TC1263
500mA Fixed Output CMOS LDO with Shutdown
Features
•
•
•
•
•
•
•
Very Low Dropout Voltage
500mA Output Current
High Output Voltage Accuracy
Standard or Custom Output Voltages
Over Current and Over Temperature Protection
SHDN Input for Active Power Management
ERROR Output Can Be Used as a Low Battery
Detector (SOIC only)
Package Type
5-Pin DDPAK
FRONT VIEW
TAB IS GND
TAB IS GND
5-Pin TO-220
TC1263
1 2
3 4 5
TC1263
1 2 3 4 5
•
•
•
•
•
•
•
Battery Operated Systems
Portable Computers
Medical Instruments
Instrumentation
Cellular/GSM/PHS Phones
Linear Post-Regulators for SMPS
Pagers
SHDN
GND
V
IN
8-Pin SOIC
V
OUT
GND
NC
BYPASS
1
2
3
4
8
V
IN
NC
SHDN
ERROR
TC1263
Device Selection Table
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
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 construction eliminates wasted ground current,
significantly extending battery life. Total supply current
is typically 80µA at full load (20 to 60 times lower than
in bipolar regulators).
TC1263 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 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.
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
+
C
OUT
1µF
SHDN
V
OUT
TC1263
GND
SHDN
2002 Microchip Technology Inc.
BYP
SHDN
GND
V
IN
V
OUT
7
6
5
V
OUT
BYP
Applications
DS21374B-page 1
©
TC1263
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
TC1263 ELECTRICAL SPECIFICATIONS
Electrical Characteristics:
V
IN
= V
OUT
+ 1V, I
L
= 100µA, C
L
= 3.3µF, SHDN > V
IH
, 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
—
Units
V
mA
V
ppm/°C
%
%/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)
SHDN = V
IH
, I
L
= 0
SHDN = 0V
F
RE
≤
1kHz
V
OUT
= 0V
Note 5
I
L
= I
OUT
MAX
Test Conditions
Note 8
—
—
V
R
±0.5%
V
R
– 2.5%
—
V
R
+ 2.5%
—
—
—
—
—
—
—
—
—
—
—
—
60
—
1.0
—
—
—
40
0.05
0.002
20
60
200
350
80
0.05
64
1200
0.04
260
—
—
—
—
0.95 x V
R
50
—
0.35
0.01
30
130
390
650
130
1
—
1400
—
—
—
15
—
400
—
—
I
DD
I
SHDN
PSRR
I
OUT
SC
∆V
OUT
/∆P
D
eN
SHDN Input
V
IH
V
IL
V
MIN
V
OL
V
TH
V
HYS
Note
1:
2:
3:
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
Minimum Operating Voltage
Output Logic Low Voltage
ERROR Threshold Voltage
ERROR Positive Hysteresis
µA
µA
dB
mA
V/W
nV/√Hz
%V
IN
%V
IN
V
mV
V
mV
ERROR Output (SOIC Only)
1 mA Flows to ERROR
Note 7
4:
5:
6:
7:
8:
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.
Hysteresis voltage is referenced to V
R
.
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
.
©
DS21374B-page 2
2002 Microchip Technology Inc.
TC1263
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
Pin No.
(8-Pin SOIC)
1
2
3
4
5
6
7
PIN FUNCTION TABLE
Symbol
V
OUT
GND
NC
BYPASS
ERROR
NC
SHDN
Regulated voltage output.
Ground terminal.
No connect.
Reference bypass input. Connecting a 470pF to this input further reduces output noise.
Out-of-Regulation Flag (open drain output). This output goes low when V
OUT
is out-of-tolerance
by approximately – 5%.
No connect.
Shutdown control input. The regulator is fully enabled when a logic high is applied to this input.
The regulator enters shutdown when a logic low is applied to this input. During shutdown, output
voltage falls to zero and supply current is reduced to 0.05µA (typical).
Unregulated supply input.
Description
8
V
IN
Pin No.
(5-Pin DDPAK)
(5-Pin TO-220)
1
2
Symbol
BYP
SHDN
Description
Reference bypass input. Connecting a 470pF to this input further reduces output noise.
Shutdown control input. The regulator is fully enabled when a logic high is applied to this input.
The regulator enters shutdown when a logic low is applied to this input. During shutdown, output
voltage falls to zero and supply current is reduced to 0.05µA (typical).
Ground terminal.
Unregulated supply input.
Regulated voltage output.
3
4
5
GND
V
IN
V
OUT
2002 Microchip Technology Inc.
DS21374B-page 3
©
TC1263
3.0
DETAILED DESCRIPTION
3.2
ERROR Output
The TC1263 is a precision, fixed output LDO. Unlike
bipolar regulators, the TC1263’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.
ERROR is driven low whenever V
OUT
falls out of
regulation 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
regardless 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 3-2.
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 3-1, ERROR can be used as a
battery low flag, or as a processor RESET signal (with
the addition 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).
FIGURE 3-1:
V
IN
1µF
C2
TYPICAL APPLICATION
CIRCUIT
V
OUT
+
+
Battery
+
1µF
C1
V
OUT
TC1263
GND
V
+
SHDN
Shutdown Control
(to CMOS Logic or Tie
to V
IN
if unused)
ERROR
R1
1M
C3 Required Only
if ERROR is used as a
Processor RESET Signal
(See Text)
FIGURE 3-2:
BATTLOW
or RESET
C3
+
ERROR OUTPUT
OPERATION
0.2µF
V
OUT
3.1
Output Capacitor
V
TH
HYSTERESIS (V
H
)
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.
ERROR
V
IH
V
OL
©
DS21374B-page 4
2002 Microchip Technology Inc.
TC1263
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 TC1263 IN
3-PIN TO-220/DDPAK
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
= 60°C/W
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)
60
= 500mW
In this example, the TC1263 dissipates a maximum of
260mW; below the allowable limit of 500mW. 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 substituting the maximum allowable
power dissipation of 500mW 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 TC1263 packages.
TABLE 4-1:
THERMAL RESISTANCE
GUIDELINES FOR TC1263 IN
8-PIN SOIC PACKAGE
Copper
Area
(Backside)
Board
Area
Thermal
Resistance
(θ
JA
)
60°C/W
60°C/W
68°C/W
74°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
2500 sq mm 2500 sq mm
2500 sq mm 2500 sq mm
*Pin 2 is ground. Device is mounted on topside.
2002 Microchip Technology Inc.
DS21374B-page 5
©
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