MAX11008:Dual RF LDMOS Bias Controller with Nonvolatile Memory

Offers Integration and Reduces Cost with Power Savings

The MAX11008 controller biases RF LDMOS power devices found in cellular base stations and other wireless infrastructure equipment. Each controller includes a high-side current-sense amplifier with programmable gains of 2, 10, and 25 to monitor the LDMOS drain current over a range of 20mA to 5A. The MAX11008 supports up to two external diode-connected transistors to monitor the LDMOS temperatures while an internal temperature sensor measures the local die temperature. A 12-bit successive-approximation register (SAR) analog-to-digital converter (ADC) converts the analog signals from the programmable-gain amplifiers (PGAs), external temperature sensors, internal temperature measurement, and two additional auxiliary inputs. The MAX11008 automatically adjusts the LDMOS bias voltages by applying temperature, AIN, and/or drain current samples to data stored in lookup tables (LUTs). The MAX11008 includes two gate-drive channels, each consisting of a 12-bit DAC to generate the positive gate voltage for biasing the LDMOS devices. Each gate-drive output supplies up to ±2mA of gate current. The gate-drive amplifier is current-limited to ±25mA and features a fast clamp to AGND. The MAX11008 contains 4Kb of on-chip, nonvolatile EEPROM organized as 256 bits x 16 bits to store LUTs and register information. The device operates from either a 4-wire 16MHz SPI™-/MICROWIRE™-compatible or an I²C-compatible serial interface. The MAX11008 operates from a +4.75V to +5.25V analog supply with a typical supply current of 2mA, and a +2.7V to +5.25V digital supply with a typical supply of 3mA. The device is packaged in a 48-pin, 7mm x 7mm, thin QFN package and operates over the extended (-40°C to +85°C) temperature range.

Key Features
  • On-Chip 4Kb EEPROM for Storing LDMOS Bias Characteristics
  • Integrated High-Side Current-Sense PGA with Gain of 2, 10, or 25
  • ±0.75% Accuracy for Sense Voltage Between +75mV and +1250mV
  • Full-Scale Sense Voltage
    • +100mV with a Gain of 25
    • +250mV with a Gain of 10
    • +1250mV with a Gain of 2
  • Common-Mode Range, LDMOS Drain Voltage: +5V to +32V
  • Adjustable Low-Noise 0 to AVDD Output Gate Bias Voltage Range
  • Fast Clamp to AGND for LDMOS Protection
  • 12-Bit DAC Control of Gate with Temperature
  • Internal Die Temperature Measurement
  • 2-Channel External Temperature Measurement through Remote Diodes
  • Internal 12-Bit ADC Measurement for Temperature, Current, and Voltage Monitoring
  • User-Selectable Serial Interface
    • 400kHz/1.7MHz/3.4MHz I²C-Compatible Interface
    • 16MHz SPI-/MICROWIRE-Compatible Interface
MAX11008: Functional Diagram
MAX11008: Functional Diagram
Applications/Uses
  • Cellular Base Stations
  • Feed-Forward Power Amps
  • Industrial Process Control
  • Microwave Radio Links
  • Transmitters
DataSheet
titleDownload file
MAX11008 Data SheetMAX11008.pdf
Parametrics
Part NumberGate Drive Range
(V)
VBIAS ClampChannelsHigh-Side Current Sense GainLoop ControlLookup Table IndexLookup Table MemoryInterfaceADCsDACsReferenceTemp. SensorAVDD
(V)
DVDD
(V)
Package/PinsBudgetary
Price
minminSee Notes
MAX110080.1 to AVDD-0.1Yes22 @ 32VInternal LUTsTemperature
Voltage
NonvolatileI2C
SPI
12-bit12-bitExternal
Internal
External
Internal
5.255.25TQFN/48$8.30 @1k
Design kits & evaluation modules
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX11008BETM+ActiveTQFN,;48 pin;50.4 mm²-40°C to +85°CLead Free
MAX11008BETM+TActiveTQFN,;48 pin;50.4 mm²-40°C to +85°CLead Free
MAX11008.pdf MAX11008
Implementing a MAX1385-Based Control Loop in C/C++ MAX1385
MAX11008.pdf MAX11008