Analog Devices Inc. LTC2909CTS8-5#TRPBF

Overview

LTC2909CTS8-5#TRPBF from Analog Devices (formerly Linear Technology) is a precision triple-input supply monitor IC designed for system-level power integrity supervision in 5V logic environments. It features dual adjustable 0.5V-threshold inputs with ±1.5% accuracy over temperature, a fixed 4.425V VCC UVLO threshold, 200ms internal reset timeout, and open-drain RST output - enabling robust undervoltage/overvoltage detection for core and I/O rails in desktop computers, network servers, and automotive ECUs.

For engineers reviewing the LTC2909CTS8-5#TRPBF datasheet, LTC2909CTS8-5#TRPBF pinout, LTC2909CTS8-5#TRPBF application, or LTC2909CTS8-5#TRPBF equivalent, key selection considerations include its TSOT-23-8 package, SEL-pin polarity configuration (supporting positive/negative supply monitoring), buffered 1V reference for offset-based negative rail sensing, 50μA quiescent current, and guaranteed 0.5V reset assertion down to VCC = 0.5V.

Technical Context

The LTC2909CTS8-5#TRPBF implements three independent voltage comparators: two with user-adjustable thresholds (0.5V nominal, ±1.5% accuracy) configured via external resistor dividers, and one fixed VCC UVLO comparator set at 4.425V (±1.5%) for 5V systems. Polarity of ADJ1/ADJ2 is selected by the three-state SEL pin (VCC/Open/GND), enabling simultaneous positive-UV/negative-OV or dual-negative monitoring without external components.

Its reset logic uses a programmable timeout stage - internally fixed at 200ms when TMR is grounded - with glitch filtering on comparator outputs and propagation delay under 500μs. The buffered 1V REF output (±15mV accuracy, ±1mA drive) serves as an offset reference for negative-supply monitoring circuits, while the 6.5V internal shunt regulator allows operation up to 6V directly or higher with series current-limiting resistance.

Key Specifications

Pinout & Package

Package: 8-lead TSOT-23 (3mm × 1.75mm), RoHS-compliant, lead-free (#TRPBF).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar supply monitoring applications.

Compared with TPS3808G33DBVR and MAX6369KA29+T, the LTC2909CTS8-5#TRPBF uniquely combines triple-input supervision (dual adjustable + VCC UVLO), polarity flexibility, and integrated REF - making it the only option capable of single-chip negative/positive dual-rail monitoring in space-constrained 5V systems.

Availability

LTC2909CTS8-5#TRPBF is available at Aetrix Electronics and suitable for desktop computing, automotive ECU, and industrial PLC applications requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across temperature.

Supply support for LTC2909CTS8-5#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2909 product line delivers precision, low-power, multi-rail voltage supervision ICs optimized for complex power architectures in computing, networking, and safety-critical embedded systems.

FAQ

What is the exact VCC undervoltage threshold for LTC2909CTS8-5#TRPBF?

The LTC2909CTS8-5#TRPBF has a fixed VCC UVLO threshold of 4.425V ±1.5% over the full operating temperature range (–40°C to 85°C). This value is factory-trimmed and specified in the Electrical Characteristics table under "VCC(UVLO)" for the -5 variant. It corresponds to 11.5% below the nominal 5V supply, ensuring reliable detection of brownout conditions before system instability occurs. The LTC2909CTS8-5#TRPBF guarantees this accuracy without external calibration.

How does the SEL pin configure input polarity on LTC2909CTS8-5#TRPBF?

The SEL pin on LTC2909CTS8-5#TRPBF selects polarity for both ADJ1 and ADJ2 inputs using three states: tied to VCC configures both for positive polarity (UV detection on positive rails), tied to GND configures both for negative polarity (UV detection on negative rails), and left open enables mixed polarity (one positive, one negative). Each state is validated in Table 1 of the datasheet. The LTC2909CTS8-5#TRPBF requires no external components to implement these modes, and leakage on the SEL pin is limited to ±10μA in the open state.

Can LTC2909CTS8-5#TRPBF monitor a single supply for both undervoltage and overvoltage?

Yes, the LTC2909CTS8-5#TRPBF can monitor one supply for both UV and OV using three external resistors and the ADJ1/ADJ2 inputs in mixed-polarity mode (SEL = Open). For example, a 5V rail can be monitored by configuring ADJ1 for UV (positive polarity) and ADJ2 for OV (negative polarity) - or vice versa. Figure 3 in the datasheet shows the resistor network topology. The LTC2909CTS8-5#TRPBF's ±1.5% threshold accuracy ensures tight fault window definition without requiring additional ICs.

What is the minimum VCC voltage that guarantees RST assertion on LTC2909CTS8-5#TRPBF?

The LTC2909CTS8-5#TRPBF guarantees RST output remains low for VCC ≥ 0.5V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. This ultralow-voltage reset capability ensures reliable power-down sequencing even during deep brownout. At VCC = 0.5V, the RST output voltage is guaranteed ≤ 0.30V with 5μA sink current. This behavior is intrinsic to the LTC2909CTS8-5#TRPBF's low-voltage drive circuitry and does not require external biasing.

Does LTC2909CTS8-5#TRPBF require an external timing capacitor for standard operation?

No, the LTC2909CTS8-5#TRPBF does not require an external timing capacitor for standard operation. When the TMR pin is tied to GND, the device uses its internal 200ms reset timeout - eliminating component count and layout complexity. External capacitors are only needed if a non-standard timeout (e.g., 16ms to 10s) is required. The LTC2909CTS8-5#TRPBF's datasheet specifies tRST(INT) = 200ms (typical) with ±30ms variation over temperature, fully characterized and production-tested.