LTC3443 Datasheet, PDF (5/16 Pages) Linear Technology – High Current Micropower 600kHz Synchronous Buck-Boost DC/DC Converter

LTC3443
TYPICAL PERFOR A CE CHARACTERISTICS (T_A = 25°C unless otherwise specified)
Error Amp Sink Current
400
V_IN = V_OUT = 3.6V
Output Frequency
0.70
V_IN = V_OUT = 3.6V
Current Limit
3.4
V_IN = V_OUT = 3.6V
350
0.65
3.2
300
0.60
3.0
250
0.55
200
–55 –25 5
35 65
TEMPERATURE (°C)
NMOS R_DS(ON)
0.15
V_IN = V_OUT = 3.6V
SWITCHES B AND C
0.13
95 125
3443 G12
0.11
0.09
0.07
0.05
–55 –25 5
35 65
TEMPERATURE (°C)
95 125
3443 G15
0.50
–55 –25 5
35 65
TEMPERATURE (°C)
PMOS R_DS(ON)
0.15
V_IN = V_OUT = 3.6V
SWITCHES A AND D
0.13
95 125
3443 G13
0.11
0.09
0.07
0.05
–50 –25 5
35 65
TEMPERATURE (°C)
95 125
3443 G16
2.8
–55
–25 5 35 65
TEMPERATURE (°C)
Minimum Start Voltage
2.30
95 125
3443 G14
2.25
2.20
2.15
2.10
–55 –25 5
35 65
TEMPERATURE (°C)
95 125
3443 G17
PI FU CTIO S
SHDN/SS (Pin 1): Combined Soft-Start and Shutdown.
Applied voltage < 0.4V shuts down the IC. Tie to >1.4V to
enable the IC and >2.4V to ensure the error amp is not
clamped from soft-start. An RC from the shutdown com-
mand signal to this pin will provide a soft-start function by
limiting the rise time of the V_C pin.
GND (Pin 2): Signal Ground for the IC.
PGND (Pins 3, 6, 13 Exposed Pad): Power Ground for the
Internal NMOS Power Switches. The exposed pad must be
soldered to PCB ground for optimal thermal performance.
SW1 (Pin 4): Switch pin where the internal switches A and
B are connected. Connect inductor from SW1 to SW2. An
optional Schottky diode can be connected from this SW1
to ground. Minimize trace length to keep EMI down.
SW2 (Pin 5): Switch pin where the internal switches C
and D are connected. An optional Schottky diode can be
connected from SW2 to V_OUT (it is required where
V_OUT > 4.3V). Minimize trace length to keep EMI down.
MODE/SYNC (Pin 7): Burst Mode Select and Oscillator
Synchronization.
MODE/SYNC = High: Enable Burst Mode Operation.
During the period where the IC is supplying energy to
the output, the inductor peak inductor current will reach
0.8A and return to zero current on each cycle. In Burst
Mode operation the operation is variable frequency,
which provides a significant efficiency improvement at
light loads. The Burst Mode operation will continue until
the pin is driven low.
sn3443 3443fs
5