My Inquiry
My Account
Analog Devices Inc. LTC1550LCS8-2#PBF
- Part No.:
- LTC1550LCS8-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1550LCS8-2#PBF.pdf
- Description:
- IC REG CHARGE PUMP -2V 20MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:167
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC1550LCS8-2#PBF from Analog Devices (formerly Linear Technology) is a fixed-output, low-noise switched-capacitor voltage inverter with integrated linear post-regulator, delivering –2.0V ±2.5% at up to 20mA load current from a 2.7V–5.25V single supply. It features 900kHz charge pump frequency, <1mVP-P output ripple, and active-low TTL-compatible shutdown (SHDN). It is optimized for GaAs FET bias generation in portable RF transmitters.
For engineers reviewing the LTC1550LCS8-2#PBF datasheet, LTC1550LCS8-2#PBF pinout, LTC1550LCS8-2#PBF application, or LTC1550LCS8-2#PBF equivalent, key selection criteria include guaranteed –2V regulation over line/load/temperature, minimal external component count (four capacitors), MSOP-8 package compatibility, and sub-1µA shutdown current.
Technical Context
The LTC1550LCS8-2#PBF integrates a 900kHz inverting charge pump stage followed by a negative linear regulator using an N-channel MOSFET pass device and internal 1.225V reference. Its feedback loop is optimized for fast transient response to suppress switching artifacts from CPOUT, enabling stable regulation despite varying input voltage and load conditions.
It operates exclusively in fixed –2V output mode (not adjustable), requires no external resistors, and uses only four external components: one 2.2µF input bypass capacitor, two 0.1µF charge pump capacitors (C1+, C1–), and one ≥10µF output filter capacitor (VOUT to GND). The REG pin is not present in the 8-pin SO package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | –2.0V ±2.5% over line, load, and temperature - ensures stable GaAs FET gate bias across operating conditions. |
| Max Output Current | 20mA at VCC ≥ 3.75V - supports moderate-power RF biasing without external amplification. |
| Output Ripple | <1mVP-P (typical, 0–10mA load) - meets low-noise requirements for sensitive RF front-end circuits. |
| Supply Range | 2.7V to 5.25V - compatible with Li-ion, Li-poly, and regulated 3.3V/5V rails in portable systems. |
| Shutdown Current | 0.2µA typical - enables ultra-low-power standby in battery-operated devices. |
| Charge Pump Freq | 900kHz - avoids IF bands (400–600kHz) and permits use of small 0.1µF ceramic flying capacitors. |
| Quiescent Current | 3.65mA typical at 5V - balances efficiency and startup speed for intermittent-use applications. |
Pinout & Package
Package: 8-lead narrow SO (S8), 150°C maximum junction temperature, θJA = 135°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (REG) | Power-OK Indicator Output | Open-drain output pulled low when VOUT is within ±5% of –2V; requires external pull-up to VCC or higher (≤6V); not functional in S8 package per datasheet - pin is NC. |
| 2 (CPOUT) | Negative Charge Pump Output | Intermediate node supplying negative voltage to linear regulator; requires 0.1µF capacitor to GND with star-ground connection to minimize ripple. |
| 3 (GND) | Analog Ground Reference | Primary ground return for regulator feedback and internal circuitry; must connect to low-impedance ground plane to avoid regulation error. |
| 4 (C1–) | Flying Capacitor Negative Terminal | Connects to negative side of 0.1µF charge pump capacitor (C1); forms half of charge transfer path with C1+. |
| 5 (SHDN) | Active-Low Shutdown Control | TTL-compatible input; pulls low to disable charge pump and reduce ICC to 0.2µA; high-impedance with no internal pull-up - external pull-up required. |
| 6 (VCC) | Positive Input Supply | Accepts 2.7V–5.25V; must be bypassed with ≥2.2µF ceramic capacitor directly to GND pin to prevent supply droop during charge pumping. |
| 7 (C1+) | Flying Capacitor Positive Terminal | Connects to positive side of 0.1µF charge pump capacitor (C1); alternately charges/discharges with C1– under 900kHz clock. |
| 8 (VOUT) | Regulated Negative Output | Delivers –2.0V; requires ≥10µF output capacitor (moderate ESR) to ground for stability and ripple suppression; parallel 0.1µF ceramic mandatory for high-frequency spike rejection. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Linear Post-Regulator | Eliminates need for external LDO; achieves <1mVP-P ripple without LC filtering, reducing BOM and board space. |
| Fixed –2V Output Configuration | No external resistors required - simplifies layout and eliminates trimming errors in production. |
| 900kHz Switching Frequency | Enables use of standard 0.1µF ceramic flying capacitors and avoids interference with common IF bands in cellular radios. |
| Ultra-Low Shutdown Current | 0.2µA typical allows >1-year battery life in always-on standby modes for portable RF modules. |
| Single-Supply Operation | Derives regulated negative rail from positive battery or system rail - eliminates need for dual supplies in compact RF designs. |
Applications
| GaAs FET Transmitter Bias | Portable Cellular RF Front-End |
|---|---|
|
Use Scenario: Providing gate bias voltage for GaAs power amplifier FETs in GSM/EDGE handsets. IC Role / Device Role / Timing Role: Fixed –2V regulated negative supply generator with fast transient response to support burst-mode transmission. Use Value: Enables stable FET operation across battery discharge (2.7V–4.2V), maintaining PA linearity and efficiency without external regulation. |
Use Scenario: Generating clean negative supply for RF switch drivers and low-noise amplifier (LNA) bias in compact smartphone RF modules. IC Role / Device Role / Timing Role: Low-ripple inverting charge pump with integrated linear post-regulator for noise-sensitive analog signal paths. Use Value: Delivers <1mVP-P ripple at 20mA, preventing AM-to-PM distortion and adjacent channel leakage in multi-band RF ICs. |
| Battery-Powered Instrumentation | Single-Supply Signal Conditioning |
|
Use Scenario: Powering op-amp-based sensor interfaces (e.g., strain gauge bridges) in handheld test equipment. IC Role / Device Role / Timing Role: Compact, low-quiescent-current negative rail generator supporting rail-to-rail input/output amplifiers. Use Value: Extends battery life via 3.65mA operating current and 0.2µA shutdown, while maintaining precision bias for 16-bit ADC front-ends. |
Use Scenario: Enabling true bipolar operation of instrumentation amplifiers and DACs from a single 3.3V or 5V supply. IC Role / Device Role / Timing Role: Fixed-output inverter providing symmetric negative rail to complement existing positive supply. Use Value: Eliminates need for isolated DC/DC converters or transformer-based solutions - reduces EMI, cost, and footprint in space-constrained PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC1550LCMS8-2#PBF | Same electrical specs and functionality, but in 8-lead MSOP package (3mm × 3mm vs SO's 4.9mm × 3.9mm); identical pinout except REG pin is functional in MSOP-8. | Preferred for space-constrained layouts where smaller footprint and thermal performance (θJA = 135°C/W vs SO's 135°C/W) are critical. | Select if board area is limited and MSOP assembly capability exists; verify REG pin usage in design. |
| LTC1261LCS8#PBF | Adjustable output (–1.2V to –5V), lower max output current (15mA), higher quiescent current (5mA), no REG pin, same SO-8 package. | Suitable for designs requiring flexible output voltage tuning, but lacks guaranteed –2V accuracy and low-noise performance of LTC1550LCS8-2#PBF. | Choose only if voltage adjustability outweighs ripple, regulation accuracy, and efficiency requirements. |
Compared with LTC1550LCMS8-2#PBF, the LTC1550LCS8-2#PBF offers identical electrical performance in a larger but more manufacturable SO package; versus LTC1261LCS8#PBF, it delivers tighter regulation, lower ripple, and lower ICC, making it superior for fixed –2V GaAs biasing where noise and stability are paramount.
Availability
LTC1550LCS8-2#PBF is available at Aetrix Electronics and suitable for portable RF transmitters, battery-powered instrumentation, and single-supply signal conditioning requiring stable component supply, consistent parametric performance, and long-term lifecycle support.
Supply support for LTC1550LCS8-2#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for legacy Linear parts including the LTC series.
The LTC1550L family was designed specifically for low-noise, low-component-count negative bias generation in portable RF systems - emphasizing GaAs FET gate drive stability, battery efficiency, and minimal external footprint.
FAQ
What is the output voltage tolerance of the LTC1550LCS8-2#PBF over temperature and load?
The LTC1550LCS8-2#PBF guarantees –2.0V output with ±2.5% regulation over the full commercial temperature range (0°C to 70°C), line (2.7V–5.25V), and load (0–20mA), as specified in the Electrical Characteristics table. This tolerance ensures reliable GaAs FET biasing across battery discharge and ambient variations without external trimming.
Can the LTC1550LCS8-2#PBF be used with a 2.7V supply to deliver –2V at 20mA?
No - the LTC1550LCS8-2#PBF requires a minimum VCC of 3.75V to sustain –2V output at 20mA load, per the "Minimum Required VCC vs VOUT and IOUT" graph and Electrical Characteristics table. At 2.7V, maximum supported load is ≤5mA; attempting 20mA will cause regulation loss and output collapse.
Is the REG pin functional on the LTC1550LCS8-2#PBF in the SO-8 package?
No - the REG pin is marked as "NC" (no internal connection) for all 8-pin SO (S8) variants including LTC1550LCS8-2#PBF. The REG function is only available on 16-pin SSOP (GN) and 8-pin MSOP (MS8) packages. Designers using the SO-8 version must omit REG-related circuitry.
What capacitor values are mandatory for stable operation of the LTC1550LCS8-2#PBF?
The LTC1550LCS8-2#PBF requires: (1) a ≥2.2µF ceramic input bypass capacitor (CIN) at VCC–GND, (2) two 0.1µF ceramic flying capacitors (C1+, C1–), (3) a ≥10µF output capacitor (COUT) at VOUT–GND with moderate ESR, plus (4) a mandatory 0.1µF ceramic capacitor in parallel with COUT to suppress high-frequency spikes. Omitting any violates stability and ripple specifications.
How does the shutdown function behave on the LTC1550LCS8-2#PBF?
The LTC1550LCS8-2#PBF features an active-low TTL-compatible SHDN pin. Pulling SHDN low disables the charge pump, collapses VOUT to 0V, and reduces supply current to 0.2µA typical. The pin has no internal pull-up; a resistor or current source must pull SHDN to VCC to ensure normal operation after power-up.
LTC1550LCS8-2#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- -2V
- Voltage - Output (Max):
- -
- Current - Output:
- 20mA
- Frequency - Switching:
- 900kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1550LCS8-2#PBF FAQ
1.How can I place an order for LTC1550LCS8-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1550LCS8-2#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 LTC1550LCS8-2#PBF reliable?
The price and inventory of LTC1550LCS8-2#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1550LCS8-2#PBF is usually 5 days.
3.What payment methods are accepted for LTC1550LCS8-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1550LCS8-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1550LCS8-2#PBF?
LTC1550LCS8-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1550LCS8-2#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 LTC1550LCS8-2#PBF?
For technical support, including LTC1550LCS8-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1550LCS8-2#PBF requirements.
6.How does Aetrix verify that LTC1550LCS8-2#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1550LCS8-2#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 LTC1550LCS8-2#PBF meets industry standards.
7.What is the process for return or replacement of LTC1550LCS8-2#PBF?
All LTC1550LCS8-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1550LCS8-2#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 LTC1550LCS8-2#PBF part is unused and in its original packaging.
Return procedure for LTC1550LCS8-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC1550LCS8-2#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…
