LM2706

Features:

Forced and Automatic Bypass modes
Miniature 10-pin lead free micro SMD package
Only three tiny surface-mount external components required
Uses small ceramic capacitors
Low output voltage ripple (<10 mV typ)
Internal soft start
Current overload protection
No external compensation


Specifications

If Military/Aerospace specified devices are required,pleasecontacttheNationalSemiconductorSalesOffice/Distributors for availability and specifications.
Supply Voltage, PV_IN ,V_DD to SGND                          -0.2V to +6V
PGND to SGND                                                         -0.2V to +0.2V
EN, FB, BYP, ABD, V_CON                                          (SGND -0.2V) to (V_DD +0.2V)
SW                                                                         (PGND -0.2V) to (V_DD +0.2V)
PV_IN to V_DD                                                             -0.2V to +0.2V
Storage Temperature Range                                   -45 to +150
Lead Temp. (Soldering, 10 sec)                                 260
Junction Temperature (Note 2)                                 +125
Minimum ESD Rating                                                 ±2kV
(Human Body Model, C = 100 pF, R = 1.5 k)
Thermal Resistance (JA) (Note 3)                            137/W 


Description

The LM2706 DC-DC converter is optimized for powering RF power amplifiers (PAs) from a single Lithium-Ion cell. It may also be used in many other applications. It steps down an input voltage from 2.7V to 5.5V to a variable output from 1.5V to 3.25V up to 300 mA. Output voltage is set using a V_CON analog input for controlling power levels and efficiency of the RF PA. An internal bypass switch allows direct con-nection to the battery for maximum power to the RF PA.

The device offers 4 modes for mobile phones and similar RF PA applications. Fixed-frequency PWM mode minimizes RF interference. Forced Bypass mode turns on an internal by-pass switch to power the PA directly from the battery. Auto-
matic bypass mode minimizes dropout by turning on the bypass switch when the battery decays to near the output
voltage. Shutdown mode turns the device off and reduces battery consumption to 0.1 A (typ.).

The device also offers internal synchronous rectification for high efficiency (95% typ at 3.25 V_OUT , 200 mA, 3.9 V_IN ).Current limit and thermal overload protection protects the device and system during fault conditions.

The LM2706 is available in a 10-pin lead free micro SMD package. This packaging uses National's chip-scale micro SMDtechnologyandoffersthesmallestpossiblesize.Ahigh switching frequency (600 kHz) allows use of tiny surface-countcomponents. Onlythreesmallexternalsurface-mount components, an inductor and two ceramic capacitors, are required.