SPX1121N-L-2.5 [SIPEX]
Fixed Positive LDO Regulator, 2.5V, 0.7V Dropout, PBCY3, TO-92, 3 PIN;
| 型号： | SPX1121N-L-2.5 |
| 厂家： | 
SIPEX CORPORATION |
| 描述： | Fixed Positive LDO Regulator, 2.5V, 0.7V Dropout, PBCY3, TO-92, 3 PIN 输出元件 调节器 |
| 文件： | 总6页 (文件大小：157K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SPX1121
150mA Low Dropout Voltage Regulator
FEATURES
APPLICATIONS
• Battery Powered Systems
• Cordless Telephones
• 1% Output Accuracy @ 2.5V, 3.3V, 5V, @ 150mA Output
• Very Low Quiescent Current
• Radio Control Systems
• Portable/Palm Top/Notebook Computers
• Portable Consumer Equipment
• Portable Instrumentation
• Bar Code Scanners
• 0.4V Dropout Voltage @ 150mA
• Extremely Tight Load And Line Regulation
• Current & Thermal Limiting
• Logic-Controlled Electronic Shutdown
• Reverse Battery Protection
• Output Programmable From 1.24 To 29V
• Equivalent Replacement For LT1121
• SMPS Post-Regulator
• Voltage Reference
• Automotive Electronics
PRODUCT DESCRIPTION
The SPX1121 is a low power voltage regulator. This device is an excellent choice for use in battery-powered applications such as
cordless telephones, radio control systems, and portable computers. The SPX1121 features very low quiescent current and very low
dropout voltage of 0.4 volts. This includes a tight initial tolerance of 1% max, and very low output temperature coefficient, making
the SPX1121 useful as a low-power voltage reference.
The error flag output feature is used as power-on reset for warning of a low output voltage, due to falling voltage input of batteries.
The SPX1121 is offered SO-8, TO-92 & SOT-223.
PIN CONNECTIONS
8-Pin Surface Mount (S)
SOT-223 (M3)
SPX1121
TO-92 (N)
1
2
3
VIN
GND
VOUT
SENSE/ ADJ
GND
1
2
3
4
8
7
6
5
1
2
3
SPX1121
GND
VOUT
VIN
GND
VIN
GND VOUT
SHDN
ERROR
Bottom View
Top View
Top View
VOUT
SHDN
OFF
ON
ON
<0.25V
>2.8V
NC
Rev.10/24/00
SPX1121
ABSOLUTE MAXIMUM RATINGS
Power Dissipation……………………...… Internally Limited
Lead Temp. (Soldering, 5 Seconds)…………….……. 260°C
Storage Temperature Range……………… -65°C to + 150°C
Operating Junction Temperature Range
Input Supply Voltage ........................................................ +30V
Shutdown Input Voltage ...................................... -0.6V to 6.5V
ESD Rating is to be determined
SPX1121……………………………..… -40°C to + 125°C
ELECTRICAL CHARACTERISTICS at V = ±15V, Ta = 25°C, unless otherwise specified.
apply over the full
Boldface
s
operating temperature range.
Parameter
Typ.
UNITS
Conditions
SPX1121
Min
Max
(Note 2)
2.5V Version
Output Voltage
2.5
2.5
16
2.475
2.525
2.550
25
V
µA
V
2.450
1mA ≤IL ≤ 150mA
Reverse Output Current
3.3V Version
Output Voltage
SPX1121-2.5 VOUT = 2.5V, VIN = 0V
3.3
3.3
16
3.267
3.217
3.333
3.382
25
1mA ≤IL ≤ 150mA
SPX1121-3.3 VOUT = 3.3V, VIN = 0V
Reverse Output Current
5V Version
Output Voltage
µA
V
5.0
5.0
16
4.950
4.880
5.050
5.120
25
1mA ≤IL ≤ 150mA
SPX1121-5.0 VOUT = 5.0V, VIN = 0V
Reverse Output Current
µA
All Voltage Options
Output Voltage
20
ppm/°C
100
10
0.6
0.9
0.16
0.25
0.55
0.70
150
500
2.5
7.0
14
Temperature Coefficient
Line Regulation ( Note 3)
(Note 1)
1.5
0.4
mV
%
6V ≤ VIN ≤30V (Note 4)
Load Regulation ( Note 3 )
IL = 1 to 150mA
IL = 0.1 to 1mA
IL = 1mA
Dropout Voltage
( Note 5 )
0.13
0.42
V
IL = 150mA
Groond Current
IL = 1mA
100
350
1.5
4.0
7
µA
IL = 10mA
IL = 50mA
IL = 100mA
IL = 150mA
mA
Current Limit
Ripple Rejection
VOUT = 0
200
58
500
VIN – VOUT 1V (Avg), VRIPPLE = 0.5Vp-p
fripple = 120Hz, ILOAD = 150mA, TJ = 25°C
VIN = -20V, VOUT = 0V
50
dB
Input Reverse Leakage Current
1.0
mA
Rev.10/24/00
SPX1121
Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2: Unless otherwise specified all limits are guaranteed for Tj = 25°C, VIN = 6V, IL = 100µA and CL = 1µF. Additional conditions for the 8-pin versions are
feedback tied to 5V tap and output tied to output sense (VOUT = 5V) and VSHUTDOWN ≤ 0.8V.
Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are
covered under the specification for thermal regulation.
Note 4: Line regulation for the SPX1121 is tested at 150°C for IL = 1 mA. For IL = 100µA and TJ = 125°C, line regulation is guaranteed by design to 0.2%. See
typical performance characteristics for line regulation versus temperature and load current.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V differential at
very low values of programmed output voltage, the minimum input supply voltage of 2V ( 2.3V over temperature) must be taken into account.
Note 6: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at 6V input. To
express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example, at a programmed output
voltage of 5V, the Error output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds remain constant as a percent of VOUT as
VOUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
APPLICATION HINTS
This problem can be fixed by adding a 100pF capacitor between
output and feedback and increasing the output capacitor to at least
3.3µF.
EXTERNAL CAPACITORS
The stability of the SPX1121 requires a 2.2µF or greater
capacitor between output and ground. Oscillation could occur
without this capacitor. Most types of tantalum or aluminum
electrolytic works fine here. For operations of below -25°C solid
tantalum is recommended since the many aluminum types have
electrolytes the freeze at about -30°C. The ESR of about 5Ω or
less and resonant frequency above 500kHz are the most
important parameters in the value of the capacitor. The capacitor
value can be increased without limit.
ERROR DETECTION COMPARATOR OUTPUT
The Comparator produces a logic low output whenever the SPX1121
output falls out of regulation by more than around 5%. This is around
60mV offset divided by the 1.235 reference voltage. This trip level
remains 5% below normal regardless of the programmed output
voltage of the regulator. Figure 1 shows the timing diagram depicting
the ERROR signal and the regulator output voltage as the SPX1121
input is ramped up and down. The ERROR signal becomes low at
around 1.3V input, and goes high around 5V input (input voltage at
which Vout = 4.75). Since the SPX1121’s dropout voltage is load
dependent, the input voltage trip point (around 5V) will vary with the
load current. The output voltage trip point (approx. 4.75V) does not
vary with load.
At lower values of output current, less output capacitance is
required for stability. For the currents below 10mA the value of
the capacitor can be reduced to 0.5µF and 0.15µF for 1mA. More
output capacitance needed for the 8-pin version at voltages below
5V since it runs the error amplifier at lower gain. At worst case
5µF or greater must be used for the condition of 250mA load at
1.23V output.
The error comparator has an open-collector output, which requires an
external pull-up resistor. Depending on the system requirements the
resistor may be returned to 5V output or other supply voltage. In
determining the value of this resistor, note that the output is rated to
sink 400µA, this value adds to battery drain in a low battery
condition. Suggested values range from 100K to 1MΩ. If the output
is unused this resistor is not required.
The SPX1121, unlike other low dropout regulators will remain
stable and in regulation with no load in addition to the internal
voltage divider.
This feature is especially important in
application like CMOS RAM keep-alive. When setting the output
voltage of the SPX1121,
recommended.
a minimum load of 10mA is
If there is more than 10 inches of wire between the input and the
AC filter capacitor or if a battery is used as the input then a 0.1µF
tantalum or aluminum electrolytic capacitor should be placed
from the input to the ground.
PROGRAMMING THE OUTPUT VOLTAGE OF
SPX1121
The SPX1121 may be pin-strapped for 5V using its internal voltage
divider by tying Pin 1 (output) to Pin 2 (sense) and Pin 7 (feedback)
to Pin 6 (5V Tap).
Instability can occur if there is stray capacitance to the SPX1121
feedback terminal (pin 7). This could cause more problems when
using a higher value of external resistors to set the output voltage.
4 .7 5 V
O U T P U T
V O L T A G E
_ _ _ _ _ _ _
E R R O R *
+
+
+
5 .0 V
I N P U T
V O L T A G E
+
1 .3 V
*
S e e A p p lic a t io n In f o .
_ _ _ _ _ _ _
F ig u r e 1 . E R R O R O u tp u t T im in g
Rev.10/24/00
SPX1121
Also, it may be programmed for any output voltage between its
1.235V reference and its 30V maximum rating. As seen in
Figure 2, an external pair of resistors is required.
Refer to the below equation for the programming of the output
voltage::
REDUCING OUTPUT NOISE
It may be an advantage to reduce the AC noise present at the output.
One way is to reduce the regulator bandwidth by increasing the size of
the output capacitor. This is the only way that noise can be reduced
on the 3 lead SPX1121 but is relatively inefficient, as increasing the
capacitor from 1µF to 220µF only decreases the noise from 430µV to
160µV Vrms for a 100kHz bandwidth at 5V output.
V
OUT = VREF × ( 1 + R1\ R2 )+ IFBR1
Noise could also be reduced fourfold by a bypass capacitor across R1,
since it reduces the high frequency gain from 4 to unity. Pick
The VREF is 1.235 and IFB is the feedback bias current, nominally
-20nA. The minimum recommended load current of 1 µA forces
an upper limit of 1.2 MΩ on value of R2. If no load is presented
the IFB produces an error of typically 2% in VOUT, which may be
eliminated at room temperature by trimming R1. To improve the
accuracy choose the value of R2 = 100k this reduces the error by
0.17% and increases the resistor program current by 12µA. Since
the SPX1121 typically draws 60 µA at no load with Pin 2 open-
circuited this is a small price to pay
C
BYPASS ≅ 1 / 2πR1 × 200 Hz
or choose 0.01µF. When doing this, the output capacitor must be
increased to 3.3µF to maintain stability. These changes reduce the
output noise from 430µV to 100µV Vrms for a 100kHz bandwidth at
5V output. With the bypass capacitor added, noise no longer scales
with output voltage so that improvements are more dramatic at higher
output voltages.
HEAT SINK REQUIREMENTS
Depending on the maximum ambient temperature and maximum
power dissipation a heat sink may be required with the SPX1121.
The junction temperature range has to be within the range
specified under Absolute Maximum Ratings under all possible
operating conditions. To find out if a heat sink is required, the
maximum power dissipation of the device needs to be calculated.
This is the maximum specific AC voltage that must be taken into
consideration at input. Figure 3 shows the condition and power
dissipation which should be calculated with the following
formula:
IIN
5V
VIN
OUT
SPX1121
IN
IL
P
TOTAL = (VIN - 5) IL + (VIN)IG
LOAD
+
Next step is to calculate the temperature rise TR (max). TJ (max)
maximum allowable junction temperature, TA (max) maximum
ambient temperature :
+
2.2 uF
GND
IIN = IL = IG
IG
TR (max) = TJ (max) - TA (max)
Junction to ambient thermal resistance θ(j-A) can be calculated
after determining of PTOTAL & TR (max):
Figure 3. 5V Regulator Circuit
θ(J-A) = TR (max)/P(max)
If the θ(J-A) is 60°C/W or higher, the device could be operated
without a heat sink. If the value is below 60°C/W then the heat
sink is required and the thermal resistance of the heat sink can be
calculated by the following formula, θ(J-C) junction to case, θ(C-H)
case to heat sink, θ(H-A) heat sink to ambient:
θ(J-A) = θ(J-C) + θ(C-H) + θ(H-A)
Rev.10/24/00
SPX1121
TYPICAL APPLICATIONS
+VIN
*VOUT = 5V
SPX1121
+
10uF
GND
SPX1121 FIXED +5V REGULATOR
VOUT
+VIN
SPX1121
R1
GND
R2
SPX1121 ADJUSTABLE REGULATOR
Rev.10/24/00
SPX1121
ORDERING INFORMATION
Ordering No.
SPX1121S
Precision
1%
Output Voltages
Packages
8 Lead SOIC
8 Lead SOIC
8 Lead SOIC
8 Lead SOIC
3 Lead TO-92
3 Lead TO-92
3 Lead TO-92
3 Lead TO-92
3 Lead TO-223
3 Lead TO-223
3 Lead TO-223
3 Lead TO-223
Adj
2.5V
3.3V
5.0V
Adj
1%
SPX1121S-2.5
SPX1121S-3.3
SPX1121S-5.0
SPX1121N
1%
1%
1%
1%
2.5V
3.3V
5.0V
Adj
SPX1121N-2.5
SPX1121N-3.3
SPX1121N-5.0
SPX1121M3
1%
1%
1%
1%
2.5V
3.3V
5.0V
SPX1121M3-2.5
SPX1121M3-3.3
SPX1121M3-5.0
1%
1%
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation
Headquarters and Main Offices:
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 935-7600
FAX: (408) 934-7500
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described
hereing; neither does it convey any license under its patent rights nor the rights of others.
Rev.10/24/00
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