Maxim Integrated Products (Sunnyvale, CA) introduced its MAX8890 power-management IC intended for cellular handsets using a single lithium-ion cell battery with input voltages from +2.5V to +5.5V. The IC contains three identical, low-noise, low-dropout (LDO) linear regulators to provide all of the supply voltage requirements for the RF portion of the handset.
The first LDO is intended to power the transmitter, receiver and synthesizer. The second LDO is intended to power the TCXO, and high-power voltage-controlled oscillators (VCOs). The third LDO is intended to power the UHF offset VCO.
Each LDO has its own individual enable (ON/OFF-bar) control to maximize design flexibility. The reference is powered on if any of the enable inputs (EN1, EN2, EN3) are logic high. The high-accuracy output voltage of each LDO is preset at an internally trimmed voltage (1.8V to 3.3V in 50mV increments). Each LDO is capable of supplying 100mA with a low 50mV dropout and is optimized for low noise and high crosstalk-isolation. Designed with internal p-channel MOSFET pass transistors, the MAX8890’s low 180µA operating supply current is independent of load.
Other features include short-circuit and thermal overload protection. The MAX8890 is available in a compact, high-power, 12-pin 4mm x 4mm QFN.
