Analog Devices Inc. LTC2901-3CGN#PBF

Overview

LTC2901-3CGN#PBF from Analog Devices (acquired Linear Technology) is a programmable quad supply monitor IC with adjustable reset and watchdog timers, designed for multivoltage systems requiring precise undervoltage detection on four independent rails. It supports 16 voltage threshold combinations (e.g., 5V/3.3V/2.5V/1.8V), ±1.5% threshold accuracy over temperature, 5%/10% selectable tolerance, and open-drain RST output. Used in telecom equipment and network servers for reliable power sequencing and fault recovery.

For engineers reviewing the LTC2901-3CGN#PBF datasheet, LTC2901-3CGN#PBF pinout, LTC2901-3CGN#PBF application, or LTC2901-3CGN#PBF equivalent, key selection criteria include its 16-lead SSOP package, guaranteed RST operation down to VCC = 1V, adjustable CRT/CWT timing capacitors, TOL pin logic-level select for 5%/10% thresholds, and individual COMP1–COMP4 monitor outputs per supply rail.

Technical Context

The LTC2901-3CGN#PBF implements four independent high-accuracy comparators with internal reference scaling, where VPG resistor-divider programming selects one of 16 preset or adjustable voltage threshold sets. Its architecture includes separate CRT and CWT capacitor-controlled timing circuits for reset delay and watchdog timeout, with glitch immunity and power-on/power-down behavior defined by VCC sourcing from the greater of V1 or V2.

Unlike variants with push-pull RST (LTC2901-2/LTC2901-4), this part uses an open-drain RST output pulled weakly to V2, while TOL pin logic-high enables 10% undervoltage monitoring. The device guarantees correct comparator and RST states for VCC ≥ 1V and supports negative adjustable inputs via VREF-referenced biasing on V4.

Key Specifications

Pinout & Package

Package: 16-lead plastic narrow SSOP (GN), 5.0mm × 6.2mm body, 0.65mm lead pitch, RoHS-compliant lead-free finish (#PBF).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3307-33D and MAX6805US33D3+T, the LTC2901-3CGN#PBF provides unique configurability across four independent rails, integrated watchdog with RST-merged timeout response, and support for both positive and negative adjustable thresholds-making it irreplaceable in complex multivoltage systems requiring diagnostics and field adaptability.

Availability

LTC2901-3CGN#PBF is available at Aetrix Electronics and suitable for desktop and notebook computers, telecom equipment, and network servers requiring stable component supply, long-term lifecycle support, and guaranteed performance across commercial temperature range (0°C to 70°C).

Supply support for LTC2901-3CGN#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The LTC2901 family was developed by Linear Technology (acquired by ADI in 2017) to address demand for highly accurate, programmable power supervision in multirail embedded systems-emphasizing threshold flexibility, low quiescent current, and robust timing control.

FAQ

What is the function of the TOL pin on the LTC2901-3CGN#PBF?

The TOL pin on the LTC2901-3CGN#PBF selects between 5% and 10% undervoltage detection thresholds: logic-low enables 5%, logic-high enables 10%. This feature is exclusive to the LTC2901-3 and LTC2901-4 variants and directly affects the trip points for all four monitored supplies. The LTC2901-3CGN#PBF uses this pin to dynamically adapt monitoring margins without changing external resistor dividers, supporting aging power supplies in telecom infrastructure.

How does the LTC2901-3CGN#PBF handle negative supply monitoring?

The LTC2901-3CGN#PBF supports negative supply monitoring in –ADJ mode on V4, using VREF (1.210V) as a level-shift reference. An external resistive divider connects the negative rail to VREF, with the inverting input (V4) referenced to ground. The trip voltage is calculated as VTRIP = VREF × (R3/R4), enabling precise detection of –1.87V, –4.64V, or other negative rails. This capability is confirmed in the datasheet's Figure 6 and Table 3 for the LTC2901-3CGN#PBF.

What is the minimum VCC required for reliable operation of the LTC2901-3CGN#PBF?

The LTC2901-3CGN#PBF guarantees correct RST and COMPX logic states for VCC ≥ 1V, where VCC is defined as the greater of V1 or V2. This ensures fail-safe reset assertion during brownout conditions well before internal bandgap reference collapse (~2V). The datasheet specifies VCCMINC = 2.32V for comparator enablement and VCCMINP = 2.42V for programming, but functional reset behavior remains valid down to 1V - a key reliability feature of the LTC2901-3CGN#PBF.

Can the LTC2901-3CGN#PBF be used without connecting the WDI pin?

Yes, the WDI pin on the LTC2901-3CGN#PBF can be left unconnected because it features a weak internal pull-up current (~10μA). In this configuration, the watchdog timer remains disabled unless actively toggled. If watchdog functionality is not required, grounding CWT (Pin 9) fully disables the timer, and the WDI pin may be tied to V1, GND, or left floating without risk. This behavior is explicitly documented for the LTC2901-3CGN#PBF in the Applications Information section.

What capacitor values are recommended for 216ms reset delay and 940ms watchdog timeout in the LTC2901-3CGN#PBF?

For the LTC2901-3CGN#PBF, a 47nF capacitor on CRT (Pin 5) yields a nominal reset delay of 216ms (tRST = 4.6ms/nF × 47nF), and a 47nF capacitor on CWT (Pin 9) yields a nominal watchdog timeout of 940ms (tWD = 20ms/nF × 47nF). These values are validated in the Typical Application schematics (Figures TA01 and TA01b) and match the datasheet's timing equations. Low-leakage ceramic capacitors are recommended to maintain accuracy.