction prevention in bridge topologies |
| Shutdown Response | Pulse-by-pulse or latched via Pin 10 - supports overcurrent protection and controlled restart sequences |
| Operating Temperature | 0 °C to +70 °C - qualified for commercial-grade power supply applications |
Pinout & Package
SG3525AN is available in 16-pin narrow-body plastic DIP (DIP16) and SO16 packages. Both variants share identical pin functions and electrical characteristics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (INVERT) | Error amplifier inverting input | Accepts feedback signal from output divider; referenced to internal 5.1 V reference |
| 2 (NON-INVERT) | Error amplifier non-inverting input | Connected to internal 5.1 V reference; enables direct error sensing against stable reference |
| 3 (COMP) | Error amplifier output / compensation node | External RC network sets loop stability; also serves as soft-start ramp node when pulled low |
| 4 (OSC) | Oscillator timing output | Provides clock signal to internal logic; used for synchronization with other SG3525A units or system clock |
| 5 (CT) | Oscillator timing capacitor connection | Charges/discharges via internal current source; sets oscillator frequency with RT and RD |
| 6 (RT) | Oscillator timing resistor connection | Sets charging current for CT; primary frequency adjustment element (2 kΩ–150 kΩ range) |
| 7 (DISCH) | Oscillator discharge resistor connection | Sets deadtime by controlling CT discharge rate; 0–500 Ω range |
| 8 (SOFT-START) | Soft-start timing capacitor connection | External capacitor ramps up internal reference; determines startup time and inrush control |
| 9 (REF) | 5.1 V reference output | Stable ±1% voltage source for feedback dividers and external circuitry; max 20 mA load |
| 10 (SHUTDOWN) | Active-high shutdown control | Triggers immediate PWM latch reset and 150 µA soft-start capacitor discharge |
| 11 (OUTPUT A) | First PWM output (NOR logic) | Drives external gate driver or MOSFET; LOW = OFF, HIGH = ON; 200 mA drive strength |
| 12 (GND) | Power ground | Common return for all analog and digital sections; separate from power ground in layout-critical designs |
| 13 (VC) | Collector supply for output transistors | Connects to high-side driver supply; supports up to 35 V; enables bootstrap or isolated gate drive |
| 14 (OUTPUT B) | Second PWM output (NOR logic) | Complementary to Output A in push-pull mode; phase-controlled via oscillator sync |
| 15 (VCC) | Main supply input | 8–35 V operating range; powers internal logic, reference, and oscillator; includes UVLO |
| 16 (VREF) | Reference voltage output (duplicate pin) | Redundant REF pin for improved layout routing; electrically identical to Pin 9 |
Key Features
| Feature | Design Value |
|---|---|
| Internal 5.1 V ±1% reference | Eliminates need for external voltage reference IC or trimming resistors in feedback networks |
| Adjustable deadtime via single resistor | Prevents shoot-through in half/full-bridge configurations without complex timing ICs or discrete logic |
| Pulse-by-pulse shutdown | Enables cycle-by-cycle current limiting using external sense resistor and comparator without auxiliary controllers |
| Sync-capable oscillator | Allows interleaving of multiple SG3525ANs to reduce input/output ripple and EMI in multi-phase systems |
| Undervoltage lockout with hysteresis | Ensures clean startup/shutdown behavior and prevents erratic operation during brownout conditions |
Applications
| Industrial DC-DC Converters | Offline AC-DC Power Supplies |
|---|---|
|
Use Scenario: Regulated 24 V to 5 V/3.3 V conversion in PLC I/O modules with 100–200 W output. IC Role / Device Role / Timing Role: Primary PWM controller generating complementary gate drive signals for MOSFET half-bridge with programmable deadtime. Use Value: Internal 5.1 V reference and wide 8–35 V supply range simplify auxiliary bias design and improve reliability under line transients. |
Use Scenario: 300 W flyback or forward converter powering server management circuits from universal AC input. IC Role / Device Role / Timing Role: Core timing and regulation engine managing duty cycle, soft-start, and overcurrent shutdown. Use Value: Pulse-by-pulse shutdown enables robust short-circuit protection without secondary sensing ICs or optocoupler latency. |
| Motor Drive Gate Control | Telecom DC-DC Modules |
|
Use Scenario: 48 V input to 12 V/24 V output for brushless DC motor gate drivers in HVAC blowers. IC Role / Device Role / Timing Role: Dual-output PWM generator with synchronized deadtime control for N-channel high-side/lower-side FETs. Use Value: NOR-output logic and 200 mA drive strength eliminate need for external level shifters or gate driver ICs. |
Use Scenario: Compact 48 V to 12 V intermediate bus converter in telecom shelf power systems. IC Role / Device Role / Timing Role: High-frequency (200–400 kHz) PWM controller minimizing magnetics size while maintaining tight regulation. Use Value: Oscillator sync capability allows interleaved operation with adjacent converters to lower input capacitor RMS current. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UC3525AN | Pin-compatible but lacks internal soft-start current source; requires external transistor for soft-start ramp generation | Higher external component count; less suitable for space-constrained designs needing minimal BOM | Preferred where legacy UC3525A designs exist and soft-start timing flexibility is acceptable |
| TL494CN | Single-ended output architecture; no built-in sync input; fixed 5.0 V reference (±2%); no dedicated deadtime resistor terminal | Limited to push-pull or single-switch topologies; unsuitable for synchronous rectified or interleaved multi-phase systems | Cost-sensitive applications with simpler topology requirements and no need for precise deadtime control |
Compared with UC3525AN and TL494CN, the SG3525AN provides superior integration for bridge-based topologies-its dedicated deadtime resistor pin, internal soft-start current source, and oscillator sync input reduce external parts count and improve system-level timing coordination in multi-controller designs.
Availability
SG3525AN is available at Aetrix Electronics and suitable for industrial DC-DC converters, offline AC-DC power supplies, and telecom intermediate bus modules requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for SG3525AN 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.
The SG3525A series belongs to ST's legacy power control IC portfolio, engineered specifically for high-reliability switching power supply designs requiring precise PWM timing, robust fault handling, and minimal external component dependency.
FAQ
What is the function of Pin 10 (SHUTDOWN) on the SG3525AN?
Pin 10 is an active-high shutdown input that simultaneously resets the internal PWM latch for immediate output disable and activates a 150 µA current sink on the soft-start capacitor (Pin 8). A short pulse enables pulse-by-pulse current limiting; a sustained high level fully discharges the capacitor for soft-start recycle on release.
How does the SG3525AN implement deadtime control?
Deadtime is set by connecting a resistor between Pin 5 (CT) and Pin 7 (DISCH). This resistor controls the discharge rate of the timing capacitor, delaying the turn-on of the second output relative to the first. Typical values range from 0 Ω to 500 Ω, yielding deadtimes from near-zero to several microseconds depending on CT value and oscillator frequency.
Can the SG3525AN drive MOSFET gates directly?
Yes-the SG3525AN's totem-pole outputs source/sink up to 200 mA each, enabling direct drive of small-to-medium power MOSFETs (e.g., ≤1 A peak gate charge). For larger devices or high-speed switching, external gate drivers are recommended to ensure adequate dV/dt and minimize propagation delay mismatch.
What is the difference between SG3525A and SG3525AN?
The "N" suffix denotes the narrow-body 16-pin plastic DIP package (0.3-inch width), distinguishing it from the wider "P" variant. Electrically and functionally identical, the SG3525AN shares all specifications, pinout, and thermal characteristics of the base SG3525A part, with only mechanical packaging differing per JEDEC MS-001-AB standards.
SG3525AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck, Push-Pull
- Number of Outputs:
- 2
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 8V ~ 35V
- Frequency - Switching:
- 100Hz ~ 400kHz
- Duty Cycle (Max):
- 49%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-DIP
SG3525AN FAQ
1.How can I place an order for SG3525AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SG3525AN 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 SG3525AN reliable?
The price and inventory of SG3525AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SG3525AN is usually 5 days.
3.What payment methods are accepted for SG3525AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SG3525AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SG3525AN?
SG3525AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SG3525AN 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 SG3525AN?
For technical support, including SG3525AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SG3525AN requirements.
6.How does Aetrix verify that SG3525AN is sourced from the original manufacturer or authorized distributors?
All SG3525AN 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 SG3525AN meets industry standards.
7.What is the process for return or replacement of SG3525AN?
All SG3525AN units undergo pre-shipment inspection (PSI). If there is an issue with SG3525AN, 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 SG3525AN part is unused and in its original packaging.
Return procedure for SG3525AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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