LTC4213IDDB#TRMPBF Linear Technology, LTC4213IDDB#TRMPBF Datasheet - Page 10

• Manufacturer Part Number: LTC4213IDDB#TRMPBF
• Description: IC CIRC BREAK ELEC 8-DFN
• Manufacturer: Linear Technology

Specifications of LTC4213IDDB#TRMPBF

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 8-DFN
• Linear Misc Type: Positive Low Voltage
• Package Type: DFN EP
• Operating Supply Voltage (min): 2.3V
• Operating Supply Voltage (max): 6V
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Length (mm): 3mm
• Mounting: Surface Mount
• Pin Count: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

OPERATIO
APPLICATIO S I FOR ATIO
LTC4213
Figure 1 shows an electronic circuit breaker (ECB) appli-
cation. An external auxiliary supply biases the V
the internal circuitry. A V
an external MOSFET. The SENSEP and SENSEN pins
OFF ON
10
Overview
The LTC4213 is an Electronic Circuit Breaker (ECB) that
senses load current with the the R
MOSFET instead of using an external sense resistor. This
no R
to the variation of R
less complex, lower cost and reduce voltage and power
loss in the switch path owing to the absence of a sense
resistor. Without the external sense resistor voltage drop,
the V
in the low voltage applications. The LTC4213 is designed
to operate over a bias supply range from 2.3V to 6V. When
bias supply voltage and the ON pin are sufficiently high, the
GATE pin starts charging after an internal debounce delay
of 60µs. During the GATE ramp-up, the circuit breaker is
not armed until the external MOSFET is fully turned on.
Once the circuit breaker is armed, the LTC4213 monitors
the load current through the R
Circuit Breaker Function
The LTC4213 provides dual level and dual response time
circuit breaker functions for overcurrent protection.
The LTC4213 circuit breaker function block consists of
two comparators, SLOWCOMP and FASTCOMP. The
1.25V
V
2.5V
BIAS
V
IN
Figure 1. LTC4213 Electronic Circuit Breaker Application
SENSE
OUT
100µF
C
IN
improvement can be quite significant especially
+
method is less precise than R
0.1µF
U
C1
U
DSON
IN
V
ON
. However, the advantages are
U
load supply powers the load via
CC
DSON
SENSEP
GND
LTC4213
of the external MOSFET.
SI4864DY
W
GATE
DSON
Q1
I
SEL
SENSE
SENSEN
READY
of the external
C
100µF
LOAD
method due
CC
U
10k
R4
+
V
pin and
CC
4213 F01
V
1.25V
3.5A
OUT
thresholds of SLOWCOMP and FASTCOMP are V
V
I
circuit breaker threshold at startup and a lower threshold
after supply current has settled. The inputs of the com-
parators are SENSEP and SENSEN pins. The voltage
across the drain and source of the external MOSFET is
sensed at SENSEP and SENSEN.
When ∆V
V
breaker after a 16µs delay. If ∆V
V
breaker in 1µs.
A severe short circuit condition can cause the load supply
to dip substantially. This does not pose a problem for the
LTC4213 as the input stages of the current limit compara-
tors are common mode to ground.
sense the load current at the drain and source of the
external MOSFET. In ECB applications, large input bypass
capacitors are usually recommended for good transient
performance.
Undervoltage Lockout
An internal undervoltage lockout (UVLO) circuit resets the
LTC4213 if the V
The UVLO comparator (UVCOMP) has a low-to-high thresh-
old of 2.07V and 100mV of hysteresis. UVLO shares the
glitch filters for both low-to-high transition (startup) and
high-to-low transition (reset) with the ON pin compara-
tors. Above 2.07V bias supply voltage, the LTC4213 starts
if the ON pin conditions are met. Short, shallow bus bias
SEL
CB(FAST)
CB(FAST)
CB(FAST)
1. V
2. V
3. V
∆V
can be stepped dynamically, such as to allow a higher
SENSE
CB
CB
CB
= 50mV and V
= 25mV and V
= 100mV and V
. The I
SENSE
, the comparator SLOWCOMP trips the circuit
, the comparator FASTCOMP trips the circuit
=
V
exceeds the V
SEL
SENSEP
CC
supply is too low for normal operation.
pin selects one of the three settings:
CB(FAST)
CB(FAST)
−
CB(FAST)
V
SENSEN
CB
= 175mV with I
= 100mV with I
threshold but is less than
= 325mV with I
SENSE
is greater than
SEL
SEL
SEL
floating
at GND
CB
at V
and
4213f
( ) 1
CC