Datasheet

LM3242
www.ti.com
SNOSB48D OCTOBER 2011REVISED MARCH 2013
System Characteristics
The following spec table entries are ensured by design providing the component values in the Typical Application Circuit are
used. These parameters are not ensured by production testing. Min and Max values apply over the full operating ambient
temperature range (30°C T
A
90°C) and over the VIN range = 2.7V to 5.5V unless otherwise specified. L = 0.5 µH, DCR
= 50 m, C
IN
= 10 µF, 6.3V, 0603(1608), C
OUT
= 4.7 µF, 6.3V, 0402.
Symbol Parameter Condition Min Typ Max Units
V
IN
= 3.7V, V
OUT
= 1.4V to 3.4V
V
OUT
rise time
0.1 µs < VCON_T
R
< 1 µs, 9
VCON change to 90%
R
L
= 12
T
VCON_TR
µs
V
IN
= 3.7V, V
OUT
= 3.4V to 1.4V
V
OUT
fall time
0.1 µs < VCON_T
F
< 1 µs, 9
VCON change to 10%
R
L
= 12
D Maximum Duty cycle 100 %
Bypass Mode Resistance V
IN
= V
GS
= 3.1V, I
OUT
= 500 mA
R
BP
75 m
(1)
VCON > 1.16V
2.7V V
IN
5.5V
750
2.5 × VCON V
IN
285 mV
Maximum output current
I
OUT
mA
capability
2.7V V
IN
5.5V
1000
2.5 × VCON V
IN
– 165 mV, Bypass mode
C
VCON
VCON input capacitance VCON = 1V, Test frequency = 100 KHz <1.0 pF
V
OUT
3 +3 %
VCON range 0.16V to
0mA I
OUT
750 mA
(2)
Linearity
1.44V
50 +50 mV
Turn-on time (time for
EN = Low-to-High
output to reach 95% final
T
ON
V
IN
= 4.2V, V
OUT
= 3.4V 50 µs
value after Enable low-to-
I
OUT
= < 1mA, C
OUT
= 4.7 µF
high transition)
Auto Bypass Detect
T
BP, NEG
Negative Threshold Delay
(3)
10
Time
µs
T
BP, POS
Auto Bypass Detect
Positive Threshold Delay
(4)
0.1
Time
V
IN
= 3.6V, V
OUT
= 0.8V
75
I
OUT
= 10 mA, ECO mode
V
IN
= 3.6V, V
OUT
= 1.8V
η Efficiency 90 %
I
OUT
= 200 mA, PWM mode
V
IN
= 3.9V, V
OUT
= 3.3V
95
I
OUT
= 500 mA, PWM mode
V
IN
= 3.6V to 4.2V, T
R
= T
F
= 10 µs,
LINE
TR
Line transient response 50 mVpk
I
OUT
= 100 mA, V
OUT
= 0.8V
V
IN
= 3.1V/3.6V/4.5V, V
OUT
= 0.8V,
LOAD
TR
Load transient response I
OUT
= 50 mA to 150 mA 50 mVpk
T
R
= T
F
= 0.1 µs
(1) Total resistance in Bypass mode. Total includes the Bypass FET resistance in parallel with the PWM switch path resistance (PFET
resistance and series inductor parasistic resistance.)
(2) Linearity limits are ±3% or ±50 mV, whichever is larger. V
OUT
is monotonic in nature with respect to VCON input.
(3) Entering Bypass Mode V
IN
is compared to the programmed output voltage (2.5 × VCON). When V
IN
(2.5 × VCON) falls below V
BP,NEG
longer than T
BP,NEG
, the Bypass FET turns on, and the switching FET turns on.
(4) Bypass Mode is exited when V
IN
(2.5 × VCON) exceeds V
BP,POS
longer than T
BP,POS
, and PWM mode resumes. The hysteresis for
the bypass detection threshold V
BP,POS
-V
BP,NEG
will always be positive and will be approximately 50 mV.
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