The MAX11014/MAX11015 set and control bias conditions
for dual MESFET power devices found in point-topoint
communication and other microwave base
stations. The MAX11014 integrates complete dual analog
closed-loop drain-current controllers for Class A
MESFET amplifier operation, while the MAX11015 targets
Class AB operation. Both devices integrate SRAM
lookup tables (LUTs) that can be used to store temperature
and drain-current compensation data.
Each device includes dual high-side current-sense
amplifiers to monitor the MESFET drain currents through
the voltage drop across the sense resistors in the 0 to
625mV range. External diode-connected transistors monitor
the MESFET temperatures while an internal temperature
sensor measures the local die temperature of the
MAX11014/MAX11015. The internal DAC sets the voltages
across the current-sense resistors by controlling
the GATE voltages. The internal 12-bit SAR ADC digitizes
internal and external temperature, internal DAC voltages,
current-sense amplifier voltages, and external GATE voltages.
Two of the 11 ADC channels are available as general-
purpose analog inputs for analog system monitoring.
The MAX11014’s gate-drive amplifier functions as an
integrator for the Class A drain-current control loop
while the MAX11015’s gate-drive amplifier functions
with a gain of -2 for Class AB applications. The currentlimited
gate-drive amplifier can be fast clamped to an
external voltage independent of the digital input from
the serial interface. Both the MAX11014 and the
MAX11015 include self-calibration modes to minimize
error over time, temperature, and supply voltage.
The MAX11014/MAX11015 feature an internal reference
and can operate from separate ADC and DAC external
references. The internal reference provides a well-regulated,
low-noise +2.5V reference for the ADC, DAC, and
temperature sensors. These integrated circuits operate
from a 4-wire 20MHz SPI?-/MICROWIRE?-compatible
or 3.4MHz I2C-compatible serial interface (pin-selectable).
Both devices operate from a +4.75V to +5.25V
analog supply (2.8mA typical supply current), a +2.7V
to +5.25V digital supply (1.5mA typical supply current),
and a -4.5V to -5.5V negative supply (1.1mA supply
current). The MAX11014/MAX11015 are available in a
48-pin thin QFN package specified over the -40°C to
+105°C temperature range.