1 Features
1• VOUT_RANGE – V OUT_ET = 0.6 V to 4.5 V
– VOUT_APT = 0.4 V to 3.81 V (or VIN – 200 mV)
• DC Boost For ET Operation:
– Boost Input Voltage Range: 2.5 V to 5 V
– High-Efficiency (90% typical) with Internal
Synchronous Rectification
– Boost Bypass Function with Low Resistance
(150 mΩ typ.)
– 2.7-MHz PWM Switching Frequency
• Buck DC-DC for APT and ET Operation:
– High Operating Frequency for Small External
Inductor and Capacitors
– V OUT_RANGE = 0.4 V to 3.81 V
(or VIN – 200 mV)
– High-Efficiency (95% typical) with Internal highSynchronous
Rectification
– Low-Power PFM Mode
• LM3291 Control:
– Automatic Control of LM3291 in ET Mode
• RFFE Control Interface:
– 1.8-V MIPI® RFFE 1.1-Compatible Digital
Control Interface
– 26-MHz Write Capability
– 13-MHz Read Capability

2 Description
The LM3290, with its companion IC LM3291, is an
RF envelope supply modulator (EM) with integrated
DC-DC boost converter optimized for Envelope
Tracking (ET) RF power amplifiers (PAs). The device
enables maximum transmit output power independent
of the input battery voltage (battery as low as 2.5 V) and is controlled by the MIPI® RFFE 1.1.
The LM3290 operates in two active modes:
Active Mode 1: For low TX output power, LM3290
may operate in Average Power Tracking (APT) mode,
providing a static, but programmable, output voltage to supply the PA. At light load and in APT mode, the
LM3290 enters into Pulse Frequency Mode (PFM)
operation automatically and operates with reduced
switching frequency. In PFM mode, the quiescent
current is reduced, which extends the battery life.
Active Mode 2: In ET mode, the LM3290 with
LM3291 efficiently provides a dynamic, highSynchronous
bandwidth supply voltage for the PA to maximize total EM + PA efficiency. The envelope modulator follows
the envelope reference input signal delivered by the
RFIC to the LM3291 via a differential analog input.
The output is a single-ended power supply signal to
the PA.
The LM3290 and LM3291 support 3G, as well as LTE
operation up to 20-MHz signal bandwidth.
The LM3290 controls the LM3291 companion-IC
through direct control signals, and no additional
controls are needed from the system. Shutdown,
standby, and idle modes turn the EM off and reduce
battery current consumption.
For the full datasheet, samples, or the EVM
hardware and software please contact a TI
representative at ET@list.ti.com.