SPX2700/01/02
700mA Low Dropout Voltage Regulators
With Shutdown
(PRELIMINARY INFORMATION)
FEATURES
•
Output Current 700mA at 3.3V and 5V
•
Internal Short Circuit Current Limit
•
Dropout Voltage 0.5V at 700mA Output
•
Extremely Tight Load and Line Regulation
•
Very Low Temperature Coefficient
•
Mirror Image Insertion Protection
•
Unregulated DC Input Can Withstand -20V Reverse Battery
and +60V Positive Transients
•
Direct Replacement For LM2937 Socket
APPLICATIONS
•
Battery Powered Systems
•
Cordless Telephones
•
Automotive Electronics
•
Portable/ Palm Top / Notebook Computers
•
Portable Consumer Equipment
•
Portable Instrumentation
•
SMPS Post-Regulator
•
Voltage Reference
PRODUCT DESCRIPTION
The SPX2700/01/02 are a low power positive voltage regulators. The SPX2700/01/02 offers 700mA output current with a dropout
voltage of only 0.5V and over temperature dropout is up to 1V. The quiescent current is 10mA at differential output of 5V and output
current of 700mA. A higher quiescent current can exist when the device is in dropout mode (V
IN
-V
OUT
≤
3V).
The regulator will automatically shut down to protect both the internal circuits and the load. This device also features short circuit and
thermal overload protection.
The SPX2700/01/02 is offered in 3 and 5 pin TO-220, TO-263 and 3-pin SOT-223 packages compatible with other 5V and 3.3V
regulators, TO-263 and 3-pin SOT-223. The device is offered in standard output voltages of 5V and 3.3V as well as in adjustable
output regulator.
PIN CONNECTIONS
TO-263-5 (T)
TO-220-5 (U)
TO-220-3 (U)
TO-263-3 (T)
SOT-223 (M3)
SPX
2700/01/02
1 2 3 4 5
SPX2700
SPX
2701/02
1 2 3 4 5
Five Lead Package Pin Functions:
1)
2)
3)
4)
5)
Error
Input
GND
Output
Shutdown
Adjust
Shutdown
GND
Input
Output
SPX2700
1
2
3
SPX2700
3
1
2
3
1
2
V
IN
GND V
OUT
V
IN
GND V
OUT
Top View
Top View
Front View
Top View
V
IN
GND V
OUT
Front View
Rev. 10/25/00
SPX2700/01/02
ABSOLUTE MAXIMUM RATINGS
Power Dissipation..........................................Internally Limited
Lead Temp. (Soldering, 10 Seconds) .............................. 260°C
Feedback Input Voltage...................................... -1.5V to +30V
Shutdown Input Voltage..................................... -0.3V to +30V
Error Comparator Output ................................... -0.3V to +30V
Continuous ......................... +12V
Transient................-20V to +60V
Storage Temperature Range .........................-65° to +150°C
Operating Junction Temperature Range ..... -40°C to +125°C
ESD Rating
.....................................2KV Min
Input Supply Voltage
ELECTRICAL CHARACTERISTICS
at V
IN
= V
O
+ 5V, I
O
= 700mA, C
O
= 10
µF,
unless otherwise specified. Limits in
Boldface
type apply over the entire operating temperature range. All other specifications are T
A
= 25°C.
Parameter
Conditions
Typ.
SPX2700/01/02A
SPX2700/01/02
(Note 2)
Min
Max Min
Max
3.3V Version
Output Voltage
-40°C≤TJ≤+125°C
1mA≤ I
L
≤500mA
5V Version
Output Voltage
-40°C≤TJ≤+125°C
1mA≤ I
L
≤700mA
All Voltage Options
Output Voltage
Temperature Coefficient
Line Regulation (Note 3)
Load Regulation (Note 3)
Dropout Voltage (Note 5)
3.3
3.3
3.267
3.217
3.333
3.382
3.234
3.185
3.366
3.415
Units
V
5.0
5.0
4.950
4.880
5.050
5.120
4.900
4.870
5.100
5.130
V
20
(Note1)
6V≤ V
IN
≤30V
(Note4)
I
L
= 1 to 700
I
L
= 0.1 to 1mA
I
L
= 1mA
I
L
= 700mA
0.03
0.04
60
375
100
4.5
15
I
L
= 700mA
20
100
0.1
0.40
0.20
0.30
100
150
400
500
150
180
2
2.5
14
16
20
22
700
800
0.2
1.0
0.60
1.0
150
0.20
0.80
0.30
0.50
100
150
400
500
150
180
2
2.5
14
16
20
22
700
800
0.2
0.60
ppm/°C
%max
%max
mV
Ground Current
I
L
= 1mA
µA
mA
Current Limit
Thermal Regulation
Output Noise, 10Hz to 100kHz
IL = 100mA
Adjustable Versions Only
Reference Voltage
Feedback Pin Bias Current
Reference Voltage Temperature
Coefficient
Feedback Pin Bias Current
Temperature Coefficient
V
OUT
= 0
0.05
C
L
= 2.2µF
C
L
= 33µF
Over Temperature
(Note 6)
400
200
1.235
20
(Note 7)
50
0.1
mA
%/w
µV
Vrms
V
nA
ppm/°C
NA/°C
1.210
1.200
1.185
1.260
1.270
1.285
40
60
1.200
1.980
1.185
1.270
1.272
1.285
60
80
Rev. 10/25/00
SPX2700/01/02
ELECTRICAL CHARACTERISTICS
at V
IN
= V
O
+ 5V, I
O
= 700mA, C
O
= 22
µF,
unless otherwise specified. Limits in
Boldface
type apply over the entire operating temperature range. All other specifications are T
A
= 25°C
.
Parameter
Conditions
Typ.
SPX2700/01/02A
SPX2700/01/02
Min
Max Min
Max
Error Comparator
Output Leakage Current
Output Low Voltage
Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis
Shutdown Input
Input Logic Voltage
Shutdown Pin Input Current
V
OH
= 30V
VIN = 4.5V
IOL = 400µA
(Note 8)
(Note 8)
(Note 8)
Low (Regulator ON)
High (Regulator OFF)
VS = 2.4V
VS = 30V
Regulator Output Current In
Shutdown
0.01
150
60
75
15
0.7
2.0
30
450
3
50
100
600
750
10
20
2.0
90
150
800
1000
15
25
µA
0.7
40
25
95
140
1.00
2.00
250
400
40
25
95
140
1.00
2.00
250
400
Units
µA
mV
mV
mV
mV
V
µA
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 T
j
= 25°C, V
IN
= 6V, I
L
= 100µA and C
L
= 1µF. Additional conditions for the 8-pin versions are
feedback tied to 5V tap and output tied to output sense (V
OUT
= 5V) and V
SHUTDOWN
≤
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 SPX2700/01/02 is tested at 150°C for I
L
= 1 mA. For I
L
= 100µA and T
J
= 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:
V
REF
≤V
OUT
≤
(Vin - 1V), 2.3
≤Vin≤30V,
100µA≤I
L
≤
250 mA, T
J
≤
T
JMAX
.
Note 7:
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 = V
OUT
/V
REF
= (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 V
OUT
as
V
OUT
is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
Note 8:
V
SHUTDOWN
≥
2V, V
IN
≤
30V, V
OUT
=0, Feedback pin tied to 5V Tap.
Note 9:
The junction -to-ambient thermal resistance of the TO-92 package is 180°C/ W with 0.4” leads and 160°C/ W with 0.25” leads to a PC board.
The thermal resistance of the 8-Pin DIP package is 105°C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient thermal resistance for the
SOIC (S) package is 160°C/W.
UNREGULATED DC
5V @ 700mA
MAX
FEEDBACK
INPUT
OUTPUT
+
SENSE
+
_
FROM
CMOS OR
TTL
180k
Ω
..
ERROR
AMPLIFIER
60k
Ω
..
+
60 mV
+ 1.23V
REFERENCE
+
_
ERROR DETECTION
COMPARATOR
______
ERROR
5V TAP
+
1
µ
F
..
330k
Ω
..
SHUTDOWN
TO CMOS OR
TTL
GROUND
SPX2700/01/02 Block Diagram
Rev. 10/25/00
SPX2700/01/02
APPLICATION HINTS
EXTERNAL CAPACITORS
The stability of the SPX2700/01/02 requires a 10µF 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 below -25°C solid
tantalum is recommended since the many aluminum types have
electrolytes that freeze at about -30°C. The ESR of about 5Ω or less
and resonant frequency above 500 kHz are the most important
parameters in the value of the capacitor. The capacitor value may be
increased without limit.
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 22µF and 0.15µF for 1mA. More output
capacitance is needed for the 8-pin version at voltages below 5V
since it runs the error amplifier at lower gain. At worst case 22µF or
greater must be used for the condition of 750mA load at 1.23V
output.
The SPX2700/01/02, 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 applications
like CMOS RAM keep-alive. When setting the output voltage of the
SPX2700/01/02 version with external resistors, a minimum load of
5mA is recommended. 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 1µA tantalum or aluminum electrolytic capacitor
should be placed from the input to the ground.
ERROR DETECTION COMPARATOR OUTPUT
4.75V
OUTPUT
VOLTAGE
_______
ERROR*
high around 5V input (input voltage at which Vout = 4.75 ). Since
the SPX2700/01/02’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.
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 250µA, 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.
PROGRAMMING
THE
OUTPUT
VOLTAGE
OF
SPX2700/01/02
The SPX2700/01/02 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:
V
OUT
= V
REF
×
(1 + R
1
\ R
2
)+ I
FB
R
1
The V
REF
is 1.235 and I
FB
is the feedback bias current, nominally -20
nA. The minimum recommended load current of 1µA forces an
upper limit of 1.2 MΩ on value of R
2
. If no load is presented the I
FB
produces an error of typically 2% in V
OUT
, which may be eliminated
at room temperature by trimming R
1
. To improve the accuracy
choose the value of R
2
= 100k this reduces the error by 0.17% and
increases the resistor program current by 12µA. Since the
SPX2700/01/02 typically draws 100µA at no load with
SHUTDOWN open-circuited this is a small price to pay
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 SPX2700/01/02 but is relatively inefficient, as
increasing the capacitor from 1µF to 220µF only decreases the noise
from 430µV to 160µV
RMS
for a 100 kHz bandwidth at 5V output.
Noise could also be reduced fourfold by a bypass capacitor across R
1
,
since it reduces the high frequency gain from 4 to unity. Pick
+
5.0V
INPUT
VOLTAGE
+
1.3V
+
+
C
BYPASS
≅
1 / 2πR
1
×
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
RMS
for a 100 kHz 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.
SHUTDOWN
V
OUT
V
IN
* See Application Info.
_______
Figure 1. ERROR Output Timing
The Comparator produces a logic low output whenever the
SPX2700/01/02 output falls out of regulation by more than around
5%. This is around 75mV 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 SPX2700/01/02 input is ramped up and down. The
ERROR signal becomes low at around 1.3V input, and goes
SPX2703
GND
ADJ
Fig.2 Adjustable Voltage Regulator
Rev. 10/25/00
PCB Design
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