1.24V and hysteresis for turn-off is provided by a 22µA current source.
Apply a voltage between 0 - 1.24V, connect a resistor to GND, or leave
open to set the current sense threshold voltage.
Apply a voltage >1.74V to enable device, a PWM signal to dim, or a
voltage <0.5V for low power shutdown.
Connect a resistor from V
O
, and a capacitor from GND to set the off-
time.
Connect to the system ground.
Connect to the gate of the external PFET.
Connect to the negative side of the sense resistor.
Connect to the positive side of the sense resistor (also connected to
VIN).
Connect at least a 1µF ceramic capacitor to V
IN
. The regulator provides
power for the PFET drive.
Connect to the input voltage.
Connect to pin 5 (GND). Place 4-6 vias from DAP to bottom layer GND
plane.
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2
LM3409/LM3409HV
Absolute Maximum Ratings
LM3409/09HV
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
VIN, EN, UVLO to GND
VIN to VCC, PGATE
VIN to PGATE
VIN to CSP, CSN
COFF to GND
COFF current
IADJ Current
Junction Temperature
-0.3V to 45V
(76V LM3409HV)
-0.3V to 7V
-2.8V for 100ns
9.5V for 100ns
-0.3V to 0.3V
-0.3V to 4V
±1 mA continuous
±5 mA continuous
150°C
Storage Temp. Range
-65°C to 125°C
ESD Rating (Note 2)
1kV
Soldering Information
Lead Temperature (Soldering,
10sec)
260°C
Infrared/Convection Reflow (15sec)
260°C
Operating Ratings (LM3409/09HV)
(Note 1)
VIN
Junction Temperature Range
Thermal Resistance
θ
JA
(eMSOP-10 Package)
(Note 5)
6V to 42V
(75V LM3409HV)
−40°C to +125°C
50°C/W
Electrical Characteristics
LM3409/LM3409HV
Symbol
Parameter
V
IN
= 24V unless otherwise indicated. Typicals and limits appearing in plain type apply
for T
A
= T
J
= +25°C (Note 3). Limits appearing in
boldface type
apply over full Operating Temperature Range. Datasheet min/
max specification limits are guaranteed by design, test, or statistical analysis.
Conditions
Min
Typ
Max
(Note 4) (Note 3) (Note 4)
188
231
198
246
0.2
1.189
3.8
1.243
5
38
2
110
2
2
5.5
6
3.73
283
30
1.122
45
1.243
25
115
300
211
1.364
6.5
1.297
6.4
208
261
Units
PEAK CURRENT COMPARATOR
V
CST
V
CSP
– V
CSN
average peak
current threshold
(Note 6)
V
ADJ
to V
CSP
– V
CSN
threshold
gain
IADJ pin open circuit voltage
IADJ pin current
CSN pin falling delay
Operating current
Shutdown hysteresis current
Driver output resistance
CSN fall - PGATE rise
Not switching
EN = 0V
Sourcing 50 mA
Sinking 50 mA
VCC REGULATOR
V
CC
V
CC-UVLO
V
CC-HYS
I
CC-LIM
V
OFT
t
D-OFF
t
ON-MIN
t
OFF-MAX
I
UVLO
VIN pin voltage - VCC pin
voltage
V
CC
under voltage lockout
threshold
V
CC
UVLO hysteresis
V
CC
regulator current limit
Off-time threshold
COFF threshold to PGATE
falling delay
Minimum on-time
Maximum off-time
UVLO pin current
V
UVLO
= 1V
V
IN
> 9V
0 < I
CC
< 20 mA
V
CC
increasing
V
CC
decreasing
V
V
mV
mA
V
ns
ns
µs
nA
V
ADJ
= 1.0V
V
ADJ
= V
ADJ-OC
0.1 < V
ADJ
< 1.2V
V
ADJ
= V
ADJ-OC
mV
A
ADJ
V
ADJ-OC
I
ADJ
t
DEL
I
IN
I
SD
PFET DRIVER
R
PGATE
V/V
V
µA
ns
mA
µA
Ω
SYSTEM CURRENTS
OFF-TIMER AND ON-TIMER
UNDER VOLTAGE LOCKOUT
10
3
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LM3409/LM3409HV
Symbol
V
UVLO-R
I
UVLO-HYS
ENABLE
I
EN
V
EN-TH
V
EN-HYS
t
EN-R
t
EN-F
θ
JA
Parameter
Rising UVLO threshold
UVLO hysteresis current
EN pin current
EN pin threshold
EN pin hysteresis
EN pin rising delay
EN pin falling delay
Junction to Ambient
V
EN
rising
V
EN
falling
Conditions
Min
Typ
Max
(Note 4) (Note 3) (Note 4)
1.175
1.243
22
10
1.74
.5
420
1.311
Units
V
µA
nA
V
mV
ns
ns
°C/W
EN rise - PGATE fall
EN fall - PGATE rise
eMSOP-10 Package (Note 5)
42
21
50
THERMAL RESISTANCE
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability
and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or other conditions beyond those indicated in
the Operating Ratings is not implied. The recommended Operating Ratings indicate conditions at which the device is functional and the device should not be
operated beyond such conditions.
Note 2:
The human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin.
Note 3:
Typical values represent most likely parametric norms at the conditions specified and are not guaranteed.
Note 4:
Min and Max limits are 100% production tested at 25°C. Limits over the operating temperature range are guaranteed through correlation using Statistical
Quality Control (SQC) methods. Limits are used to calculate National's Average Outgoing Quality Level (AOQL).
Note 5:
θ
JA
of 50°C/W with DAP soldered to a minimum of 2 square inches of 1oz. copper on the top or bottom PCB layer. Actual value will be different depending
upon the application enviroment.
Note 6:
The current sense threshold limits are calculated by averaging the results from the two polarities of the high-side differential amplifier.
Note 7:
The measurements were made using the Bill of Materials from Design #3.
Note 8:
The measurements were made using the Bill of Materials from Design #3 except the LM3409 was substituted for the LM3409HV.
Note 9:
The waveforms were acquired using the standard evaluation board from AN-1953.
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4
LM3409/LM3409HV
Typical Performance Characteristics
T
A
= +25°C, V
IN
= 24V, and characteristics are identical for LM3409 and LM3409HV unless otherwise specified.
