LTC6102HVCDD(RevB) 查看數據表（PDF） - Linear Technology
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LTC6102HVCDD Datasheet PDF : 20 Pages
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LTC6102/LTC6102HV
APPLICATIONS INFORMATION
The LTC6102HV can be used at voltages up to 105V. This
additional voltage requires that more power be dissipated
for a given level of current. This will further limit the allowed
output current at high ambient temperatures.
It is important to note that the LTC6102 has been designed
to provide at least 1mA to the output when required, and
can deliver more depending on the conditions. Care must
be taken to limit the maximum output current by proper
choice of sense and input resistors and, if input fault
conditions are likely, an external clamp.
Output Filtering
The output voltage, VOUT, is simply IOUT • ZOUT. This
makes filtering straightforward. Any circuit may be used
which generates the required ZOUT to get the desired filter
response. For example, a capacitor in parallel with ROUT
will give a low pass response. This will reduce unwanted
noise from the output, and may also be useful as a charge
reservoir to keep the output steady while driving a switch-
ing circuit such as a mux or ADC. This output capacitor
in parallel with an output resistor will create a pole in the
output response at:
f – 3dB
=
2
•
1
• ROUT
•
COUT
Useful Equations
Input Voltage: VSENSE = ISENSE • RSENSE
Voltage Gain: VOUT = ROUT
VSENSE RIN
Current Gain:
IOUT
ISENSE
=
RSENSE
RIN
Transconductance: IOUT = 1
VSENSE RIN
Transimpedance:
VOUT
ISENSE
=
RSENSE
•
ROUT
RIN
VBAT
RSENSE
RIN
+IN
LOAD
(V+ – 2V) TO V+ V–
+–
LTC6102
–INS
–INF
V+
VREG
V+
0.1μF
OUT
VOUT
ROUT
6102 F05
Figure 5. V+ Powered Separately from Load Supply (VBAT)
Input Sense Range
The inputs of the LTC6102 can function from V+ to (V+ – 2V).
Not only does this allow a wide VSENSE range, it also allows
the input reference to be separate from the positive supply
(Figure 5). Note that the difference between VBAT and V+
must be no more than the input sense voltage range listed
in the Electrical Characteristics table.
Monitoring Voltages Above V+ and Level Translation
The LTC6102 may be configured to monitor voltages that are
higher than its supply, provided that the negative terminal
of the input voltage is within the input sense range of the
LTC6102. Figure 6 illustrates a circuit in which the LTC6102
has its supply pin tied to the lower potential terminal of the
sense resistor instead of the higher potential terminal. The
operation of the LTC6102 is such that the –INS and –INF
pins will servo to within a few microvolts of +IN, which is
shorted to V+. Since the input sense range of the LTC6102
includes V+, the circuit will operate properly. The voltage
across RSENSE will be held across RIN by the LTC6102,
causing current VSENSE/RIN to flow to ROUT. In this case,
the supply current of the LTC6102 is also monitored, as
it flows through RSENSE.
6102fb
13
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