NSC LP3928TL-1828

LP3928
High Speed Bi-Directional Level Shifter and Ultra
Low-Dropout CMOS Voltage Regulator
General Description
The LP3928 is designed for portable and wireless applications with demanding performance and space requirements.
The LP3928 provides level shifting and power conversion
needed for applications interfacing differing voltage levels.
The part contains a bi-directional level shifter for three signals to translate the levels between 1.8V and 2.85V and an
ultra low-dropout CMOS 2.85V voltage regulator.
The three level shifted signals are individually direction controlled. Signals going from 2.85V to 1.8V can also be latched
using an external clock source. The latches are powered
from internal 2.85V. There is also an option to by-pass the
latches.
The built-in low-dropout voltage regulator is ideal for mobile
phone and battery powered wireless applications. It provides
up to 150 mA from a 3.05V to 6.0V input, and is characterized by extremely low dropout voltage, low quiescent current
and low output noise voltage. It is stable with small 1.5 µF
± 30% ceramic and high quality tantalum output capacitors,
requiring smallest possible PC board area.
A shutdown mode is available for the level shifters and the
regulator. High performance is achieved over various load
conditions with very low rise and fall times.
Key Specifications
n 2 ns rise and fall times (typ.)
n 20 ns direction switch response time
n 2 µA input/output leakage current
Low-Dropout Regulator:
n 3.05V to 6.0V input range
n 150 mA guaranteed output
n Fast Turn-On time: 200 µs (typ.)
n 100 mV maximum dropout with 150 mA load
Features
n Ultra small micro SMD package
n Bi-directional level-shifter for three individual signals:
1.8V to 2.85V and 2.85V to 1.8V signal level translation
n Logic controlled enable pins: 4 different operation
modes
n LDO stable with ceramic and high quality tantalum
capacitors
n Thermal shutdown
Applications
n
n
n
n
Multi-Media Cards for Cellular Phones
SD Cards for Cellular Handsets
Logic Level Translation
Portable Information Appliances
Level Shifter:
n 4 ns propagation delay (typ.)
© 2002 National Semiconductor Corporation
DS200391
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LP3928 High Speed Bi-Directional Level Shifter and Ultra Low-Dropout CMOS Voltage Regulator
October 2002
LP3928
Typical Application Circuit
20039101
Block Diagram
20039102
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2
LP3928
Package Outline and Connection Diagrams
20039104
Note: The actual physical placement of the package marking will vary from
part to part. The package marking “XY” will designate the date code, “TT” is
a NSC internal code for die traceability. Both will vary considerably. L8B
identifies the device.
Top View
20039103
Bottom View
16 Bump micro SMD Package
See NSC Package Number TLA16AAA
Pin Description
Pin Name
micro SMD
Bump Identifier
Logic Level
Function
A1
C4
1.8V
1.8V I/O Channel, (Note 1)
A2
D4
1.8V
1.8V I/O Channel, (Note 1)
A3
D3
1.8V
1.8V I/O Channel, (Note 1)
B1
C1
2.85V
2.85V I/O Channel, (Note 1)
B2
D1
2.85V
2.85V I/O Channel, (Note 1)
B3
D2
2.85V
2.85V I/O Channel, (Note 1)
DIR1
B3
1.8V
Direction control input Channel 1: ‘1’: A→B; 0; B→A
Direction control input Channel 2: ‘1’: A→B; 0; B→A
Direction control input Channel 3: ‘1’: A→B; 0; B→A
DIR2
B2
1.8V
DIR3
C3
1.8V
VCCA
B4
IC supply to the 1.8V side
VCCB
B1
IC supply, 2.85V output from LDO
VBAT
A1
LDO supply, Battery voltage
GND
A3
Power ground connection
EN1
A4
1.8V
Mode pin 1, see Table 1 for modes and settings
EN2
A2
1.8V
Mode pin 2, see Table 1 for modes and settings
LatchClk
C2
2.85V
Clock input: rising edge latches B inputs (DIR=0, normal mode)
Note 1: Pin pairs A1–B1, A2–B2 and A3–B3 form 3 independent bi-directional level-shifting channels.
TABLE 1. Operation Modes
Inputs
State
EN1
EN2
0
0
Level shifter off: High Z state on A1–A3, B1–B3, LDO off
0
1
Level shifter off: High Z state on A1–A3, B1–B3, LDO on
1
0
Latch bypassed in B to A direction, LDO=on (Note 2)
1
1
ON, normal mode (latch active)
Note 2: LatchClk is not used here. It should not be left floating.
3
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LP3928
Pin Description
(Continued)
TABLE 2. Direction Control and LatchCLK (Normal Mode)
Inputs
Outputs and Direction
DIRx
LatchClk
1
X
0
↓
No change (on Ax)
0
↑
Bx to Ax, see example
Ax to Bx
Example for Latch Mode, DIR1 = ‘0’, EN1 = EN2 = ‘1’ (delay not shown):
20039105
Ordering Information
For micro SMD Package
Output Voltage (V)
Grade
LP3928 Supplied As 250 Units, Tape & Reel
LP3928 Supplied As 3000 Units, Tape & Reel
2.85
STD
LP3928TL-1828
LP3928TLX-1828
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4
Maximum Power Dissipation
micro SMD
(Notes 3,
4)
ESD Rating (Note 6)
Human Body Model
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
VBAT, VCCB
−0.2V to +6.5V
VCCA
−0.2V to +3.3V
A1–A3, EN, DIR
−0.2V to VCCA + 0.2V
B1–B3, LatchClk
−0.2V to VCCB + 0.2V
Junction Temperature
150˚C
Storage Temperature
−65˚C to +150˚C
Lead Temperature (Note 27)
235˚C
Pad Temperature (Note 27)
235˚C
Power Dissipation (Note 5)
θJA (micro SMD), typical
180˚C/W
360 mW
2 kV
Operating Conditions (Notes 3, 4)
VBAT
3.05V to 6.0V
VCCA
1.65V to 1.95V
VCCB
(Note 7)
Junction Temperature
−40˚C to +125˚C
Ambient Temperature
−40˚C to +85˚C
Maximum Power Dissipation (Note 8)
220 mW
Electrical Characteristics Unless otherwise specified: H = VIH min, L = VIL max, CVBAT = 1 µF, IOUT = 1
mA, CVCCB = 1 µF, CVCCA = 1 µF. Typical values and limits appearing in standard typeface apply for TJ = 25˚C. Limits appearing in boldface type apply over the entire junction temperature range for operation, −40˚C to +125˚C. (Note 9)
Level Shifter DC Voltage Levels
Unless otherwise specified: EN1 = H, EN2 = X; 3.05V ≤ VBAT ≤ 6V, 1.65V ≤ VCCA ≤ 1.95V.
Symbol
Parameter
VIHA
High Level Input Voltage
VILA
Low Level Input Voltage
VOHA
High Level Output Voltage
VOLA
Low Level Output Voltage
VIHB
High Level Input Voltage
VILB
Low Level Input Voltage
VOHB
High Level Output Voltage
VOLB
Low Level Output Voltage
VIHEN-DIR
High Level Input Voltage
VILEN-DIR
Low Level Input Voltage
VIHLatClk
High Level Input Voltage
VILLatClk
Low Level Input Voltage
Conditions
For A Pins
For A Pins
Typ
Max
Units
VCCA+0.2
V
0
VCCA*0.35
V
IOH =4 mA
VCCA−0.45
1.5
VCCA+0.2
V
IOL =4 mA
0
0.1
VCCA*0.25
V
For B Pins
For B Pins
Min
VCCA*0.65
IOH =4 mA
VCCB*0.7
VCCB+0.2
V
0
VCCB*0.3
V
2.75
VCCB+0.2
V
0.1
VCCB*0.2
V
VCCB*0.7
IOL =4 mA
For EN and DIR Pins
For LatchClk Pin
0
VCCA*0.75
VCCA+0.2
V
0
VCCA*0.27
V
VCCB*0.7
VCCB+0.2
V
0
VCCA*0.3
V
Level Shifter DC Current Levels
Unless otherwise specified: EN1 = H, EN2 = X; VBAT = 6V or VCCA = 1.95V as applicable to B or A respectively.
Typ
Max
Units
IIA
Symbol
Input Leakage Current Ai
Parameter
ViA =0/1.9V, DIRi=H
(VCCA = 1.8V when ViA = 1.9V)
Conditions
0.001
±2
µA
IIDIR_EN
Input Leakage Current
DIR/EN
(Note 11)
Vi=0/1.9V (VCCA = 1.8V when Vi =
1.9V)
0.001
±2
µA
IIB
Input Leakage Current Bi,
LatchClk (Note 12)
ViB =0/2.95V, DIRi=L
0.001
±2
µA
ICHA→B
Static ICCB Current/Channel
Static ICCB Current Total
(Notes 13, 17)
EN2=H, DIRi=H,
Total Includes IBCOM
550
2050
875
3330
µA
ICHB→A
Static ICCB Current/Channel
Static ICCB Current Total
(Notes 14, 17)
EN2=L, DIRi=L
Total Includes IBCOM
2
406
30
840
µA
5
Min
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LP3928
Absolute Maximum Ratings
LP3928
Electrical Characteristics Unless otherwise specified: H = VIH min, L = VIL max, CVBAT = 1 µF, IOUT = 1 mA,
CVCCB = 1 µF, CVCCA = 1 µF. Typical values and limits appearing in standard typeface apply for TJ = 25˚C. Limits appearing in
boldface type apply over the entire junction temperature range for operation, −40˚C to +125˚C. (Note 9) (Continued)
Level Shifter DC Current Levels
(Continued)
Unless otherwise specified: EN1 = H, EN2 = X; VBAT = 6V or VCCA = 1.95V as applicable to B or A respectively.
Typ
Max
Units
IBCOM
Symbol
Common Static Level-Shifter
ICCB Current (Notes 15, 17)
Parameter
Conditions
Min
400
750
µA
IA
Static Level-Shifter ICCA
Current (Notes 16, 17)
90
165
µA
ICCBEXT
Off State ICCB Current with
External VCCB (Note 7)
VBAT =3.6V, EN1=L, EN2=L
15
IOFFA
Off State VCCA Current
VCCA =1.9V, EN1,2=0, Ai=0V, Bi=0V,
DIRi=0V, LatchClk=0V
1.5
µA
5
µA
IOFFBAT
Off State VBAT Current
EN1,2=L
0.005
3
µA
IOZA
Output Leakage Current Ai
VCCA =1.9V, ViA =0/1.9V, EN1=L
0.001
µA
IOZB
Output Leakage Current Bi
ViB =0V, VBAT =3.35V, VCCB =0, EN1=L
0.001
ViB =2.95V, VBAT =3.35V, VCCB =2.95V,
EN1=L
0.001
±2
±2
±2
Short Circuit Current/ Channel
Ai Output, VCCA =1.9V,
DIRi=L, EN2=L
ISCA
Short Circuit Current/ Channel
Bi Output, VBAT =2.95V,
DIRi=H
ISCB
Ai=0V, Bi=H
−27
−17
Ai=VCCA, Bi=L
−90
56
−58
Bi=2.95V, Ai=L
µA
mA
36
Bi=0V, Ai=H
µA
mA
mA
60
90
mA
Level Shifter AC Electrical Characteristics
Unless otherwise specified: EN1 = H, 3.05V ≤ VBAT ≤ 6V, 1.65V ≤ VCCA = 1.95V. ((Note 28), (Note 29))
Symbol
Typ
Max
Units
Propagation Delay An to Bn or Bn to An
CLB = 35 pF, CLA = 15 pF
4
7
ns
CLB = 35 pF, CLA = 15 pF
4
7
ns
tR
Rise Time
CLB = 35 pF, CLA = 15 pF
2
4
ns
tF
Fall Time
CLB = 35 pF, CLA = 15 pF
2
4
ns
tMATCH
Delay Differences between Channel Outputs at
Identical Input Signals
1.5
ns
tSL
Latch Set Up Time
1
2
ns
tHL
Latch Hold Time
1
2
ns
tLS
Level-Shifter Mode Switch Response Time
(Note 18)
100
ns
tDIR
Level-Shifter Direction Switch Response Time
(Note 19)
20
ns
tPHL
Parameter
Conditions
tPLH
Min
LDO Electrical Characteristics
Unless otherwise specified: EN1 = L, EN2 = H; VOUTnom = 2.85V, VBAT = VOUT(nom) + 0.5V.
Symbol
∆VOUT
Parameter
Conditions
Output Voltage Tolerance
IOUT = 1 mA
Line Regulation Error (Note 20)
VBAT = (VOUT(nom) + 0.5V) to 6.0V,
IOUT = 1 mA
Load Regulation Error (Note 21)
IOUT = 1 mA to 150 mA
Output AC Line Regulation
VBAT = VOUT(nom) + 1V,
IOUT = 100 mA,
COUT = 4.7 µF (Figure 1)
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Typical
1.5
Limit
Units
Min
Max
−2
−3
2
3
% of
VOUT(nom)
−0.10
0.10
%/V
0.005
%/mA
mVPP
LDO Electrical Characteristics
(Continued)
Unless otherwise specified: EN1 = L, EN2 = H; VOUTnom = 2.85V, VBAT = VOUT(nom) + 0.5V.
Symbol
PSRR
IQ
Parameter
Power Supply Rejection Ratio
(Note 29)
Conditions
Typical
Limit
Min
Max
VBAT = VOUT(nom) + 1V,
f = 1 kHz, IOUT = 50 mA, (Figure 2)
40
VBAT = VOUT(nom) + 1V,
f = 50 kHz, IOUT = 50 mA, (Figure 2)
20
Quiescent Current
IOUT = 1mA
85
150
IOUT = 1 mA to 150 mA
130
200
Dropout Voltage (Note 22)
IOUT = 1 mA
0.4
2
IOUT = 50 mA
20
35
IOUT = 100 mA
45
70
100
∆VDO
Units
dB
IOUT = 150 mA
60
ISC
Short Circuit Current Limit
VBAT = 6V, Output Grounded (Steady
State)
500
IOUT(PK)
Peak Output Current
VOUT ≥ VOUT(nom) − 5%, VBAT = 6V
460
200
TON
Turn-On Time (Note 23) (Note
29)
200
130
µA
mV
mA
mA
430
µs
ρn (1/f)
Output Noise Density
f = 1 kHz, COUT = 1 µF
0.6
en
Output Noise Voltage
BW = 10 Hz to 100 kHz, COUT = 1 µF
45
Output
Capacitor
Output Filter Capacitance
(Note 24)
VBAT = 3.05V to 6V,
IOUT = 1mA to 150 mA
1
22
µF
Output Filter Capacitance ESR
(Note 25)
VBAT = 3.05V to 6V,
IOUT = 1mA to 150 mA
5
500
mΩ
Thermal
Shutdown
µV/√Hz
µVrms
Thermal Shutdown Temperature
(Note 26)
160
˚C
Thermal Shutdown Hysteresis
20
˚C
Note 3: Absolute Maximum Ratings are limits beyond which damage to the device 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 condition, see Electrical
Characteristics tables.
Note 4: All voltages are with respect to the potential at the GND pin.
Note 5: The Absolute Maximum power dissipation depends on the ambient temperature and can be calculated using the formula
P = (TJ − TA)/θJA,
(1)
Where TJ is the junction temperature, TA is the ambient temperature, and θJA is the junction-to-ambient thermal resistance. The 360 mW rating appearing under
Absolute Maximum Ratings results from substituting the Absolute Maximum junction temperature, 150˚C, for TJ, 85˚C for TA, and 180˚C/W for θJA. More power can
be dissipated safely at ambient temperatures below 85˚C. The thermal resistance can be better or worse than 180˚C/W depending on board layout. Larger copper
planes and thermal vias should be used to conduct heat away from the micro SMD solder bumps.
Note 6: The Human Body Model is 100 pF discharged through 1.5 kΩ resistor into each pin.
Note 7: VCCB can be supplied from an external voltage source in the range of 1.65V to 3.6V, as long as both VBAT and VCCB are connected to the external source.
Only the LDO quiescent current (see DC electrical specifications) will add to the level-shifter current consumption. This Operating Rating does not imply guaranteed
performance. For guaranteed performance limits and associated test conditions, see Electrical Characteristics tables.
Note 8: Like the Absolute Maximum power dissipation, the maximum power dissipation for operation depends on the ambient temperature. The 220 mW rating
appearing under Operating Ratings results from substituting the maximum junction temperature for operation, 125˚C, for TJ, 85˚C for TA, and 180˚C/W for θJA into
(1) above. More power can be dissipated at ambient temperatures below 85˚C. The thermal resistance can be better or worse than 180˚C/W depending on board
layout. Larger copper planes and thermal vias should be used to conduct heat away from the micro SMD solder bumps.
Note 9: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production with TJ = 25˚C or correlated using
Statistical Quality Control (SQC) methods. All hot and cold limits are guaranteed by correlating the electrical characteristics to process and temperature variations
and applying statistical process control.
Note 10: The target output voltage, which is labeled VOUT(target), is the desired or ideal output voltage. The nominal output voltage, which is labeled VOUT(nom), is
the output voltage measured with the input 0.5V above VOUT(target) and a 1 mA load.
Note 11: Input leakage current for pins DIRi, EN1, EN2.
Note 12: Input leakage current for pins Bi, LatchClk.
Note 13: This is the static current consumption from VCCB for channel (i) when DIRi=H (A→B direction).
Note 14: This is the static current consumption from VCCB for channel (i) when DIRi=L (B→ A direction).
Note 15: This is the static current consumption from VCCB for the part common to the channels.
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LP3928
Electrical Characteristics Unless otherwise specified: H = VIH min, L = VIL max, CVBAT = 1 µF, IOUT = 1 mA,
CVCCB = 1 µF, CVCCA = 1 µF. Typical values and limits appearing in standard typeface apply for TJ = 25˚C. Limits appearing in
boldface type apply over the entire junction temperature range for operation, −40˚C to +125˚C. (Note 9) (Continued)
LP3928
Note 16: This is the static current consumption from VCCA for the part common to the channels.
Note 17: Only ICCBTOTAL for DIR1=DIR2=DIR3=H and ICCATOTAL for DIR1=DIR2=DIR3=L will be tested in production.
Calculation example: assuming DIR1=H, DIR2=L, DIR3=L, then the typical ICCB current will be:
ICCBTOTAL = IBCOM + ICHA→B + 2 * ICHB→A = 450 µA + 530 µA + 2 * 2 µA = 984 µA
The typical ICCA current is: ICCATOTAL = IA = 90 µA.
Note 18: This is the time it takes either to switch the level shifter on or off, or the time it takes to turn the latch by-pass on/off.
Note 19: This is the time it takes to switch the direction of the level shifter. After this time a signal can be applied on the new input. For the B→A direction, if EN2=1,
the latch set-up time has to be considered separately.
Note 20: The output voltage changes slightly with line voltage. An increase in the line voltage results in a slight increase in the output voltage and vice versa.
Note 21: The output voltage changes slightly with load current. An increase in the load current results in a slight decrease in the output voltage and vice versa.
Note 22: Dropout voltage is the input-to-output voltage difference at which the output voltage is 100 mV below its normal value. This specification does not apply
for input voltages below 2.7V.
Note 23: Turn-on time is that between the enable input just exceeding VIH and the output voltage just reaching 95% of its nominal value.
Note 24: Range of capacitor values for which the device will remain stable. This electrical specification is guaranteed by design.
Note 25: Range of capacitor ESR values for which the device will remain stable. This electrical specification is guaranteed by design.
Note 26: The built-in thermal shut-down of the LDO is also used to put all Ai and Bi outputs in tristate mode.
Note 27: Additional information on lead temperature and pad temperature can be found in National Semiconductor Application Note (AN-1112).
Note 28: Unused inputs must be terminated.
Note 29: This electrical specification is guaranteed by design.
20039106
FIGURE 1. Output AC Line Regulation
20039107
FIGURE 2. PSRR Input Perturbation
Typical Performance Characteristics
Unless otherwise specified: CVBAT = 1 µF, CVCCA = 1 µF,
CVCCB = 1 µF, VBAT = 3.3V, VCCA = 1.8V, TA = 25˚C.
Level Shifter Propagation Delay A→B
Level Shifter Propagation Delay B→A
20039109
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20039110
8
Power Supply Rejection Ratio (VBAT=3.46V)
20039108
ceramic capacitor is in the range of 20 mΩ to 40 mΩ, which
easily meets the ESR requirement for stability by the
LP3928.
Application Hints
EXTERNAL CAPACITORS
Like any low-dropout regulator, the LP3928 requires external
capacitors for regulator stability. The LP3928 is specifically
designed for portable applications requiring minimum board
space and smallest components. These capacitors must be
correctly selected for good performance.
The ceramic capacitor’s capacitance can vary with temperature.
Most large value ceramic capacitors (≅ 2.2 µF) are manufactured with Z5U or Y5V temperature characteristics, which
results in the capacitance dropping by more than 50% as the
temperature goes from 25˚C to 85˚C.
A better choice for temperature coefficient in ceramic capacitor is X7R, which holds the capacitance within ± 15%.
Tantalum capacitors are less desirable than ceramic for use
as output capacitors because they are more expensive when
comparing equivalent capacitance and voltage ratings in the
1 µF to 4.7 µF range.
Another important consideration is that tantalum capacitors
have higher ESR values than equivalent size ceramics. This
means that while it may be possible to find a tantalum
capacitor with an ESR value within the stable range, it would
have to be larger in capacitance (which means bigger and
more costly) than a ceramic capacitor with the same ESR
value. It should also be noted that the ESR of a typical
tantalum will increase about 2:1 as the temperature goes
from 25˚C down to −40˚C, so some guard band must be
allowed.
INPUT CAPACITOR
An input capacitance of ≅ 1 µF is required between the
LP3928 VBAT pin and ground (the amount of the capacitance
may be increased without limit).
This capacitor must be located a distance of not more than
1 cm from the VBAT pin and returned to a clean analog
ground. Any good quality ceramic, tantalum, or film capacitor
may be used at the input.
Important: Tantalum capacitors can suffer catastrophic failures due to surge current when connected to a lowimpedance source of power (like a battery or a very large
capacitor). If a tantalum capacitor is used at the input, it must
be guaranteed by the manufacturer to have a surge current
rating sufficient for the application.
There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be ≅ 1 µF over the entire operating temperature
range.
OUTPUT CAPACITOR
The LP3928 is designed specifically to work with very small
ceramic output capacitors, any ceramic capacitor (dielectric
types Z5U, Y5V or X7R) in 1.5 µF to 22 µF range with 5 mΩ
to 500 mΩ ESR range is suitable in the LP3928 application
circuit.
It may also be possible to use tantalum or film capacitors at
the output, but these are not as attractive for reasons of size
and cost (see section Capacitor Characteristics).
The output capacitor must meet the requirement for minimum amount of capacitance and also have an ESR (Equivalent Series Resistance) value which is within a stable range.
The output capacitor should be placed as near to the VCCB
pin as possible.
FAST ON-TIME
The LP3928 utilizes a speed up circuitry to ramp up the
internal VREF voltage to its final value to achieve a fast
output turn on time.
CAPACITOR CHARACTERISTICS
The LP3928 is designed to work with ceramic capacitors on
the output to take advantage of the benefits they offer: for
capacitance values in the range of 1 µF to 4.7 µF range,
ceramic capacitors are the smallest, least expensive and
have the lowest ESR values (which makes them best for
eliminating high frequency noise). The ESR of a typical 1 µF
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LP3928
Typical Performance Characteristics Unless otherwise specified: CVBAT = 1 µF, CVCCA = 1 µF,
CVCCB = 1 µF, VBAT = 3.3V, VCCA = 1.8V, TA = 25˚C. (Continued)
LP3928
Application Hints
The wavelengths which have most detrimental effect are
reds and infra-reds, which means that the fluorescent lighting used inside most buildings has very little effect on performance.
(Continued)
NO-LOAD STABILITY
The LDO of the LP3928 will remain stable and in regulation
with no external load connected to the LDO output VCCB.
This is especially important in CMOS RAM keep-alive applications.
A micro SMD test board was brought to within 1 cm of a
fluorescent desk lamp and the effect on the regulated output
voltage was negligible, showing a deviation of less thanTBD
from nominal.
LEVEL SHIFTER DIRECTION CONTROL AND LATCH
CLOCK
The direction of the level shifter is set to Ax →Bx by pulling
the DIRx pin to high. The direction of each of the three
channels can be set individually. In this mode a change at
the LatchClk pin has no effect.
A low at the DIRx pin sets the direction to Bx→Ax. If EN2 is
set to high (enabling latch mode), a rising edge of LatchClk
will update Ax depending on the level at Bx. A falling edge of
LatchClk will not change Ax.
OPERATION MODES, EN1 AND EN2
The output of the LDO (VCCB) is turned off and the level
shifter channels are set to a high Z state by pulling the
enable input pins EN1 and EN2 low.
EN1=0 and EN2=1 turns the LDO on and the level shifter
off.
EN1=1 and EN2=0 turns the LDO on and the latch of the
level shifter is bypassed in B to A direction. The Latch Clock
is not used in this mode. The LatchClk pin should not be left
floating but actively terminated.
EN1=1 and EN2=1 turns the LDO on and activates the latch
in B to A direction.
MICRO SMD ASSEMBLY
For assembly recommendations of micro SMD package
please refer to National Semiconductor Application Note
AN-1112.
To assure proper operation, the signal source used to drive
the EN input pins must be able to swing above and below the
specified turn-on/off voltage thresholds listed in the Electrical
Characteristics section under Level Shifter DC Voltage Levels.
Both pins, EN1 and EN2 must be actively terminated.
MICRO SMD LIGHT SENSITIVITY
Exposing the micro SMD device to direct sunlight will cause
misoperation of the device. Light sources such as Halogen
lamps can effect electrical performance if brought near to the
device.
www.national.com
10
inches (millimeters) unless otherwise noted
micro SMD, 16 Bump
NS Package Number TLA16AAA
The Dimensions for X1, X2 and X3 are as follows:
X1 = 1.996mm
X2 = 1.996mm
X3 = 0.600mm
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
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Americas Customer
Support Center
Email: [email protected]
Tel: 1-800-272-9959
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Fax: +49 (0) 180-530 85 86
Email: [email protected]
Deutsch Tel: +49 (0) 69 9508 6208
English Tel: +44 (0) 870 24 0 2171
Français Tel: +33 (0) 1 41 91 8790
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
National Semiconductor
Asia Pacific Customer
Support Center
Fax: 65-6250 4466
Email: [email protected]
Tel: 65-6254 4466
National Semiconductor
Japan Customer Support Center
Fax: 81-3-5639-7507
Email: [email protected]
Tel: 81-3-5639-7560
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
LP3928 High Speed Bi-Directional Level Shifter and Ultra Low-Dropout CMOS Voltage Regulator
Physical Dimensions