Analog Devices Inc. LTC2902-2IGN#TRPBF

Overview

LTC2902-2IGN#TRPBF from Analog Devices (formerly Linear Technology) is a programmable quad supply monitor IC with push-pull RST output, designed for multivoltage system power sequencing and brownout detection. It simultaneously monitors four independent supplies (e.g., 5V/3.3V/2.5V/1.8V), offers ±1.5% threshold accuracy over temperature, selectable 5–12.5% supply tolerance, and adjustable reset timeout via external capacitor - used in telecom equipment, network servers, and desktop computers.

For engineers reviewing the LTC2902-2IGN#TRPBF datasheet, LTC2902-2IGN#TRPBF pinout, LTC2902-2IGN#TRPBF application, or LTC2902-2IGN#TRPBF equivalent, key selection criteria include guaranteed RST assertion down to VCC = 1V, individual nondelayed comparator outputs (COMP1–COMP4), push-pull RST logic compatibility with CMOS/TTL loads, and resistor-programmable voltage combinations using VPG/VREF.

Technical Context

The LTC2902-2IGN#TRPBF implements four independent high-accuracy voltage comparators referenced to a buffered 1.210V bandgap (±0.7% over temp), with thresholds digitally scaled per T0/T1 inputs to deliver 5%, 7.5%, 10%, or 12.5% below nominal supply levels. Its internal VCC is derived from the greater of V1 or V2, enabling operation even when only one rail is active during power-up.

Reset timing is controlled by an external capacitor on CRT pin (4.6 ms/nF scaling), while RDIS provides hardware-level reset disable for supply margining. The push-pull RST output actively drives high to V2 (not open-drain), ensuring fast rise time (~206 ns with 150 pF load) and eliminating need for external pull-up resistors in most applications.

Key Specifications

Pinout & Package

Package: 16-lead narrow SSOP (GN), 0.150-inch body width, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2902-1IGN#TRPBF, the LTC2902-2IGN#TRPBF eliminates external pull-up components and reduces RST rise time by >400×, simplifying layout and improving timing margin; versus LTC1326-2.5, it adds a fourth monitor channel, programmable tolerance, and adjustable reset timeout - essential for complex multivoltage systems requiring field-serviceable margining.

Availability

LTC2902-2IGN#TRPBF is available at Aetrix Electronics and suitable for desktop computers, network servers, and telecom equipment requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant manufacturing.

Supply support for LTC2902-2IGN#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC2902 product line delivers precision, low-power, programmable supply monitoring ICs targeting multivoltage systems in computing, communications, and industrial infrastructure where reliability and design flexibility are critical.

FAQ

What is the function of the RDIS pin on the LTC2902-2IGN#TRPBF?

The RDIS pin on the LTC2902-2IGN#TRPBF is a digital input that, when pulled low, forces the RST output high regardless of supply voltage status. This enables supply margin testing without issuing a system reset. The pin features an internal 10 µA pull-up, so it may be left floating for normal operation. In the LTC2902-2IGN#TRPBF, this feature works in conjunction with the push-pull RST output to provide deterministic high-state control during margining sequences.

How does the CRT pin determine reset timeout on the LTC2902-2IGN#TRPBF?

The CRT pin on the LTC2902-2IGN#TRPBF sets reset timeout by connecting an external capacitor to GND. The relationship is linear: tRST = 4.6 ms per nanofarad (e.g., 47 nF yields ~216 ms). Leaving CRT unconnected gives ~50 µs minimum delay. Capacitor leakage directly impacts timing accuracy, so low-leakage ceramic types are recommended. The LTC2902-2IGN#TRPBF uses this analog timing method to avoid requiring clock sources or internal oscillators, reducing system complexity and power consumption.

Can the LTC2902-2IGN#TRPBF monitor negative supply voltages?

Yes, the LTC2902-2IGN#TRPBF supports negative supply monitoring via its –ADJ mode on V4 (Pin 13). In this configuration, V4 connects to a resistive divider between the negative rail and VREF (1.21 V), enabling accurate trip-point setting (e.g., –4.64 V for –5 V rail at 5% tolerance). The device's –0.3 V to 7 V input range and internal reference scaling allow robust operation without external level-shifting circuitry. This capability is explicitly validated in the LTC2902-2IGN#TRPBF datasheet Figure 6 and Typical Application TA03.

What is the significance of the push-pull RST output in the LTC2902-2IGN#TRPBF versus open-drain?

The push-pull RST output in the LTC2902-2IGN#TRPBF actively drives both high and low states, eliminating the need for an external pull-up resistor required by open-drain variants like the LTC2902-1IGN#TRPBF. This reduces BOM count, improves rise time (~206 ns vs ~86 µs), and ensures defined logic levels under high-impedance or floating-load conditions. For the LTC2902-2IGN#TRPBF, VOH is guaranteed ≥ 0.8 × V2 at 200 µA source current, making it compatible with standard CMOS/TTL inputs without additional biasing.

How is voltage threshold combination selected on the LTC2902-2IGN#TRPBF?

Voltage threshold combination on the LTC2902-2IGN#TRPBF is selected via a precision resistor divider from VREF (Pin 12) to GND, with the tap connected to VPG (Pin 11). Sixteen discrete ratios (e.g., 0.094, 0.156, up to 1.000) correspond to specific V1/V2/V3/V4 configurations listed in Table 1 of the datasheet. The part samples VPG during a ~150 µs window after VCC reaches 2.4 V, then locks the configuration. No capacitance may be added to VPG, and 1% resistors are required to maintain threshold accuracy within the specified ±1.5%.