Electrical Characteristics
(Continued)
Limits in standard typeface and typical values apply for T
J =25
oC. Limits in boldface type apply over the operating junction
temperature range. Unless otherwise specified: 2.6
≤ V
IN
≤ 5.5V, V(EN) = V
IN,C1 =C2 = 1F, CIN =COUT = 10F. (Note 9) Symbol
Parameter
Conditions
Min
Typ
Max
Units
POK Characteristics
V
T-POK
Threshold of output voltage
for POK transition
POK transition L to H
95
99
%of
V
OUT-NOM
POK transition H to L
83
92
Hysterisis
3
I
POK-H
POK-high leakage current
V(POK) = 3.6V
1
5
A
V
POK-L
POL-low pull-down voltage
I(POK) = -100A
200
300
mV
BATOK Characteristics
V
T-BATOK
Input voltage threshold for
BATOK transition
BATOK transition L to H
2.85
3.0
V
BATOK transition H to L
2.4
2.65
Hysterisis
0.20
I
BATOK-H
BATOK-high leakage
current
V(BATOK) = 3.6V
1
5
A
V
BATOK-L
BATOK-low pull-down
voltage
I(BATOK) = - 100A
200
300
mV
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of
the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the
Electrical Characteristics tables.
Note 2: All voltages are with respect to the potential at the GND pin.
Note 3: Voltage on the EN pin must not be brought above VIN + 0.3V.
Note 4: Thermal shutdown circuitry protects the device from permanent damage.
Note 5: The human-body model is a 100 pF capacitor discharged through a 1.5k
resistor into each pin. The machine model is a 200pF capacitor discharged
directly into each pin.
Note 6: Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 125
oC), the maximum power
dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the
following equation: TA-MAX =TJ-MAX-OP -(θJA xPD-MAX). The ambient temperature operating rating is provided merely for convenience. This part may be operated
outside the listed TA rating so long as the junction temperature of the device does not exceed the maximum operating rating of 125
oC.
Note 7: Junction-to-ambient thermal resistance is highly dependent on application conditions and PC board layout. In applications where high maximum power
dissipation exists, special care must be paid to thermal dissipation issues. For more information on these topics, please refer to the Power Dissipation section of
this datasheet.
Note 8: All room temperature limits are 100% tested or guaranteed through statistical analysis. All limits at temperature extremes are guaranteed by correlation
using standard Statistical Quality Control methods (SQC). All limits are used to calculate Average Outgoing Quality Level (AOQL). Typical numbers are not
guaranteed, but do represent the most likely norm.
Note 9: CIN,COUT,C1, and C2 : Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics
Note 10: VOUT (NOM) is the nominal output voltage of the part. An example: VOUT-NOM of LM2798MM-1.8 is 1.8V.
Note 11: Efficiency is measured versus VIN, with VIN being swept in small increments from 3.0V to 4.2V. The average is calculated from these measurement results.
Weighting to account for battery voltage discharge characteristics (VBAT vs. Time) is not done in computing the average.
Note 12: Turn-on time is measured from when the EN signal is pulled high until the output voltage crosses 90% of its final value. Resistive load used for startup
measurement, with value chosen to give IOUT = 100mA when the output voltage is fully established.
LM2797/LM2798
www.national.com
4