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Analog Devices Inc. LTC1261CS8-4#TRPBF
- Part No.:
- LTC1261CS8-4#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1261CS8-4#TRPBF.pdf
- Description:
- IC REG CHARGE PUMP -4V 12MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,941
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Product details
Overview
LTC1261CS8-4#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-output switched-capacitor voltage inverter IC that generates a regulated –4V negative supply from a single 3V–8V positive input. It delivers up to 12mA output current with ±5% regulation, features an open-drain REG pin for power-valid indication, and operates in doubler mode using only one external 0.1µF flying capacitor-targeted for space-constrained battery-powered systems requiring clean, low-noise negative bias.
For engineers reviewing the LTC1261CS8-4#TRPBF datasheet, LTC1261CS8-4#TRPBF pinout, LTC1261CS8-4#TRPBF application, or LTC1261CS8-4#TRPBF equivalent, key selection criteria include its fixed –4V output, SO-8 package compatibility, shutdown quiescent current of 5µA, 550kHz internal oscillator, and guaranteed regulation across 0°C to 70°C commercial temperature range.
Technical Context
The LTC1261CS8-4#TRPBF implements a charge-pump-based doubler topology with internal 1.24V reference and dual comparators: COMP1 regulates output by dynamically adjusting duty cycle, while COMP2 drives the open-drain REG pin when output reaches within 5% of –4V. Its SO-8 pinout omits C2+ and C2– pins, enforcing exclusive doubler-mode operation without tripler capability.
Regulation relies on feedback via the ADJ/COMP pin tied internally to a resistor string configured for –4V output; optional 100pF compensation capacitor at ADJ/COMP reduces output ripple to ≤5mV (typ) at 5mA load. Input supply rejection is maintained across 3V–8V, with output short-circuit protection and indefinite short-duration tolerance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed –4V ±5%; stable regulation over 0–12mA load and 3V–8V input. |
| Supply Current | 600µA typical operating current; drops to 5µA in shutdown-enables ultra-low-power standby. |
| Oscillator Frequency | 550kHz internal clock; enables compact 0.1µF flying capacitor and low output ripple. |
| Output Ripple | 5mV typical at 5mA load with 3.3µF output capacitor-suitable for analog sensor biasing. |
| REG Pin Function | Open-drain output sinking 8mA at 5V VCC; asserts low when |VOUT| ≥ 95% of setpoint-provides hardware power-good signal. |
| Operating Temperature | 0°C to 70°C commercial grade; validated across full range for regulation accuracy and startup reliability. |
| Package | 8-lead plastic SOIC (SO-8); footprint-compatible with standard PCB assembly processes. |
Pinout & Package
Package: 8-lead plastic SOIC (SO-8), 150°C/W junction-to-ambient thermal resistance, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VCC) | Positive power supply input | Accepts 3V–8V; requires ≥0.1µF ceramic bypass capacitor placed adjacent to pin. |
| 2 (C1+) | Flying capacitor positive terminal | Connects to C1– via 0.1µF ceramic capacitor; forms charge-transfer path in doubler mode. |
| 3 (C1–) | Flying capacitor negative terminal | Completes flying capacitor loop; no connection to ground or other nodes-floats in proper configuration. |
| 4 (GND) | Ground reference | Low-impedance return path for all internal circuits; must connect to solid ground plane. |
| 5 (COMP) | Compensation/adjust pin | Internally tied to –4V divider; add 100pF to GND to reduce ripple; not used for external adjustment. |
| 6 (OUT) | Negative regulated output | Delivers –4V; requires ≥3.3µF low-ESR output capacitor for specified ripple performance. |
| 7 (REG) | Regulation status indicator | Open-drain output; pull-up required externally; sinks 8mA when |VOUT| ≥ 3.8V. |
| 8 (SHDN) | Shutdown control | Pull low for normal operation; float or pull high to enter 5µA shutdown state. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed –4V output with no external resistors | Eliminates BOM cost and layout area; factory-trimmed for ±5% accuracy over temperature. |
| Doubler-only architecture in SO-8 | Enables minimal external component count: one 0.1µF flying cap + three bypass caps. |
| REG pin with 5% regulation window | Provides deterministic power-valid signal for microcontroller reset sequencing or system enable logic. |
| 550kHz switching frequency | Supports use of small, low-cost 0.1µF ceramic flying capacitors and reduces EMI compared to lower-frequency pumps. |
| 5µA shutdown quiescent current | Extends battery life in portable instrumentation where periodic wake-up cycles are required. |
Applications
| Portable Medical Sensors | Industrial Data Acquisition |
|---|---|
|
Use Scenario: Powering precision op-amps and ADC front-ends in handheld ECG or pulse oximeter units. IC Role / Device Role / Timing Role: Generates clean –4V analog supply rail isolated from noisy digital domains. Use Value: Enables true bipolar signal conditioning with <5mV ripple-preserving 16-bit ADC effective resolution. |
Use Scenario: Biasing GaAs FETs in 4–20mA loop-powered transmitters deployed in hazardous areas. IC Role / Device Role / Timing Role: Provides regulated negative gate bias independent of loop supply variations. Use Value: Maintains FET linearity across 12–24V loop range with guaranteed regulation down to 3V input. |
| Battery-Powered Test Equipment | Single-Supply Signal Chain Modules |
|
Use Scenario: Enabling dual-rail operation in portable oscilloscope preamplifiers powered by Li-ion cells. IC Role / Device Role / Timing Role: Supplies –4V rail for rail-to-rail input op-amps while minimizing standby current drain. Use Value: Achieves 5µA shutdown current-extending runtime between charges without compromising signal fidelity. |
Use Scenario: Generating negative bias for DAC output buffers in modular PLC I/O cards with shared 5V backplane. IC Role / Device Role / Timing Role: Delivers stable –4V from 5V backplane, decoupled from digital noise sources. Use Value: Ensures monotonic DAC output swing and eliminates zero-crossing distortion in 0–10V analog outputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switched-capacitor voltage inverter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX680ESA+ | Fixed –5V output; 120kHz oscillator; requires two 10µF flying caps; SO-8 package. | Higher output ripple (~20mV), lower max load (10mA), wider input range (4.5V–20V). | Select when –5V output is mandatory and higher input voltage tolerance is needed. |
| ICL7660SIPAZ | Adjustable output (–1.5V to –VIN); 10kHz oscillator; SO-8; no REG pin; 50mA peak current. | No regulation feedback or power-good signaling; higher ripple; suited for non-critical biasing. | Choose for cost-sensitive designs where precise regulation and status indication are unnecessary. |
Compared with LTC1261CS8-4#TRPBF, MAX680ESA+ offers higher input voltage support but sacrifices ripple performance and regulation precision, while ICL7660SIPAZ provides greater output flexibility at the cost of regulation accuracy and system-level monitoring capability-making LTC1261CS8-4#TRPBF optimal for applications demanding verified –4V stability with hardware validation.
Availability
LTC1261CS8-4#TRPBF is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition modules, battery-powered test equipment, and single-supply signal chain modules requiring stable component supply with guaranteed long-term manufacturability.
Supply support for LTC1261CS8-4#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC1261 family.
The LTC1261 series was designed specifically for compact, low-quiescent-current negative voltage generation in space- and power-constrained systems-emphasizing regulation accuracy, minimal external components, and robust thermal performance in SO packages.
FAQ
What output voltage does the LTC1261CS8-4#TRPBF provide?
The LTC1261CS8-4#TRPBF provides a fixed regulated output voltage of –4V ±5% across its full operating temperature range (0°C to 70°C) and load range (0–12mA). This value is factory-configured using an internal resistor string tied to the ADJ/COMP pin-no external resistors are required or supported for adjustment.
Can the LTC1261CS8-4#TRPBF operate from a 3V supply?
Yes, the LTC1261CS8-4#TRPBF is fully specified to operate from a 3V supply and deliver regulated –4V output at up to 12mA. Electrical characteristics-including regulation accuracy, output ripple, and startup behavior-are guaranteed across the full 3V–8V input range per the official datasheet.
What is the purpose of the REG pin on the LTC1261CS8-4#TRPBF?
The REG pin on the LTC1261CS8-4#TRPBF is an open-drain output that pulls low when the magnitude of the output voltage reaches ≥95% of the nominal –4V setpoint (i.e., |VOUT| ≥ 3.8V). It sinks up to 8mA at 5V VCC and requires an external pull-up resistor to function as a hardware power-valid indicator for system sequencing.
Does the LTC1261CS8-4#TRPBF support tripler-mode operation?
No, the LTC1261CS8-4#TRPBF does not support tripler-mode operation. Its SO-8 package lacks C2+ and C2– pins, and the internal circuitry is configured exclusively for doubler-mode charge pumping-requiring only one 0.1µF flying capacitor between C1+ and C1–.
What is the minimum output capacitor required for the LTC1261CS8-4#TRPBF?
The LTC1261CS8-4#TRPBF requires a minimum 3.3µF output capacitor to achieve the specified 5mV typical output ripple at 5mA load. A 1µF capacitor meets basic bypass requirements but increases ripple significantly; ceramic or low-ESR tantalum types are recommended, and adding a parallel 0.1µF ceramic cap suppresses high-frequency spikes.
LTC1261CS8-4#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
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 8V
- Voltage - Output (Min/Fixed):
- -4V
- Voltage - Output (Max):
- -
- Current - Output:
- 12mA
- Frequency - Switching:
- 550kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1261CS8-4#TRPBF FAQ
1.How can I place an order for LTC1261CS8-4#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1261CS8-4#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 LTC1261CS8-4#TRPBF reliable?
The price and inventory of LTC1261CS8-4#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1261CS8-4#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1261CS8-4#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1261CS8-4#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1261CS8-4#TRPBF?
LTC1261CS8-4#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1261CS8-4#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 LTC1261CS8-4#TRPBF?
For technical support, including LTC1261CS8-4#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1261CS8-4#TRPBF requirements.
6.How does Aetrix verify that LTC1261CS8-4#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1261CS8-4#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 LTC1261CS8-4#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1261CS8-4#TRPBF?
All LTC1261CS8-4#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1261CS8-4#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 LTC1261CS8-4#TRPBF part is unused and in its original packaging.
Return procedure for LTC1261CS8-4#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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