Linear Technology LTC3350, Руководство пользователя

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LTC3350
7
3350fc
For more information www.linear.com/LTC3350
elecTrical characTerisTics
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= V
OUT
= 12V, V
DRVCC
= V
INTVCC
unless otherwise
noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
t
SU,STO
Stop Condition Set-Up Time 0.6 µs
t
HD,DATO
Output Data Hold Time 0 900 ns
t
HD,DATI
Input Data Hold Time 0 ns
t
SU,DAT
Data Set-Up Time 100 ns
t
SP
Input Spike Suppression Pulse Width 50 ns
V
SMBALERT
SMBALERT Output Low Voltage I
SINK
= 1mA 200 mV
I
SMBALERT
SMBALERT High-Z Leakage Current V
SMBALERT
= 5V
l
1 μA
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 LTC3350 is tested under pulsed load conditions such that
T
J
≈ T
A
. The LTC3350E is guaranteed to meet specifications from
0°C to 125°C junction temperature. Specifications over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3350I is guaranteed over the –40°C to 125°C operating junction
temperature range. Note that the maximum ambient temperature
consistent with these specifications is determined by specific operating
conditions in conjunction with board layout, the rated package thermal
impedance and other environmental factors. The junction temperature
(T
J
, in °C) is calculated from the ambient temperature (T
A
, in °C) and
power dissipation (P
D
, in Watts) according to the formula:
T
J
= T
A
+ (P
D
•
θ
JA
)
where
θ
JA
= 34°C/W for the UHF package.
Note 3: The LTC3350 includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125˚C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See the Applications Information
section.
Note 5: Measurement error is the magnitude of the difference between the
actual measured value and the ideal value. V
SNSI
is the voltage between
VOUTSP and VOUTSN, representing input current. V
SNSC
is the voltage
between ICAP and VCAP, representing charge current. Error for V
SNSI
and
V
SNSC
is expressed in μV, a conversion to an equivalent current may be
made by dividing by the sense resistors, R
SNSI
and R
SNSC
, respectively.
Typical perForMance characTerisTics
Supercapacitor Backup Operation HV Electrolytic Backup Operation Shunt Operation Using V
CAP2
V
IN
2V/DIV
V
CAP
2V/DIV
V
OUT
2V/DIV
400ms/DIV
BACK PAGE APPLICATION CIRCUIT
0V
3350 G01
P
BACKUP
= 25W
V
IN
5V/DIV
V
CAP
5V/DIV
V
OUT
5V/DIV
20ms/DIV
APPLICATION CIRCUIT 6
0V
3350 G02
P
BACKUP
= 25W
V
CAP2
(V)
2.64
CURRENT (A)
3
4
5
2.67 2.69
3350 G03
2
1
2.65 2.66 2.68
I
CAP2
2.70 2.71
0
–1
I
CHARGE
V
SHUNT
= 2.7V
T
A
= 25°C, Application Circuit 4 unless otherwise noted.