My Inquiry
My Account
Analog Devices Inc. LTC1147CS8-3.3#TRPBF
- Part No.:
- LTC1147CS8-3.3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1147CS8-3.3#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,463
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC1147CS8-3.3#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, constant off-time current-mode step-down switching regulator controller designed to drive an external P-channel MOSFET. It delivers a fixed 3.3V output with ±3% regulation over 5mA–2A load, supports 3.5V–16V input, achieves >95% efficiency at full load, and features Burst Mode™ operation for 160µA light-load quiescent current.
For engineers reviewing the LTC1147CS8-3.3#TRPBF datasheet, LTC1147CS8-3.3#TRPBF pinout, LTC1147CS8-3.3#TRPBF application, or LTC1147CS8-3.3#TRPBF equivalent, this controller enables compact, high-efficiency DC/DC conversion in battery-powered portable systems where low standby power, wide VIN range, and stable light-load performance are critical.
Technical Context
The LTC1147CS8-3.3#TRPBF implements a constant off-time (COT) current-mode architecture with internal 1.25V reference and programmable current-sense threshold (25–150mV). Its CT pin sets switching frequency via external capacitor, while ITH adjusts current-comparator threshold dynamically to track load transients.
Burst Mode™ operation disables switching when output voltage exceeds regulation, reducing IQ to 160µA; shutdown draws <20µA. The device supports 100% duty cycle for ultra-low dropout and includes short-circuit protection via extended off-time during overload.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% (3.23–3.43V at 700mA), enabling direct replacement of LDOs in 3.3V logic rails. |
| Input Voltage Range | 3.5V to 16V - supports single-cell Li-ion (4.2V), dual-cell NiMH (3.0V min), and 12V industrial rails. |
| Quiescent Current | 160µA in Burst Mode™ - sustains >100-hour runtime on 200mAh coin cell at light load. |
| Current Sense Threshold | 25mV to 150mV - allows RSENSE selection from 0.05Ω to 0.15Ω for IMAX = 0.67A–3A. |
| Shutdown Current | <20µA at VSHDN ≥ 0.8V - ensures negligible battery drain in system sleep states. |
| Off-Time | 3.8–6.5µs (CT = 390pF) - determines minimum on-time and dropout behavior; scales with VOUT. |
| Operating Temperature | 0°C to 70°C (Commercial grade) - validated for notebook, GPS, and handheld instrument environments. |
Pinout & Package
Package: 8-lead plastic SO (SO-8), surface-mount, θJA = 150°C/W, RoHS-compliant, tape-and-reel (#TRPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 3.5–16V; requires local 100µF + 0.1µF ceramic decoupling to minimize noise and supply sag. |
| CT (Pin 2) | Timing capacitor connection | Sets switching frequency; discharge current proportional to VOUT enables VIN-tracking frequency stability. |
| ITH (Pin 3) | Current comparator threshold control | Voltage applied here raises current trip point - used for dynamic load transient optimization. |
| SENSE– (Pin 4) | Inverting current sense input | Internal resistive divider sets 3.3V feedback; also (–) input of current comparator for peak-current limiting. |
| SENSE+ (Pin 5) | Non-inverting current sense input | (+) input of current comparator; offset vs. Pin 4 defines 25–150mV trip window across RSENSE. |
| SHDN/VFB (Pin 6) | Shutdown control / feedback | Logic-level input: <0.8V = normal operation; >0.8V = micropower shutdown (<20µA); not used as VFB in fixed-3.3V version. |
| GND (Pin 7) | Analog & power ground | Two independent ground paths required: one to COUT (–) and one to diode cathode/CIN (–) to prevent noise coupling. |
| PDRIVE (Pin 8) | High-current P-MOSFET gate driver | Swings rail-to-rail (VIN to GND); drives >29nC gate charge at <200ns transition time - compatible with Si4431DY, etc. |
Key Features
| Feature | Design Value |
|---|---|
| Constant off-time current-mode control | Delivers fast line/load transient response without external compensation; maintains stable ripple current across input and load variations. |
| Burst Mode™ operation | Reduces IQ to 160µA at light loads while maintaining tight output regulation - eliminates need for external enable sequencing in battery systems. |
| 100% duty-cycle capability | Enables dropout <100mV at full load by holding P-MOSFET fully on - supports operation down to VIN ≈ VOUT + RDS(ON)·ILOAD. |
| Short-circuit protection | Automatically extends off-time during overload to limit average short-circuit current to ~IMAX - prevents thermal runaway without latch-off. |
| Logic-compatible shutdown | CMOS-level SHDN pin (0.5–2V threshold) allows direct interface with microcontroller GPIOs - no pull-up or level-shifting required. |
Applications
| Portable Medical Monitors | GPS Navigation Units |
|---|---|
Use Scenario: Compact handheld ECG or pulse oximeter powered by single Li-ion cell (3.0–4.2V), requiring clean 3.3V for MCU, ADC, and BLE radio. IC Role / Device Role / Timing Role: Primary step-down controller regulating 3.3V rail; manages dynamic load shifts between sensing bursts and wireless transmission. Use Value: Burst Mode™ extends battery life >3× vs. continuous-mode controllers; 160µA IQ enables multi-day operation on 500mAh battery. |
Use Scenario: Automotive-grade GPS receiver operating from 9–16V vehicle supply, needing regulated 3.3V for RF front-end and baseband processor. IC Role / Device Role / Timing Role: Input-stage buck controller driving external P-MOSFET; handles cold-crank (6.5V) and load-dump (28V transient protected externally) conditions. Use Value: Wide 3.5–16V input range eliminates need for pre-regulator; 100% duty cycle maintains 3.3V output even during cranking dips to 6.5V. |
| Industrial Handheld Scanners | Smart Meter Communication Modules |
Use Scenario: Rugged barcode scanner using alkaline AA batteries (1.8–3.2V per cell), requiring stable 3.3V for imager and Wi-Fi SoC under pulsed 500mA loads. IC Role / Device Role / Timing Role: High-efficiency buck controller with external P-MOSFET; manages rapid 0→500mA load steps during scan activation. Use Value: Constant off-time architecture delivers <50µs recovery from 500mA step; 95% peak efficiency minimizes heat in sealed enclosure. |
Use Scenario: PLC-connected smart meter with isolated RS-485 and NB-IoT modem, powered from 3.3V rail derived from 12V auxiliary supply. IC Role / Device Role / Timing Role: Secondary 12V-to-3.3V converter supplying isolated communication ICs; must survive 10-year field deployment with zero maintenance. Use Value: SO-8 package and 0°C–70°C rating ensure long-term reliability; low 20µA shutdown current prevents battery backup drain during mains failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3502AEDD-3.3#TRPBF | Integrated 3.3V buck regulator (no external FET); 3.3V ±1.5% accuracy; 2.5–36V input; 1.2MHz fixed frequency. | Eliminates external MOSFET/diode but limits max current to 1.2A and increases solution size due to integrated switch losses. | Select when board space is constrained and 1.2A output suffices; avoid when >2A or ultra-low IQ (<100µA) is required. |
| TPS54202DDCR | Integrated 3.3V synchronous buck (2A); 4.5–28V input; 500kHz–2.5MHz adjustable frequency; 25µA shutdown IQ. | Higher integration reduces BOM count but lacks Burst Mode™ - light-load efficiency drops below 85% at <10mA. | Select for cost-sensitive, medium-efficiency apps with stable 5–24V input; avoid for battery systems requiring sub-100µA standby. |
Compared with LT3502AEDD-3.3#TRPBF and TPS54202DDCR, the LTC1147CS8-3.3#TRPBF offers superior light-load efficiency via Burst Mode™ and higher output current capability using optimized external FETs, at the cost of added design complexity and component count.
Availability
LTC1147CS8-3.3#TRPBF is available at Aetrix Electronics and suitable for portable medical monitors, GPS navigation units, industrial handheld scanners, and smart meter communication modules requiring stable component supply across long production lifecycles.
Supply support for LTC1147CS8-3.3#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC1147 series was developed by Linear Technology specifically for high-efficiency, low-quiescent-current step-down control in portable and battery-critical applications - emphasizing Burst Mode™ operation, wide input range, and robust external FET drive capability.
FAQ
What is the maximum output current supported by the LTC1147CS8-3.3#TRPBF?
The LTC1147CS8-3.3#TRPBF itself does not deliver output current - it controls an external P-channel MOSFET. With proper selection of RSENSE (e.g., 0.05Ω), inductor, and MOSFET (e.g., Si4431DY), the LTC1147CS8-3.3#TRPBF-based converter reliably delivers up to 2A continuous output current while maintaining regulation and thermal safety.
Does the LTC1147CS8-3.3#TRPBF require external compensation components?
No, the LTC1147CS8-3.3#TRPBF uses a constant off-time current-mode architecture that is inherently stable and does not require external loop compensation. The standard Figure 1 application circuit - with specified CT, RSENSE, L, CIN, and COUT - provides adequate phase margin across all operating conditions without added RC networks.
Can the LTC1147CS8-3.3#TRPBF be used with a 3.0V input supply?
No - the LTC1147CS8-3.3#TRPBF has a minimum input voltage of 3.5V per datasheet Absolute Maximum Ratings and Electrical Characteristics tables. For 3.0V operation, the LTC1147LCS8-3.3 (L-version) is specified down to 3.5V, and true sub-3.5V designs require alternative controllers such as the LTC3642 or TPS62130.
How does Burst Mode™ operation affect output voltage ripple on the LTC1147CS8-3.3#TRPBF?
In Burst Mode™, the LTC1147CS8-3.3#TRPBF stops switching when VOUT reaches regulation, causing output voltage to decay slowly until hysteresis triggers the next burst. This results in low-frequency (1–10kHz) ripple of ≤50mVP-P at zero load - acceptable for most digital logic but may require additional LC filtering for sensitive analog circuits.
Is the LTC1147CS8-3.3#TRPBF pin-compatible with other members of the LTC1147 family?
Yes - all LTC1147 variants (e.g., LTC1147CS8-5, LTC1147LCS8-3.3) share identical 8-pin SO packaging and pinout. However, functional differences exist: Pin 6 serves as SHDN on fixed-output versions like LTC1147CS8-3.3#TRPBF but as VFB on adjustable LTC1147L variants, requiring schematic review before substitution.
LTC1147CS8-3.3#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 3.5V ~ 14V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1147CS8-3.3#TRPBF FAQ
1.How can I place an order for LTC1147CS8-3.3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1147CS8-3.3#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 LTC1147CS8-3.3#TRPBF reliable?
The price and inventory of LTC1147CS8-3.3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1147CS8-3.3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1147CS8-3.3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1147CS8-3.3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1147CS8-3.3#TRPBF?
LTC1147CS8-3.3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1147CS8-3.3#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 LTC1147CS8-3.3#TRPBF?
For technical support, including LTC1147CS8-3.3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1147CS8-3.3#TRPBF requirements.
6.How does Aetrix verify that LTC1147CS8-3.3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1147CS8-3.3#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 LTC1147CS8-3.3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1147CS8-3.3#TRPBF?
All LTC1147CS8-3.3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1147CS8-3.3#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 LTC1147CS8-3.3#TRPBF part is unused and in its original packaging.
Return procedure for LTC1147CS8-3.3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC1147CS8-3.3#TRPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
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…
