How it Works
National
Loading...
LM2750LD-5.0
Schematic [ru]
17 pgs800.65 Kb0
Table of contents
Loading...

National LM2750LD-5.0, LM2750LD-ADJ, LM2750SD-5.0, LM2750SD-ADJ Schematic [ru]

LM2750 Low Noise Switched Capacitor Boost Regulator
LM2750 Low Noise Switched Capacitor Boost Regulator
December 2005

General Description

The LM2750 is a regulated switched-capacitor doubler that produces a low-noise output voltage. The 5.0V output volt­age option (LM2750-5.0) can supply up to 120mA of output current over a 2.9V to 5.6V input range, as well as up to 40mA of output current when the input voltage is as low as
A perfect fit for space-constrained, battery-powered applica­tions, the LM2750 requires only 3 external components: one input capacitor, one output capacitor, and one flying capaci­tor. Small, inexpensive ceramic capacitors are recom­mended for use. These capacitors, in conjunction with the
1.7MHz fixed switching frequency of the LM2750, yield low output voltage ripple, beneficial for systems requiring a low­noise supply. Pre-regulation minimizes input current ripple, reducing input noise to negligible levels.
A tightly controlled soft-start feature limits inrush currents during part activation. Shutdown completely disconnects the load from the input. Output current limiting and thermal shutdown circuitry protect both the LM2750 and connected devices in the event of output shorts or excessive current loads.

Features

n Inductorless solution: Application requires only 3 small
ceramic capacitors
n Fixed 5.0V output and adjustable output voltage options
available
n 85% Peak Efficiency
70% Average Efficiency over Li-Ion Input Range (2.9V-to-4.2V)
n Output Current up to 120mA with 2.9V ≤ V
Output Current up to 40mA with 2.7V ≤ V
n Wide Input Voltage Range: 2.7V to 5.6V n Fixed 1.7MHz switching frequency for a low-noise,
low-ripple output signal
n Pre-regulation minimizes input current ripple, keeping
the battery line (V
n Tiny LLP package with outstanding power dissipation:
Usually no derating required.
n Shutdown Supply Current less than 2µA
) virtually noise-free
IN
IN
IN
≤ 5.6V
≤ 2.9V

Applications

n White and Colored LED-based Display Lighting n Cellular Phone SIM cards n Audio Amplifier Power Supplies n General Purpose Li-Ion-to-5V Conversion

Typical Application Circuit

20035101
© 2005 National Semiconductor Corporation DS200351 www.national.com

Connection Diagram

LM2750
LM2750
10-Pin Leadless Leadframe Package (LLP) - 3mm X 3mm
NS Package Number LDA10A (Shown below), and SDA10A
Pin Names and Numbers apply to both SDA10A and LDA10A packages.
20035102

Pin Descriptions

Pin #(s) Pin Name Description
8, 9 V
1, 2 V
10 CAP+ Flying Capacitor Positive Terminal
7 CAP- Flying Capacitor Negative Terminal
4SD
3
5, 6, DAP GND Ground - These pins must be connected externally.
LM2750-5.0: GND
LM2750-ADJ: FB Feedback Pin
IN
OUT
Input Voltage - The pins must be connected externally.
Output Voltage - These pins must be connected externally.
Active-Low Shutdown Input. A 200kΩ resistor is connected internally between this pin and GND to pull the voltage on this pin to 0V, and shut down the part, when the pin is left floating.
This pin must be connected exernally to the ground pins (pins 5, 6, and the DAP).

Ordering Information

Output Voltage
Option
5.0 LM2750LD-5.0 LDA10A S002B 1000 Units, Tape and Reel
5.0 LM2750LDX-5.0 LDA10A S002B 4500 Units, Tape and Reel
Adjustable LM2750LD-ADJ LDA10A S003B 1000 Units, Tape and Reel
Adjustable LM2750LDX-ADJ LDA10A S003B 4500 Units, Tape and Reel
5.0 LM2750SD-5.0 SDA10A S005B 1000 Units, Tape and Reel
5.0 LM2750SDX-5.0 SDA10A S005B 4500 Units, Tape and Reel
Adjustable LM2750SD-ADJ SDA10A S004B 1000 Units, Tape and Reel
Adjustable LM2750SDX-ADJ SDA10A S004B 4500 Units, Tape and Reel
Note 1: LDA10A Package: 10 pad pullback LLP. SDA10A Package: 10 pad non-pullback LLP. For more details, refer to the package drawings in the Physical Dimensions section at the end of this datasheet.
Ordering
Information
Package
(Note 1)
Package
Marking
Supplied as
www.national.com 2
LM2750

Absolute Maximum Ratings (Notes 2, 3)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
Pin: Voltage to Ground −0.3V to 6V
V
IN
SD Pin: Voltage to GND
Junction Temperature (T
J-MAX-ABS
) 150˚C
Continuous Power Dissipation Internally Limited
(Note 4)
Maximum Output Current (Note 5) 175mA
Storage Temperature Range −65˚C to 150˚C
Maximum Lead Temperature 260˚C
−0.3V to +0.3V)
(V
IN
Operating Ratings (Notes 2, 3)
LM2750-5.0 Input Voltage Range 2.7V to 5.6V
LM2750-ADJ Input Voltage Range
3.8V ≤ V
4.9V ≤ V
LM2750-ADJ Output Voltage Range 3.8V to 5.2V
Recommended Output Current
2.9V ≤ V
2.7V ≤ V
Junction Temperature (T
Ambient Temperature (T
(Note 7)
≤ 4.9V: 2.7V to (V
OUT
≤ 5.2V: 2.7V to 5.6V
OUT
≤ 5.6V 0 to 120mA
IN
≤ 2.9V 0 to 40mA
IN
) Range -40˚C to 125˚C
J
) Range -40˚C to 85˚C
A
OUT
(Soldering, 5 sec.)
ESD Rating (Note 6)
Human-body model: Machine model
2kV
100V

Thermal Information

Junction-to-Ambient Thermal Resistance, LLP-10 55˚C/W
Package (θJA) (Note 8)
Electrical Characteristics (Notes 3, 9)
Typical values and limits in standard typeface apply for TJ=25oC. Limits in boldface type apply over the operating junction temperature range. Unless otherwise specified: 2.9V ≤ V = 2 x 1µF, C
= 2 x 1µF (Note 10).
OUT
≤ 5.6V, V
IN
Symbol Parameter Conditions Min Typ Max Units
2.9V ≤ V
V
OUT
I
Q
I
SD
V
FB
Output Voltage (LM2750-5.0)
Operating Supply Current I
Shutdown Supply Current V(SD) = 0V 2 µA
Feedback Pin Voltage
I
OUT
2.7V ≤ V I
OUT
OUT
V
IH(MIN)
VIN= 3.1V 1.170 1.232 1.294 V
≤ 5.6V,
IN
≤ 120mA
≤ 2.9V,
IN
≤ 40mA
= 0mA,
≤ V(SD) ≤V
(LM2750-ADJ)
I
FB
Feedback Pin Input Current
VFB= 1.4V 1 nA
(LM2750-ADJ)
V
E
E
f
t
R
PEAK
AVG
SW
ON
Output Ripple C
Peak Efficiency (LM2750-5.0)
Average Efficiency over Li-Ion Input Range (LM2750-5.0) (Note 12)
= 10µF, I
OUT
C
= 2.2µF, I
OUT
VIN= 2.7V, I
V
= 2.9V, I
IN
Range: 2.9V - 4.2V,
V
IN
I
OUT
V
Range: 2.9V - 4.2V,
IN
I
OUT
OUT
OUT
= 120mA
= 40mA
Switching Frequency 1.0 1.7 MHz
V
Turn-On Time VIN= 3.0V, I
OUT
OUT
(Note 11)
I
LIM
Current Limit V
shorted to GND 300 mA
OUT
Shutdown Pin (SD) Characteristics
V
IH
V
IL
I
IH
I
IL
Logic-High SD Input 1.3 V
Logic-Low SD Input 0 0.4 V
SD Input Current (Note 13) 1.3V ≤ V(SD) ≤ V
SD Input Current V(SD) = 0V −1 1 µA
= 5.0V (LM2750-ADJ), V(SD) = VIN,C
OUT
4.80
5.0 5.20
(-4%)
4.80
5.0 5.20
(-4%)
FLY
(+4%)
(+4%)
= 1µF, C
51012mA
IN
= 100mA 4
OUT
= 100mA 15
OUT
= 40mA 87 %
= 120mA 85
70 %
67
= 100mA,
IN
0.5 ms
IN
15 50 µA
+0.7V)
IN
V
(%)
mVp-p
V
www.national.com3
Electrical Characteristics (Notes 3, 9) (Continued)
Typical values and limits in standard typeface apply for TJ=25oC. Limits in boldface type apply over the operating junction
LM2750
temperature range. Unless otherwise specified: 2.9V ≤ V = 2 x 1µF, C
= 2 x 1µF (Note 10).
OUT
Symbol Parameter Conditions Min Typ Max Units
Capacitor Requirements
C
IN
C
OUT
Required Input Capacitance(Note 14)
Required Output Capacitance(Note 14)
Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operation of the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical Characteristics tables.
Note 3: All voltages are with respect to the potential at the GND pin.
Note 4: Thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at T
Note 5: Absiolute Maximum Output Current guaranteed by design. Recommended input voltage range for output currents in excess of 120mA: 3.1V to 4.4V.
Note 6: The Human body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. MIL-STD-883 3015.7. The machine model is a 200pF
capacitor discharged directly into each pin.
Note 7: Maximum ambient temperature (T dissipation of the device in the application (P following equation: T equation: P I
are the maximum voltage/current of the specific application, and not necessarily the maximum rating of the LM2750.
OUT-MAX
The maximum ambient temperature rating of 85 V
= 5.5V and I
IN-MAX
20mW above 727mW (again assuming that θ
Leadframe Package (LLP) and the Power Efficiency and Power Dissipation section of this datasheet.
Note 8: Junction-to-ambient thermal resistance (θ
standard JESD51-7. The test board is a 4 layer FR-4 board measuring 102mm x 76mm x 1.6mm witha2x1array of thermal vias. The ground plane on the board is 50mm x 50mm. Thickness of copper layers are 36µm/18µm /18µm/36µm (1.5oz/1oz/1oz/1.5oz). Ambient temperature in simulation is 22˚C, still air. Power dissipation is 1W.
The value of θ conditions. In applications where high maximum power dissipation exists (high V information on these topics, please refer to Application Note 1187: Leadless Leadframe Package (LLP) and the Layout Recommendations section of this datasheet.
Note 9: Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm.
Note 10: C
Note 11: Turn-on time is measured from when SD signal is pulled high until the output voltage crosses 90% of its final value.
Note 12: Efficiency is measured versus VIN, with VINbeing swept in small increments from 3.0V to 4.2V. The average is calculated from these measurements
results. Weighting to account for battery voltage discharge characteristics (V
Note 13: SD Input Current (I
Note 14: Limit is the minimum required output capacitance to ensure proper operation. This electrical specification is guaranteed by design.
A-MAX=TJ-MAX-OP
=(V
D-MAX
FLY,CIN
IN-MAXxIIN-MAX
OUT-MAX
of the LM2750 in LLP-10 could fall in a range as wide as 50oC/W to 150oC/W (if not wider), depending on PCB material, layout, and environmental
JA
, and C
OUT
)-(V
= 115mA, for example). Maximum ambient temperature must be derated by 1.1oC for every increase in internal power dissipation of
: Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics
) is due to a 200kΩ (typ.) pull-down resistor connected internally between the SD pin and GND.
IH
) is dependent on the maximum operating junction temperature (T
A-MAX
), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by the
D-MAX
-(θJAxP
JA
). Maximum power dissipation of the LM2750 in a given application can be approximated using the following
D-MAX
OUTxIOUT-MAX
o
C is determined under the following application conditions: θJA=55oC/W, P
=55oC/W in the application). For more information on these topics, please refer to Application Note 1187: Leadless
) is taken from a thermal modeling result, performed under the conditions and guidelines set forth in the JEDEC
JA
I
60mA ≤ I
I
60mA ≤ I
)=[V
≤ 5.6V, V
IN
≤ 60mA 1.0 µF
OUT
≤ 120mA 2.0
OUT
≤ 60mA 1.0 µF
OUT
≤ 120mA 2.0
OUT
x((2xI
IN-MAX
OUT-MAX
, high I
IN
vs. Time) is not done in computing the average.
BAT
= 5.0V (LM2750-ADJ), V(SD) = VIN,C
OUT
=150˚C (typ.) and disengages at TJ=135˚C (typ.).
J
= 125oC), the maximum power
J-MAX-OP
) + 5mA)] - (V
), special care must be paid to thermal dissipation issues. For more
OUT
OUTxIOUT-MAX
). In this equation, V
D-MAX
FLY
IN-MAX,IIN-MAX
= 727mW (achieved when
= 1µF, C
IN
, and
www.national.com 4

Block Diagram

LM2750
20035103
www.national.com5

Typical Performance Characteristics Unless otherwise specified: V

2.2µF, C
LM2750
= 1.0µF, C
FLY
Output Voltage vs. Output Current Output Voltage vs. Output Current
Output Voltage vs. Input Voltage Power Efficiency
= 2.2µF. Capacitors are low-ESR multi-layer ceramic capacitors (MLCC’s).
OUT
20035115 20035116
= 3.6V, TA=25oC, CIN=
IN
20035117 20035118
Input Current vs. Output Current Quiescent Supply Current
20035119
20035120
www.national.com 6
Loading...
+ 11 hidden pages
Buy Points How it Works FAQ Contact Us Questions and Suggestions Privacy Policy Cookie Policy Terms of Use