Analog Devices Inc. LTC2902-1CGN#PBF

Overview

LTC2902-1CGN#PBF from Analog Devices (formerly Linear Technology) is a programmable quad supply monitor IC with open-drain RST output, designed for reliable power-on reset and brownout detection in multivoltage systems. It simultaneously monitors four supplies (e.g., 5V, 3.3V, 2.5V, 1.8V), offers ±1.5% threshold accuracy over temperature, selectable 5–12.5% supply tolerance, 43µA quiescent current, and adjustable reset delay via external capacitor - used in telecom equipment and network servers.

For engineers reviewing the LTC2902-1CGN#PBF datasheet, LTC2902-1CGN#PBF pinout, LTC2902-1CGN#PBF application, or LTC2902-1CGN#PBF equivalent, key selection criteria include guaranteed RST assertion down to VCC = 1V, individual nondelayed comparator outputs per supply, resistor-programmable voltage combinations (16 options), and compatibility with margining via RDIS pin.

Technical Context

The LTC2902-1CGN#PBF implements four independent high-accuracy voltage comparators referenced to a buffered 1.210V bandgap, with thresholds digitally programmed via VPG pin using a 1% resistive divider. Tolerance selection (5%, 7.5%, 10%, 12.5%) is controlled by dual digital inputs T0/T1, which scale the internal reference voltage accordingly.

Its open-drain RST output (LTC2902-1 variant) features weak internal pull-up to V2 (~6µA), while COMP1–COMP4 outputs are also open-drain with identical pull-up behavior. The device guarantees correct logic state for VCC ≥ 1V and supports both positive-adjustable (ADJ) and negative-adjustable (–ADJ) monitoring modes on V3/V4 inputs.

Key Specifications

Pinout & Package

Package: 16-lead narrow SSOP (GN), 0.150-inch body width, RoHS-compliant, lead-free (Pb-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2902-2CGN#PBF, the LTC2902-1CGN#PBF provides open-drain RST for voltage-level translation and shared-bus applications, while LTC1326-2.5 sacrifices programmability and channel count for tighter threshold accuracy and lower cost in fixed-triple configurations.

Availability

LTC2902-1CGN#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 RoHS-compliant packaging.

Supply support for LTC2902-1CGN#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 its high-performance analog and power management product lines with rigorous reliability standards.

The LTC2902 family was designed for precision multirail power monitoring in commercial and industrial systems where deterministic reset behavior, low quiescent current, and hardware-programmable flexibility are essential.

FAQ

What is the function of the RDIS pin on the LTC2902-1CGN#PBF?

The RDIS pin on the LTC2902-1CGN#PBF is a digital input that, when pulled low, forces the RST output high regardless of supply voltage conditions. This enables supply margin testing without issuing a system reset. The pin has an internal 10µA pull-up, so it may be left floating for normal operation. Its behavior is identical across all LTC2902-1 variants including LTC2902-1CGN#PBF.

How does the CRT capacitor affect reset timing in the LTC2902-1CGN#PBF?

The CRT capacitor connected between Pin 5 (CRT) and GND sets the reset timeout period tRST for the LTC2902-1CGN#PBF according to tRST = 4.6ms/nF. For example, a 1500pF capacitor yields ~6.9ms delay. Leaving CRT unconnected gives a minimum ~50µs delay. Capacitor leakage and tolerance directly impact timing accuracy, so low-leakage ceramic types are recommended for the LTC2902-1CGN#PBF.

Can the LTC2902-1CGN#PBF monitor negative voltages?

Yes - the LTC2902-1CGN#PBF supports negative voltage monitoring on V4 using the –ADJ mode. In this configuration, V4's inverting input connects to an external resistor divider between the negative supply and VREF (1.21V), enabling accurate trip-point setting (e.g., –4.64V). VREF provides the necessary level shift, and the LTC2902-1CGN#PBF's internal architecture ensures correct comparator operation without external op-amps.

What is the minimum VCC required for valid RST output in the LTC2902-1CGN#PBF?

The LTC2902-1CGN#PBF guarantees correct RST logic state for VCC ≥ 1V. Below 1V, RST may float due to diminished pull-down strength. This specification ensures reliable reset assertion during brownout conditions common in AC-DC and battery-backed systems. The guarantee applies across the full 0°C to 70°C operating range for the LTC2902-1CGN#PBF.

How many voltage combinations can be programmed on the LTC2902-1CGN#PBF?

The LTC2902-1CGN#PBF supports 16 distinct voltage-monitoring combinations selected via a resistor divider on the VPG pin. These include presets like 5V/3.3V/2.5V/1.8V and mixed modes such as 5V/3.0V/1.8V/ADJ or 3.3V/2.5V/1.5V/–ADJ. Each combination is validated in Table 1 of the datasheet, and all 16 are fully supported by the LTC2902-1CGN#PBF without firmware or register writes.