LTC1266 Linear Technology, LTC1266 Datasheet - Page 6

• Manufacturer Part Number: LTC1266
• Description: Synchronous Regulator Controller for N- or P-Channel MOSFETs
• Manufacturer: Linear Technology

PI FU CTIO S
LTC1266
LTC1266-3.3/LTC1266-5
6
TDrive (Pin 1): High Current Drive for Topside MOSFET.
This MOSFET can be either P-channel or N-channel, user
selectable by Pin 3. Voltage swing at this pin is from PWR
V
PWR V
closely decoupled to power ground (Pin 15).
PINV (Pin 3): Phase Invert. Sets the phase of the topside
driver to drive either a P-channel or an N-channel MOSFET
as follows:
BINH (Pin 4): Burst Mode Operation Inhibit. A CMOS logic
high on this pin will disable the Burst Mode operation
feature forcing continuous operation down to zero load.
V
C
the operating frequency. The actual frequency is also
dependent on the input voltage.
I
comparator threshold increases with the Pin 7 voltage.
Sense
which sets the output voltage in LTC1266-3.3 and
LTC1266-5 versions. Pin 8 is also the (–) input for the
current comparator.
TH
IN
IN
T
P-channel: Pin 3 = 0V
N-channel: Pin 3 = PWR V
(Pin 6): External Capacitor. C
U
(Pin 7): Gain Amplifier Decoupling Point. The current
to ground.
(Pin 5): Main Supply Pin.
–
IN
(Pin 8): Connects to internal resistive divider
(Pin 2): Power Suppy for Drive Signals. Must be
U
U
IN
T
from Pin 4 to ground sets
Sense
A built-in offset between Pins 8 and 9 in conjunction with
R
V
serves as the feedback pin from an external resistive
divider used to set the output voltage. On LTC1266-3.3
and LTC1266-5 versions this pin is not used.
SHDN (Pin 11): When grounded, the LTC1266 series
operates normally. Pulling Pin 11 high holds both MOSFETs
off and puts the LTC1266 in micropower shutdown mode.
Requires CMOS logic signal with t
left floating.
SGND (Pin 12): Small-Signal Ground. Must be routed
separately from other grounds to the (–) terminal of C
LB
input is compared to an internal 1.25V reference.
LB
Comparator. This pin will sink current when Pin 13 is
below 1.25V.
PGND (Pin 15): Driver Power Ground. Connects to source
of N-channel MOSFET and the (–) terminal of C
BDrive (Pin 16): High Current Drive for Bottom N-Chan-
nel MOSFET. Voltage swing at Pin 16 is from ground to
PWR V
FB
SENSE
IN
OUT
(Pin 10): For the LTC1266 adjustable version, Pin 10
(Pin 13): Input to the Low-Battery Comparator. This
+
(Pin 14): Open Drain Output of the Low-Battery
IN
sets the current trip threshold.
(Pin 9): The (+) Input to the Current Comparator.
.
r
, t
f
< 1 s. Should not be
IN
.
OUT
.