Datasheet

3
LTC3490
3490fa
I
L(PMOS)
Leakage Current, PMOS Switch 0.1 µA
R
ON(PMOS)
On-Resistance, PMOS Switch 0.13 Ω
V
IH
Input High (CELLS) V
IN
– 0.4 V
Input High (SHDN) V
IN
• 0.9 V
V
IL
Input Low (CELLS) 0.4 V
Input Low (SHDN) V
IN
• 0.2 V
I
IN
Input Current (CTRL/SHDN, CELLS) 0.01 µA
K
CTRL
Control Gain, I
LED
/V
CTRL
Scales Linearity with V
IN
, V
IN
= 1V 500 mA/V
R
ON(LOBAT)
On-Resistance, LOBAT Output V
IN
< V
IN(LOBAT)
● 300 Ω
V
IN(LOBAT1)
Input Voltage, Low Battery, 1 Cell V
CELLS
= 0V ● 0.8 1.12 V
V
IN(LOBAT2)
Input Voltage, Low Battery, 2 Cells V
CELLS
= V
IN
● 1.8 2.24 V
V
IN(UVLO2)
Input Voltage, Undervoltage Lockout, V
CELLS
= V
IN
● 1.4 1.8 V
2 Cells
V
IN(UVLO1)
Input Voltage, Undervoltage Lockout, V
CELLS
= 0 V ● 0.7 0.9 V
1 Cell
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are T
A
= 25°C. V
IN
= 2.5V unless otherwise specified.
ELECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3490 is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C range are
assured by design, characterization and correlation with statistical process
controls.
Note 3: The LTC3490 input voltage may drop below the minimum start-up
voltage once the LED voltage has risen above 2.3V.
Note 4: This device includes overtemperature protection intended to
protect the device during momentary overload conditions. The maximum
junction temperature may be exceeded when overtemperature protection
is active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 5: The Exposed Pad of the DFN package must be soldered to a
PCB pad for optimum thermal conductivity. This pad must be connected
to ground.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Oscillator Frequency
vs Temperature
I
LED
vs V
CTRL
V
CTRL
/V
IN
(V)
0
I
LED
(mA)
150
200
250
0.6
1
3490 G02
100
50
0
0.2 0.4 0.8
300
350
400
MAXIMUM
MINIMUM
I
LED
vs V
IN
V
IN
(V)
I
LED
(mA)
325
350
375
2.5
3490 G03
300
275
250
1
1.5
2
3
V
LED
= 3.5V
TEMPERATURE (°C)
–50
FREQUENCY (MHz)
1.280
1.320
3490 G01
1.240
1.200
0
50
100
1.400
1.360