LTC2923CDE#PBF Linear Technology, LTC2923CDE#PBF Datasheet - Page 9

• Manufacturer Part Number: LTC2923CDE#PBF
• Description: IC POWER SUPPLY CONTROLLER 12DFN
• Manufacturer: Linear Technology

Specifications of LTC2923CDE#PBF

• Applications: Power Supply Controller
• Voltage - Supply: 2.9 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 12-DFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Voltage - Input: -
• Lead Free Status / Rohs Status: Compliant

APPLICATIO S I FOR ATIO
The LTC2923 features an electronic circuit breaker func-
tion that protects the optional series FET against short
circuits. When the FET is fully enhanced (GATE > RAMP +
4.9V), the electronic circuit breaker is enabled. Then, if the
voltage across the FET (V
from V
gate of the FET is pulled down with 20mA, turning it off.
Because the slaved supplies track the RAMP pin, they are
pulled low by the tracking circuit when a short-circuit fault
occurs. Following a short-circuit fault, the FET is latched
off until the fault is cleared by pulling the ON pin below
0.4V.
CC
to the RAMP pin for more than about 10µs the
U
R
R
TB2
TA2
DS
U
R
R
R
R
ONB
ONA
TB1
TA1
) exceeds 200mV as measured
ON
RAMPBUF
TRACK1
TRACK2
1.2V
W
+
–
Figure 6. Simplified Functional Diagram
1×
U
V
CC
200mV
+ –
V
V
V
CC
CC
CC
10µA
10µA
Ramp Buffer
The RAMPBUF pin provides a buffered version of the
RAMP pin voltage that drives the resistive dividers on the
TRACKx pins. When there is no external FET, it provides up
to 2mA to drive the resistors even though the GATE pin
only supplies 10µA. The RAMPBUF pin also proves useful
in systems with an external FET. Since the track cell in the
simplified functional diagram above drives 0.8V on the
TRACKx pins, if R
source, the TRACKx pin could potentially pull up the FET’s
source towards 0.8V when the FET is off. RAMPBUF
blocks this path.
+
–
+
+
–
–
0.8V
0.8V
TBx
RAMP
GATE
FB1
FB2
is connected directly to the FET’s
R
R
2923 F06
FA1
FA2
DC/DC
DC/DC
C
GATE
R
R
FB1
FB2
Q1
LTC2923
MASTER
SLAVE1
SLAVE2
2923fa
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