MIC2019A-2YM6 TR Micrel Inc, MIC2019A-2YM6 TR Datasheet - Page 26

• Manufacturer Part Number: MIC2019A-2YM6 TR
• Description: IC POWER SWITCH 2.0A SOT23-6
• Manufacturer: Micrel Inc
• Type: High Side Switchr

Specifications of MIC2019A-2YM6 TR

• Number Of Outputs: 1
• Rds (on): 220 mOhm
• Internal Switch(s): Yes
• Current Limit: Adjustable
• Voltage - Input: 2.5 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3584-2

The value of R2 is calculated using:
The vale of R1 is calculated using:
Where for both equations:
When working with large value resistors, a small amount
of leakage current from the VUVLO terminal can cause
voltage
Therefore, the maximum recommended resistor value
for R2 is 100kΩ.
Using the divider loading current I
of R2 can be estimated by:
Now the value of R1 can be calculated by:
Where:
The VUVLO comparator uses no Hysteresis. This is
because the VUVLO blanking timer prevents any
chattering that might otherwise occur if V
the trigger point. The timer is reset by upward crossings
of the trip point such that V
point for the full 32ms period for load disengagement to
occur.
In selecting a V
not make this value less than 2.5V. A minimum of 2.5V
is required for the MIC20X6’s internal circuitry to operate
properly. VUVLO trip points below 2.5V will result in
erratic or unpredictable operation.
Kickstart™
Only parts in bold have Kickstart™.
(Not available in 5-pin SOT-23 packages).
Kickstart™ allows brief current surges to pass to the
load before the onset of normal current limiting, which
permits dynamic loads to draw bursts of energy without
sacrificing system safety.
Functionally, Kickstart™ is a forced override of the
normal current limiting function provided by the switch.
The Kickstart™ period is governed by an internal timer
which allows current to pass up to the secondary current
February 2011
2003
2013
Micrel, Inc.
V
V
V
R =
R1
R
R
VUVLO
TRIP
VUVLO
1
2
2
=
=
=
. 2
R2
= 4.75V (for a 5V supply)
2004
2014
100
. 0
offsets
V
k 5
= 0.25V
= 0.25V
VUVLO
I
25
DIV
×
µA
Ω
⎛
⎜ ⎜
⎝
V
×
TRIP
V
2005X
V
⎛
⎜
⎝
=
VUVLO
2015
TRIP
. 0
. 4
. 2
that
voltage, the designer is cautioned to
75
25
k 5
V
V
Ω
−
−
1
2006
2016
degrade
⎞
⎟ ⎟
⎠
1
IN
⎞
⎟
⎠
=
must remain below the trip
45
2007
2017
k
DIV
system
of 100uA, the value
2008
2018
IN
varies about
accuracy.
2009X
2019X
26
limit (I
(primary) current limiting goes into action.
During Kickstart™ a secondary current limiting circuit is
monitoring output current to prevent damage to the
switch, as a hard short combined with a robust power
supply can result in currents of many tens of amperes.
This secondary current limit is nominally set at 4A and
reacts immediately and independently of the Kickstart™
period. Once the Kickstart™ timer has finished its count
the primary current limiting circuit takes over and holds
I
load persists.
Once the switch drops out of current limiting the
Kickstart™ timer initiates a lock-out period of 128ms
such that no further bursts of current above the primary
current limit, will be allowed until the lock-out period has
expired.
Kickstart™ may be over-ridden by the thermal protection
circuit
Kickstart™ will be terminated and I
cooling, if the load is still present I
I
Automatic Load Discharge
Only parts in bold have automatic load discharge.
Automatic discharge is a valuable feature when it is
desirable to quickly remove charge from the V
This allows for a quicker power-down of the load. This
also prevents any charge from being presented to a
device being connected to the V
USB, 1394, PCMCIA, and CableCARD™.
Automatic discharge is performed by a shunt MOSFET
from V
break before make action is performed turning off the
main power MOSFET and then enabling the shunt
OUT
LIMIT_2nd
2003
2013
to its programmed limit for as long as the excessive
LIMIT_2nd
OUT
.
and
2004
2014
pin to GND. When the switch is disabled, a
) to the load for 128ms and then normal
if
2005X
2015
Figure 11. Kickstart™
sufficient
2016
2006
internal
2007
2017
OUT
OUT
pin, for example,
OUT
MIC20xx Family
heating
M9999-020311-D
2008
2018
0A. Upon
I
LIMIT
2009X
2019X
OUT
occurs,
, not
pin.