My Inquiry
My Account
Analog Devices Inc. LTC1261LCMS8#TRPBF
- Part No.:
- LTC1261LCMS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1261LCMS8#TRPBF.pdf
- Description:
- IC REG CHARG PUMP ADJ 20MA 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,624
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC1261LCMS8#TRPBF from Analog Devices (formerly Linear Technology) is a switched-capacitor regulated negative voltage inverter IC that generates a stable –4V output from a single 4.5V–5.25V positive supply. It delivers up to 20mA output current with ±4.5% regulation accuracy, features an open-drain REG flag for power-valid indication, and operates with only three external capacitors. It is used in GaAs FET bias generation and battery-powered systems requiring compact, low-quiescent-power negative rails.
For engineers reviewing the LTC1261LCMS8#TRPBF datasheet, LTC1261LCMS8#TRPBF pinout, LTC1261LCMS8#TRPBF application, or LTC1261LCMS8#TRPBF equivalent, key selection criteria include fixed –4V output specification, MSOP-8 package compatibility, shutdown current of 5µA, REG pin logic behavior, and guaranteed regulation across 0°C to 70°C commercial temperature range.
Technical Context
The LTC1261LCMS8#TRPBF implements a 650kHz internal oscillator-driven charge pump topology with feedback regulation via an internal 1.23V reference and comparator-based duty-cycle control. Output voltage is stabilized by monitoring a divided replica of VOUT at the ADJ/COMP pin relative to this reference.
Its REG pin functions as an open-drain indicator that pulls low when |VOUT| is within 5% of the set –4V value - requiring an external pull-up. Shutdown is asserted by pulling SHDN high, disabling the charge pump and reducing quiescent current to 5µA while collapsing VOUT to 0V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed –4V, guaranteed over 4.35V–5.25V input and 0–20mA load, enabling direct replacement of dual-supply rails. |
| Supply Voltage Range | 4.35V to 5.25V - minimum VCC ensures ±4.5% regulation; operation below 4.35V not specified for –4V accuracy. |
| Output Regulation Accuracy | ±4.5% over full load (0–20mA) and input range - defines worst-case deviation from nominal –4V in production designs. |
| Quiescent Current | 650µA typical during operation; drops to 5µA in shutdown - critical for battery life in portable instrumentation. |
| Oscillator Frequency | 650kHz typical - determines charge-transfer timing, output ripple magnitude, and allowable external capacitor values. |
| REG Pin Behavior | Open-drain output sinking ≥5mA at 5V VCC when |VOUT| ≥ 3.8V - provides system-level power-good signaling without additional logic. |
| Shutdown Threshold | VIH ≥ 2V, VIL ≤ 0.8V at VCC = 5V - compatible with standard CMOS logic levels for microcontroller-controlled power sequencing. |
Pinout & Package
Package: 8-lead plastic MSOP (MS8), 3.00mm × 3.00mm body, 0.65mm pitch, exposed pad not electrically connected. Thermal resistance θJA = 200°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Positive power input | Must be bypassed with ≥1µF ceramic capacitor near pin; supplies energy for charge pump switching and internal circuitry. |
| C1+ (Pin 2) | Flying capacitor positive terminal | Connects to one end of 0.1µF flying capacitor; forms half of charge-transfer path during pump cycle. |
| C1– (Pin 3) | Flying capacitor negative terminal | Connects to other end of 0.1µF flying capacitor; referenced to GND during charging phase, to OUT during transfer phase. |
| GND (Pin 4) | Analog and power ground reference | Low-impedance return path for all currents; layout with ground plane minimizes regulation error from noise coupling. |
| COMP (Pin 5) | Compensation / feedback node | Internally tied to fixed resistor divider for –4V output; optional 100pF capacitor to GND reduces output ripple by stabilizing regulation loop. |
| OUT (Pin 6) | Negative regulated output | Delivers –4V to load; requires ≥3.3µF output capacitor with low ESR to maintain regulation and limit ripple under 20mA load. |
| REG (Pin 7) | Regulation status indicator | Open-drain N-channel output; sinks current when |VOUT| ≥ 3.8V - must be pulled up externally to monitor power validity. |
| SHDN (Pin 8) | Enable/shutdown control | Active-high logic input; floating defaults to operational mode via internal 5µA pull-down; high state disables charge pump and reduces ICC to 5µA. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed –4V output with no external resistors | Eliminates component count and tuning effort; simplifies BOM and layout for GaAs FET bias applications. |
| Integrated 650kHz oscillator and charge pump | Removes need for external clock source or discrete switching elements; enables compact, low-noise DC/DC conversion. |
| REG pin with ±5% regulation window | Provides deterministic power-good signal for microcontrollers or supervisors without requiring external comparators. |
| 5µA shutdown current | Extends battery runtime in portable devices by cutting supply draw by >99% versus active mode (650µA). |
| Three-capacitor solution (0.1µF flying + input/output bypass) | Reduces bill-of-materials cost and PCB area versus inductor-based inverters; supports high-density portable designs. |
Applications
| GaAs FET Bias Generation | Negative Supply for Single-Supply Op Amps |
|---|---|
Use Scenario: Providing precise –4V gate bias to GaAs power amplifier stages in RF transmitters operating from 5V battery input. IC Role / Device Role / Timing Role: Regulated negative voltage inverter generating stable –4V rail independent of load current up to 20mA. Use Value: Enables high-efficiency RF amplification without dual supplies; REG pin confirms bias rail readiness before PA enable. |
Use Scenario: Generating –4V reference for rail-splitting in single-supply op amp circuits used in portable data acquisition front-ends. IC Role / Device Role / Timing Role: Compact charge-pump inverter supplying clean negative rail with minimal external components. Use Value: Eliminates bulky inductors and transformers; 650kHz switching allows small ceramic capacitors and reduces EMI in sensitive analog signal paths. |
| Battery-Powered Instrumentation | Power-Valid Sequencing in Embedded Systems |
Use Scenario: Creating –4V auxiliary supply for LCD contrast control or sensor excitation in handheld test equipment powered by Li-ion cells. IC Role / Device Role / Timing Role: Low-quiescent-current inverter supporting long standby time and fast wake-up via SHDN control. Use Value: 5µA shutdown current extends battery life; turn-on time <1.5ms ensures rapid system readiness after wake command. |
Use Scenario: Coordinating power-up sequence between microcontroller and analog subsystems requiring validated –4V rail before initialization. IC Role / Device Role / Timing Role: Regulation monitor providing hardware-level "power good" assertion via REG pin. Use Value: Prevents firmware lockup by blocking MCU boot until –4V rail settles within ±5%; eliminates software polling overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar regulated negative voltage inverter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX680ESA+ | Fixed –5V output; 100kHz oscillator; requires four external capacitors; SO-8 only. | Higher output magnitude but lower switching frequency increases output ripple and capacitor size requirements. | Select when –5V is required and board space permits larger 10µF output capacitor; avoid if 650kHz EMI sensitivity exists. |
| TPS60403DBVR | Adjustable –1.5V to –5.5V output; 1MHz oscillator; 2.7–5.5V input; SOT-23-6 package. | Smaller footprint but limited to 60mA max output; no REG pin; requires two external resistors for adjustment. | Select for ultra-compact designs needing adjustable output and higher current; omit if hardware power-good signaling is mandatory. |
Compared with MAX680ESA+ and TPS60403DBVR, the LTC1261LCMS8#TRPBF offers unique integration of fixed –4V output, REG status flag, and MSOP-8 packaging - making it optimal for GaAs bias and power-sequencing applications where precision, compactness, and hardware validation are jointly required.
Availability
LTC1261LCMS8#TRPBF is available at Aetrix Electronics and suitable for GaAs FET bias generation, portable instrumentation power supplies, and embedded system power-sequencing applications requiring stable component supply and guaranteed commercial-temperature performance.
Supply support for LTC1261LCMS8#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 its legacy precision analog and power management product lines with full datasheet, reliability, and support continuity.
The LTC1261L series was designed specifically for compact, low-component-count generation of regulated negative voltages in space-constrained, battery-operated systems - emphasizing simplicity, regulation accuracy, and integrated status signaling.
FAQ
What is the exact output voltage tolerance of the LTC1261LCMS8#TRPBF?
The LTC1261LCMS8#TRPBF delivers a fixed –4V output with guaranteed regulation of ±4.5% across its full operating conditions - meaning VOUT remains between –3.82V and –4.18V for input voltages from 4.35V to 5.25V and load currents from 0mA to 20mA. This tolerance is explicitly specified in the Electrical Characteristics table and applies over the 0°C to 70°C commercial temperature range.
Can the LTC1261LCMS8#TRPBF operate from a 3.3V supply?
No - the LTC1261LCMS8#TRPBF is a fixed –4V variant (LTC1261L-4) and requires a minimum supply voltage of 4.35V to guarantee ±4.5% output regulation. Operation below 4.35V is possible per Note 5, but output accuracy is not assured. For 3.3V-compatible negative generation, consider the adjustable LTC1261LCMS8#TRPBF or alternative parts like the TPS60403DBVR.
How does the REG pin on the LTC1261LCMS8#TRPBF function in practice?
The REG pin on the LTC1261LCMS8#TRPBF is an open-drain output that pulls low when |VOUT| is within 5% of the nominal –4V setpoint (i.e., ≥3.8V). It sinks ≥5mA at 5V VCC but requires an external pull-up resistor (typically 10kΩ to VCC or system IO voltage) to assert a logic-high state when regulation is achieved. This provides hardware-level power-valid signaling without firmware polling.
What external capacitors are mandatory for stable operation of the LTC1261LCMS8#TRPBF?
The LTC1261LCMS8#TRPBF requires three mandatory capacitors: a 0.1µF ceramic flying capacitor between C1+ and C1–, a ≥1µF ceramic input bypass capacitor from VCC to GND, and a ≥3.3µF ceramic output capacitor from OUT to GND. An optional 100pF capacitor from COMP to GND further reduces output ripple by compensating the regulation loop bandwidth.
Is the LTC1261LCMS8#TRPBF pin-compatible with other variants in the LTC1261L family?
Yes - all LTC1261L variants, including the LTC1261LCMS8#TRPBF, share identical 8-pin MSOP (MS8) pinouts and electrical pin functions. The only functional differences lie in internal resistor network configuration (fixed –4V vs adjustable), which affects only the ADJ/COMP pin behavior and output voltage setting - not pin assignment, package dimensions, or thermal characteristics.
LTC1261LCMS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Negative
- Topology:
- Charge Pump
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.25V
- Voltage - Output (Min/Fixed):
- -1.23V
- Voltage - Output (Max):
- -5V
- Current - Output:
- 20mA
- Frequency - Switching:
- 650kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LTC1261LCMS8#TRPBF FAQ
1.How can I place an order for LTC1261LCMS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1261LCMS8#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 LTC1261LCMS8#TRPBF reliable?
The price and inventory of LTC1261LCMS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1261LCMS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1261LCMS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1261LCMS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1261LCMS8#TRPBF?
LTC1261LCMS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1261LCMS8#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 LTC1261LCMS8#TRPBF?
For technical support, including LTC1261LCMS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1261LCMS8#TRPBF requirements.
6.How does Aetrix verify that LTC1261LCMS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1261LCMS8#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 LTC1261LCMS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1261LCMS8#TRPBF?
All LTC1261LCMS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1261LCMS8#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 LTC1261LCMS8#TRPBF part is unused and in its original packaging.
Return procedure for LTC1261LCMS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC1261LCMS8#TRPBF 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…
