MAX881R:Low-Noise Bias Supply in µMAX with Power OK for GaAsFET PA

1mVP-P Output Voltage Ripple

The MAX881R low-noise, inverting power supply is designed for biasing GaAsFET power amplifiers in portable wireless applications. This device is a chargepump inverter followed by a negative linear regulator. The input voltage range is 2.5V to 5.5V. The output is preset at -2.0V or can be set, using two resistors, to any voltage from -0.5V to (-VIN + 0.6V). It can deliver up to 4mA. The internal linear regulator also filters the output to 1mVP-P ripple and noise. Other features include a power-OK (active-low POK) output that signals when the negative voltage is within 7.5% of its set point. It protects the GaAsFET by not allowing power to be applied to the GaAsFET's drain until it is properly biased. The signal can be routed either to a microcontroller or directly to a switch at the GaAsFET drain. The MAX881R is available in a 10-pin µMAX® package.

Key Features
  • Small µMAX Package
  • 1mVP-P Output Voltage Ripple and Noise
  • Power-OK Signal to Control GaAsFET Drain Switch
  • 0.05µA Logic-Controlled Shutdown
  • 1ms Guaranteed Startup
  • 2.5V to 5.5V Input
  • -0.5V to (-VIN + 0.6V) Output at up to 4mA
  • Operates with One 4.7µF and Three 0.22µF Capacitors (no inductors needed)
MAX881R: Typical Operating Circuit
MAX881R: Typical Operating Circuit
Applications/Uses
  • Cell Phones Wireless Modems
  • PCS Phones Two-Way Pagers
  • PHS Phones Mobile Radios
  • Wireless Handsets Wireless Computers
DataSheet
titleDownload file
MAX881R Data SheetMAX881R.pdf
Parametrics
Part NumberTopologyVIN
(V)
VIN
(V)
ICC
(mA)
Unadj. VOUT
(V)
Adj. VOUT
(V)
Adj. VOUT
(V)
IOUT
(A)
Oper. Freq.
(kHz)
Oper. Temp.
(°C)
Package/PinsBudgetary
Price
minmaxmaxminmaxtypSee Notes
MAX881RInverter
Regulated
2.55.50.95-2-VIN-0.6-0.50.01100-40 to +85µMAX/10$1.85 @1k
Design kits & evaluation modules
Quality and Environmental Data
Related Products
  • MAX852:Low-Noise, Regulated, Negative Charge Pump Power Supplies for GaAsFET Bias
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX881REUBNo Longer AvailableMAX881REUB+µMAX,;10 pin;15.4 mm²-40°C to +85°CNo
MAX881REUB+ActiveµMAX,;10 pin;15.4 mm²-40°C to +85°CLead Free
MAX881REUB+TActiveµMAX,;10 pin;15.4 mm²-40°C to +85°CLead Free
MAX881REUB-TNo Longer AvailableMAX881REUB+TµMAX,;10 pin;15.4 mm²-40°C to +85°CNo
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