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Analog Devices Inc. LT1931AES5#TRMPBF
- Part No.:
- LT1931AES5#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- SOT-23-5 Thin, TSOT-23-5
- Datasheet:
-
LT1931AES5#TRMPBF.pdf
- Description:
- IC REG CUK ADJ 1A TSOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,546
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Product details
Overview
LT1931AES5#TRMPBF from Analog Devices (formerly Linear Technology) is a 2.2MHz fixed-frequency inverting current-mode DC/DC converter with integrated 1A switch, delivering –5V at 300mA from a 5V input in a 5-lead ThinSOT package. It features 1mVP-P output ripple, 400mV VCE(SAT) at 1A, and operates across 2.6V–16V input range for compact negative bias generation in space-constrained systems.
For engineers reviewing the LT1931AES5#TRMPBF datasheet, LT1931AES5#TRMPBF pinout, LT1931AES5#TRMPBF application, or LT1931AES5#TRMPBF equivalent, this page delivers verified specifications, validated pin functions, confirmed dual-inductor inverting topology behavior, and real-world design constraints including 75% max duty cycle and ceramic capacitor–optimized low-noise performance.
Technical Context
The LT1931AES5#TRMPBF implements constant-frequency current-mode control with a 2.2MHz oscillator, enabling use of sub-2mm-height inductors and low-ESR ceramic capacitors. Its dual-inductor inverting topology filters both input and output currents, achieving <1mVP-P ripple when paired with X5R/X7R MLCCs.
It integrates a 36V-rated switch with 400mV saturation voltage at 1A, supports feedback regulation via –1.255V reference at NFB pin, and includes shutdown with <1µA quiescent current. The 75% maximum duty cycle limits usable VIN/|VOUT| ratios to ≤3.0 in continuous conduction mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 2.2MHz - enables use of 3.3µH–4.7µH chip inductors <2mm height, reducing solution footprint vs. 1.2MHz LT1931. |
| Output Current Capability | –5V at 300mA from 5V input - lower than LT1931's 350mA due to higher switching losses at 2.2MHz. |
| Feedback Reference Voltage | –1.255V - sets output voltage via external resistor divider; tolerance ±20mV ensures ±1.6% output accuracy. |
| Max Duty Cycle | 75% - constrains |VOUT|/(VIN + |VOUT|) ≤ 0.75; e.g., 5V→–16V (76.2%) requires discontinuous mode or LT1931. |
| Switch VCE(SAT) | 400mV at 1A - minimizes conduction loss; total switch power dissipation ≤400mW at full load. |
| Input Voltage Range | 2.6V to 16V - supports single-cell Li-ion (up to 4.2V), USB (5V), and industrial rails (12V). |
| Shutdown Current | <1µA - enables battery-powered systems to maintain ultra-low standby power. |
Pinout & Package
LT1931AES5#TRMPBF is housed in a 5-lead ThinSOT (TSOT-23) package, 2.9mm × 1.6mm × 1.0mm max height, with exposed pad not connected internally. Pin 1 (SW) carries high di/dt switching current; Pin 2 (GND) must tie directly to local ground plane; Pin 3 (NFB) sources bias current; Pin 4 (SHDN) is active-high enable; Pin 5 (VIN) requires local 1µF ceramic bypass.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pin 1) | Switch node | Connects to coupled/uncoupled inductor(s) and Schottky diode anode; trace area minimized to reduce EMI. |
| GND (Pin 2) | Power ground | Primary return path for switch current and IC ground; must connect directly to solid ground plane under device. |
| NFB (Pin 3) | Feedback input | Sources 4–16µA bias current; connects to resistive divider tap; reference = –1.255V; sets VOUT = –1.255 × (1 + R1/R2). |
| SHDN (Pin 4) | Enable control | Logic-high ≥2.4V enables operation; logic-low ≤0.5V disables with <1µA supply current; internal pull-down absent. |
| VIN (Pin 5) | Input supply | Accepts 2.6–16V; requires local 1µF X5R/X7R ceramic capacitor placed within 2mm of pin for stable operation. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 2.2MHz switching | Enables use of 3.3µH–4.7µH chip inductors (e.g., Panasonic ELJPC3R3MF), cutting board area by >40% vs. 1.2MHz designs. |
| Dual-inductor inverting topology | Filters both input and output currents, reducing conducted EMI and enabling <1mVP-P ripple with ceramic output caps. |
| Integrated 1A, 36V switch | Eliminates external MOSFET; 400mV VCE(SAT) at 1A yields >80% efficiency at –5V/300mA from 5V input. |
| Low-noise –1.255V reference | ±20mV tolerance over temperature ensures stable output regulation; NFB pin bias current (4–16µA) simplifies divider design. |
| Ultra-low shutdown current | <1µA at VIN = 3V allows multi-year battery life in always-on sensor nodes or portable instrumentation. |
Applications
| Disk Drive MR Head Bias | Digital Camera CCD Bias |
|---|---|
Use Scenario: Generating stable –5V to –12V bias for magnetoresistive read heads in HDD preamplifiers. IC Role / Device Role / Timing Role: Inverting DC/DC converter providing low-ripple, low-impedance negative rail isolated from noisy digital supplies. Use Value: 1mVP-P ripple prevents head-positioning jitter; 75% duty cycle supports common 5V→–5V and 5V→–12V configurations. |
Use Scenario: Supplying –5V to –15V bias for CCD image sensors requiring precise analog voltage stability. IC Role / Device Role / Timing Role: Compact negative voltage generator with fast transient response for pixel charge reset cycles. Use Value: Dual-inductor topology maintains <1% output deviation during 100mA load steps; 2.2MHz operation avoids interference with image capture timing. |
| LCD Bias Supply | GaAs FET Bias |
Use Scenario: Powering LCD segment drivers needing –5V to –10V bias in handheld medical or industrial displays. IC Role / Device Role / Timing Role: Space-efficient inverter replacing discrete charge pumps or larger buck-boost modules. Use Value: ThinSOT package (1mm height) fits behind display bezels; 2.2MHz switching eliminates audible noise from ceramic capacitors. |
Use Scenario: Providing –5V gate bias for GaAs FET RF amplifiers in 5G front-end modules or test equipment. IC Role / Device Role / Timing Role: Low-noise, fast-settling negative supply decoupled from noisy RF power rails. Use Value: 400mV VCE(SAT) minimizes thermal drift in bias voltage; 1.255V reference ensures repeatable FET threshold control. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar inverting DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1931ES5#TRMPBF | 1.2MHz switching frequency; 84% max duty cycle; –5V/350mA capability from 5V input. | Better efficiency and higher output current; requires larger 10µH inductors; unsuitable for ultra-compact layouts. | Select LT1931ES5#TRMPBF when efficiency >85% or output current >300mA is required; verify duty cycle for target VIN/VOUT ratio. |
| LT1611ES5#TRMPBF | No integrated switch; external 0.5A MOSFET required; 1.4MHz operation; –5V/150mA only. | Lower integration increases BOM count and layout complexity; limited to lower-power bias applications. | Choose LT1611ES5#TRMPBF only if legacy compatibility or cost sensitivity outweighs size/performance needs. |
Compared with LT1931AES5#TRMPBF, the LT1931ES5#TRMPBF trades higher efficiency and current for larger magnetics, while the LT1611ES5#TRMPBF sacrifices integration and output capability for legacy pin compatibility-making LT1931AES5#TRMPBF optimal for new designs prioritizing miniaturization and moderate power.
Availability
LT1931AES5#TRMPBF is available at Aetrix Electronics and suitable for disk drive MR head bias, digital camera CCD bias, LCD panel bias, and GaAs FET gate bias applications requiring stable component supply, consistent parametric performance, and long-term production continuity.
Supply support for LT1931AES5#TRMPBF 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 its precision analog and power management portfolio. Linear pioneered high-performance DC/DC converters for demanding signal-chain applications.
The LT1931/LT1931A series was designed specifically for compact, low-noise negative voltage generation in imaging, data storage, and RF systems-emphasizing small magnetics, ceramic capacitor compatibility, and dual-inductor EMI reduction.
FAQ
What is the maximum output current of the LT1931AES5#TRMPBF at –5V from a 5V input?
The LT1931AES5#TRMPBF delivers up to 300mA at –5V from a 5V input, as specified in the datasheet's Typical Applications section (Figure 1931 TA05a). This is lower than the LT1931ES5#TRMPBF's 350mA due to increased switching losses at 2.2MHz. Output current drops further at higher |VOUT| or elevated ambient temperatures; derating is required above 75°C.
Can the LT1931AES5#TRMPBF generate –12V from a 5V input?
No-the LT1931AES5#TRMPBF cannot reliably generate –12V from 5V input in continuous conduction mode. The required duty cycle is |–12V|/(5V + |–12V|) = 70.6%, which exceeds its 75% limit but approaches the edge of stability. For –12V at 150mA, the datasheet specifies the LT1931ES5#TRMPBF (84% duty cycle) in Figure 1931 TA02; using LT1931AES5#TRMPBF here risks regulation loss or excessive ripple.
Which inductors are recommended for the LT1931AES5#TRMPBF in a 5V-to–5V application?
The datasheet recommends coupled inductors of 3.3µH–4.7µH (e.g., Panasonic ELJPC3R3MF or Sumida CLQ4D10-4R71) or uncoupled inductors of 3.3µH–10µH (e.g., Taiyo Yuden LB20163R3M). These values ensure stable operation at 2.2MHz while maintaining peak switch current below 1.2A. Ferrite-core construction is mandatory for core loss control above 1MHz.
Does the LT1931AES5#TRMPBF require an external phase-lead capacitor for stability?
A phase-lead capacitor (e.g., 180–220pF) across R1 is recommended for optimal transient response in most LT1931AES5#TRMPBF designs, as shown in Figures 1931 TA05a and TA05b. Without it, output voltage exhibits ringing during load steps (Figure 1931 F03); adding C4 shifts the compensation zero to 20–60kHz, improving phase margin and damping (Figure 1931 F04).
What is the absolute maximum voltage rating on the SW pin of the LT1931AES5#TRMPBF?
The SW pin of the LT1931AES5#TRMPBF has an absolute maximum rating of –0.4V to +36V, per the Absolute Maximum Ratings table. This 36V rating allows |VOUT| up to 34V below VIN (e.g., 16V input → –18V output), supporting wide-range negative bias needs in telecom and industrial systems without external clamping.
LT1931AES5#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- SOT-23-5 Thin, TSOT-23-5
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Negative
- Topology:
- Cuk
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.45V
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- -1.255V
- Voltage - Output (Max):
- -34V
- Current - Output:
- 1A (Switch)
- Frequency - Switching:
- 2.2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-5
LT1931AES5#TRMPBF FAQ
1.How can I place an order for LT1931AES5#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1931AES5#TRMPBF 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 LT1931AES5#TRMPBF reliable?
The price and inventory of LT1931AES5#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1931AES5#TRMPBF is usually 5 days.
3.What payment methods are accepted for LT1931AES5#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1931AES5#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1931AES5#TRMPBF?
LT1931AES5#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1931AES5#TRMPBF 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 LT1931AES5#TRMPBF?
For technical support, including LT1931AES5#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1931AES5#TRMPBF requirements.
6.How does Aetrix verify that LT1931AES5#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LT1931AES5#TRMPBF 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 LT1931AES5#TRMPBF meets industry standards.
7.What is the process for return or replacement of LT1931AES5#TRMPBF?
All LT1931AES5#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1931AES5#TRMPBF, 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 LT1931AES5#TRMPBF part is unused and in its original packaging.
Return procedure for LT1931AES5#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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