MIC2005-0.5LYM5 TR Micrel Inc, MIC2005-0.5LYM5 TR Datasheet - Page 26

• Manufacturer Part Number: MIC2005-0.5LYM5 TR
• Description: Fixed Current Limit Single High-Side Switch + Flag + Cslew, Active Low- 0.5A -
• Manufacturer: Micrel Inc
• Type: High Side Switchr

Specifications of MIC2005-0.5LYM5 TR

• Number Of Outputs: 1
• Rds (on): 100 mOhm
• Internal Switch(s): Yes
• Current Limit: 500mA
• Voltage - Input: 2.5 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3397-2

August 2011
To prevent false triggering of the VUVLO feature, the
MIC20X6 includes a delay timer to blank out
momentary excursions below the VUVLO trip point. If
V
32ms (typical), then the load is disengaged and the
MIC20X6 will wait 128ms before reapplying power to
the load. If V
then the load will be powered for the 32ms blanking
period and then again disengaged. This is illustrated in
the scope plot below. If V
trip point MIC20X6 resumes normal operation.
VUVLO and Kickstart™ operate independently in the
MIC2016. If the high-current surge allowed by
Kickstart™ causes V
point for more than 32ms, VUVLO will disengage the
load, even though the Kickstart™ timer has not timed
out.
Micrel, Inc.
IN
Supply
stays below the VUVLO trip point for longer than
Input
I
IN_LOAD
Figure 10. VUVLO Application Circuit
+
Figure 9. VUVLO Operation
IN
remains below the VUVLO trip point,
IN
R1
R2
to dip below the VUVLO trip
IN
remains above the VUVLO
VIN
VUVLO
MIC20X6
VOUT
+
26
Calculating VUVLO Resistor Divider Values
The VUVLO feature is designed to keep the internal
switch off until the voltage on the VUVLO pin is greater
than 0.25V. A resistor divider network connected to the
VUVLO and VIN pins is used to set the input trip
voltage V
chosen to minimize the load on the input supply I
the value of R1 sets the trip voltage V
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 offsets that degrade system
accuracy. Therefore, the maximum recommended
resistor value for R2 is 100kΩ.
Using the divider loading current I
value of R2 can be estimated by:
Now the value of R1 can be calculated by:
where:
V
V
TRIP
VUVLO
= 4.75V (for a 5V supply)
V
= 0.25V
R =
R1
R
R
VUVLO
1
2
2
TRIP
=
=
=
. 2
R2
100
. 0
V
k 5
= 0.25V
VUVLO
I
(see Figure 10). The value of R2 is
25
DIV
×
µA
Ω
⎛
⎜ ⎜
⎝
V
×
V
V
=
⎛
⎜
⎝
VUVLO
TRIP
. 0
. 4
. 2
75
25
k 5
V
V
Ω
−
−
1
⎞
⎟ ⎟
⎠
1
⎞
⎟
⎠
=
45
k
DIV
TRIP
MIC20xx Family
M9999-080211-D
.
of 100µA, the
DIV
and