LM2734YMK/NOPB [TI]
LM2734 Thin SOT 1A Load Step-Down DC-DC Regulator; LM2734薄型SOT 1A负载降压型DC -DC稳压器
| 型号： | LM2734YMK/NOPB |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | LM2734 Thin SOT 1A Load Step-Down DC-DC Regulator |
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LM2734
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SNVS288I –SEPTEMBER 2004–REVISED APRIIL 2013
LM2734 Thin SOT 1A Load Step-Down DC-DC Regulator
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1
FEATURES
DESCRIPTION
The LM2734 regulator is a monolithic, high frequency,
PWM step-down DC/DC converter in a 6-pin Thin
SOT package. It provides all the active functions to
provide local DC/DC conversion with fast transient
response and accurate regulation in the smallest
possible PCB area.
234
•
Thin SOT-6 Package
•
3.0V to 20V Input Voltage Range
0.8V to 18V Output Voltage Range
1A Output Current
•
•
•
550kHz (LM2734Y) and 1.6MHz (LM2734X)
Switching Frequencies
With a minimum of external components and online
design support through WEBENCH®, the LM2734 is
easy to use. The ability to drive 1A loads with an
internal 300mΩ NMOS switch using state-of-the-art
0.5µm BiCMOS technology results in the best power
density available. The world class control circuitry
allows for on-times as low as 13ns, thus supporting
exceptionally high frequency conversion over the
entire 3V to 20V input operating range down to the
minimum output voltage of 0.8V. Switching frequency
is internally set to 550kHz (LM2734Y) or 1.6MHz
(LM2734X), allowing the use of extremely small
surface mount inductors and chip capacitors. Even
though the operating frequencies are very high,
efficiencies up to 90% are easy to achieve. External
shutdown is included, featuring an ultra-low stand-by
current of 30nA. The LM2734 utilizes current-mode
control and internal compensation to provide high-
•
•
•
•
•
•
•
•
300mΩ NMOS Switch
30nA Shutdown Current
0.8V, 2% Internal Voltage Reference
Internal Soft-Start
Current-Mode, PWM Operation
WEBENCH® Online Design Tool
Thermal Shutdown
LM2734XQ/LM2734YQ are AEC-Q100 Grade 1
Qualified and are Manufactured on an
Automotive Grade Flow
APPLICATIONS
•
•
•
•
•
•
•
•
Local Point of Load Regulation
Core Power in HDDs
Set-Top Boxes
performance regulation over
a wide range of
operating conditions. Additional features include
internal soft-start circuitry to reduce inrush current,
pulse-by-pulse current limit, thermal shutdown, and
output over-voltage protection.
Battery Powered Devices
USB Powered Devices
DSL Modems
Notebook Computers
Automotive
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2
3
4
WEBENCH is a registered trademark of Texas Instruments, Inc..
WEBENCH is a registered trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2013, Texas Instruments Incorporated
LM2734
SNVS288I –SEPTEMBER 2004–REVISED APRIIL 2013
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Typical Application Circuit
D2
V
BOOST
SW
V
IN
IN
C3
D1
C1
L1
V
OUT
LM2734
ON
C2
EN
R1
OFF
FB
GND
R2
Figure 1.
Figure 2. Efficiency vs Load Current
VIN = 5V, VOUT = 3.3V
Connection Diagram
1
2
3
BOOST
1
2
3
6
5
4
SW
6
5
4
GND
FB
V
IN
EN
Figure 3. 6-Lead SOT
See Package Number DDC (R-PDSO-G6)
Figure 4. Pin 1 Indentification
PIN DESCRIPTIONS
Pin
Name
Function
1
BOOST
Boost voltage that drives the internal NMOS control switch. A bootstrap
capacitor is connected between the BOOST and SW pins.
2
3
4
GND
FB
Signal and Power ground pin. Place the bottom resistor of the feedback
network as close as possible to this pin for accurate regulation.
Feedback pin. Connect FB to the external resistor divider to set output
voltage.
EN
Enable control input. Logic high enables operation. Do not allow this pin to
float or be greater than VIN + 0.3V.
5
6
VIN
Input supply voltage. Connect a bypass capacitor to this pin.
SW
Output switch. Connects to the inductor, catch diode, and bootstrap
capacitor.
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
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Absolute Maximum Ratings(1)(2)
VIN
-0.5V to 24V
-0.5V to 24V
-0.5V to 30V
-0.5V to 6.0V
-0.5V to 3.0V
-0.5V to (VIN + 0.3V)
150°C
SW Voltage
Boost Voltage
Boost to SW Voltage
FB Voltage
EN Voltage
Junction Temperature
ESD Susceptibility(3)
Storage Temp. Range
Soldering Information Reflow Peak Pkg. Temp.(15sec)
2kV
-65°C to 150°C
260°C
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For specific specifications and the test conditions,
see Electrical Characteristics.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
(3) Human body model, 1.5kΩ in series with 100pF.
Operating Ratings(1)
VIN
3V to 20V
-0.5V to 20V
-0.5V to 25V
1.6V to 5.5V
−40°C to +125°C
118°C/W
SW Voltage
Boost Voltage
Boost to SW Voltage
Junction Temperature Range
(2)
Thermal Resistance θJA
(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is intended to be functional, but specific performance is not ensured. For specific specifications and the test conditions,
see Electrical Characteristics.
(2) Thermal shutdown will occur if the junction temperature exceeds 165°C. The maximum power dissipation is a function of TJ(MAX) , θJA
and TA . The maximum allowable power dissipation at any ambient temperature is PD = (TJ(MAX) – TA)/θJA . All numbers apply for
packages soldered directly onto a 3” x 3” PC board with 2oz. copper on 4 layers in still air. For a 2 layer board using 1 oz. copper in still
air, θJA = 204°C/W.
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Electrical Characteristics
Specifications with standard typeface are for TJ = 25°C, and those in boldface type apply over the full Operating
Temperature Range (TJ = -40°C to 125°C). VIN = 5V, VBOOST - VSW = 5V unless otherwise specified. Datasheet min/max
specification limits are ensured by design, test, or statistical analysis.
Symbol
Parameter
Feedback Voltage
Conditions
Min(1)
0.784
Typ(2)
0.800
0.01
10
Max(1)
0.816
Units
V
VFB
ΔVFB/ΔVIN Feedback Voltage Line Regulation
VIN = 3V to 20V
% / V
nA
IFB
Feedback Input Bias Current
Undervoltage Lockout
Undervoltage Lockout
UVLO Hysteresis
Sink/Source
VIN Rising
VIN Falling
250
2.74
2.3
0.44
1.6
0.55
92
2.90
UVLO
2.0
0.30
1.2
0.40
85
V
0.62
1.9
LM2734X
FSW
DMAX
DMIN
Switching Frequency
Maximum Duty Cycle
Minimum Duty Cycle
MHz
%
LM2734Y
0.66
LM2734X
LM2734Y
90
96
LM2734X
2
%
LM2734Y
1
RDS(ON)
ICL
Switch ON Resistance
Switch Current Limit
VBOOST - VSW = 3V
VBOOST - VSW = 3V
Switching
300
1.7
1.5
30
600
2.5
2.5
mΩ
A
1.2
1.8
IQ
Quiescent Current
mA
nA
Quiescent Current (shutdown)
VEN = 0V
LM2734X (50% Duty Cycle)
LM2734Y (50% Duty Cycle)
VEN Falling
2.5
1.0
3.5
1.8
0.4
IBOOST
Boost Pin Current
mA
V
Shutdown Threshold Voltage
Enable Threshold Voltage
Enable Pin Current
VEN_TH
VEN Rising
IEN
Sink/Source
10
40
nA
nA
ISW
Switch Leakage
(1) Specified to Average Outgoing Quality Level (AOQL).
(2) Typicals represent the most likely parametric norm.
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Typical Performance Characteristics
All curves taken at VIN = 5V, VBOOST - VSW = 5V, L1 = 4.7 µH ("X"), L1 = 10 µH ("Y"), and TA = 25°C, unless specified
otherwise.
Efficiency vs Load Current - "X" VOUT = 5V
Efficiency vs Load Current - "Y" VOUT = 5V
Figure 5.
Figure 6.
Efficiency vs Load Current - "X" VOUT = 3.3V
Efficiency vs Load Current - "Y" VOUT = 3.3V
Figure 7.
Figure 8.
Efficiency vs Load Current - "X" VOUT = 1.5V
Efficiency vs Load Current - "Y" VOUT = 1.5V
Figure 9.
Figure 10.
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Typical Performance Characteristics (continued)
All curves taken at VIN = 5V, VBOOST - VSW = 5V, L1 = 4.7 µH ("X"), L1 = 10 µH ("Y"), and TA = 25°C, unless specified
otherwise.
Oscillator Frequency vs Temperature - "X"
Oscillator Frequency vs Temperature - "Y"
Figure 11.
Figure 12.
Current Limit vs Temperature
VIN = 5V
Current Limit vs Temperature
VIN = 20V
Figure 13.
Figure 14.
VFB vs Temperature
RDSON vs Temperature
Figure 15.
Figure 16.
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Typical Performance Characteristics (continued)
All curves taken at VIN = 5V, VBOOST - VSW = 5V, L1 = 4.7 µH ("X"), L1 = 10 µH ("Y"), and TA = 25°C, unless specified
otherwise.
Line Regulation - "X"
VOUT = 1.5V, IOUT = 500mA
IQ Switching vs Temperature
Figure 17.
Figure 18.
Line Regulation - "Y"
VOUT = 1.5V, IOUT = 500mA
Line Regulation - "X"
VOUT = 3.3V, IOUT = 500mA
Figure 19.
Figure 20.
Line Regulation - "Y"
VOUT = 3.3V, IOUT = 500mA
Figure 21.
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Block Diagram
V
IN
V
IN
Current-Sense Amplifier
R
SENSE
Internal
+
-
EN
Regulator
and
ON
C
IN
D2
Enable
Thermal
Shutdown
Circuit
OFF
BOOST
SW
V
BOOST
Under
Voltage
Lockout
0.3W
Switch
C
Output
Control
Logic
BOOST
L
Driver
Current
Limit
V
SW
V
OUT
OVP
Comparator
I
D
1
L
Oscillator
C
OUT
Reset
Pulse
-
0.88V
+
-
+
R
1
PWM
Comparator
-
I
SENSE
+
FB
-
Internal
Compensation
+
+
Error
Signal
R
2
V
+
REF
Corrective Ramp
-
Error Amplifier
GND
0.8V
Figure 22.
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APPLICATION INFORMATION
THEORY OF OPERATION
The LM2734 is a constant frequency PWM buck regulator IC that delivers a 1A load current. The regulator has a
preset switching frequency of either 550kHz (LM2734Y) or 1.6MHz (LM2734X). These high frequencies allow the
LM2734 to operate with small surface mount capacitors and inductors, resulting in DC/DC converters that require
a minimum amount of board space. The LM2734 is internally compensated, so it is simple to use, and requires
few external components. The LM2734 uses current-mode control to regulate the output voltage.
The following operating description of the LM2734 will refer to the Simplified Block Diagram (Figure 22) and to
the waveforms in Figure 23. The LM2734 supplies a regulated output voltage by switching the internal NMOS
control switch at constant frequency and variable duty cycle. A switching cycle begins at the falling edge of the
reset pulse generated by the internal oscillator. When this pulse goes low, the output control logic turns on the
internal NMOS control switch. During this on-time, the SW pin voltage (VSW) swings up to approximately VIN, and
the inductor current (IL) increases with a linear slope. IL is measured by the current-sense amplifier, which
generates an output proportional to the switch current. The sense signal is summed with the regulator’s
corrective ramp and compared to the error amplifier’s output, which is proportional to the difference between the
feedback voltage and VREF. When the PWM comparator output goes high, the output switch turns off until the
next switching cycle begins. During the switch off-time, inductor current discharges through Schottky diode D1,
which forces the SW pin to swing below ground by the forward voltage (VD) of the catch diode. The regulator
loop adjusts the duty cycle (D) to maintain a constant output voltage.
V
SW
D = T /T
ON SW
V
IN
SW
Voltage
T
T
OFF
ON
0
D
t
V
T
SW
I
L
I
PK
Inductor
Current
0
t
Figure 23. LM2734 Waveforms of SW Pin Voltage and Inductor Current
BOOST FUNCTION
Capacitor CBOOST and diode D2 in Figure 24 are used to generate a voltage VBOOST. VBOOST - VSW is the gate
drive voltage to the internal NMOS control switch. To properly drive the internal NMOS switch during its on-time,
VBOOST needs to be at least 1.6V greater than VSW. Although the LM2734 will operate with this minimum voltage,
it may not have sufficient gate drive to supply large values of output current. Therefore, it is recommended that
VBOOST be greater than 2.5V above VSW for best efficiency. VBOOST – VSW should not exceed the maximum
operating limit of 5.5V.
5.5V > VBOOST – VSW > 2.5V for best performance.
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V
BOOST
D2
BOOST
V
V
IN
IN
C
C
IN
LM2734
BOOST
L
SW
V
OUT
GND
C
D1
OUT
Figure 24. VOUT Charges CBOOST
When the LM2734 starts up, internal circuitry from the BOOST pin supplies a maximum of 20mA to CBOOST. This
current charges CBOOST to a voltage sufficient to turn the switch on. The BOOST pin will continue to source
current to CBOOST until the voltage at the feedback pin is greater than 0.76V.
There are various methods to derive VBOOST
1. From the input voltage (VIN)
:
2. From the output voltage (VOUT
)
3. From an external distributed voltage rail (VEXT
)
4. From a shunt or series zener diode
In the Simplifed Block Diagram of Figure 22, capacitor CBOOST and diode D2 supply the gate-drive current for the
NMOS switch. Capacitor CBOOST is charged via diode D2 by VIN. During a normal switching cycle, when the
internal NMOS control switch is off (TOFF) (refer to Figure 23), VBOOST equals VIN minus the forward voltage of D2
(VFD2), during which the current in the inductor (L) forward biases the Schottky diode D1 (VFD1). Therefore the
voltage stored across CBOOST is
VBOOST - VSW = VIN - VFD2 + VFD1
(1)
(2)
(3)
(4)
(5)
When the NMOS switch turns on (TON), the switch pin rises to
VSW = VIN – (RDSON x IL),
forcing VBOOST to rise thus reverse biasing D2. The voltage at VBOOST is then
VBOOST = 2VIN – (RDSON x IL) – VFD2 + VFD1
which is approximately
2VIN - 0.4V
for many applications. Thus the gate-drive voltage of the NMOS switch is approximately
VIN - 0.2V
An alternate method for charging CBOOST is to connect D2 to the output as shown in Figure 24. The output
voltage should be between 2.5V and 5.5V, so that proper gate voltage will be applied to the internal switch. In
this circuit, CBOOST provides a gate drive voltage that is slightly less than VOUT
.
In applications where both VIN and VOUT are greater than 5.5V, or less than 3V, CBOOST cannot be charged
directly from these voltages. If VIN and VOUT are greater than 5.5V, CBOOST can be charged from VIN or VOUT
minus a zener voltage by placing a zener diode D3 in series with D2, as shown in Figure 25. When using a
series zener diode from the input, ensure that the regulation of the input supply doesn’t create a voltage that falls
outside the recommended VBOOST voltage.
(VINMAX – VD3) < 5.5V
(VINMIN – VD3) > 1.6V
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D2
D3
V
V
BOOST
V
IN
IN
BOOST
C
BOOST
C
LM2734
IN
L
V
SW
OUT
GND
C
D1
OUT
Figure 25. Zener Reduces Boost Voltage from VIN
An alternative method is to place the zener diode D3 in a shunt configuration as shown in Figure 26. A small
350mW to 500mW 5.1V zener in a SOT or SOD package can be used for this purpose. A small ceramic
capacitor such as a 6.3V, 0.1µF capacitor (C4) should be placed in parallel with the zener diode. When the
internal NMOS switch turns on, a pulse of current is drawn to charge the internal NMOS gate capacitance. The
0.1 µF parallel shunt capacitor ensures that the VBOOST voltage is maintained during this time.
Resistor R3 should be chosen to provide enough RMS current to the zener diode (D3) and to the BOOST pin. A
recommended choice for the zener current (IZENER) is 1 mA. The current IBOOST into the BOOST pin supplies the
gate current of the NMOS control switch and varies typically according to the following formula for the X version:
IBOOST = 0.56 x (D + 0.54) x (VZENER – VD2) mA
(6)
IBOOST can be calculated for the Y version using the following:
IBOOST = 0.22 x (D + 0.54) x (VZENER - VD2) µA
(7)
where D is the duty cycle, VZENER and VD2 are in volts, and IBOOST is in milliamps. VZENER is the voltage applied to
the anode of the boost diode (D2), and VD2 is the average forward voltage across D2. Note that this formula for
IBOOST gives typical current. For the worst case IBOOST, increase the current by 40%. In that case, the worst case
boost current will be
IBOOST-MAX = 1.4 x IBOOST
(8)
R3 will then be given by
R3 = (VIN - VZENER) / (1.4 x IBOOST + IZENER
)
(9)
For example, using the X-version let VIN = 10V, VZENER = 5V, VD2 = 0.7V, IZENER = 1mA, and duty cycle D = 50%.
Then
IBOOST = 0.56 x (0.5 + 0.54) x (5 - 0.7) mA = 2.5mA
(10)
(11)
R3 = (10V - 5V) / (1.4 x 2.5mA + 1mA) = 1.11kΩ
V
Z
D2
C4
D3
R3
C
BOOST
V
IN
V
V
BOOST
IN
C
BOOST
LM2734
IN
L
SW
V
OUT
GND
C
D1
OUT
Figure 26. Boost Voltage Supplied from the Shunt Zener on VIN
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ENABLE PIN / SHUTDOWN MODE
The LM2734 has a shutdown mode that is controlled by the enable pin (EN). When a logic low voltage is applied
to EN, the part is in shutdown mode and its quiescent current drops to typically 30nA. Switch leakage adds
another 40nA from the input supply. The voltage at this pin should never exceed VIN + 0.3V.
SOFT-START
This function forces VOUT to increase at a controlled rate during start up. During soft-start, the error amplifier’s
reference voltage ramps from 0V to its nominal value of 0.8V in approximately 200µs. This forces the regulator
output to ramp up in a more linear and controlled fashion, which helps reduce inrush current. Under some
circumstances at start-up, an output voltage overshoot may still be observed. This may be due to a large output
load applied during start up. Large amounts of output external capacitance can also increase output voltage
overshoot. A simple solution is to add a feed forward capacitor with a value between 470pf and 1000pf across
the top feedback resistor (R1). See Figure 28 for further detail.
OUTPUT OVERVOLTAGE PROTECTION
The overvoltage comparator compares the FB pin voltage to a voltage that is 10% higher than the internal
reference Vref. Once the FB pin voltage goes 10% above the internal reference, the internal NMOS control
switch is turned off, which allows the output voltage to decrease toward regulation.
UNDERVOLTAGE LOCKOUT
Undervoltage lockout (UVLO) prevents the LM2734 from operating until the input voltage exceeds 2.74V(typ).
The UVLO threshold has approximately 440mV of hysteresis, so the part will operate until VIN drops below
2.3V(typ). Hysteresis prevents the part from turning off during power up if VIN is non-monotonic.
CURRENT LIMIT
The LM2734 uses cycle-by-cycle current limiting to protect the output switch. During each switching cycle, a
current limit comparator detects if the output switch current exceeds 1.7A (typ), and turns off the switch until the
next switching cycle begins.
THERMAL SHUTDOWN
Thermal shutdown limits total power dissipation by turning off the output switch when the IC junction temperature
exceeds 165°C. After thermal shutdown occurs, the output switch doesn’t turn on until the junction temperature
drops to approximately 150°C.
Design Guide
INDUCTOR SELECTION
The Duty Cycle (D) can be approximated quickly using the ratio of output voltage (VO) to input voltage (VIN):
VO
D =
VIN
(12)
The catch diode (D1) forward voltage drop and the voltage drop across the internal NMOS must be included to
calculate a more accurate duty cycle. Calculate D by using the following formula:
VO + VD
D =
VIN + VD - VSW
(13)
VSW can be approximated by:
VSW = IO x RDS(ON)
(14)
The diode forward drop (VD) can range from 0.3V to 0.7V depending on the quality of the diode. The lower VD is,
the higher the operating efficiency of the converter.
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The inductor value determines the output ripple current. Lower inductor values decrease the size of the inductor,
but increase the output ripple current. An increase in the inductor value will decrease the output ripple current.
The ratio of ripple current (ΔiL) to output current (IO) is optimized when it is set between 0.3 and 0.4 at 1A. The
ratio r is defined as:
DiL
r =
lO
(15)
One must also ensure that the minimum current limit (1.2A) is not exceeded, so the peak current in the inductor
must be calculated. The peak current (ILPK) in the inductor is calculated by:
ILPK = IO + ΔIL/2
(16)
If r = 0.5 at an output of 1A, the peak current in the inductor will be 1.25A. The minimum specified current limit
over all operating conditions is 1.2A. One can either reduce r to 0.4 resulting in a 1.2A peak current, or make the
engineering judgement that 50mA over will be safe enough with a 1.7A typical current limit and 6 sigma limits.
When the designed maximum output current is reduced, the ratio r can be increased. At a current of 0.1A, r can
be made as high as 0.9. The ripple ratio can be increased at lighter loads because the net ripple is actually quite
low, and if r remains constant the inductor value can be made quite large. An equation empirically developed for
the maximum ripple ratio at any current below 2A is:
-0.3667
r = 0.387 x IOUT
(17)
Note that this is just a guideline.
The LM2734 operates at frequencies allowing the use of ceramic output capacitors without compromising
transient response. Ceramic capacitors allow higher inductor ripple without significantly increasing output ripple.
See the output capacitor section for more details on calculating output voltage ripple.
Now that the ripple current or ripple ratio is determined, the inductance is calculated by:
VO + VD
x (1-D)
L =
IO x r x fS
(18)
where fs is the switching frequency and IO is the output current. When selecting an inductor, make sure that it is
capable of supporting the peak output current without saturating. Inductor saturation will result in a sudden
reduction in inductance and prevent the regulator from operating correctly. Because of the speed of the internal
current limit, the peak current of the inductor need only be specified for the required maximum output current. For
example, if the designed maximum output current is 0.5A and the peak current is 0.7A, then the inductor should
be specified with a saturation current limit of >0.7A. There is no need to specify the saturation or peak current of
the inductor at the 1.7A typical switch current limit. The difference in inductor size is a factor of 5. Because of the
operating frequency of the LM2734, ferrite based inductors are preferred to minimize core losses. This presents
little restriction since the variety of ferrite based inductors is huge. Lastly, inductors with lower series resistance
(DCR) will provide better operating efficiency. For recommended inductors see Example Circuits.
INPUT CAPACITOR
An input capacitor is necessary to ensure that VIN does not drop excessively during switching transients. The
primary specifications of the input capacitor are capacitance, voltage, RMS current rating, and ESL (Equivalent
Series Inductance). The recommended input capacitance is 10µF, although 4.7µF works well for input voltages
below 6V. The input voltage rating is specifically stated by the capacitor manufacturer. Make sure to check any
recommended deratings and also verify if there is any significant change in capacitance at the operating input
voltage and the operating temperature. The input capacitor maximum RMS input current rating (IRMS-IN) must be
greater than:
r2
12
IRMS-IN = IO x
D x
1-D +
(19)
It can be shown from the above equation that maximum RMS capacitor current occurs when D = 0.5. Always
calculate the RMS at the point where the duty cycle, D, is closest to 0.5. The ESL of an input capacitor is usually
determined by the effective cross sectional area of the current path. A large leaded capacitor will have high ESL
and a 0805 ceramic chip capacitor will have very low ESL. At the operating frequencies of the LM2734, certain
capacitors may have an ESL so large that the resulting impedance (2πfL) will be higher than that required to
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provide stable operation. As a result, surface mount capacitors are strongly recommended. Sanyo POSCAP,
Tantalum or Niobium, Panasonic SP or Cornell Dubilier ESR, and multilayer ceramic capacitors (MLCC) are all
good choices for both input and output capacitors and have very low ESL. For MLCCs it is recommended to use
X7R or X5R dielectrics. Consult capacitor manufacturer datasheet to see how rated capacitance varies over
operating conditions.
OUTPUT CAPACITOR
The output capacitor is selected based upon the desired output ripple and transient response. The initial current
of a load transient is provided mainly by the output capacitor. The output ripple of the converter is:
1
)
DVO = DiL x (RESR
+
8 x fS x CO
(20)
When using MLCCs, the ESR is typically so low that the capacitive ripple may dominate. When this occurs, the
output ripple will be approximately sinusoidal and 90° phase shifted from the switching action. Given the
availability and quality of MLCCs and the expected output voltage of designs using the LM2734, there is really no
need to review any other capacitor technologies. Another benefit of ceramic capacitors is their ability to bypass
high frequency noise. A certain amount of switching edge noise will couple through parasitic capacitances in the
inductor to the output. A ceramic capacitor will bypass this noise while a tantalum will not. Since the output
capacitor is one of the two external components that control the stability of the regulator control loop, most
applications will require a minimum at 10 µF of output capacitance. Capacitance can be increased significantly
with little detriment to the regulator stability. Like the input capacitor, recommended multilayer ceramic capacitors
are X7R or X5R. Again, verify actual capacitance at the desired operating voltage and temperature.
Check the RMS current rating of the capacitor. The RMS current rating of the capacitor chosen must also meet
the following condition:
r
IRMS-OUT = IO x
12
(21)
CATCH DIODE
The catch diode (D1) conducts during the switch off-time. A Schottky diode is recommended for its fast switching
times and low forward voltage drop. The catch diode should be chosen so that its current rating is greater than:
ID1 = IO x (1-D)
(22)
The reverse breakdown rating of the diode must be at least the maximum input voltage plus appropriate margin.
To improve efficiency choose a Schottky diode with a low forward voltage drop.
BOOST DIODE
A standard diode such as the 1N4148 type is recommended. For VBOOST circuits derived from voltages less than
3.3V, a small-signal Schottky diode is recommended for greater efficiency. A good choice is the BAT54 small
signal diode.
BOOST CAPACITOR
A ceramic 0.01µF capacitor with a voltage rating of at least 6.3V is sufficient. The X7R and X5R MLCCs provide
the best performance.
OUTPUT VOLTAGE
The output voltage is set using the following equation where R2 is connected between the FB pin and GND, and
R1 is connected between VO and the FB pin. A good value for R2 is 10kΩ.
VO
x R2
- 1
R1=
VREF
(23)
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PCB Layout Considerations
When planning layout there are a few things to consider when trying to achieve a clean, regulated output. The
most important consideration when completing the layout is the close coupling of the GND connections of the CIN
capacitor and the catch diode D1. These ground ends should be close to one another and be connected to the
GND plane with at least two through-holes. Place these components as close to the IC as possible. Next in
importance is the location of the GND connection of the COUT capacitor, which should be near the GND
connections of CIN and D1.
There should be a continuous ground plane on the bottom layer of a two-layer board except under the switching
node island.
The FB pin is a high impedance node and care should be taken to make the FB trace short to avoid noise pickup
and inaccurate regulation. The feedback resistors should be placed as close as possible to the IC, with the GND
of R2 placed as close as possible to the GND of the IC. The VOUT trace to R1 should be routed away from the
inductor and any other traces that are switching.
High AC currents flow through the VIN, SW and VOUT traces, so they should be as short and wide as possible.
However, making the traces wide increases radiated noise, so the designer must make this trade-off. Radiated
noise can be decreased by choosing a shielded inductor.
The remaining components should also be placed as close as possible to the IC. Please see Application Note
AN-1229 SNVA054 for further considerations and the LM2734 demo board as an example of a four-layer layout.
LM2734X Circuit Examples
D2
BOOST
SW
V
V
IN
IN
C3
D1
L1
C1
R3
V
OUT
LM2734
ON
C2
EN
R1
R2
OFF
FB
GND
Figure 27. LM2734X (1.6MHz)
VBOOST Derived from VIN
5V to 1.5V/1A
Table 1. Bill of Materials for Figure 27
Part ID
Part Value
Part Number
Manufacturer
Texas Instruments
TDK
U1
1A Buck Regulator
10µF, 6.3V, X5R
10µF, 6.3V, X5R
0.01uF, 16V, X7R
0.3VF Schottky 1A, 10VR
1VF @ 50mA Diode
4.7µH, 1.7A,
LM2734X
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
L1
C3216X5ROJ106M
C3216X5ROJ106M
C1005X7R1C103K
MBRM110L
TDK
TDK
ON Semi
Diodes, Inc.
TDK
1N4148W
VLCF4020T- 4R7N1R2
CRCW06038871F
CRCW06031022F
CRCW06031003F
R1
8.87kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
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D2
L1
12V
V
IN
BOOST
SW
VIN
EN
C3
V
OUT
C1
R3
3.3V
LM2734
D1
C2
ON
R1
R2
C
FF
OFF
FB
GND
Figure 28. LM2734X (1.6MHz)
VBOOST Derived from VOUT
12V to 3.3V/1A
Table 2. Bill of Materials for Figure 28
Part ID
Part Value
Part Number
Manufacturer
LM2734X
TDK
U1
1A Buck Regulator
10µF, 25V, X7R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
1000pF 25V
NSC
C1, Input Cap
C3225X7R1E106M
C3216X5ROJ226M
C1005X7R1C103K
C0603X5R1E102K
SS1P3L
C2, Output Cap
TDK
C3, Boost Cap
TDK
CFF
TDK
D1, Catch Diode
0.34VF Schottky 1A, 30VR
1VF @ 50mA Diode
4.7µH, 1.7A
Vishay
Diodes, Inc.
TDK
D2, Boost Diode
1N4148W
L1
VLCF4020T- 4R7N1R2
CRCW06033162F
CRCW06031002F
CRCW06031003F
R1
R2
R3
31.6kΩ, 1%
Vishay
Vishay
Vishay
10kΩ, 1%
100kΩ, 1%
16
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C4
D3
R4
D2
BOOST
SW
V
V
IN
IN
C3
D1
L1
C1
R3
V
OUT
LM2734
ON
C2
EN
OFF
R1
R2
FB
GND
Figure 29. LM2734X (1.6MHz)
VBOOST Derived from VSHUNT
18V to 1.5V/1A
Table 3. Bill of Materials for Figure 29
Part ID
Part Value
Part Number
Manufacturer
Texas Instruments
TDK
U1
1A Buck Regulator
10µF, 25V, X7R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
0.1µF, 6.3V, X5R
0.4VF Schottky 1A, 30VR
1VF @ 50mA Diode
5.1V 250Mw SOT
6.8µH, 1.6A,
LM2734X
C1, Input Cap
C2, Output Cap
C3, Boost Cap
C4, Shunt Cap
D1, Catch Diode
D2, Boost Diode
D3, Zener Diode
L1
C3225X7R1E106M
C3216X5ROJ226M
C1005X7R1C103K
C1005X5R0J104K
SS1P3L
TDK
TDK
TDK
Vishay
1N4148W
Diodes, Inc.
Vishay
BZX84C5V1
SLF7032T-6R8M1R6
CRCW06038871F
CRCW06031022F
CRCW06031003F
CRCW06034121F
TDK
R1
8.87kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
R4
4.12kΩ, 1%
Vishay
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D3
D2
BOOST
SW
V
IN
V
IN
C3
D1
L1
C1
R3
V
OUT
LM2734
ON
C2
EN
R1
R2
OFF
FB
GND
Figure 30. LM2734X (1.6MHz)
VBOOST Derived from Series Zener Diode (VIN)
15V to 1.5V/1A
Table 4. Bill of Materials for Figure 30
Part ID
Part Value
1A Buck Regulator
Part Number
Manufacturer
Texas Instruments
TDK
U1
LM2734X
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
D3, Zener Diode
L1
10µF, 25V, X7R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
0.4VF Schottky 1A, 30VR
1VF @ 50mA Diode
11V 350Mw SOT
6.8µH, 1.6A,
C3225X7R1E106M
C3216X5ROJ226M
C1005X7R1C103K
SS1P3L
TDK
TDK
Vishay
1N4148W
Diodes, Inc.
Diodes, Inc.
TDK
BZX84C11T
SLF7032T-6R8M1R6
CRCW06038871F
CRCW06031022F
CRCW06031003F
R1
8.87kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
18
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SNVS288I –SEPTEMBER 2004–REVISED APRIIL 2013
D3
D2
BOOST
SW
V
V
IN
IN
C3
D1
L1
R3
C1
V
OUT
LM2734
ON
C2
EN
R1
R2
OFF
FB
GND
Figure 31. LM2734X (1.6MHz)
VBOOST Derived from Series Zener Diode (VOUT
15V to 9V/1A
)
Table 5. Bill of Materials for Figure 31
Part ID
Part Value
1A Buck Regulator
Part Number
Manufacturer
Texas Instruments
TDK
U1
LM2734X
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
D3, Zener Diode
L1
10µF, 25V, X7R
22µF, 16V, X5R
0.01µF, 16V, X7R
0.4VF Schottky 1A, 30VR
1VF @ 50mA Diode
4.3V 350mw SOT
6.8µH, 1.6A,
C3225X7R1E106M
C3216X5R1C226M
C1005X7R1C103K
SS1P3L
TDK
TDK
Vishay
1N4148W
Diodes, Inc.
Diodes, Inc.
TDK
BZX84C4V3
SLF7032T-6R8M1R6
CRCW06031023F
CRCW06031022F
CRCW06031003F
R1
102kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
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LM2734Y Circuit Examples
D2
BOOST
SW
V
V
IN
IN
C3
D1
L1
C1
R3
V
OUT
LM2734
ON
C2
EN
R1
R2
OFF
FB
GND
Figure 32. LM2734Y (550kHz)
VBOOST Derived from VIN
5V to 1.5V/1A
Table 6. Bill of Materials for Figure 32
Part ID
Part Value
Part Number
Manufacturer
Texas Instruments
TDK
U1
1A Buck Regulator
10µF, 6.3V, X5R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
0.3VF Schottky 1A, 10VR
1VF @ 50mA Diode
10µH, 1.6A,
LM2734Y
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
L1
C3216X5ROJ106M
C3216X5ROJ226M
C1005X7R1C103K
MBRM110L
TDK
TDK
ON Semi
Diodes, Inc.
TDK
1N4148W
SLF7032T-100M1R4
CRCW06038871F
CRCW06031022F
CRCW06031003F
R1
8.87kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
20
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SNVS288I –SEPTEMBER 2004–REVISED APRIIL 2013
D2
L1
12V
V
IN
BOOST
SW
VIN
EN
C3
V
OUT
C1
R3
3.3V
LM2734
D1
C2
ON
R1
R2
C
FF
OFF
FB
GND
Figure 33. LM2734Y (550kHz)
VBOOST Derived from VOUT
12V to 3.3V/1A
Table 7. Bill of Materials for Figure 33
Part ID
Part Value
Part Number
Manufacturer
Texas Instruments
TDK
U1
1A Buck Regulator
10µF, 25V, X7R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
0.34VF Schottky 1A, 30VR
0.6VF @ 30mA Diode
10µH, 1.6A,
LM2734Y
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
L1
C3225X7R1E106M
C3216X5ROJ226M
C1005X7R1C103K
SS1P3L
TDK
TDK
Vishay
BAT17
Vishay
SLF7032T-100M1R4
CRCW06033162F
CRCW06031002F
CRCW06031003F
TDK
R1
31.6kΩ, 1%
Vishay
R2
10.0 kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
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C4
D3
R4
D2
BOOST
SW
V
V
IN
IN
C3
D1
L1
C1
R3
V
OUT
LM2734
ON
C2
EN
OFF
R1
R2
FB
GND
Figure 34. LM2734Y (550kHz)
VBOOST Derived from VSHUNT
18V to 1.5V/1A
Table 8. Bill of Materials for Figure 34
Part ID
Part Value
Part Number
Manufacturer
Texas Instruments
TDK
U1
1A Buck Regulator
10µF, 25V, X7R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
0.1µF, 6.3V, X5R
0.4VF Schottky 1A, 30VR
1VF @ 50mA Diode
5.1V 250Mw SOT
15µH, 1.5A
LM2734Y
C1, Input Cap
C2, Output Cap
C3, Boost Cap
C4, Shunt Cap
D1, Catch Diode
D2, Boost Diode
D3, Zener Diode
L1
C3225X7R1E106M
C3216X5ROJ226M
C1005X7R1C103K
C1005X5R0J104K
SS1P3L
TDK
TDK
TDK
Vishay
1N4148W
Diodes, Inc.
Vishay
BZX84C5V1
SLF7045T-150M1R5
CRCW06038871F
CRCW06031022F
CRCW06031003F
CRCW06034121F
TDK
R1
8.87kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
R4
4.12kΩ, 1%
Vishay
22
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SNVS288I –SEPTEMBER 2004–REVISED APRIIL 2013
D3
D2
BOOST
SW
V
IN
V
IN
C3
D1
L1
C1
R3
V
OUT
LM2734
ON
C2
EN
R1
R2
OFF
FB
GND
Figure 35. LM2734Y (550kHz)
VBOOST Derived from Series Zener Diode (VIN)
15V to 1.5V/1A
Table 9. Bill of Materials for Figure 35
Part ID
Part Value
1A Buck Regulator
Part Number
Manufacturer
Texas Instruments
TDK
U1
LM2734Y
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
D3, Zener Diode
L1
10µF, 25V, X7R
22µF, 6.3V, X5R
0.01µF, 16V, X7R
0.4VF Schottky 1A, 30VR
1VF @ 50mA Diode
11V 350Mw SOT
15µH, 1.5A,
C3225X7R1E106M
C3216X5ROJ226M
C1005X7R1C103K
SS1P3L
TDK
TDK
Vishay
1N4148W
Diodes, Inc.
Diodes, Inc.
TDK
BZX84C11T
SLF7045T-150M1R5
CRCW06038871F
CRCW06031022F
CRCW06031003F
R1
8.87kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
Copyright © 2004–2013, Texas Instruments Incorporated
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D3
D2
BOOST
SW
V
V
IN
IN
C3
D1
L1
R3
C1
V
OUT
LM2734
ON
C2
EN
R1
R2
OFF
FB
GND
Figure 36. LM2734Y (550kHz)
VBOOST Derived from Series Zener Diode (VOUT
15V to 9V/1A
)
Table 10. Bill of Materials for Figure 36
Part ID
Part Value
1A Buck Regulator
Part Number
Manufacturer
Texas Instruments
TDK
U1
LM2734Y
C1, Input Cap
C2, Output Cap
C3, Boost Cap
D1, Catch Diode
D2, Boost Diode
D3, Zener Diode
L1
10µF, 25V, X7R
22µF, 16V, X5R
0.01µF, 16V, X7R
0.4VF Schottky 1A, 30VR
1VF @ 50mA Diode
4.3V 350mw SOT
22µH, 1.4A,
C3225X7R1E106M
C3216X5R1C226M
C1005X7R1C103K
SS1P3L
TDK
TDK
Vishay
1N4148W
Diodes, Inc.
Diodes, Inc.
TDK
BZX84C4V3
SLF7045T-220M1R3-1PF
CRCW06031023F
CRCW06031022F
CRCW06031003F
R1
102kΩ, 1%
Vishay
R2
10.2kΩ, 1%
Vishay
R3
100kΩ, 1%
Vishay
24
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SNVS288I –SEPTEMBER 2004–REVISED APRIIL 2013
REVISION HISTORY
Changes from Revision H (April 2013) to Revision I
Page
•
Changed layout of National Data Sheet to TI format .......................................................................................................... 24
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PACKAGE OPTION ADDENDUM
www.ti.com
11-Apr-2013
PACKAGING INFORMATION
Orderable Device
LM2734XMK/NOPB
LM2734XMKX/NOPB
LM2734XQMK/NOPB
LM2734XQMKE/NOPB
LM2734XQMKX/NOPB
Status Package Type Package Pins Package
Eco Plan Lead/Ball Finish
MSL Peak Temp
Op Temp (°C)
-40 to 125
-40 to 125
-40 to 125
-40 to 125
-40 to 125
Top-Side Markings
Samples
Drawing
Qty
(1)
(2)
(3)
(4)
ACTIVE
SOT
SOT
SOT
SOT
SOT
DDC
6
6
6
6
6
1000
Green (RoHS
& no Sb/Br)
CU SN
CU SN
CU SN
CU SN
CU SN
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
SFDB
ACTIVE
ACTIVE
ACTIVE
ACTIVE
DDC
DDC
DDC
DDC
3000
1000
250
Green (RoHS
& no Sb/Br)
SFDB
SUKB
SUKB
SUKB
Green (RoHS
& no Sb/Br)
Green (RoHS
& no Sb/Br)
3000
Green (RoHS
& no Sb/Br)
LM2734YMK
ACTIVE
ACTIVE
SOT
SOT
DDC
DDC
6
6
1000
1000
TBD
Call TI
CU SN
Call TI
-40 to 125
-40 to 125
SFEB
SFEB
LM2734YMK/NOPB
Green (RoHS
& no Sb/Br)
Level-1-260C-UNLIM
LM2734YMKX
ACTIVE
ACTIVE
SOT
SOT
DDC
DDC
6
6
3000
3000
TBD
Call TI
CU SN
Call TI
-40 to 125
-40 to 125
SFEB
SFEB
LM2734YMKX/NOPB
Green (RoHS
& no Sb/Br)
Level-1-260C-UNLIM
LM2734YQMK/NOPB
LM2734YQMKE/NOPB
LM2734YQMKX/NOPB
ACTIVE
ACTIVE
ACTIVE
SOT
SOT
SOT
DDC
DDC
DDC
6
6
6
1000
250
Green (RoHS
& no Sb/Br)
CU SN
CU SN
CU SN
Level-1-260C-UNLIM
Level-1-260C-UNLIM
Level-1-260C-UNLIM
-40 to 125
-40 to 125
-40 to 125
SVCB
SVCB
SVCB
Green (RoHS
& no Sb/Br)
3000
Green (RoHS
& no Sb/Br)
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
11-Apr-2013
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
Multiple Top-Side Markings will be inside parentheses. Only one Top-Side Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a
continuation of the previous line and the two combined represent the entire Top-Side Marking for that device.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
OTHER QUALIFIED VERSIONS OF LM2734, LM2734-Q1 :
Catalog: LM2734
•
Automotive: LM2734-Q1
•
NOTE: Qualified Version Definitions:
Catalog - TI's standard catalog product
•
Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects
•
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Apr-2013
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
B0
K0
P1
W
Pin1
Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant
(mm) W1 (mm)
LM2734XMK/NOPB
LM2734XMKX/NOPB
LM2734XQMK/NOPB
LM2734XQMKE/NOPB
LM2734XQMKX/NOPB
LM2734YMK
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
6
6
6
6
6
6
6
6
6
6
6
6
1000
3000
1000
250
178.0
178.0
178.0
178.0
178.0
178.0
178.0
178.0
178.0
178.0
178.0
178.0
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.4
8.4
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
3.2
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
1.4
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
4.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
8.0
Q3
Q3
Q3
Q3
Q3
Q3
Q3
Q3
Q3
Q3
Q3
Q3
3000
1000
1000
3000
3000
1000
250
LM2734YMK/NOPB
LM2734YMKX
LM2734YMKX/NOPB
LM2734YQMK/NOPB
LM2734YQMKE/NOPB
LM2734YQMKX/NOPB
3000
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
8-Apr-2013
*All dimensions are nominal
Device
Package Type Package Drawing Pins
SPQ
Length (mm) Width (mm) Height (mm)
LM2734XMK/NOPB
LM2734XMKX/NOPB
LM2734XQMK/NOPB
LM2734XQMKE/NOPB
LM2734XQMKX/NOPB
LM2734YMK
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
SOT
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
DDC
6
6
6
6
6
6
6
6
6
6
6
6
1000
3000
1000
250
210.0
210.0
210.0
210.0
210.0
210.0
210.0
210.0
210.0
210.0
210.0
210.0
185.0
185.0
185.0
185.0
185.0
185.0
185.0
185.0
185.0
185.0
185.0
185.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
35.0
3000
1000
1000
3000
3000
1000
250
LM2734YMK/NOPB
LM2734YMKX
LM2734YMKX/NOPB
LM2734YQMK/NOPB
LM2734YQMKE/NOPB
LM2734YQMKX/NOPB
3000
Pack Materials-Page 2
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
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Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
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No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
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