LTC2927CDDB View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
LTC2927CDDB Datasheet PDF : 16 Pages
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LTC2927
TYPICAL PERFOR A CE CHARACTERISTICS
VON(TH) vs Temperature
1.240
1.235
1.230
1.225
1.220
1.215
1.210
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
2927 G04
VRAMPBUF(OL) vs Temperature
28
26
24
22
20
18
16
14
12
10
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
2927 G05
VRAMPBUF(OH) vs Temperature
70
65
60
55
50
45
40
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
2927 G06
MAX ITRACK vs VCC
60
VTRACK = 0V
50
40
30
20
10
2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
VCC (V)
2927 G07
Tracking Cell Error vs ITRACK
5
ERROR =
VTRACK
0.8V
•
IFB
ITRACK
–1
4
3
2
1
0
1
2
3
4
5
ITRACK (mA)
2927 G0
VSDO(OL) vs VCC
1.0
0.8
0.6
ISDO = 5mA
0.4
0.2
0.0
0
ISDO = 10μA
1
2
3
4
VCC (V)
5
2927 G0
PIN FUNCTIONS TSOT/DFN Packages
VCC (Pin 1/Pin 8): Supply Voltage Input. Operating range
is from 2.9V to 5.5V. An undervoltage lockout asserts SDO
until VCC > 2.5V. VCC should be bypassed to GND with a
0.1μF capacitor.
SDO (Pin 2/Pin 7): Slave Supply Shutdown Output. SDO
is an open-drain output that holds the shutdown (RUN/SS)
pin of the slave supply low until the VCC pin is pulled above
2.5V, and the ON pin is pulled above 1.23V, or RAMP is
above 200mV. SDO is pulled low again when both RAMP
< 200mV and ON < 1.23V. If the slave supply is capable
of operating with an input supply that is lower than the
LTC2927’s minimum operating voltage of 2.9V, the SDO
4
pin can be used to hold off the slave supply. Tie the SDO
pin to GND if unused.
FB (Pin 3/Pin 6): Feedback Control Output. FB pulls up
on the feedback node of the slave supply. Tracking is
achieved by mirroring the current from TRACK into FB.
A resistive divider connecting RAMPBUF and TRACK will
force the output voltage of the slave supply to track RAMP.
To prevent damage to the slave supply, the FB pin will not
force the slave’s feedback node above 2.3V. In addition,
the LTC2927 will not actively sink current from this node,
even when it is unpowered.
2927fb
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