lm2706 National Semiconductor Corporation, lm2706 Datasheet - Page 4

• Manufacturer Part Number: lm2706
• Description: Miniature, Variable, Step-down Dc-dc Converter With Bypass For Rf Power Amplifiers
• Manufacturer: National Semiconductor Corporation

www.national.com
Tresponse
Ton_pwm
Z
T_bypass
Ton_bypass Bypass FET turn on time
CON
Electrical Characteristics
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but device specifications may not be guaranteed. For guaranteed specifications and associated test conditions, see the Min and Max limits and Conditions
in the Electrical Characteristics table. Electrical characteristics table limits are guaranteed by production testing, design or correlation using standard Statistical
Quality Control methods. Typical (typ) specifications are mean or average values at 25˚C and are not guaranteed.
Note 2: Thermal shutdown will occur if the junction temperature exceeds 150˚C.
Note 3: Thermal resistance specified with 1.2" x 1.2" (2 layer 1.5 oz. Cu.) board.
Note 4: The LM2706 is designed for mobile phone applications where turn-on after power-up is controlled by the system controller and where requirements for a
small package size overrule increased die size for internal Under Voltage Lock-Out (UVLO) circuitry. Thus, it should be kept in shutdown by holding the EN pin low
until the input voltage exceeds 2.7V.
Note 5: Over-Voltage protection (OVP) hysteresis is the voltage above the nominal V
Note 6: V
turns on and the switching FETS turn off. This is called the bypass mode. Bypass mode is exited when V
T
Note 7: Shutdown current includes the leakage currents of the PFET and Bypass FET.
Note 8: Current limit is built-in, fixed, and not adjustable. The current limit tests are done by using DC measurement methods.
System Characteristics
nent values in the typical application circuit are used.These parameters are not guaranteed by production testing.
Symbol
BYPASS
, and PWM mode returns.
IN
is compared to the programmed output voltage (V
Time for V
3.25V (PWM Mode)
Turn on time in pwm mode
V
Auto bypass detect delay
CON
input capacitance
OUT
Parameter
to rise from 1.5V to
The following specifications are based on design limits and assume that the compo-
(Continued)
OUT
V
R
EN = L to H,
V
C
V
(Note 6)
V
C
IN
IN
CON
IN
LOAD
OUT
OUT
, PROG). When V
=3.6V,V
= 4.2V,C
- V
=1V, Test freq = 100kHz
= 4.7 µF, R
= 4.7µF, R
OUT
= 15 Ω
OUT
= 0.25V
Conditions
OUT
4
=3.25V,
IN
LOAD
OUT
= 4.7 µF,
LOAD
–V
OUT
where the OVP comparator turns off the PFET switch while in PWM mode.
=10 Ω
= 15 Ω
, PROG falls below V
IN
–V
BYPASS−
OUT
Min
8
, PROG exceeds V
for longer than T
Typ
600
25
10
BYPASS
BYPASS
Max
900
30
15
12
30
+ for longer than
the bypass FET
Units
pF
µs
µs
µs
µs