My Inquiry
My Account
Analog Devices Inc. LT1533IS#PBF
- Part No.:
- LT1533IS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1533IS#PBF.pdf
- Description:
- IC REG PUSH-PULL ADJ 1A 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,221
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT1533IS#PBF from Analog Devices (formerly Linear Technology) is an ultralow-noise, dual-output, current-mode switching regulator IC designed for EMI-sensitive applications. It integrates two 1A power switches, independently programmable voltage and current slew rates (11 V/µs rising, 14.5 V/µs falling), 20–250 kHz oscillator, and dual-polarity regulation capability (±1.25 V reference for FB, –2.5 V for NFB). It is used in precision instrumentation power supplies where sub-100 µVP-P output noise is required.
For engineers reviewing the LT1533IS#PBF datasheet, LT1533IS#PBF pinout, LT1533IS#PBF application, or LT1533IS#PBF equivalent, key selection considerations include its independent slew rate control via RVSL/RCSL pins, dual-phase push-pull topology support, ±40°C to +100°C operating temperature range, and ability to regulate both positive and negative outputs simultaneously using FB and NFB pins.
Technical Context
The LT1533IS#PBF employs a fixed-frequency, current-mode architecture with internal slope compensation for stability at high duty cycles. Its dual out-of-phase 1A switches drive push-pull transformer topologies, while the error amplifier (transconductance gm = 1.5 m℧ typ) regulates by controlling switch current trip points rather than voltage.
Slew control is implemented via two independent feedback loops-one for collector voltage dV/dt (set by RVSL), another for emitter current dI/dt (set by RCSL)-combined internally to ensure smooth transition between modes. The VC pin serves triple duty: loop compensation node, current limit adjustment point, and soft-start interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 23 V - supports wide industrial input rails including 3.3 V, 5 V, 12 V, and 24 V systems without external regulators. |
| Switch Current Limit | 1.25 A max - ensures robust 1A continuous operation with margin for transient overload and thermal derating. |
| Oscillator Frequency | 20 kHz to 250 kHz - user-adjustable via RT/CT; enables harmonic placement control and low-frequency filtering for noise-sensitive circuits. |
| Output Noise | <100 µVP-P (BW = 100 MHz) - measured at 12 V output; confirms suitability for high-resolution ADC/DAC reference supplies. |
| Shutdown Current | 12 µA typical - enables battery-powered portable instrumentation with multi-week standby life. |
| Reference Voltage | +1.25 V (FB), –2.5 V (NFB) - allows direct regulation of dual-polarity outputs without external op-amps or level-shifting networks. |
| Voltage Slew Rate | 11 V/µs (rising), 14.5 V/µs (falling) - programmable via RVSL resistor; reduces high-frequency harmonic energy by up to 40 dB vs conventional switchers. |
| Current Slew Rate | 1.3 A/µs (both edges) - set by RCSL; minimizes di/dt-induced EMI while maintaining efficiency within 3% of fast-slew operation. |
Pinout & Package
LT1533IS#PBF is housed in a 16-pin narrow SOIC (S package) with exposed pad not present; thermal resistance θJA = 100°C/W. Pin 9 (GND) is signal ground; Pin 16 (PGND) is power switch ground with recommended 25 nH trace inductance for slew loop stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COL A (Pin 2) | Collector of Switch A | Drives first half of push-pull transformer primary; alternates conduction with COL B; requires short PCB traces to minimize radiated EMI. |
| COL B (Pin 15) | Collector of Switch B | Drives second half of push-pull transformer primary; 180° out-of-phase with COL A; may be paralleled for boost mode. |
| FB (Pin 7) | Positive Feedback Input | Inverting input of transconductance error amp referenced to 1.25 V internal bandgap; sets positive output voltage via resistor divider. |
| NFB (Pin 8) | Negative Feedback Input | Inverting input of dedicated negative-feedback amplifier (gain = –0.5); regulates negative output to –2.5 V; includes 100 kΩ internal source resistor. |
| VC (Pin 10) | Error Amplifier Output | Integrates FB/NFB errors; sets switch current trip point; connects to RC compensation network; clamped externally for current limiting or soft-start. |
| RVSL (Pin 13) | Voltage Slew Control | Resistor-to-ground sets collector voltage slew rate (VSLEW ≈ 220/RVSL kΩ V/µs); enables precise EMI harmonic shaping. |
| RCSL (Pin 12) | Current Slew Control | Resistor-to-ground sets emitter current slew rate (ISLEW ≈ 33/RCSL kΩ A/µs); decouples di/dt noise from dv/dt noise optimization. |
| DUTY (Pin 3) | 50% Duty Cycle Override | Grounding forces fixed 50% duty cycle at half oscillator frequency; simplifies unregulated DC transformer designs. |
| SYNC (Pin 4) | External Clock Input | Accepts square wave ≥1.4 V; rising edge triggers oscillator discharge; enables deterministic harmonic placement for EMC compliance. |
| SHDN (Pin 11) | Shutdown Control | Logic-low disables all internal circuitry; reduces supply current to 12 µA; compatible with microcontroller GPIO or system power sequencer. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow EMI Operation | Reduces high-frequency harmonic power by up to 40 dB via independent voltage/current slew programming-enables Class B EMC compliance without shielding or ferrites. |
| Dual-Polarity Regulation | Simultaneous +VOUT and –VOUT regulation using FB and NFB pins eliminates need for separate negative regulators in bipolar analog front-ends. |
| Programmable Oscillator Sync | SYNC pin accepts external clock to precisely position switching harmonics-critical for avoiding interference with RF receivers or high-speed data links. |
| Thermal & Overcurrent Protection | Integrated thermal shutdown, cycle-by-cycle current limiting, and undervoltage lockout protect against fault conditions without external components. |
| Low Minimum Input Voltage | 2.55 V minimum VIN enables operation from single Li-ion cells or low-voltage industrial rails-supports portable medical and handheld test equipment. |
Applications
| Precision Instrumentation Systems | Isolated Supplies for Industrial Automation |
|---|---|
Use Scenario: Powering 24-bit delta-sigma ADC reference buffers and low-noise op-amp bias networks in benchtop multimeters. IC Role / Device Role / Timing Role: Dual-output switching regulator providing clean ±5 V rails with <100 µVP-P noise floor and synchronized switching to avoid beat frequencies with sampling clocks. Use Value: Enables 110+ dB SNR measurements by eliminating switching artifacts that would otherwise corrupt LSB resolution. | Use Scenario: Generating isolated ±15 V supplies for PLC I/O modules interfacing with 4–20 mA current loops and field sensors. IC Role / Device Role / Timing Role: Push-pull DC/DC controller driving center-tapped transformer; uses DUTY pin for fixed 50% mode and SYNC pin to align switching with PLC scan timing. Use Value: Eliminates need for optocoupler-based feedback, reducing component count and improving long-term drift stability in harsh factory environments. |
| Medical Instruments | Wireless Communications |
Use Scenario: Supplying analog front-end circuitry in portable ECG monitors requiring ultra-low-noise, battery-efficient power. IC Role / Device Role / Timing Role: Low-quiescent-current switching regulator with 12 µA shutdown mode; regulates ±3.3 V from single-cell Li-ion using FB/NFB feedback. Use Value: Extends battery life beyond 72 hours while maintaining ECG signal integrity free from switching ripple-induced baseline wander. | Use Scenario: Powering RF front-end LNA and mixer stages in small-cell base stations where spectral purity is critical. IC Role / Device Role / Timing Role: EMI-optimized regulator supplying 5 V to LNA and –5 V to mixer bias; slew rates tuned to suppress harmonics near LTE bands (700 MHz, 2.6 GHz). Use Value: Prevents in-band spurs from degrading adjacent channel leakage ratio (ACLR), enabling full compliance with 3GPP TS 36.104. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output, low-EMI switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3891EFE#PBF | Higher input voltage (4–60 V), integrated MOSFET drivers, no independent slew control; 150 kHz fixed freq. | Targets automotive 12 V/24 V systems; lacks NFB pin for direct negative regulation. | Choose when input exceeds 23 V or when external FETs are undesirable; avoid if dual-polarity regulation or EMI tuning is required. |
| TPS54202DDCR | Single-output, 2 A, 4.5–17 V input; no slew control, no negative regulation; 500 kHz sync-capable oscillator. | Optimized for compact DC/DC conversion in space-constrained digital systems-not suitable for bipolar analog supplies. | Use only for unipolar, high-density applications; cannot replace LT1533IS#PBF in dual-rail or EMI-critical roles. |
Compared with LTC3891EFE#PBF and TPS54202DDCR, the LT1533IS#PBF uniquely delivers programmable slew rates for EMI reduction, native dual-polarity regulation, and guaranteed 1A per switch in a 16-pin SOIC-making it irreplaceable in precision analog power design where noise floor and rail symmetry are non-negotiable.
Availability
LT1533IS#PBF is available at Aetrix Electronics and suitable for precision instrumentation systems, isolated industrial power supplies, medical diagnostics equipment, and wireless infrastructure requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1533IS#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1533IS#PBF belongs to ADI's legacy Linear Technology switching regulator product line, specifically engineered for EMI-sensitive analog power applications where traditional switchers fail-emphasizing ultralow noise, dual-rail capability, and deterministic harmonic control.
FAQ
What is the maximum junction temperature rating for the LT1533IS#PBF?
The LT1533IS#PBF has a maximum junction temperature of 125°C and is specified for operation from –40°C to +100°C ambient (I-grade). Thermal shutdown activates before reaching 125°C to prevent damage. The 16-pin SOIC package has θJA = 100°C/W, so at 429 mW dissipation (typical 10 V/0.4 A application), junction temperature rises ~43°C above ambient-well within safe limits at 70°C ambient.
Can the LT1533IS#PBF regulate both positive and negative outputs simultaneously?
Yes, the LT1533IS#PBF can regulate both polarities simultaneously using the FB pin (for +VOUT referenced to GND) and NFB pin (for –VOUT referenced to GND). When both are active, the IC prevents either rail from exceeding its setpoint; the highest-loaded output dominates control. This enables true dual-rail supplies for op-amps and ADCs without external regulators-though load regulation symmetry is slightly compromised.
How does slew rate programming reduce EMI in the LT1533IS#PBF?
The LT1533IS#PBF reduces EMI by independently programming voltage slew (via RVSL) and current slew (via RCSL) to suppress high-frequency harmonic content. Slower edges lower dv/dt and di/dt, directly attenuating conducted and radiated emissions-measured at up to 40 dB reduction in harmonic power. This eliminates reliance on external filters or shielding in sensitive applications like medical imaging or precision metrology.
What is the function of the DUTY pin on the LT1533IS#PBF?
The DUTY pin on the LT1533IS#PBF forces a fixed 50% duty cycle when grounded, overriding normal current-mode control. In this mode, both switches operate at half the oscillator frequency in strict alternation-ideal for unregulated push-pull transformer applications where precise voltage regulation is unnecessary but waveform symmetry is critical for core reset and low distortion.
Does the LT1533IS#PBF support synchronization to an external clock?
Yes, the LT1533IS#PBF supports external clock synchronization via the SYNC pin. A square wave ≥1.4 V applied to SYNC causes the internal oscillator to discharge on each rising edge, locking switching harmonics to the external source. This enables deterministic EMI placement-essential for avoiding interference with RF receivers, high-speed serial links, or time-sensitive measurement systems using the LT1533IS#PBF.
LT1533IS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive or Negative, Isolation Capable
- Topology:
- Push-Pull
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 23V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 30V (Switch)
- Current - Output:
- 1A (Switch)
- Frequency - Switching:
- 20kHz ~ 250kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 100°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
LT1533IS#PBF FAQ
1.How can I place an order for LT1533IS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1533IS#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 LT1533IS#PBF reliable?
The price and inventory of LT1533IS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1533IS#PBF is usually 5 days.
3.What payment methods are accepted for LT1533IS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1533IS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1533IS#PBF?
LT1533IS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1533IS#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 LT1533IS#PBF?
For technical support, including LT1533IS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1533IS#PBF requirements.
6.How does Aetrix verify that LT1533IS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1533IS#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 LT1533IS#PBF meets industry standards.
7.What is the process for return or replacement of LT1533IS#PBF?
All LT1533IS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1533IS#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 LT1533IS#PBF part is unused and in its original packaging.
Return procedure for LT1533IS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT1533IS#PBF 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…
