TC1263
500mA Fixed Output CMOS LDO with Shutdown
FEATURES
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Very Low Dropout Voltage
Guaranteed 500mA Output
High Output Voltage Accuracy
Standard or Custom Output Voltages
Over-Current and Over-Temperature Protection
SHDN Input for Active Power Management
ERROR Output to Detect Low Battery (SOIC Only)
GENERAL DESCRIPTION
The TC1263 is a fixed output, high accuracy (typically
±0.5%)
CMOS low dropout regulator. Designed specifically
for battery-operated systems, the TC1263’s CMOS con-
struction eliminates wasted ground current, significantly
extending battery life. Total supply current is typically 80
µA
at full load
(20 to 60 times lower than in bipolar regulators
).
TC1263 key features include ultra low noise, very low
dropout voltage (typically 350mV at full load), and fast
response to step changes in load. The TC1263 incorporates
both over-temperature and over-current protection. The
TC1263 is stable with an output capacitor of only 1µF and
has a maximum output current of 500mA. It is available in
8-Pin SOIC, 5-Pin TO-220, and 5-Pin DDPAK packages.
APPLICATIONS
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Battery-Operated Systems
Portable Computers
Medical Instruments
Instrumentation
Cellular / GSM / PHS Phones
Linear Post-Regulator for SMPS
Pagers
ORDERING INFORMATION
Part
Number
TC1263-xxVOA
TC1263-xxVAT
TC1263-xxVET
Package
8-Pin SOIC
5-Pin TO-220
5-Pin DDPAK
Junction
Temp. Range
– 40°C to +125°C
– 40°C to +125°C
– 40°C to +125°C
PIN CONFIGURATION
5-Pin DDPAK
FRONT VIEW
TAB IS GND
5-Pin TO-220
TAB IS GND
Available Output Voltages:
2.5, 2.8, 3.0, 3.3, 5.0
xx indicates output voltages
Other output voltages are available. Please contact Microchip
Technology Inc. for details.
TC1263
TC1263
1 2
3 4 5
1 2 3 4 5
TYPICAL APPLICATION
BYP
SHDN
GND
V
IN
V
OUT
BYP
SHDN
GND
V
IN
V
OUT
8-Pin SOIC
V
OUT
GND
NC
BYPASS
1
2
3
4
8
7
V
IN
NC
SHDN
ERROR
V
IN
V
IN
V
OUT
V
OUT
C
OUT
1µF
SHDN
TC1263
GND
SHDN
TC1263
6
5
© 2001 Microchip Technology Inc.
DS21374A
TC1263-2 12/01/00
500mA Fixed Output CMOS LDO with
Shutdown
TC1263
ABSOLUTE MAXIMUM RATINGS*
Input Voltage .............................................................. 6.5V
Output Voltage ........................... (V
SS
– 0.3) to (V
IN
+ 0.3)
Power Dissipation .................... Internally Limited (Note 7)
Operating Temperature .................... – 40°C < T
J
< 125°C
Storage Temperature ............................ – 65°C to +150°C
Maximum Voltage on Any Pin ........... V
IN
+ 0.3V to – 0.3V
Lead Temperature (Soldering, 10 Sec.) ................ +260°C
*Absolute Maximum Ratings indicate device operation limits beyond
damage may occur. Device operation beyond the limits listed in Electrical
Characteristics is not recommended.
ELECTRICAL CHARACTERISTICS:
V
IN
= V
OUT
+ 1V, I
L
= 100
µA,
C
L
= 3.3µF, SHDN > V
IH
, T
A
= 25°C, unless
otherwise specified.
BOLDFACE
type specifications apply for junction tempera-
tures of – 40°C to +125°C.
Symbol
V
IN
I
OUTMAX
V
OUT
∆V
OUT
/∆T
∆V
OUT
/∆V
IN
∆V
OUT
/V
OUT
V
IN
– V
OUT
Parameter
Input Operating Voltage
Maximum Output Current
Output Voltage
V
OUT
Temperature Coefficient
Line Regulation
Load Regulation
Dropout Voltage
Test Conditions
(SOIC-8 TBD)
Note 1
Note 2
(V
R
+ 1V) < V
IN
< 6V
I
L
= 0.1mA to I
OUTMAX
(Note 3)
I
L
= 100µA
I
L
= 100mA
I
L
= 300mA
I
L
= 500mA
(Note 4)
SHDN = V
IH,
I
L
= 0
SHDN = 0V
F
RE
≤
1KHz
V
OUT
= 0V
Note 5
I
L
= I
OUTMAX
Min
Typ
Max
Units
V
mA
V
ppm/°C
%
%/mA
mV
—
—
6.0
500
—
—
—
V
R
±
0.5%
—
V
R
– 2.5%
—
V
R
+ 2.5%
—
40
—
—
0.05
0.35
—
0.002
0.01
—
20
30
—
60
130
—
200
390
—
350
650
—
—
—
—
—
—
60
—
80
0.05
64
1200
0.04
260
—
—
130
1
—
1400
—
—
—
15
I
DD
I
SHDN
PSRR
I
OUTSC
∆V
OUT
/∆P
D
eN
SHDN Input
V
IH
V
IL
Supply Current
Shutdown Supply Current
Power Supply Rejection Ratio
Output Short Circuit Current
Thermal Regulation
Output Noise
SHDN Input High Threshold
SHDN Input Low Threshold
µA
µA
dB
mA
V/W
nV/√Hz
%V
IN
%V
IN
ERROR Output (SOIC Only)
V
MIN
V
OL
V
TH
V
HYS
Minimum Operating Voltage
Output Logic Low Voltage
ERROR Threshold Voltage
ERROR Positive Hysteresis
1mA Flows to ERROR
Note 7
1.0
—
—
—
—
—
0.95 x V
R
50
—
400
—
—
V
mV
V
mV
NOTES:
1. V
R
is the regulator output voltage setting.
2. T
C
V
OUT
= (V
OUTMAX
– V
OUTMIN
) x 10
6
V
OUT
x
∆T
3. Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested over a load range
from 0.1mA to the maximum specified output current. Changes in output voltage due to heating effects are covered by the thermal regulation
specification.
4. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at a 1V
differential.
5. Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or
line regulation effects. Specifications are for a current pulse equal to I
LMAX
at V
IN
= 6V for T = 10msec.
6. The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature, and the
thermal resistance from junction-to-air (i.e. T
A
, T
J
,
θ
JA
). Exceeding the maximum allowable power dissipation causes the device to initiate
thermal shutdown. Please see
Thermal Considerations
section of this data sheet for more details.
7. Hysteresis voltage is referenced to V
R
.
TC1263-2 12/01/00
2
© 2001 Microchip Technology Inc.
DS21374A
500mA Fixed Output CMOS LDO with
Shutdown
TC1263
DETAILED DESCRIPTION
The TC1263 is a precision, fixed output LDO. Unlike
bipolar regulators, the TC1263 supply current does not
increase with load current. In addition, V
OUT
remains stable
and within regulation at very low load currents (an important
consideration in RTC and CMOS RAM battery backup
applications). Figure 1 shows a typical application circuit.
V
IN
1µF
C2
BATTERY
GND
V
OUT
1µF
C1
V
OUT
of timing capacitor C3). R1 x C3 should be chosen to
maintain ERROR below V
IH
of the processor RESET input
for at least 200 msec to allow time for the system to stabilize.
Pull-up resistor R1 can be tied to V
OUT
, V
IN
or any other
voltage less than (V
IN
+ 0.3V.)
V
OUT
V
TH
Hysteresis (V
H
)
TC1263
ERROR
V
IH
V
+
ERROR
R1
1M
BATTLOW
or RESET
SHDN
Shutdown Control
(to CMOS Logic or Tie
to V
IN
if unused)
V
OL
C3 Required Only
if ERROR is used as a
Processor RESET Signal
(See Text)
Figure 2: ERROR Output Operation
C3
0.2µF
Thermal Considerations
Thermal Shutdown
Integrated thermal protection circuitry shuts the regula-
tor off when die temperature exceeds 160°C. The regulator
remains off until the die temperature drops to approximately
150°C.
Power Dissipation
The amount of power the regulator dissipates is prima-
rily a function of input and output voltage, and output current.
The following equation is used to calculate worst case
actual
power dissipation:
P
D
≈
(V
INMAX
– V
OUTMIN
)I
LOADMAX
Where:
P
D
=
V
INMAX
=
V
OUTMIN
=
I
LOADMAX
=
worst case actual power dissipation
maximum voltage on V
IN
minimum regulator output voltage
maximum output (load) current
Equation 1.
Figure 1: Typical Application Circuit
Output Capacitor
A 1µF (min) capacitor from V
OUT
to ground is required.
The output capacitor should have an effective series resis-
tance of 5Ω or less, and a resonant frequency above 1 MHz.
A 1µF capacitor should be connected from V
IN
to GND if
there is more than 10 inches of wire between the regulator
and the AC filter capacitor, or if a battery is used as the power
source. Aluminum electrolytic or tantalum capacitor types
can be used. (Since many aluminum electrolytic capacitors
freeze at approximately –30°C, solid tantalums are recom-
mended for applications operating below –25°C.) When
operating from sources other than batteries, supply-noise
rejection and transient response can be improved by in-
creasing the value of the input and output capacitors and
employing passive filtering techniques.
ERROR Output
ERROR is driven low whenever V
OUT
falls out of regu-
lation by more than – 5% (typical). This condition may be
caused by low input voltage, output current limiting, or
thermal limiting.
The ERROR threshold is 5% below rated V
OUT
regard-
less of the programmed output voltage value (e.g., ERROR
= V
OL
at 4.75V (typ) for a 5.0V regulator and 2.85V (typ) for
a 3.0V regulator). ERROR output operation is shown in
Figure 2. Note that ERROR is active when V
OUT
is at or
below V
TH
, and inactive when V
OUT
is above V
TH
+ V
H
.
As shown in Figure 1, ERROR can be used as a battery
low flag, or as a processor RESET signal (with the addition
© 2001 Microchip Technology Inc.
DS21374A
The maximum
allowable
power dissipation (Equation 2)
is a function of the maximum ambient temperature (T
AMAX
),
the maximum allowable die temperature (125°C) and the
thermal resistance from junction-to-air (
JA
).
P
DMAX
=
(T
JMAX
– T
AMAX
)
JA
Where all terms are previously defined.
Equation 2.
3
TC1263-2 12/01/00
500mA Fixed Output CMOS LDO with
Shutdown
TC1263
Table 1 shows various values of
JA
for the TC1263
mounted on a 1/16 inch, 2-layer PCB with 1 oz. copper foil.
Table 1. Thermal Resistance Guidelines for TC1263 in
8-Pin SOIC Package
Copper
Area
(Topside)*
2500 sq mm
1000 sq mm
225 sq mm
100 sq mm
Copper
Area
(Backside)
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
Board
Area
2500 sq mm
2500 sq mm
2500 sq mm
2500 sq mm
Thermal
Resistance
(
JA
)
60°C/W
60°C/W
68°C/W
74°C/W
FIND: 1. Actual power dissipation
2. Maximum allowable dissipation
Actual power dissipation:
P
D
≈
(V
INMAX
– V
OUTMIN
)I
LOADMAX
= [(3.3 x 1.1) – (2.7 x .995)]275 x 10
-3
= 260mW
Maximum allowable power dissipation:
(T
JMAX
– T
AMAX
)
P
D
MAX
=
JA
=
=
NOTES:
*Pin 2 is ground. Device is mounted on topside.
(125 – 95)
59
508mW
Table 2. Thermal Resistance Guidelines for TC1263 in
3-Pin DDPAK/TO-220 Package
Copper
Area
(Topside)*
2500 sq mm
1000 sq mm
125 sq mm
Copper
Area
(Backside)
2500 sq mm
2500 sq mm
2500 sq mm
Board
Area
2500 sq mm
2500 sq mm
2500 sq mm
Thermal
Resistance
(
JA
)
25°C/W
27°C/W
35°C/W
In this example, the TC1263 dissipates a maximum of
only 260mW; far below the allowable limit of 508 mW. In a
similar manner, Equation 1 and Equation 2 can be used to
calculate maximum current and/or input voltage limits. For
example, the maximum allowable V
IN
is found by substitut-
ing the maximum allowable power dissipation of 508mW
into Equation 1, from which V
INMAX
= 4.6V.
NOTES:
*Tab of device attached to topside copper
Equation 1 can be used in conjunction with Equation 2
to ensure regulator thermal operation is within limits. For
example:
GIVEN:
V
INMAX
V
OUTMIN
I
LOAD
T
AMAX
JA
=
=
=
=
=
3.3V
±
10%
2.7V
±
0.5%
275mA
95°C
59°C/W
TC1263-2 12/01/00
4
© 2001 Microchip Technology Inc.
DS21374A
500mA Fixed Output CMOS LDO with
Shutdown
TC1263
TYPICAL CHARACTERISTICS
Line Regulation vs. Temperature
0.020
0.018
0.016
0.014
0.012
0.010
0.008
0.006
0.004
0.002
0.000
—40¡C 0¡C
0.0
25¡C
70¡C
85¡C 125¡C
0.01
0.01
1
10
100
1000
TEMPERATURE (¡C)
I
DD
vs. Temperature
150
135
0.25
Output Noise vs. Frequency
10.0
0.0100
R
LOAD
= 50 ‰
C
OUT
= 1 F
0.0090
0.0080
0.0070
0.0060
0.0050
0.0040
0.0030
0.0020
0.0010
Load Regulation vs. Temperature
1.0
LOAD REGULATION %/mA
LINE REGULATION (%)
NOISE ( V/√/ HZ)
2.5V
5V
1mA to 500mA
0.1
1mA to 500mA
0.0100
—40¡C
0¡C
25¡C
70¡C
85¡C
125¡C
FREQUENCY (KHz)
TEMPERATURE (¡C)
5.0V Dropout Voltage vs. I
LOAD
0.50
0.40
85¡C
0.30
70¡C
25¡C
0.20
0¡C
0.10
—40¡C
125¡C
2.5V Dropout Voltage vs. I
LOAD
DROPOUT VOLTAGE (V)
105
I
DD
( A)
90
75
60
45
30
15
0
—40¡C 0¡C
2.5V
5V
0.15
TC1315-4.85
0.1
TC1315-5.0
0.05
DROPOUT VOLTAGE (V)
120
0.2
TC1315-3.3
0
0.00
0
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
25¡C
70¡C
85¡C 125¡C
0
100
200
300
400
500
TEMPERATURE (¡C)
2.5V VOUT VS. Temperature
2.70
2.50
2.30
I
L
= 0.1mA
5.20
5.10
5.00
4.90
4.80
4.70
4.60
4.50
4.40
4.30
4.20
4.10
4.00
—40¡C
I
OUT
(A)
5.0V VOUT VS. Temperature
—30dB
I
L
= 0.1mA
I
LOAD
(mA)
Power Supply Rejection Ratio
V
OUT
= 3V
—35dB R
LOAD
= 50‰
V
INAC
= 50mVp-p
—40dB
—45dB
VOUT (V)
2.10
1.90
1.70
I
L
= 300mA
I
L
= 500mA
I
L
= 300mA
I
L
= 500mA
PSRR (dB)
VOUT (V)
—50dB
—55dB
—60dB
—65dB
—70dB
—75dB
C
OUT
= 1 F
1.50
—40¡C
0¡C
25¡C
70¡C
85¡C
125¡C
0¡C
25¡C
70¡C
85¡C
125¡C
—80dB
10
100
1K
10K
100K 1M
FREQUENCY (KHz)
TEMPERATURE (¡C)
TEMPERATURE (¡C)
© 2001 Microchip Technology Inc.
DS21374A
5
TC1263-2 12/01/00
Industrial Control Electronics
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