TC1262
500mA Fixed Output CMOS LDO
Features
•
•
•
•
•
Very Low Dropout Voltage
500mA Output Current
High Output Voltage Accuracy
Standard or Custom Output Voltages
Over Current and Over Temperature Protection
Package Type
3-Pin TO-220
Tab is GND
3-Pin DDPAK
Front View
Tab is GND
TC1262
1
2
3
TC1262
1
2
3
Applications
•
•
•
•
•
•
•
Battery Operated Systems
Portable Computers
Medical Instruments
Instrumentation
Cellular/GSM/PHS Phones
Linear Post-Regulators for SMPS
Pagers
V
OUT
GND
Front View
3
Tab is GND
V
OUT
2
GND
Device Selection Table
Part Number
TC1262-xxVDB
TC1262-xxVAB
TC1262-xxVEB
Package
3-Pin SOT-223
3-Pin TO-220
3-Pin DDPAK
Junction
Temp. Range
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
TC1262
1
V
IN
General Description
The TC1262 is a fixed output, high accuracy (typically
±0.5%) CMOS low dropout regulator. Designed specif-
ically for battery-operated systems, the TC1262’s
CMOS construction eliminates wasted ground current,
significantly extending battery life. Total supply current
is typically 80
µ
A at full load (20 to 60 times lower than
in bipolar regulators).
TC1262 key features include ultra low noise operation,
very low dropout voltage (typically 350mV at full load),
and fast response to step changes in load.
The TC1262 incorporates both over temperature and
over current protection. The TC1262 is stable with an
output capacitor of only 1µF and has a maximum
output current of 500mA. It is available in 3-Pin
SOT-223, 3-Pin TO-220 and 3-Pin DDPAK packages.
NOTE:
xx indicates output voltages.
Available Output Voltages: 2.5, 2.8, 3.0, 3.3, 5.0.
Other output voltages are available. Please contact Microchip
Technology Inc. for details.
Typical Application
V
IN
V
IN
V
OUT
+
C1
1µF
V
OUT
TC1262
GND
2002 Microchip Technology Inc.
DS21373B-page 1
V
OUT
V
IN
GND
V
IN
3-Pin SOT-223
©
TC1262
1.0
ELECTRICAL
CHARACTERISTICS
*Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to the device. These
are stress ratings only and functional operation of the device
at these or any other conditions above those indicated in the
operation sections of the specifications is not implied.
Exposure to Absolute Maximum Rating conditions for
extended periods may affect device reliability.
Absolute Maximum Ratings*
Input Voltage .........................................................6.5V
Output Voltage.................. (V
SS
– 0.3V) to (V
IN
+ 0.3V)
Power Dissipation................Internally Limited
(Note 6)
Maximum Voltage on Any Pin ........ V
IN
+0.3V to -0.3V
Operating Temperature Range...... -40°C < T
J
< 125°C
Storage Temperature.......................... -65°C to +150°C
TC1262 ELECTRICAL SPECIFICATIONS
Electrical Characteristics:
V
IN
= V
OUT
+ 1V, I
L
= 100µA, C
L
= 3.3µF, T
A
= 25°C, unless otherwise noted.
Boldface
type
specifications apply for junction temperatures of -40°C to +125°C.
Symbol
V
IN
I
OUT
MAX
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
Min
2.7
500
Typ
—
—
Max
6.0
—
—
V
R
+ 2.5%
—
0.35
0.01
30
130
390
650
130
—
—
—
—
Units
V
mA
V
ppm/°C
%/V
%/mA
mV
Note 1
Note 2
(V
R
+ 1V)
≤
V
IN
≤
6V
I
L
= 0.1mA to I
OUT
MAX
(Note 3)
I
L
= 100µA
I
L
= 100mA
I
L
= 300mA
I
L
= 500mA
(Note 4)
I
L
= 0
F
RE
≤
1kHz
V
OUT
= 0V
Note 5
I
L
= I
OUT
MAX
, F
RE
= 10kHz
Note 7
Test Conditions
—
V
R
±0.5%
V
R
– 2.5%
—
—
—
—
—
—
—
—
—
—
—
—
40
.003
0.002
20
60
200
350
80
64
1200
0.04
260
I
DD
PSRR
I
OUT
SC
∆V
OUT
/∆P
D
eN
Note
1:
2:
3:
Supply Current
Power Supply Rejection Ratio
Output Short Circuit Current
Thermal Regulation
Output Noise
µA
dB
mA
V/W
nV/√Hz
4:
5:
6:
7:
V
R
is the regulator output voltage setting.
TC V
OUT
= (V
OUT
MAX
– V
OUT
MIN
) x 10
6
V
OUT
x
∆T
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.
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.
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
L
MAX
at V
IN
= 6V for T = 10 msec.
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 Section 4.0 Thermal Considerations for more details.
The minimum V
IN
has to justify the conditions: V
IN
≥
V
R
+ V
DROPOUT
and V
IN
≥
2.7V for I
L
= 0.1mA to I
OUT
MAX
.
©
DS21373B-page 2
2002 Microchip Technology Inc.
TC1262
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
Pin No.
(3-Pin SOT-223)
(3-Pin TO-220)
(3-Pin DDPAK)
1
2
3
PIN FUNCTION TABLE
Symbol
Description
V
IN
GND
V
OUT
Unregulated supply input.
Ground terminal.
Regulated voltage output.
3.0
DETAILED DESCRIPTION
3.1
Output Capacitor
The TC1262 is a precision, fixed output LDO. Unlike
bipolar regulators, the TC1262’s supply current does
not increase with load current. In addition, V
OUT
remains stable and within regulation over the entire
0mA to I
LOAD
MAX
load current range (an important
consideration in RTC and CMOS RAM battery back-up
applications).
Figure 3-1 shows a typical application circuit.
FIGURE 3-1:
TYPICAL APPLICATION
CIRCUIT
+
V
IN
C1
1µF
V
OUT
+
V
OUT
C2
1µF
+
Battery
–
TC1262
GND
A 1µF (min) capacitor from V
OUT
to ground is required.
The output capacitor should have an effective series
resistance greater than 0.1Ω and less than 5Ω, and a
resonant frequency above 1MHz. 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 recommended for applications operating
below -25°C.) When operating from sources other than
batteries, supply-noise rejection and transient
response can be improved by increasing the value of
the input and output capacitors and employing passive
filtering techniques.
2002 Microchip Technology Inc.
DS21373B-page 3
©
TC1262
4.0
4.1
THERMAL CONSIDERATIONS
Thermal Shutdown
TABLE 4-2:
Integrated thermal protection circuitry shuts the
regulator off when die temperature exceeds 160°C.
The regulator remains off until the die temperature
drops to approximately 150°C.
THERMAL RESISTANCE
GUIDELINES FOR TC1262 IN
3-PIN DDPAK/TO-220
PACKAGE
Copper
Area
(Backside)
Board
Area
Thermal
Resistance
(θ
JA
)
25°C/W
27°C/W
35°C/W
Copper
Area
(Topside)*
4.2
Power Dissipation
2500 sq mm 2500 sq mm 2500 sq mm
1000 sq mm 2500 sq mm 2500 sq mm
125 sq mm
2500 sq mm 2500 sq mm
The amount of power the regulator dissipates is
primarily a function of input and output voltage, and
output current. The following equation is used to
calculate worst case actual power dissipation:
*Tab of device attached to topside copper
Equation 4-1 can be used in conjunction with Equation
4-2 to ensure regulator thermal operation is within
limits. For example:
Given:
V
IN
MAX
= 3.3V ± 10%
V
OUT
MIN
= 2.7V ± 0.5%
I
LOAD
MAX
= 275mA
T
J
MAX
T
A
MAX
θ
JA
= 125°C
= 95°C
= 59°C/W (SOT-223)
EQUATION 4-1:
P
D
≈
(V
IN
MAX
– V
OUT
MIN
)I
LOAD
MAX
Where:
P
D
=
V
IN
MAX
=
V
OUT
MIN
=
I
LOAD
MAX
=
Worst case actual power dissipation
Maximum voltage on V
IN
Minimum regulator output voltage
Maximum output (load) current
The maximum allowable power dissipation (Equation
4-2) is a function of the maximum ambient temperature
(T
A
MAX
), the maximum allowable die temperature
(T
J
MAX
) and the thermal resistance from junction-to-air
(θ
JA
).
Find: 1. Actual power dissipation
2. Maximum allowable dissipation
Actual power dissipation:
P
D
≈
(V
IN
MAX
– V
OUT
MIN
)I
LOAD
MAX
= [(3.3 x 1.1) – (2.7 x .995)]275 x 10
–3
= 260mW
Maximum allowable power dissipation:
P
D
MAX
= (T
J
MAX
– T
A
MAX
)
θ
JA
= (125 – 95)
59
= 508mW
In this example, the TC1262 dissipates a maximum of
260mW; below the allowable limit of 508mW. In a
similar manner, Equation 4-1 and Equation 4-2 can be
used to calculate maximum current and/or input
voltage limits. For example, the maximum allowable
V
IN
, is found by sustituting the maximum allowable
power dissipation of 508mW into Equation 4-1, from
which V
IN
MAX
= 4.6V.
EQUATION 4-2:
P
D
MAX
= (T
J
MAX
– T
A
MAX
)
θ
JA
Where all terms are previously defined.
Table 4-1 and Table 4-2 show various values of
θ
JA
for
the TC1262 packages.
TABLE 4-1:
THERMAL RESISTANCE
GUIDELINES FOR TC1262 IN
SOT-223 PACKAGE
Copper
Area
(Backside)
Board
Area
Thermal
Resistance
(θ
JA
)
45°C/W
45°C/W
53°C/W
59°C/W
52°C/W
55°C/W
Copper
Area
(Topside)*
2500 sq mm 2500 sq mm 2500 sq mm
1000 sq mm 2500 sq mm 2500 sq mm
225 sq mm
100 sq mm
1000 sq mm
2500 sq mm 2500 sq mm
2500 sq mm 2500 sq mm
0 sq mm
1000 sq mm
1000 sq mm 1000 sq mm 1000 sq mm
*Tab of device attached to topside copper
©
DS21373B-page 4
2002 Microchip Technology Inc.
TC1262
5.0
Note:
TYPICAL CHARACTERISTICS
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein are
not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Line Regulation vs. Temperature
0.020
0.018
LINE REGULATION (%)
0.016
NOISE (µV/√Hz)
0.014
0.012
0.010
0.008
0.006
0.004
0.002
0.000
-40°C
0.0
0°C
25°C
70°C
85°C
125°C
1.0
10.0
Output Noise vs. Frequency
R
LOAD
= 50µΩ
C
OUT
= 1µF
Load Regulation vs. Temperature
0.0100
0.0090
LOAD REGULATION (%/mA)
0.0080
0.0070
0.0060
0.0050
0.0040
0.0030
0.0020
0.0010
0.0100
-40°C
0°C
25°C
70°C
85°C
125°C
5V
2.5V
1mA to 500mA
0.1
1mA to 500mA
0.01
0.01
1
10
100
1000
TEMPERATURE (°C)
FREQUENCY (kHz)
TEMPERATURE (°C)
I
DD
vs. Temperature
150
135
2.5V Dropout Voltage vs. I
LOAD
0.50
125°C
0.50
85°C
70°C
0.30
25°C
0.40
85°C
0.30
70°C
25°C
0.20
125°C
LOAD
DROPOUT VOLTAGE (V)
105
90
75
60
45
30
15
0
-40°C
2.5V
5V
0.20
-40°C
0.10
0°C
DROPOUT VOLTAGE (V)
120
0.40
I
DD
(µA)
0°C
0.10
-40°C
0.00
0°C
25°C
70°C
85°C 125°C
0
100
TEMPERATURE (°C)
200
300
400
ILOAD (mA)
500
0.00
0
100
200
300
400
ILOAD (mA)
500
2.5V V
OUT
vs. Temperature
2.70
2.50
2.30
V
OUT
(V)
V
OUT
(V)
2.10
1.90
1.70
1.50
-40°C
I
L
= 300mA
A
I
L
= 500mA
A
I
L
= 0.1mA
5.20
5.10
5.00
4.90
4.80
4.70
4.60
4.50
4.40
4.30
5.0V V
OUT
vs. Temperature
I
L
= 0.1mA
I
L
I
L
0°C
25°C
70°C
85°C
125°C
4.20
4.10
4.00
-40°C
0°C
25°C
70°C
85°C
125°C
TEMPERATURE (°C)
TEMPERATURE (°C)
2002 Microchip Technology Inc.
DS21373B-page 5
©
Automotive Electronics
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