Simplified Block Diagram
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- Three 100mA Low-Dropout Linear Regulators
- Low 50mV Dropout Voltage at 100mA
- ±1% Output Voltage Accuracy Over Temperature
- Preset 1.8V to 3.3V Output Voltages (in 50mV Increments)
- Low 45µVRMS Output Voltage Noise
- Low 180µA Operating Supply Current
- 2.5V to 5.5V Input Voltage Range
- 67dB PSRR
- 10µVP-P Channel-to-Channel Crosstalk
- Short-Circuit Protection
- Thermal Overload Protection
- 0.01µA Shutdown Current
- Tiny 12-Pin 4mm x 4mm QFN Package
- CCD Imaging
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/active-low OFF) 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 package with a metal pad on the underside.