LTC3829_15 Datasheet, PDF (8/40 Pages) Linear Technology – 3-Phase, Single Output Synchronous Step-Down DC/DC Controller with Diffamp

LTC3829
TYPICAL PERFORMANCE CHARACTERISTICS
Shutdown Current
vs Input Voltage
50
40
30
20
10
0
5 10 15 20 25 30 35 40
INPUT VOLTAGE (V)
3829 G20
Shutdown Current vs Temperature
70
60
50
40
30
20
10
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3829 G21
Quiescent Current vs Temperature
without EXTV_CC
6
5
4
3
2
1
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3829 G22
PIN FUNCTIONS (UHF/FE)
DIFFN (Pin 1/Pin 3): Negative Input of Remote Sensing
Differential Amplifier. Connect this to the remote load
ground pin.
DIFFP (Pin 2/Pin 4): Positive Input of Remote Sensing
Differential Amplifier. Must connect this to the remote load
positive terminal directly even when diffamp is not used.
RUN (Pin 3/Pin 5): Run Control Input. A voltage above
1.22V on this pin turns on the IC. There is a 1.0µA pull-up
current for this pin. Once the RUN pin rises above 1.22V,
an additional 4.5µA pull-up current is added to the pin.
AVP (Pin 4/Pin 6): Active Voltage Positioning Load Slope
Programming Pin. A resistor tied between this pin and the
DIFFP pin sets the load slope. The AVP function can only
be used with the remote sensing differential amplifier.
Float or connect a 1kΩ resistor to DIFFP pin when AVP
function is not used.
SENSE1⁺, SENSE2⁺, SENSE3⁺ (Pins 5, 7, 11/Pins 7, 9,
13): Current Sense Comparator Inputs. The (+) inputs to
the current comparators are normally connected to DCR
sensing networks or current sensing resistors.
SENSE1^–, SENSE2^–, SENSE3^– (Pins 6, 8, 12/Pins 8, 10,
14): Current Sense Comparator Inputs. The (–) inputs
to the current comparators are connected to the output.
TK/SS (Pin 9/Pin 11): Output Voltage Tracking and Soft-
Start Input. When one particular IC is configured to be the
master of two ICs, a capacitor to ground at this pin sets
the ramp rate for the master IC’s output voltage. When the
IC is configured to be the slave of two ICs, the V_FB voltage
of the master IC is reproduced by a resistor divider and
applied to this pin. An internal soft-start current of 1.25µA
is charging this pin.
FREQ (Pin 10/Pin 12): There is a precision 10µA current
sourced out of this pin. A resistor to ground sets a voltage
which in turn programs the frequency. Alternatively, this
pin can be driven with a DC voltage to vary the frequency
of the internal oscillator.
V_FB (Pin 13/Pin 15): Error Amplifier Feedback Input. This
pin receives the remotely sensed feedback voltage from
an external resistive divider.
I_TH (Pin 14/Pin 16): Current Control Threshold and Error
Amplifier Compensation Point. Each associated channels’
current comparator tripping threshold increases with this
I_TH control voltage.
3829fc
8
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