Analog Devices Inc. LTC2901-3IGN#PBF

Overview

LTC2901-3IGN#PBF from Analog Devices (acquired Linear Technology) is a programmable quad supply monitor IC with open-drain RST output, 5% or 10% undervoltage tolerance selection via TOL pin, ±1.5% threshold accuracy over temperature, 43μA typical supply current, and adjustable reset/watchdog timing using external capacitors. It monitors four independent supplies (e.g., 5V, 3.3V, 2.5V, 1.8V) in multivoltage systems such as telecom equipment and network servers.

For engineers reviewing the LTC2901-3IGN#PBF datasheet, LTC2901-3IGN#PBF pinout, LTC2901-3IGN#PBF application, or LTC2901-3IGN#PBF equivalent, key selection criteria include its TOL-pin-controlled 5%/10% threshold tolerance, guaranteed RST assertion down to VCC ≥ 1V, open-drain RST output compatible with mixed-voltage logic, and 16 preset/adjustable voltage combinations selectable via VPG resistor divider.

Technical Context

The LTC2901-3IGN#PBF implements four independent high-accuracy comparators with glitch-immune inputs, each feeding a nondelayed COMPX output and contributing to a shared open-drain RST output. Its internal bandgap reference (1.210V ±1.5%) enables precise threshold generation across –40°C to 85°C.

Reset and watchdog timing are capacitor-programmed: CRT sets reset timeout (4.6 ms/nF), CWT sets watchdog timeout (20 ms/nF); both support minimum delays of 50μs and 200μs respectively when left unconnected. The TOL pin selects between 5% and 10% undervoltage thresholds - active only on LTC2901-3/LTC2901-4 variants.

Key Specifications

Pinout & Package

Package: 16-lead narrow SSOP (GN16), RoHS-compliant, 5.0mm × 6.2mm footprint, 0.635mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2901-4IGN#PBF, the LTC2901-3IGN#PBF provides open-drain RST essential for multi-source reset arbitration; compared with TPS3307-33DGNR, it delivers full configurability across four rails, ±1.5% accuracy, and watchdog functionality - making it suitable for complex, high-reliability systems.

Availability

LTC2901-3IGN#PBF is available at Aetrix Electronics and suitable for desktop computers, telecom equipment, and network servers requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for LTC2901-3IGN#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 semiconductors, formed through the acquisition of Linear Technology in 2017.

The LTC2901 family was designed by Linear Technology specifically for high-accuracy, low-power, multirail power supervision in demanding industrial and communications infrastructure applications - emphasizing threshold precision, glitch immunity, and flexible configuration.

FAQ

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

The TOL pin on the LTC2901-3IGN#PBF selects between 5% and 10% undervoltage threshold tolerance: logic low configures 5% (e.g., 4.675V for 5V rail), logic high configures 10% (e.g., 4.425V). This feature is exclusive to LTC2901-3 and LTC2901-4 variants and requires no external components - enabling dynamic tolerance selection in the same hardware design. The LTC2901-3IGN#PBF uses this pin to adapt fault sensitivity without changing resistor networks or firmware.

How does the LTC2901-3IGN#PBF support negative voltage monitoring?

The LTC2901-3IGN#PBF supports negative voltage monitoring via its –ADJ mode on the V4 input. In this mode, an external resistor divider connects between the negative supply and VREF (1.21V), with V4 tied to the divider tap. The internal comparator references 0V, and VREF provides level shifting - enabling accurate trip points like –4.64V (using Table 3 values). This allows direct supervision of negative rails in op-amp biasing or legacy interface circuits without additional level-shifting ICs. The LTC2901-3IGN#PBF's ±1.5% threshold accuracy applies across the full –ADJ range.

What is the minimum VCC required for the LTC2901-3IGN#PBF to assert a valid RST signal?

The LTC2901-3IGN#PBF guarantees correct RST logic state for VCC ≥ 1V, meaning it can assert a valid active-low reset even when the greater of V1 or V2 drops to 1V. This specification ensures robust brownout protection during partial power failure or slow discharge scenarios. Below 1V, internal circuitry may become undefined, but the LTC2901-3IGN#PBF maintains RST low until VCC falls below this limit - preventing spurious releases. This behavior is confirmed across the full –40°C to +85°C operating range.

Can the LTC2901-3IGN#PBF monitor fewer than four supplies?

Yes, the LTC2901-3IGN#PBF can monitor fewer than four supplies. Unused inputs (e.g., V3 or V4) may be tied to a valid voltage within the –0.3V to 7V absolute maximum rating - such as connecting V3 to V2 - ensuring they remain above their programmed thresholds and do not trigger RST. Alternatively, in ADJ or –ADJ modes, unused inputs can be configured to thresholds outside the operating range (e.g., 0.5V) and left floating with appropriate bypassing. The LTC2901-3IGN#PBF's architecture allows flexible configuration without performance penalty or increased current draw.

What capacitor values are recommended for 216ms reset and 940ms watchdog timeouts on the LTC2901-3IGN#PBF?

For a 216ms reset timeout, a 47nF capacitor on CRT yields tRST = 47nF × 4.6 ms/nF = 216ms. For a 940ms watchdog timeout, a 47nF capacitor on CWT yields tWD = 47nF × 20 ms/nF = 940ms. These values match the typical application circuits shown in the LTC2901-3IGN#PBF datasheet (Figures TA01 and TA01b). Low-leakage ceramic or silver-mica capacitors are recommended to maintain timing accuracy, as leakage currents affect the 2μA internal charging current. The LTC2901-3IGN#PBF's timing equations (CRT = tRST × 217 pF/ms, CWT = tWD × 50 pF/ms) allow precise scaling for other durations.