Linear LTC3388-3 18v dual input micropower powerpath prioritizer Datasheet

LTC4419
18V Dual Input Micropower
PowerPath Prioritizer
Features
Description
Selects Highest Priority Valid Supply from Two Inputs
nn Wide 1.8V to 18V Operating Range
nn Internal Dual 2Ω, 0.5A Switches
nn Low 3.6µA Operating Current
nn Low 320nA V2 Current When V1 Connected to OUT
nn Blocks Reverse and Cross Conduction Currents
nn Reverse Supply Protection to –15V
nn V2 Freshness Seal/Ship Mode
nn ±1.5% Accurate Adjustable Switchover Threshold
nn Two Auxiliary ±2.3% Accurate Voltage Comparators
nn Overcurrent and Thermal Protection
nn Thermally Enhanced 10-Pin 3mm × 3mm DFN
and 12-Lead Exposed Pad MSOP Packages
The LTC®4419 is a dual input monolithic PowerPath™
prioritizer with low operating current, that provides backup
switchover for keeping critical circuitry alive during brown
out and power loss conditions. Unlike diode-OR products,
little current is drawn from the inactive supply even if its
voltage is greater than the active supply.
nn
Applications
Low Power Battery Backup
Portable Equipment
nn Point-of-Sale (POS) Equipment
nn
Internal 2Ω, current limited PMOS switches provide power
path selection from a primary input (V1) or a backup input
(V2) to the output. An adjustable voltage monitor set via
an external resistive divider provides flexibility in setting
the V1 to V2 switchover threshold. When primary input V1
drops, the ADJ monitor input causes OUT to be switched
to V2. Fast non-overlap switchover circuitry prevents both
reverse and cross conduction while minimizing output
droop.
The LTC4419 has two auxiliary comparators with opendrain outputs that provide flexible voltage monitoring. The
V2ON output indicates if V2 is powering OUT. Freshness
seal mode prevents V2 battery discharge during storage
or shipment.
nn
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Typical Application
Typical Switchover Waveforms
5V
WALL
ADAPTER
C1
10µF
V1
OUT
1M
OUT
1M
1M
ADJ
CMPOUT1
V1UV
CMP1
CMPOUT2
V2UV
237k
121k
+
7.4V
Li-Ion
LTC4419
V2
V2ON
V2ON
SWITCHOVER
THRESHOLD: V1 < 4V (V1 FALLING)
V1UV THRESHOLD: V1 < 4.4V (V1 FALLING)
V2UV THRESHOLD: V2 < 6V (V2 FALLING)
4.02M
CMP2
280k
V2
2V/DIV
V1
2V/DIV
GND
OUT
COUT = 10µF
ILOAD = 100mA
SWITCHOVER
THRESHOLD
50µs/DIV
4419 TA01b
4419 TA01a
4419f
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1
LTC4419
Absolute Maximum Ratings
(Notes 1, 2)
Input Supply Voltage
V1, V2.......................................................–15V to 24V
OUT........................................................ –0.3V to 24V
OUT – V2..................................................–24V to 39V
OUT – V1..................................................–24V to 39V
Input Voltages
ADJ, CMP1, CMP2 (Note 3) ................... –0.3V to 24V
Output Voltages
CMPOUT1, CMPOUT2, V2ON (Note 3) ... –0.3V to 24V
Pin Currents (Note 2)
ADJ, CMP1, CMP2, CMPOUT1, CMPOUT2,
V2ON..................................................................–1mA
Operating Ambient Temperature Range
LTC4419C................................................. 0°C to 70°C
LTC4419I..............................................–40°C to 85°C
Junction Temperature (Notes 4, 5)......................... 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MSOP Package.................................................. 300°C
Pin Configuration
TOP VIEW
TOP VIEW
V1
1
10 V2
CMP1
2
9 CMP2
ADJ
3
GND
4
CMPOUT1
5
11
GND
8 OUT
7 V2ON
6 CMPOUT2
V1
NC
CMP1
ADJ
GND
CMPOUT1
1
2
3
4
5
6
13
GND
12
11
10
9
8
7
V2
NC
CMP2
OUT
V2ON
CMPOUT2
MSE PACKAGE
12-LEAD PLASTIC MSOP
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 43°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
TJMAX = 125°C, θJA = 40°C/W
EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB
Order Information
(http://www.linear.com/product/LTC4419#orderinfo)
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC4419CDD#PBF
LTC4419CDD#TRPBF
LGMS
10-Lead (3mm × 3mm) Plastic DFN
0°C to 70°C
LTC4419IDD#PBF
LTC4419IDD#TRPBF
LGMS
10-Lead (3mm × 3mm) Plastic DFN
–40°C to 85°C
LTC4419CMSE#PBF
LTC4419CMSE#TRPBF
4419
12-Lead Plastic Exposed Pad MSOP
0°C to 70°C
LTC4419IMSE#PBF
LTC4419IMSE#TRPBF
4419
12-Lead Plastic Exposed Pad MSOP
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
4419f
2
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LTC4419
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. V1 = 3.6V, V2 = 3.6V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage and Currents
18
V
3.6
500
6.3
800
µA
nA
3.3
320
120
6
650
220
µA
nA
nA
1
2
5
Ω
l
34
64
94
ms
1.032
1.047
1.062
V1, V2
Operating Voltage Range
IV1
V1 Current, V1 Powering OUT
V1 Current, V2 Powering OUT
IOUT = 0, V1 = 8.4V, V2 = 3.6V
V1 = 8.4V, V2 = 3.6V
l
l
IV2
V2 Current, V2 Powering OUT
V2 Current, V1 Powering OUT
V2 Current in Freshness Seal Mode
IOUT = 0, V1 = 3.6V, V2 = 8.4V
V1 = 3.6V, V2 = 8.4V
V1 = GND, V2 = 5V
l
l
l
RON
Switch Resistance
V1 = V2 = 5V, IOUT = –100mA
l
tVALID(V1)
Input Qualification Time
V1 Rising, ADJ Rising
l
1.8
Input Comparators
VTHA
ADJ Threshold
ADJ Falling
l
V
VHYSTA
ADJ Comparator Hysteresis
ADJ Rising
l
30
50
70
VTHC
CMP1, CMP2 Threshold
CMP1, CMP2 Falling
l
0.378
0.387
0.396
V
VHYSTC
CMP1, CMP2 Hysteresis
CMP1, CMP2 Rising
l
7.5
10
12.5
mV
tPDA
ADJ Comparator Falling Response Time
10% Overdrive
l
4
7.3
12
µs
tPDC
CMP1, CMP2 Comparator Response Times
20% Overdrive
l
30
65
µs
mV
Power Path Function
ILIM
Output Current Limit
V1, V2 = 8.4V
l
0.5
1.1
1.6
A
VREV
Reverse Comparator Threshold
(V1, V2) – VOUT for Power Path Turn-On
l
25
50
75
mV
tSWITCH
Break-Before-Make Switchover Time
V1 = V2 = 5V, IOUT < –10mA
l
1
2.5
5
µs
15
120
50
250
mV
mV
1.65
2.3
V
±50
±150
nA
I/O Specifications
VOL
Output Voltage Low, CMPOUT1, CMPOUT2
and V2ON
I = 100µA
I = 1mA
l
l
VOH
V2ON Output High Voltage
I = –1µA, V2 = 5V
l
IOH
CMPOUT1, CMPOUT2 and V2ON,
Output High Leakage
CMPOUT1, CMPOUT2, V2ON = 18V
l
IPU(V2ON)
V2ON Pull-Up Current
V2 = 5V, ADJ = 0V, V2ON = 0V
l
ILEAK
ADJ, CMP1, CMP2 Leakage Current
ADJ, CMP1, CMP2 = 0V, 1.5V
l
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: All currents into pins are positive; all voltages are referenced to
GND unless otherwise noted.
Note 3: These pins can be tied to voltages down to –5V through a resistor
that limits the current to less than –1mA.
1.05
–2.7
–5
–8
µA
±1
±5
nA
Note 4: The LTC4419 includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 5: The LTC4419 is tested under pulsed load conditions such that
TJ ≈ TA. The junction temperature (TJ in °C) is calculated from the ambient
temperature (TA in °C) and power dissipation (PD in Watts) according to
the formula:
TJ = TA + (PD • θJA)
4419f
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3
LTC4419
Typical Performance Characteristics
4.5
V1 Current, V1 Powers OUT
(IOUT = 0)
4.0
V1 = 1.8V
V1 = 3.6V
V1 ≥ 6V
(TA = 25°C, V1 = V2 = 3.6V unless otherwise indicated).
V2 Current, V2 Powers OUT
(IOUT = 0)
V2 Current, V1 Powers OUT
450
V2 = 1.8V
V2 = 3.6V
V2 ≥ 6V
V1 = V2
400
3.5
350
V2 CURRENT (nA)
3.5
V2 CURRENT (µA)
V1 CURRENT (µA)
4.0
3.0
300
250
3.0
–40°C
25°C
85°C
200
2.5
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
2.5
–50
125
–25
0
25
50
75
TEMPERATURE (°C)
4419 G01
200
450
150
350
300
5
10
15
V2 VOLTAGE (V)
Open-Drain (CMPOUT1, CMPOUT2,
V2ON) VOL vs Pull-Down Current
5
10
15
V2 VOLTAGE (V)
20
1.010
1.000
0.995
50
0
0.0
20
Normalized CMP1 and CMP2
Falling Thresholds vs Temperature
1.005
100
–40°C
25°C
85°C
0
0
4419 G03
NORMALIZED VTHC
500
VOL (mV)
V1 CURRENT (nA)
250
V1 = V2
400
150
125
4419 G02
V1 Current, V2 Powers OUT
550
100
0.5
1.0
1.5
PULL-DOWN CURRENT (mA)
4419 G04
2
0.990
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
4419 G05
Normalized Falling
ADJ Threshold vs Temperature
4419 G06
ADJ Hysteresis vs Temperature
1.010
125
ADJ Leakage vs Temperature
70
3.0
VADJ = 0V, 1.5V
1.000
0.995
0.990
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
4419 G07
60
ADJ LEAKAGE (nA)
ADJ HYSTERESIS (mV)
NORMALIZED VTHA
1.005
2.5
50
40
30
–50
2.0
1.5
1.0
–25
0
25
50
75
TEMPERATURE (°C)
100
125
4419 G08
0.5
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
4419 G09
4419f
4
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LTC4419
Typical Performance Characteristics
Output Current Limit vs
Temperature
Output Current IOUT Response for
Different Shorting Impedances
IOUT vs VOUT for Different Input
Supply Voltages
3.0
2.5
1.20
2.0
IOUT (A)
1.30
1.10
1.2
1.2Ω
2.2Ω
3.3Ω
3.9Ω
5.0Ω
1.5
1.0
0.4
0.90
0.5
0.2
0
0
0
25
50
75
TEMPERATURE (°C)
100
125
250
5V
3.6V
2V
1.8V
3.6V
5V
≥6V
V2 CURRENT (nA)
200
3
5
4419 G12
V1 = 0V
100
50
–25
0
25
50
75
TEMPERATURE (°C)
100
0
–50
125
–25
0
25
50
TEMPERATURE (°C)
75
4419 G13
Switchover from a Higher to a
Lower Voltage
OUT
2V/DIV
4
150
2
V2
100
4419 G14
Output Voltage and Current
Waveforms During Switchover
COUT = 10µF
IOUT = 200mA
V1
2
3
VOUT (V)
Freshness Seal Current
vs V2 Voltage and Temperature
5
RON (Ω)
1
4419 G11
Switch RON vs Temperature
1
–50
0
40µs/DIV
4419 G10
4
OHMIC
0.6
1.0
–25
CURRENT
LIMIT
0.8
1.00
0.80
–50
VIN = 1.8V
VIN = 3.6V
VIN = 5V
FOLDBACK
IOUT (A)
1.40
CURRENT LIMIT (A)
(TA = 25°C, V1 = V2 = 3.6V unless otherwise indicated).
V1 Reverse Voltage Blocking with
V2 Powering OUT
V2
5V/DIV
10V
6V
10V
DISCONNECT FROM V1
V2
6V
OUT
COUT = 10µF
C1 = C2 = 10µF
ILOAD = 50mA
IOUT
0.5A/DIV
CONNECT TO V2
3ms/DIV
V1
2V/DIV
4419 G15
10µs/DIV
4419 G16
V1
10V/DIV
–10V
IOUT
0.5A/DIV
ILOAD = 50mA
20ms/DIV
4419 G17
4419f
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5
LTC4419
Pin Functions
ADJ: Adjustable V1 Switchover Threshold Input. ADJ
is the noninverting input to the switchover threshold
comparator. If V1 ≥ 1.55V and ADJ ≥ 1.097V for at least
64ms, OUT is switched internally to the primary V1 input.
When the ADJ input voltage is lower than 1.047V, OUT is
switched internally to V2, if V2 ≥ 1.55V. Otherwise, OUT
stays unpowered. Tie ADJ via a resistive divider to V1 to
set the V1 to V2 switchover voltage. Do not leave open.
CMP1: Auxiliary Comparator 1 Monitor Input. CMP1 is the
noninverting input to an auxiliary comparator. The inverting input is internally connected to a 0.387V reference.
Connect CMP1 to GND when it is not used.
CMP2: Auxiliary Comparator 2 Monitor Input. CMP2 is
the noninverting input to a second auxiliary comparator.
The inverting input is internally connected to a 0.387V
reference. Connect CMP2 to GND when it is not used.
CMPOUT1: Auxiliary Comparator 1 Output. This open-drain
comparator output is pulled low when CMP1 is below
0.387V and during power-up, otherwise it is released.
Once released, connecting a resistor between CMPOUT1
and a desired supply voltage up to 18V causes this pin to
be pulled high. Leave open if unused.
CMPOUT2: Auxiliary Comparator 2 Output. This open-drain
comparator output is pulled low when CMP2 is below
0.387V and during power-up, otherwise it is released.
Once released, connecting a resistor between CMPOUT1
and a desired supply voltage up to 18V causes this pin to
be pulled high. Leave open if unused.
Exposed Pad: For best thermal performance, solder exposed pad to a large PCB area.
GND: Device Ground.
NC: No Connection. Not internally connected.
OUT: Output Voltage Supply. OUT is a prioritized voltage
output that is either connected to V1, V2 or is unpowered
as indicated in Table 1 of the Applications Information
section. Additionally, OUT must be at least 50mV below
the input supply for a connection to that supply to be
activated. Bypass with a capacitor of 1µF or greater. See
Applications Information section for bypass capacitor
recommendations.
V1: Primary Power Supply. OUT is internally switched to
V1 if V1 ≥ 1.55V and ADJ ≥ 1.097V. When in freshness
seal mode, applying V1 ≥ 1.55V and ADJ ≥ 1.097V for
32ms disables freshness seal. Bypass with 1µF or greater.
Tie to GND if unused.
V2: Backup Power Supply. V2 is valid if its voltage is
≥1.55V. OUT is internally switched to V2 if ADJ < 1.047V
or V1 < 1.55V, provided V2 is valid. Refer to Table 1 of
the Applications Information section. Bypass with 1µF or
greater. Tie to GND if unused.
V2ON: V2 Connected Status. V2ON is an output that is
driven high with a 5µA pull-up when the V2 to OUT power
path is active. Otherwise it is driven low. Connect a resistor between OUT or V2 and this pin to provide additional
pull-up. As this pin is used to enable freshness seal, do
not force low or connect a pull-down resistor to this pin.
Leave open if unused.
4419f
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LTC4419
Functional Diagram
CMPOUT1
+
–
CP1
CMP1
0.397V/
0.387V
+
–
CP2
CMP2
0.397V/
0.387V
CMPOUT2
V1
OUT
V2
EN1
OUT
+–
–
+
EN2
CREV1
50mV
–
+
50mV
+–
OUT
1.55V/
1.52V
–
+
2.5V
CUV1
–
+
CUV2
CREV2
CONTROL LOGIC
1.55V/
1.52V
FRESHNESS
SEAL
ADJ
1.097V/
1.047V
5µA
V2ON
GND
–
+
CADJ
64ms
7.3µs
4419 FD
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7
LTC4419
Operation
The Functional Diagram shows the major blocks of the
LTC4419. The LTC4419 is a PowerPath prioritizer that
switches output OUT between primary (V1) and backup
(V2) sources depending on their validity and priority with
V1 having the highest priority. If neither supply is valid,
OUT stays unpowered. A resistive divider between V1, ADJ
and GND and comparators CUV1 and CADJ are used to
monitor V1’s voltage to establish validity. V1 is valid if V1
≥ 1.55V and ADJ ≥ 1.097V for 64ms after V1 rises above
1.55V. Otherwise V1 is invalid. V2 is valid if its voltage as
monitored by comparator CUV2 is ≥1.55V. Otherwise, it
is invalid. Switchover threshold is independent of relative
V1 and V2 voltages, permitting V1 to be lower or higher
than V2 when V1 powers OUT and vice versa.
Power connection to the output is made by enhancing backto-back internal P-channel MOSFETs. Current passed by
the MOSFETs is limited to typically 1.1A if OUT is greater
than 1V. Otherwise it is limited to 250mA. When switching
from V1 to V2, the V1 to OUT power path is first disabled
and comparator CREV2 is enabled. After the OUT voltage
drops 50mV below V2, as detected by CREV2, OUT is
then connected to V2. V2ON pulls high after switchover.
This break-before-make strategy prevents OUT from
backfeeding V2. Switchover back to V1 occurs in a similar
manner once V1 has been revalidated. V2ON pulls low if
the V2 power path is disabled and during initial power-up
when V1 or V2 is first applied.
The LTC4419 blocks reverse voltages up to –15V when
a reverse condition occurs on an inactive channel. The
LTC4419 also disables a channel if the corresponding
input supply falls below 1.52V. A small ~3µA current is
drawn from either the prioritized input supply or the highest
input supply if both input supplies are below 1.55V. Very
little current (~320nA) is drawn from the unused supply.
The LTC4419 provides two additional comparators, CP1
and CP2, whose open-drain outputs pull low when CMP1
and CMP2 pin voltages fall below 0.387V and during initial
power-up. These comparators can be used to monitor
supplies to provide early power failure warning and other
useful information.
The LTC4419 can be put into a V2 freshness seal mode
to prevent battery discharge during storage or shipment.
The Applications Information section lists the steps to
engage and disengage V2 freshness seal.
4419f
8
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LTC4419
Applications Information
The LTC4419 is a low quiescent current 2-channel prioritizer that powers both its internal circuitry and its output
OUT from a prioritized valid input supply. Unlike an ideal
diode-OR, the LTC4419 does not draw current from the
highest supply as long as any one supply is greater than
1.8V. Table 1 lists the input supply from which the LTC4419
draws its internal quiescent current ICC and the supply to
which OUT is connected after input supplies have been
qualified.
Table 1. OUT and LTC4419 ICC Power Table
INPUT VOLTAGES
V1 > 1.55V
OUT
ADJ > 1.097V V2 > 1.55V CONNECTION ICC SOURCE
Y†
Y†
X
N
Y
V2
V2
Y
N
N
Hi-Z
V1
N
X
Y
V2
V2
N
X
N
Hi-Z
VMAX*
X
V1
V1
Note: X = Don’t Care.
*VMAX = Higher of V1 and V2. †For 64ms.
A typical battery backup application is shown in Figure 1.
V1 is powered by a 2-cell Li-ion battery pack whose safe
discharge limit is between 5.6V and 6V. V2 is powered by a
9V alkaline hold-up battery which is completely discharged
when its voltage drops to 6V. In order to protect the 2-cell
Li-ion battery on V1, switchover threshold is set to ~5.6V.
After switchover to V2, the Li-ion battery primarily supplies
only divider R1-R3’s current, as the LTC4419 draws only a
small standby current from V1. Monitor inputs CMP1 and
CMP2 are configured to provide V1 and V2 undervoltage
+
2-CELL
7.4V
Li-Ion
C1
4.7µF
R3
1M
R2
150k
R1
78.7k
+
9V
ALKALINE
C2
4.7µF
R5
4.02M
R4
280k
V1
OUT
ADJ
OUT
R6
1M
COUT
10µF
R7
1M
CMPOUT2
V2UV
CMP1 CMPOUT1
LTC4419
V1UV
SWITCHOVER THRESHOLD:
V1< 5.6V (V1 FALLING)
V1UV: V1 < 6V (V1 FALLING)
V2UV: V2 < 6V (V2 FALLING)
V2
CMP2
GND
4419 F01
warnings. Outputs V1UV and V2UV are driven low when
V1 and V2 voltages fall below 6V. Relevant equations used
to calculate these component values are discussed in the
following subsections.
Setting the Switchover Threshold
Several factors affect switchover voltage and should
be taken into account when calculating resistor values.
These include resistor tolerance, 1.5% ADJ comparator
threshold error, divider impedance and worst-case ADJ
pin leakage. These factors also apply to resistive dividers
connected to monitor inputs CMP1 and CMP2. Referring
to Figure 1 and the Electrical Characteristics table, the
typical V1 switchover threshold is:
VSW1 =
VTHA
• (R1+R2+R3)
R1+R2
(1)
Typical V1 undervoltage threshold is:
VV1UV =
VTHC
• (R1+R2+R3)
R1
(2)
and typical V2 undervoltage threshold is:
VV2UV =
VTHC
• (R4+R5)
R4
(3)
Equations 1-3 assume ADJ and CMP pin leakages are
negligible. To account for pin leakage, equations 1-3 must
be modified by an ILEAK • REQ term, where equivalent
resistance, REQ, must be calculated on a case-by-case
basis. Worst-case component values and reference voltage
tolerances must be used to calculate the maximum and
minimum threshold voltages. For example, to calculate
minimum falling switchover threshold voltage, VSW1(MIN),
use VTHA(MIN), (R2 + R1)(MAX), and R3(MIN) in equation 1.
Selecting Output Capacitor, COUT
COUT can be selected to control either output voltage droop
during switchover or output rising slew rate during initial
power-up or when switching to a higher supply.
In general, output droop, ∆VOUT, can be calculated by:
Figure 1. The LTC4419 Protecting a 2-Cell Li-Ion Battery Pack on
V1 from Discharge Below Its Safe Minimum Voltage
∆VOUT =
tNOV •IOUT
COUT
(4)
4419f
For more information www.linear.com/LTC4419
9
LTC4419
Applications Information
t
•I
COUT ≥ NOV OUT
∆VOUT
(5)
limits output droop to less than ∆VOUT.
In order to estimate tNOV and IOUT, first consider a scenario
where power supplies are present on both V1 and V2, and
their voltages are changing slowly compared to the ADJ
comparator propagation delay tPDA. In such cases, IOUT is
ILOAD and tNOV is tSWITCH. COUT can be sized according to
equation 5 with IOUT = ILOAD(MAX) and tNOV = tSWITCH(MAX)
to limit maximum output droop when switching to a higher
supply. When switching to a lower supply, switchover is
initiated only after OUT falls VREV below the supply that
is being switched in. In such cases, total output droop is
∆VOUT + VREV.
Next consider a scenario where the input power source
powering OUT is unplugged. OUT back-feeds circuitry
connected to the input supply pin. Both input and output
droop at the same rate. Referring to Figure 1, assume
the battery on V1 is unplugged when OUT is connected
to V1. IOUT is the sum of ILOAD and the reverse current
IBACK, which in this example is IR3. As OUT and V1, since
the two are connected, droop below the ADJ threshold,
switchover occurs to V2 with a dead time:
tNOV = tPDA + tSWITCH
(6)
where tPDA is an overdrive dependent ADJ comparator
delay. As an approximation, use tPDA from the Electrical
Characteristics table to estimate tNOV. Use this tNOV and:
IOUT = (IBACK + ILOAD)
(7)
in equation 5 to size COUT:
COUT ≥
( tPDA + tSWITCH ) •IOUT
∆VOUT
(8)
Refer to Figure 2 for a more accurate estimate of tPDA versus
dVOUT/dt. If ADJ is filtered with capacitor, its discharge
time via divider R1-R3 increases tPDA. This results in a
higher output droop than estimated by equation 8.
In order to limit output rising slew rate dVOUT/dt, size:
COUT ≥
ILIM
dVOUT
dt
(9)
as the LTC4419 limits OUT charging current to ILIM until
OUT approaches the input supply to within ILIM • RON,
where RON is the channel switch resistance. Refer to the
Thermal Protection and Maximum COUT section to determine maximum allowed COUT.
125
100
t PDA (µs)
where IOUT is the current supplied by COUT during nonoverlap or “dead” time tNOV. Choosing:
75
50
25
0
10
100
1k
dVADJ/dt (V/s)
10k
100k
4419 F02
Figure 2. ADJ Comparator Propagation Delay
as a Function of Slew Rate; tPDA vs dVADJ/dt
Inductive Effects
Parasitic inductance and resistance can impact circuit
performance by causing overshoot and undershoot of
input and output voltages depending on the scenario. Parasitic inductance in the power path causes positive-going
overshoot on the input and a negative-going undershoot
on the output when the LTC4419 turns off. Another cause
of positive input overshoot is R-L-C tank ringing during
hot plug of an input supply. Input overshoot is most pronounced when the total resistance of the input tank is low.
Care must be taken to ensure overvoltage transients do
not exceed the absolute maximum ratings of the LTC4419.
Additionally, parasitic resistance and inductance can cause
input undershoot during power path turn-on. If severe
enough, undershoot can temporarily invalidate a supply
and cause repeated power up cycles (“motorboating”) or
unwanted switchover between sources.
4419f
10
For more information www.linear.com/LTC4419
LTC4419
Applications Information
V1
LTC4419
LPAR1
V1
RSN1
0.5Ω
LPAR2
OUT
OPTIONAL
CSN1
5µF
OUT
RSN2
1Ω
COUT2
10µF
OPTIONAL
D1
1N5818
COUT1
1µF
4419 F03
Figure 3. Recommended Inductive Transient Suppression Circuitry
The first step to avoid these issues is to minimize parasitic
inductance and resistance in the power path. Guidelines
are given in the layout section for minimizing parasitic
inductance on the printed circuit board (PCB). External
to the PCB, twist the power and ground wires together to
minimize inductance.
damp R-L-C ringing if required. Size COUT2 to obtain the
required total output capacitance. Also add a diode between
OUT and ground close to the LTC4419 to clamp negative
ringing if the OUT pin rings below –0.3V.
Second, use a bypass capacitor at the input to limit input
voltage overshoot during LTC4419 power path turn off. A
few micro farads is sufficient for most applications. When
hot plugging supplies with large parasitic inductances, it
is possible for the R-L-C tank to ring to more than twice
the nominal supply voltage. Wall adapters and batteries
typically have enough loss (i.e. series resistance) to prevent
ringing of this magnitude. However, if this is a problem,
snub input capacitor CSN1 with resistor RSN1, typically
0.5Ω. Place this network close to the supply pin.
In some applications, built-in CMP1 hysteresis may be insufficient. In such cases, CMP1 hysteresis can be increased
as shown in Figure 4. Hysteresis at the monitored input
VMON with R8 present and assuming R9 << R8 is given by:
Third, if an input capacitor is not permissible, use a TVS
(such as SMAJ16CA) in applications when supply pin
transients can exceed 24V. Use a bidirectional TVS in
applications requiring reverse input protection. Note that
a TVS does not address droop and motorboating, which
are solved only by input bypassing.
During normal operation, the LTC4419 limits power path
current to < 1.6A and internal circuitry prevents OUT from
ringing below ground during power path turn off. This is
also true for output shorts when the short is close to the
LTC4419’s OUT pin. However, if the output is shorted
through a long wire, current in the wire inductance (LPAR2
in Figure 3) builds up due to the discharge of COUT1 and
can be much higher than 1.6A. This current causes the
OUT pin to ring below its −0.3V absolute maximum rating
once COUT1 has been fully discharged. For this special
case, split the output capacitor between COUT1 and COUT2
and make COUT1 small. Snub COUT1 with resistor RSN2 to
Increasing CMP1 and CMP2 Hysteresis
VHYST = VHYSTC •
R3
R3
+ VPU •
R1||R3||R8
R8
(10)
where VHYSTC and VTHC are found in the Electrical Characteristics table and are typically 10mV and 0.387V respectively.
Account for supply VPU and resistor R8 when calculating
rising and falling thresholds of monitored input VMON.
Supply Impedance and ADJ Comparator Hysteresis
VMON
R3
VPU
CMP1
R1
LTC4419
R9
CMPOUT1
R8
4419 F04
Figure 4. Increasing CMP1 Hysteresis
In some applications, V1 could be supplied by a battery
pack with high ESR or through a long cable with appreciable
series resistance. Load current, IOUT, flowing through this
resistance reduces the monitored V1 voltage by:
∆V1 = IOUT • RESR
(11)
4419f
For more information www.linear.com/LTC4419
11
LTC4419
Applications Information
The drop can be as high as:
∆V1 = ILIM • RESR
(12)
when COUT is initially being charged. Voltage droop at the
V1 pin can result in repeated switchover between V1 and
V2 if built-in V1 (ADJ) hysteresis is insufficient.
In such cases, CMP1 can be used to set V1 hysteresis as
shown in Figure 5. When V1 falls, ADJ and CMP2 are pulled
low when CMP1 falls below VTHC and output CMPOUT2
activates hysteresis resistor R8. When switching from
V1 to V2, current supplied by V1 will go to zero, resulting in a voltage increase on V1. Switchover back to V1 is
prevented due to increased V1 hysteresis as determined
by equation 10.
V1 droop is higher during the initial charging of COUT.
Referring to Figure 5, to prevent repeated switchover
when COUT is initially being charged, add input capacitor
C1. Ideally, if V1 is greater than switchover threshold
VSW1 by ∆V, size:


∆V
VSW1 •COUT • 1–

 2 •ILIM •RESR 
C1≥
∆V
(13)
A filter capacitor CADJ can also be added to ADJ to ride
through the initial output charge up time. CADJ should be
minimized as it slows ADJ response, resulting in a larger
ESR
+
V1
R2
C1 +
R8
R1
V1
V2
V2
Input Shorts and Supply Brown-Out
The LTC4419 temporarily turns off its active power path
during input shorts or brown-out conditions if the input
supply falls below OUT by 0.7V. If the primary input supply
becomes invalid, switchover to the backup supply occurs.
The power path is reactivated when the input recovers to
within 0.7V of the output.
Figure 6 shows the response of the LTC4419 to a brownout and recovery on V1 where switchover to V2 does not
occur as V1 stays above 1.8V. When V1 falls, OUT gets
disconnected from V1 and is slowly discharged by load
resistance ROUT. When V1 recovers, the power path is
reactivated and OUT tracks V1. In Figure 7, when V1 falls,
OUT gets disconnected from V1 as V1 drops below the
V1
5V/DIV
to ensure no switchover occurs when COUT is initially being charged. If the resulting C1 value causes large inrush
current, is physically too big or requires a large snubber
resistor when V1 is plugged in (refer to the Typical Applications section), select C1 to be as high a value as the
application can tolerate.
R3
output droop when the input supply powering V1 is either
unplugged or drops quickly.
OUT
OUT
COUT
V2
5V/DIV
OUT
5V/DIV
COUT = 10µF
ROUT = 100Ω
100µs/DIV
4419 F06
Figure 6. Voltage Waveforms During a Brown-Out
on V1 that Does Not Result in a Switchover to V2.
Switchover Threshold = 1.8V
V1
5V/DIV
V2
5V/DIV
LTC4419
OUT
5V/DIV
CMP1
CMPOUT2
COUT = 10µF
ROUT = 100Ω
CMPOUT1
100µs/DIV
ADJ
CMP2
4419 F05
Figure 5. Increasing Supply Hysteresis in High ESR Applications
4419 F07
Figure 7. Voltage Waveforms When a Brown-Out
on V1 Results in Switchover to V2. Switchover
Threshold = 3V
4419f
12
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LTC4419
Applications Information
switch-over threshold. When V1 recovers, it needs to be
qualified for 64ms before it is reconnected to OUT. OUT
gets discharged by ROUT and is connected to V2 once its
voltage is 50mV less than V2.
5V
INPUT
Reverse Voltage Blocking
The LTC4419 blocks reverse voltages on supply pins V1
and V2 up to –15V relative to GND and up to –39V relative
to OUT. Transient voltage suppressors (TVS) connected to
V1 and V2 must be bidirectional and capacitors connected
to these pins must be rated to handle reverse voltages. A
reverse voltage on V2 does not disrupt V1 operation and
vice versa.
Freshness Seal
Freshness seal mode prevents V2 battery discharge by
keeping V2 disconnected from OUT even if V1 is absent
or invalid. Very little current is drawn from V2—typically
just 120nA. The following sequence (refer to Figure 8)
puts the LTC4419 in freshness seal mode:
1. Power up V2 while holding V1 low and wait for at least
10ms.
2. Drive V2ON below 50mV.
3. Power up V1 and ADJ for at least 94ms. Freshness seal
is enabled.
1
V2
2
3
1.8V
DRIVEN LOW
EXTERNALLY
V2ON
ADJ
1.8V
1.116V
RSN1
0.5Ω
C1
2.2µF
R3
365k
R2
88.7k
R1
44.2k
C2
2.2µF
+
2-CELL
Li-Ion
7.4V
R5
1.37M
R4
95.3k
V1
ADJ
OUT
R6
1M
CMPOUT1
R7
1M
OUT
COUT
15µF
PFV1
LTC4419
CMP1
CMPOUT2
V2UV
V2
CMP2
GND
4419 F09
Figure 9. Design Example
Design Example
In Figure 9, the LTC4419 prioritizes between a 5V supply
connected to V1 and a 7.4V 2-cell Li-Ion battery connected
to V2. The system is designed to switch OUT to V2 when
V1 drops below 4V, provide early power failure warning
when V1 drops below 4.5V and low battery warning when
the backup battery voltage drops below 6V. Maximum
anticipated load current is 100mA and maximum allowed
output droop is 100mV. Output rising slew rate is limited
to <0.1V/µs and V1 and V2 input capacitors are limited to
10µF to avoid large inrush current. 1% tolerance resistors
are used. ADJ and CMP pin leakages are ignored as their
design impact is small.
First choose total resistive divider current to be ~10µA
for V1 and ~5µA for V2. For the 5V supply, this results in:
10ms
V1
next time V1 is revalidated. Limit V2ON pin capacitance
to less than 10nF in order to prevent freshness seal mode
from accidentally being engaged.
FSEAL
ENABLED
94ms
R1+R2+R3 =
4419 F08
Figure 8. Freshness Seal Engage Procedure
Engage this mode if V2 is a backup battery either during
storage or during shipment. Once freshness seal has been
engaged, if V1 is disconnected, V2 stays disconnected
from OUT. Freshness seal is automatically disabled the
5V
= 500kΩ
10µA
(14)
Since desired switchover threshold, VSW1, and the total
divider impedance are known, use equation 1 to first
calculate R3. Using R3 and equation 2, calculate R1 and
R2. Rewriting equation 1 results in:
(R1+R2) =
VTHA • (R1+R2+R3)
VSW1
(15)
4419f
For more information www.linear.com/LTC4419
13
LTC4419
Applications Information
Using (R1 + R2 + R3) = 500kΩ from equation 14, results in:
(R1+R2) =
1.047V • 500kΩ
=130.9kΩ
4V
R3 ~ (500kΩ – 130.9kΩ) = 369.1kΩ
(16)
(17)
Using the nearest 1% resistor value yields R3 = 365kΩ.
Rearranging equation 2 results in
COUT affects both OUT droop during switchover as determined by equation 4 and OUT rising slew rate as determined
by equation 9. Calculate minimum COUT required to meet
desired output droop and slew rate specifications using
equations 8 and 9 and size COUT to be the larger of the
two values.
COUT required to limit OUT droop to < 100mV is given by
equation 8:
R1=
VTHC • (R2+R2+R3)
VPFV1
(18)
COUT ≥
R1=
0.387V
• (500kΩ)
4.5V
(19)
COUT ≥
( tPDA + tSWITCH ) •ILOAD
100mV
(7.3µs+2.5µs) • 0.1A = 9.8µF
100mV
(23)
(24)
Solving equations 16 and 19 results in R1 = 43.3kΩ and
R2 = 87.6kΩ. Using the nearest 1% resistors results in
R2 = 88.7kΩ. Recalculating equation 1 using calculated
R2 and R3 values and using standard 1% resistor values
close to 43.3kΩ for R1 results in R1 = 44.2kΩ.
COUT required to limit OUT slew rate to < 0.1V/µs is given
by equation 9:
A similar procedure is used to calculate R4 and R5 using
equation 3 and total divider current. The design equations
are shown below:
Choose a COUT capacitor whose minimum value is 11µF
accounting for voltage and temperature coefficients. Do
this for other capacitors as well. Assuming correct PCB
layout, choose C1 to be 2.2µF, which is ~ 1/5th of COUT to
suppress inductive transients. Also snub C1 with a 0.5Ω
resistor to prevent ringing.
R4+R5 =
7.4V
=1.48MΩ
5µA
(20)
as desired current in the divider is 5µA.
Rewriting equation 3 neglecting pin leakage and assuming
R5 >> R4 results in:
R4 =
VTHC • (R4+R5)
VV2UV
(21)
R4 =
0.387V •1.48MΩ
6V
(22)
Solving 20 and 22 results in R4 = 96.2kΩ and R5 = 1.38MΩ.
Choosing the nearest 1% resistor results in R4 = 95.3kΩ
and R5 = 1.37MΩ.
COUT ≥
ILIM
=11µF
0.1V/µs
(25)
Layout Consideration
Make power and ground traces as wide as possible. Place
bypass capacitors, snubbers and TVS devices as close to
the pin as possible to reduce power path resistance and
parasitic inductance. These result in smaller overvoltage
transients and improved overvoltage protection. Place
resistive dividers close to the pins to improve noise immunity. Use a 4-layer board if possible with layer 2 as
dedicated GND and solder the exposed pad to a large PCB
GND trace for better heat dissipation. A partial layout for
a 2-Layer PCB is shown in Figure 10.
4419f
14
For more information www.linear.com/LTC4419
LTC4419
Applications Information
GND
GND
C1
V1
C2
V2
LTC4419
OUT
COUT
GND
4419 F10
Figure 10. Recommended 12-Lead MSE Layout for a 2-Layer PCB
Depending on the difference between input and output
voltages, the LTC4419’s internal power dissipation can be
high when operating in current limit mode. This usually
occurs when a large COUT is being charged either during
initial power up or when OUT switches over to a higher
supply. The situation is made worse if a DC load is present
on OUT, as this reduces the current available to charge COUT.
In such cases, self heating can cause power path turn-off
due to activation of the thermal protection circuitry. The
power path is reactivated when die temperature drops to
a safe value. This process can repeat indefinitely if COUT is
discharged fully by load current IOUT in the interval when
the power path is off.
Maximum allowed COUT to prevent activation of the thermal
protection circuit depends on several factors such as input
supply and output voltages, starting ambient temperature,
heat dissipation in the PCB and DC output current. Choose
COUT < 500µF if possible. If a larger COUT is necessary, use
Figure 11 to choose COUT.. Follow PCB layout guidelines
to improve heat dissipation.
60k
ILOAD = 0
10k
COUT (µF)
Thermal Protection and Maximum COUT
1k
100
–40°C
25°C
85°C
5
10
15
VIN (V)
20
4419 F11
Figure 11. Maximum Allowed COUT vs Input Voltage for Different TA
4419f
For more information www.linear.com/LTC4419
15
LTC4419
Typical Applications
Battery Backup with Interface to Low Voltage Logic
5V TO 18V
WALL ADAPTER
V1
RSN1
0.5Ω
C1
10µF
OUT
R3
365k
ADJ
C3
10µF
R6
1M
V2
R9
1M
SYSTEM
V2UV
CMPOUT2
V2ON
V2ON
R5
1M
R7
1M
V1UV
CMPOUT1
R1
44.2k
RSN2
0.5Ω
C2
10µF
3.3V
LTC4419
R2
88.7k
CMP1
3.6V TO 18V
BACKUP
COUT
10µF
IN
OUT
LTC1763-3.3V
SHDN GND
SWITCHOVER THRESHOLD: V1 < 4V (V1 FALLING)
V1UV THRESHOLD: V1 < 4.5V (V1 FALLING)
V2UV THRESHOLD: V2 < 3V (V2 FALLING)
CMP2
R4
150k
4419 TA02
GND
SuperCap Backup with SuperCap Charging
L1 3.3µH
C1
10µF
1.7V TO 5.5V
INPUT
R8
1M
C2
120pF
R12
12.1k
R13
127k
SW1
RSENP
RSENS
SW2
VOUT
MID
LTC3128
IN
PROG
MAXV
C2: MURATA DMF3Z5R5H474M3DTA0
GND
FB
RUN
4.2V
C2
940mF
940mF
R3
1M
R5
1.87M
R4A
61.9k
R4B
237k
M1
2N4351
R2
237k
R1
121k
V1
V2
OUT
LTC4419
COUT
10µF
R6
1M
R7
1M
OUT
ADJ
CMPOUT1
V1UV
CMP1
CMPOUT2
V2UV
CMP2
V2ON
GND
4419 TA03
SWITCHOVER THRESHOLD: V1 < 4V (V1 FALLING)
V1UV THRESHOLD: V1 < 4.4V (V1 FALLING)
V2UV THRESHOLD: V2 < 3.5V (V2 FALLING)
4419f
16
For more information www.linear.com/LTC4419
LTC4419
Typical Applications
Triple Supply Monitor with Primary Battery Pack Protection
+
V1
4-CELL
14.8V
Li-Ion
OUT
R5
2M
ADJ
R1
191k
+
CMP2
10µF
R11
5.36M
R6
1M
COUT
10µF
CMPOUT1
V2UV
CMPOUT2
OUTUV
V2ON
CMP1
R10
316k
R7
1M
R4
113k
LTC4419
V2
9V
ALKALINE
OUT
R3
2M
10µF
GND
4419 TA04
V2ON
SWITCHOVER THRESHOLD: V1 < 12V (V1 FALLING)
V2UV THRESHOLD: V2 < 7V (V2 FALLING)
OUTUV THRESHOLD: OUT < 7.5V (OUT FALLING)
Early Power Failure Warning with Low Battery Indication
L1, 10µH
C4
0.1µF
5V TO 15V
INPUT
C8
10µF
SW1
SW2
C5
0.1µF
BST1
BST2
LTC3111
VIN
VOUT
COMP
R13
1M
R14
137k
C7
1nF
R12
44.2k
C6
39pF
RUN
SNSGND
FB
VCC
PWM
TO OTHER
CIRCUITS
12V
R8
20k
C9
18pF
R10
2.21M
4-CELL +
14.8V
Li-Ion
C1
22µF
V1
OUT
COUT
10µF
OUT
R6
1M
R7
1M
ADJ
R2
75k
R11
158k
C3
1µF
R3
1M
LTC4419
CMP1
R1
41.2k
CMPOUT1
PFV1
CMPOUT2
V2UV
V2ON
V2ON
V2
C2
10µF
R5
5.23M
CMP2
PFV1: V1 POWER FAILURE THRESHOLD: V1 < 10.6V (V1 FALLING)
SWITCHOVER THRESHOLD: V1 < 10V (V1 FALLING)
V2UV THRESHOLD: V2 < 12V (V2 FALLING)
R4
174k
GND
4419 TA05
4419f
For more information www.linear.com/LTC4419
17
LTC4419
Package Description
Please refer to http://www.linear.com/product/LTC4419#packaging for the most recent package drawings.
DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1699 Rev C)
0.70 ±0.05
3.55 ±0.05
1.65 ±0.05
2.15 ±0.05 (2 SIDES)
PACKAGE
OUTLINE
0.25 ± 0.05
0.50
BSC
2.38 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
3.00 ±0.10
(4 SIDES)
R = 0.125
TYP
6
0.40 ± 0.10
10
1.65 ± 0.10
(2 SIDES)
PIN 1 NOTCH
R = 0.20 OR
0.35 × 45°
CHAMFER
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.75 ±0.05
0.00 – 0.05
5
1
(DD) DFN REV C 0310
0.25 ± 0.05
0.50 BSC
2.38 ±0.10
(2 SIDES)
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).
CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
4419f
18
For more information www.linear.com/LTC4419
LTC4419
Package Description
Please refer to http://www.linear.com/product/LTC4419#packaging for the most recent package drawings.
MSE Package
12-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1666 Rev G)
BOTTOM VIEW OF
EXPOSED PAD OPTION
2.845 ±0.102
(.112 ±.004)
5.10
(.201)
MIN
2.845 ±0.102
(.112 ±.004)
0.889 ±0.127
(.035 ±.005)
6
1
1.651 ±0.102
(.065 ±.004)
1.651 ±0.102 3.20 – 3.45
(.065 ±.004) (.126 – .136)
12
0.65
0.42 ±0.038
(.0256)
(.0165 ±.0015)
BSC
TYP
RECOMMENDED SOLDER PAD LAYOUT
0.254
(.010)
0.35
REF
4.039 ±0.102
(.159 ±.004)
(NOTE 3)
0.12 REF
DETAIL “B”
CORNER TAIL IS PART OF
DETAIL “B” THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
7
NO MEASUREMENT PURPOSE
0.406 ±0.076
(.016 ±.003)
REF
12 11 10 9 8 7
DETAIL “A”
0° – 6° TYP
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
4.90 ±0.152
(.193 ±.006)
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
DETAIL “A”
1.10
(.043)
MAX
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
1 2 3 4 5 6
0.650
(.0256)
BSC
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL
NOT EXCEED 0.254mm (.010") PER SIDE.
0.86
(.034)
REF
0.1016 ±0.0508
(.004 ±.002)
MSOP (MSE12) 0213 REV G
4419f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LTC4419
19
LTC4419
Typical Application
High Efficiency Backup
5V
WALL
ADAPTER
RSN1
0.5Ω
C1
10µF
R3
1M
R2
237k
R1
121k
C2
10µF
+
2-CELL
7.4V
Li-Ion
R5
4.02M
R4
280k
V1
OUT
ADJ
COUT
10µF
R13
1.1M
R12
1.05M
LTC4419
CMP1
C3
2.2µF
V2
CMPOUT1
CMPOUT2
CMP2
V2ON
L1
3.3µH
BST1 SW1
VIN
RUN
C5
22nF
SW2 BST2
OUT
RUN
LTC3129-1
MPPC
VS2
VS1
VCC PWM GND PGND VS3
5V
C4
10µF
R7
1M
R6
1M
SYSTEM
C4
22nF
V1UV
V2UV
V2_ON
GND
SWITCHOVER THRESHOLD: V1< 4V (V1 FALLING)
V1UV THRESHOLD: V1 < 4.4V (V1 FALLING)
V2UV THRESHOLD: V2 < 6V (V2 FALLING)
4419 TA06
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
LT1763
500mA, Low Noise Micropower LDO Regulators
VIN: 1.8V to 20V, 12-DFN, SO-8 Packages
LTC2952
Pushbutton PowerPath Controller with Supervisor
VIN: 2.7V to 28V, On/Off Timers, ±8kV HBM ESD, TSSOP-20 and
QFN-20 Packages
LTC3103
15V, 300mA Synchronous Step-Down
DC/DC Converter
VIN: 2.5V-15V, DFN-10 and MSE-10 Packages
LTC3129/LTC3129-1
15V, 200mA Synchronous Buck-Boost
DC/DC Converter with 1.3µA Quiescent Current
VIN: 1.92V to 15V, QFN-16 and MSE-16 Packages
LTC3388-1/LTC3388-3 20V, 50mA High Efficiency Nanopower
Step-Down Regulator
VIN: 2.7V to 20V, DFN-10 and MSE-10 Packages
LTC4411
2.6A Low Loss Ideal Diode in ThinSOT™
Internal 2.6A P-channel, 2.6V to 5.5V, IQ = 40μA, SOT-23 Package
LTC4412
36V Low Loss PowerPath Controller in ThinSOT
2.5V to 36V, P-channel, IQ = 11μA, SOT-23 Package
LTC4415
Dual 4A Ideal Diodes with Adjustable Current Limit
Dual Internal P-channel, 1.7V to 5.5V, MSOP-16 and DFN-16 Packages
LTC4416
36V Low Loss Dual PowerPath Controller
for Large PFETs
3.6V to 36V, 35μA per IQ Supply, MSOP-10 Package
LTC4417
3-Channel Prioritized PowerPath Controller
Triple P-Channel Controller, 2.5V to 36V, SSOP-24 and QFN-24 Packages
LTC4355
Positive High Voltage Ideal Diode-OR with Supply
and Fuse Monitors
Dual N-channel, 9V to 80V, SO-16, MSOP-16 and DFN-14 Packages
LTC4359
Ideal Diode Controller with Reverse Input Protection
N-channel, 4V to 80V, MSOP-8 and DFN-6 Packages
4419f
20 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTC4419
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC4419
LT 0816 • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2015