Microchip Technology T2801-PLH

Overview

T2801-PLH from Atmel is a single-chip DECT transceiver IC integrating image-rejection mixer, IF amplifiers, FM demodulator, baseband filter, RSSI, TX preamplifier, ramp-signal generator, fully integrated VCO, and advanced closed-loop modulation circuitry. It operates from 3.0 V to 4.6 V, supports 10.368/13.824/20.736 MHz reference clocks, delivers 0 dBm TX output at 1.9 GHz, and enables non-blindslot and unlimited multislot operation in low-power cordless telephony systems.

For engineers reviewing the T2801-PLH datasheet, T2801-PLH pinout, T2801-PLH application, or T2801-PLH equivalent, key selection considerations include its HP-VFQFP-N48 package, 48-pin configuration with dedicated RAMP_OUT and RAMP_SET for SiGe PA control, integrated auxiliary and VCO regulators, and support for advanced closed-loop modulation with MCC and GF circuits.

Technical Context

The T2801-PLH implements a fully integrated PLL-based synthesizer with programmable main counter (SMC = 32–35), swallow counter (SSC = 0–31), and reference counter (SRC = 3/4/6/8), generating LO frequencies from 1769–1824 MHz (RX-VCO) and 1881–1934 MHz (TX-VCO). Its dual-path architecture separates RX and TX VCO control via bit D13, enabling independent frequency planning.

It features a 3-wire serial bus (CLOCK/DATA/ENABLE) for channel programming and production tuning, supporting two 23-bit data words: Data Word 1 configures PLL settings, Gaussian filter (GF), and modulation compensation circuit (MCC); Data Word 2 adjusts DEMOD_DAC, MCCS, and CPCS for calibration. The integrated ramp generator provides controlled voltage slew at RAMP_OUT with external capacitor setting at RAMP_SET.

Key Specifications

Pinout & Package

Package: HP-VFQFP-N48 - 48-pin, 7 mm × 7 mm, 0.5 mm pitch, thermally enhanced plastic quad flat package with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DECT transceiver applications.

Compared with STW81101B and RFMD RF5105, the T2801-PLH uniquely integrates ramp-slope control (RAMP_SET), closed-loop modulation compensation (MCC), and dual-VCO switching in a single HP-VFQFP-N48 package-enabling faster time-to-market for standards-compliant DECT handsets with minimal external tuning.

Availability

T2801-PLH is available at Aetrix Electronics and suitable for DECT handset design, base station RF front-end development, and low-power IoT voice gateway applications requiring stable component supply and long-term lifecycle support.

Supply support for T2801-PLH 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

Atmel Corporation (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, RF ICs, and wireless connectivity solutions for consumer, industrial, and automotive markets.

The T2801-PLH belongs to Atmel's DECT transceiver product line, designed specifically for low-power, single-chip cordless telephony systems requiring full integration of RF, IF, baseband, and modulation functions without mechanical tuning.

FAQ

What reference clock frequencies does the T2801-PLH support?

The T2801-PLH supports three standard reference clock inputs: 10.368 MHz, 13.824 MHz, and 20.736 MHz, applied to Pin 4 (REF_CLK) as AC-coupled sinewave signals. These frequencies align with DECT timing requirements and determine the PLL's phase detector frequency (fPD = 3.456 MHz) and overall LO synthesis resolution. The T2801-PLH uses internal SRC bits (D21–D22) to select the active reference source.

How does the T2801-PLH achieve closed-loop modulation without external components?

The T2801-PLH achieves closed-loop modulation through its integrated modulation compensation circuit (MCC) and Gaussian filter (GF), both programmable via the 3-wire bus. The MCC dynamically adjusts modulation index based on feedback from the PLL, while GF shapes TX_DATA with B*T = 0.5. Calibration is performed using MCCS bits (E3–E5) and GFCS bits (D6–D8), eliminating need for external loop filters or DACs. This architecture is intrinsic to the T2801-PLH's design.

What is the function of the RAMP_SET pin on the T2801-PLH?

The RAMP_SET pin (Pin 37) on the T2801-PLH sets the slew rate of the ramp signal generated at RAMP_OUT (Pin 36) by controlling external capacitor value. A 270 pF capacitor yields 5 µs rise/fall time-meeting DECT spectral mask requirements. This direct hardware control avoids software timing dependencies and ensures repeatable PA turn-on characteristics across units. The T2801-PLH's ramp generator is fully integrated and requires no external op-amps or timers.

Can the T2801-PLH operate in both blindslot and non-blindslot DECT modes?

Yes, the T2801-PLH explicitly supports both blindslot and non-blindslot operation as stated in its official features list. This is enabled by flexible control of RX_ON/TX_ON pins and programmable PLL reconfiguration via the 3-wire bus, allowing dynamic slot assignment and synchronization with base station timing. The T2801-PLH's architecture handles frame timing, carrier sense, and slot arbitration internally-no external controller modifications are needed to switch modes.

What power supply configurations are required for the T2801-PLH's internal regulators?

The T2801-PLH requires two distinct supply domains: VS_REG (Pin 10, 3.2–4.6 V) powers the auxiliary regulator that outputs 3.0 V at Pin 8 (VREG); VS_VCO (Pin 14) and VS_PLL (Pin 7) must each be supplied 3.0–4.6 V independently to ensure noise isolation for sensitive RF blocks. The T2801-PLH's internal VCO regulator (VREG_VCO = 2.7 V ±0.1 V at Pin 15) derives from VS_VCO, not VS_REG-requiring separate filtering per supply rail as specified in Figure 6 of the datasheet.