Datasheet TC1054-2.5VCT, TC1055-2.7VCT, TC1055-2.5VCT, TC1054-5.0VCT, TC1055-5.0VCT Datasheet (TelCom Semiconductor)
...Page 1
50mA CMOS LDO WITH SHUTDOWN
PRELIMINARY INFORMATION
AND ERROR OUTPUT
50mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT
TC1054
TC1054
FEATURES
■ Zero Ground Current for Longer Battery Life
■ Very Low Dropout Voltage
■ Guaranteed 50mA Output
■ High Output Voltage Accuracy
■ Standard or Custom Output Voltages
■ Power-Saving Shutdown Mode
■ ERROR Output can be Used as a Low Battery
Detector, or Processor Reset Generator
■ Over-Current and Over-Temperature Protection
■ Space-Saving SOT-23A-5 Package
■ Pin Compatible Upgrades for Bipolar Regulators
APPLICATIONS
■ Battery Operated Systems
■ Portable Computers
■ Medical Instruments
■ Instrumentation
■ Cellular/GSMS/PHS Phones
■ Linear Post-Regulators for SMPS
■ Pagers
ORDERING INFORMATION
Output Junction
Part No. Voltage **(V) Package Temp. Range
TC1054-2.5VCT 2.5 SOT-23A-5* – 40°C to +125°C
TC1054-2.7VCT 2.7 SOT-23A-5* – 40°C to +125°C
TC1054-3.0VCT 3.0 SOT-23A-5* – 40°C to +125°C
TC1054-3.3VCT 3.3 SOT-23A-5* – 40°C to +125°C
TC1054-5.0VCT 5.0 SOT-23A-5* – 40°C to +125°C
NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A)
** Other output voltages available. Please contact TelCom
Semiconductor for details
PIN CONFIGURATION
V
OUT
ERROR
45
GENERAL DESCRIPTION
The TC1054 is a high accuracy (typically ±0.5%) CMOS
upgrade for older (bipolar) low dropout regulators. Designed specifically for battery-operated systems, the
TC1054’s CMOS construction eliminates wasted ground
current, significantly extending battery life. Total supply
current is typically 50µA at full load (
than in bipolar regulators
!).
TC1054 key features include ultra low noise operation,
very low dropout voltage (typically 100mV at full load) and
internal feed-forward compensation for fast response to
step changes in load. An error output (ERROR) is asserted
when the TC1054 is out-of-regulation (due to a low input
voltage or excessive output current). ERROR can be used
as a low battery warning or as a processor RESET signal
(with the addition of an external RC network). Supply current
is reduced to less than 1µA, and both V
are disabled when the shutdown input is low. The TC1054
incorporates both over-temperature and over-current protection.
The TC1054 is stable with an output capacitor of only
1µF and has a maximum output current of 50mA. For higher
output current regulators, please see the TC1055
(I
= 100mA) regulator and TC1107, TC1108 (I
OUT
300mA) data sheets.
TYPICAL APPLICATION
V
IN
1
V
IN
2
GND
34
SHDN
TC1054
20 to 60 times lower
and ERROR
OUT
5
V
OUT
1µF
1M
ERROR
OUT
V
OUT
ERROR
=
TC1054
(SOT-23A-5*)
2
GND
3
SHDN
TOP VIEW
1
V
IN
NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A)
TC1054-01 6/12/97
TelCom Semiconductor reserves the right to make changes in the circuitry and specifications of its devices
Shutdown Control
(from Power Control Logic)
1
Page 2
PRELIMINARY INFORMATION
TC1054
50mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
ABSOLUTE MAXIMUM RATINGS*
Input Voltage .................................................................7V
Output Voltage ............................. (– 0.3V) to (VIN + 0.3V)
Power Dissipation ....................Internally Limited (Note 7)
*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.
Operating Temperature Range ........ – 40°C < TJ < 125°C
Storage Temperature ............................– 65°C to +150°C
Maximum Voltage on Any Pin ............ VIN +0.3V to – 0.3V
Lead Temperature (Soldering, 10 Sec.)................+260°C
ELECTRICAL CHARACTERISTICS:
VIN = V
+ 1V, IL = 0.1mA, CL = 3.3µF, SHDN > VIH, T
OUT
= 25°C, unless otherwise noted.
A
BOLDFACE type specifications apply for junction temperatures of – 40°C to
+125°C.
Symbol Parameter Test Conditions Min Typ Max Units
V
IN
I
OUT
MAX
V
OUT
TC V
OUT
∆V
/∆V
OUT
IN
∆V
OUT/VOUT
– V
V
IN
OUT
I
GND
I
IN
I
INSD
R
OUT
PSRR Power Supply Rejection Ratio FRE ≤ 1kHz — 64 — dB
I
OUT
SC
∆V
/∆P
OUT
D
T
SD
∆T
SD
eN Output Noise IL = I
Input Operating Voltage — — 6.5 V
Maximum Output Current 50 —— mA
Output Voltage Note 1 VR – 2.5% VR ±0.5% VR + 2.5% V
V
Temperature Coefficient Note 2 — — — ppm/°C
OUT
40
Line Regulation (VR + 1V) < VIN < 6V — 0.01 0.05 %/V
Load Regulation IL = 0.1mA to I
OUT
MAX
— 0.5 — %
(Note 3)
Dropout Voltage IL = 0.1mA — 5 — mV
IL = 20mA — 65
IL = 50mA — 95
(Note 4)
Ground Pin Current IL = I
OUT
MAX,
(Note 5)
— 0 — µA
Supply Current SHDN = VIH, IL = 0 — 50 — µA
Shutdown Supply Current SHDN = 0V — — 0.05 µA
Output Resistance during Shutdown
Output Short Circuit Current V
SHDN < V
OUT
IL
= 0V — 200 450 mA
100 x VR160 x V
R
—kΩ
Thermal Regulation Note 6 — 0.04 — %W
Thermal Shutdown Die Temperature
— 160 — °C
Thermal Shutdown Hysteresis — 10 — °C
OUT
MAX
— 160 — µV
SHDN Input
V
IH
V
IL
SHDN Input High Threshold V
SHDN Input Low Threshold V
= 2.5V to 6.5V 45 — — %V
IN
= 2.5V to 6.5V — — 15 %V
IN
IN
IN
TC1054-01 6/12/97
2
Page 3
50mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
PRELIMINARY INFORMATION
TC1054
ELECTRICAL CHARACTERISTICS:
V
IN
= V
+ 1V, IL = 0.1mA, CL = 3.3µF, SHDN > VIH, T
OUT
= 25°C, unless otherwise noted.
A
Symbol Parameter Test Conditions Min Typ Max Units
ERROR Output
V
MIN
V
OL
V
TH
V
HYS
NOTES: 1. VR is the regulator output voltage setting. VR = 2.5V, 2.7V, 3.0V, 3.3V, 5.0V.
2. TC V
3. Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested over a load
4. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value.
5. Ground pin current is the regulator pass transistor gate current. The total current drawn from the input supply is the sum of the load
6. Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load
7. The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature and the
8. Hysteresis voltage is referenced by VR.
Minimum Operating Voltage 1.0 — — V
Output Logic Low Voltage 1mA Flows to ERROR — — 400 mV
ERROR Threshold Voltage See Figure 2 — 0.95 x V
R
—V
ERROR Positive Hysteresis Note 8 — 50 — mV
= V
OUT
OUT
V
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.
current, ground current and supply current (i.e. IIN = I
or line regulation effects. Specifications are for a current pulse equal to I
thermal resistance from junction-to-air (i.e. TA, TJ, qJA). Exceeding the maximum allowable power dissipation causes the device to
initiate thermal shutdown. Please see
MAX –
OUT
V
x
OUT
∆T
MIN
6
x 10
Thermal Considerations
SUPPLY
+ I
+ I
GND
section of this data sheet for more details.
).
LOAD
at VIN = 6V for T = 10msec.
LMAX
PIN DESCRIPTION
Pin No.
(SOT-23A-5) Symbol Description
1VINUnregulated supply input.
2 GND Ground terminal.
3 SHDN 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, ERROR is open circuited and supply current is reduced to 0.05 microamp
(typical).
4 ERROR Out-of-Regulation Flag. (Open drain output). This output goes low when V
by approximately – 5%.
5V
OUT
Regulated voltage output.
is out-of-tolerance
OUT
TC1054-01 6/12/97
3
Page 4
PRELIMINARY INFORMATION
TC1054
50mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
DETAILED DESCRIPTION
The TC1054 is a precision fixed output voltage regulator. (If an adjustable version is desired, please see the
TC1070 or TC1071 data sheets.) Unlike the bipolar regulators, the TC1054 supply current does not increase with load
current. In addition, V
tion at very low load currents (an important consideration in
RTC and CMOS RAM battery back-up applications).
Figure 1 shows a typical application circuit. The regulator is enabled any time the shutdown input (SHDN) is at or
above VIH, and shutdown (disabled) when SHDN is at or
below VIL. SHDN may be controlled by a CMOS logic gate,
or I/O port of a microcontroller. If the SHDN input is not
required, it should be connected directly to the input supply.
While in shutdown, supply current decreases to 0.05µA
(typical) and V
OUT
circuited.
1µF
BATTERY
Shutdown Control
(to CMOS Logic or Tie
to V
if unused)
IN
Figure 1. Typical Application Circuit
remains stable and within regula-
OUT
falls to zero volts and ERROR is open
1µF
C1
+
R1
1M
0.2µF
C2
V
OUT
BATTLOW
or RESET
V
IN
GND
TC1054VCT
C2 Requires Only
if ERROR is used as a
Processor RESET Signal
(See Text)
V
OUT
ERRORSHDN
V
Pull-up resistor R1 can be tied to V
, VIN or any other
OUT
voltage less than (VIN = 0.3V).
V
OUT
ERROR
V
TH
V
IH
V
OL
Figure 2. ERROR Output Operation
HYSTERESIS (V
HYS
)
Output Capacitor
A 1µF(min) capacitor from V
mended. The output capacitor should have an effective
series resistance of 5Ω or less, and a resonant frequency
above 1MHz. A 1µF capacitor should be connected from
VIN 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.
to ground is recom-
OUT
ERROR Open Drain Output
ERROR is driven low whenever V
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
regardless of the programmed output voltage value
OUT
(e.g. ERROR = VOL at 4.75 (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
inactive when V
rises above VTH = V
OUT
As shown in Figure 1, ERROR can be used as a battery
low flag, or as a processor RESET signal (with the addition
of timing capacitor C2). R1 x C2 should be chosen to
maintain ERROR below VIH of the processor RESET input
for at least 200msec to allow time for the system to stabilize.
TC1054-01 6/12/97
falls out of regu-
OUT
falls to VTH, and
OUT
.
HYS
Thermal Considerations
Thermal Shutdown
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.
Power Dissipation
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:
4
Page 5
50mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
P
D ≈ (VIN
Where:
PD= Worst case actual power dissipation
V
V
OUT
I
LOAD
The maximum
= Maximum voltage on V
IN
MAX
= Minimum regulator output voltage
MIN
= Maximum output (load) current
MAX
allowable
is a function of the maximum ambient temperature (T
the maximum allowable die temperature (125°C) and the
thermal resistance from junction-to-air (θJA). SOT-23A-5
package has a θJA of approximately
mounted on a single layer FR4 dielectric copper clad PC
board.
–
MAX
Equation 1.
V
OUT
MIN
I
LOAD
)
IN
MAX
power dissipation (Equation 2)
220°C/Watt
A
MAX
when
PRELIMINARY INFORMATION
TC1054
In this example, the TC1054 dissipates a maximum of
only 18.5mW; far below the allowable limit of 318mW. In a
similar manner, Equation 1 and Equation 2 can be used to
calculate maximum current and/or input voltage limits.
Layout Considerations
The primary path of heat conduction out of the package
is via the package leads. Therefore, layouts having a
ground plane, wide traces at the pads, and wide power
supply bus lines combine to lower θJA and therefore increase the maximum allowable power dissipation limit.
),
P
D
MAX
=
(T
J
MAX
– T
J
)
MAX
θ
JA
Where all terms are previously defined.
Equation 2.
Equation 1 can be used in conjunction with Equation 2
to ensure regulator thermal operation is within limits. For
example:
Given:
V
V
OUT
I
T
IN
MAX
LOAD
AMAX
MIN
= 3.0V ±5%
= 2.7V ±0.5V
= 40mA
= 55°C
Find: 1. Actual power dissipation
2. Maximum allowable dissipation
Actual power dissipation:
P
D ≈ (VIN
= [(3.0 x 1.05) – (2.7 x .995)]40 x 10
MAX
–
V
OUT
MIN
I
LOAD
)
MAX
–3
= 18.5mW
Maximum allowable power dissipation:
P
θ
DMAX
= (T
J
MAX
– T
JA
A
= (125 – 55)
220
= 318mW
TC1054-01 6/12/97
MAX
)
5
Page 6
PRELIMINARY INFORMATION
TC1054
50mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
MARKINGS
SOT-23A-5
PACKAGE DIMENSIONS
a & b = part number code + temperature range and voltage
TC1054 (V) Code
2.5 C1
2.7 C2
3.0 C3
3.3 C4
5.0 C6
c represents year and quarter code
d represents lot ID number
SOT-23A-5*
0.75 (1.90)
REFERENCE
.122 (3.10)
.098 (2.50)
.020 (0.50)
.012 (0.30)
.057 (1.45)
.035 (0.90)
.006 (0.15)
.000 (0.00)
NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A)
Sales Offices
TelCom Semiconductor
1300 Terra Bella Avenue
P.O. Box 7267
Mountain View, CA 94039-7267
TEL: 415-968-9241
FAX: 415-967-1590
E-Mail: liter@c2smtp.telcom-semi.com
TC1054-01 6/12/97
.071 (1.80)
.059 (1.50)
.037 (0.95)
REFERENCE
.122 (3.10)
.106 (2.70)
10° MAX.
TelCom Semiconductor
Austin Product Center
9101 Burnet Rd. Suite 214
Austin, TX 78758
TEL: 512-873-7100
FAX: 512-873-8236
6
.010 (0.25)
.004 (0.09)
.022 (0.55)
.008 (0.20)
Dimensions: inches (mm)
TelCom Semiconductor H.K. Ltd.
10 Sam Chuk Street, Ground Floor
San Po Kong, Kowloon
Hong Kong
TEL: 852-2324-0122
FAX: 852-2354-9957
Printed in the U.S.A.
Page 7
100mA CMOS LDO WITH SHUTDOWN
PRELIMINARY INFORMATION
AND ERROR OUTPUT
100mA CMOS LDO WITH SHUTDOWN AND ERROR OUTPUT
TC1055
TC1055
FEATURES
■ Zero Ground Current for Longer Battery Life
■ Very Low Dropout Voltage
■ Guaranteed 100mA Output
■ High Output Voltage Accuracy
■ Standard or Custom Output Voltages
■ Power-Saving Shutdown Mode
■ ERROR Output can be Used as a Low Battery
Detector, or Processor Reset Generator
■ Over-Current and Over-Temperature Protection
■ Space-Saving SOT-23A-5 Package
■ Pin Compatible Upgrades for Bipolar Regulators
APPLICATIONS
■ Battery Operated Systems
■ Portable Computers
■ Medical Instruments
■ Instrumentation
■ Cellular/GSMS/PHS Phones
■ Linear Post-Regulators for SMPS
■ Pagers
ORDERING INFORMATION
GENERAL DESCRIPTION
The TC1055 is a high accuracy (typically ±0.5%) CMOS
upgrade for older (bipolar) low dropout regulators. Designed specifically for battery-operated systems, the
TC1055’s CMOS construction eliminates wasted ground
current, significantly extending battery life. Total supply
current is typically 50µA at full load (
than in bipolar regulators
!).
TC1055 key features include ultra low noise operation,
very low dropout voltage (typically 200mV at full load) and
internal feed-forward compensation for fast response to
step changes in load. An error output (ERROR) is asserted
when the TC1055 is out-of-regulation (due to a low input
voltage or excessive output current). ERROR can be used
as a low battery warning or as a processor RESET signal
(with the addition of an external RC network). Supply current
is reduced to less than 1µA, and both V
are disabled when the shutdown input is low. The TC1055
incorporates both over-temperature and over-current protection.
The TC1055 is stable with an output capacitor of only
1µF and has a maximum output current of 100mA. For
higher output current regulators, please see the TC1107,
TC1108 (I
= 300mA) data sheets.
OUT
20 to 60 times lower
and ERROR
OUT
Output Junction
Part No. Voltage **(V) Package Temp. Range
TC1055-2.5VCT 2.5 SOT-23A-5* – 40°C to +125°C
TC1055-2.7VCT 2.7 SOT-23A-5* – 40°C to +125°C
TC1055-3.0VCT 3.0 SOT-23A-5* – 40°C to +125°C
TC1055-3.3VCT 3.3 SOT-23A-5* – 40°C to +125°C
TC1055-5.0VCT 5.0 SOT-23A-5* – 40°C to +125°C
NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A)
** Other output voltages available. Please contact TelCom
Semiconductor for details
PIN CONFIGURATION
V
OUT
V
NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A)
ERROR
45
TC1055
(SOT-23A-5*)
3
2
1
GND
IN
SHDN
TOP VIEW
TYPICAL APPLICATION
V
IN
Shutdown Control
(from Power Control Logic)
1
V
IN
2
GND
34
SHDN
TC1055
V
OUT
ERROR
5
1M
1µF
V
OUT
ERROR
TC1055-01 6/5/97
TelCom Semiconductor reserves the right to make changes in the circuitry and specifications of its devices
1
Page 8
PRELIMINARY INFORMATION
TC1055
100mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
ABSOLUTE MAXIMUM RATINGS*
Input Voltage .................................................................7V
Output Voltage ............................. (– 0.3V) to (VIN + 0.3V)
Power Dissipation ....................Internally Limited (Note 7)
*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.
Operating Temperature Range ........ – 40°C < TJ < 125°C
Storage Temperature ............................– 65°C to +150°C
Maximum Voltage on Any Pin ............ V
ELECTRICAL CHARACTERISTICS:
+0.3V to – 0.3V
IN
V
= V
IN
+ 1V, IL = 0.1mA, CL = 3.3µF, SHDN > VIH, T
OUT
= 25°C, unless otherwise noted.
A
Symbol Parameter Test Conditions Min Typ Max Units
V
IN
I
OUT
MAX
V
OUT
TC V
OUT
∆V
/∆V
OUT
IN
∆V
OUT/VOUT
– V
V
IN
OUT
I
GND
I
IN
I
INSD
R
OUT
PSRR Power Supply Rejection Ratio FRE ≤ 1kHz — 64 — dB
I
OUT
SC
∆V
/∆P
OUT
D
eN Output Noise IL = I
Input Operating Voltage Note 9 — — 6.5 V
Maximum Output Current Note 9 100 —— mA
Output Voltage Notes 1, 9 VR – 2.5% VR ±0.5% VR + 2.5% V
V
Temperature Coefficient Note 2, 9 — 20 — ppm/°C
OUT
40
Line Regulation (VR + 1V) < VIN < 6V — 0.05 — %
Load Regulation IL = 0.1mA to I
OUT
MAX
— 0.5 — %
(Note 3)
Dropout Voltage IL = 0.1mA — 20 — mV
IL = 20mA — 70
IL = 50mA — 100
IL = 100mA — 200
(Note 4)
Ground Pin Current IL = I
OUT
MAX,
(Note 5, 9)
— 0 — µA
Supply Current SHDN = VIH, IL = 0 — 50 80 µA
Shutdown Supply Current SHDN = 0V — — 0.05 µA
Output Resistance during Shutdown
Output Short Circuit Current V
SHDN < V
OUT
IL
= 0V — 300 500 mA
100 x VR160 x V
R
—kΩ
Thermal Regulation Note 6 — 0.04 — %W
OUT
MAX
— 160 — nV/√Hz
SHDN Input
V
IH
V
IL
SHDN Input High Threshold VIN = 2.5V to 6.5V 45 — — %V
SHDN Input Low Threshold VIN = 2.5V to 6.5V — — 15 %V
IN
IN
TC1055-01 6/5/97
2
Page 9
100mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
PRELIMINARY INFORMATION
TC1055
ELECTRICAL CHARACTERISTICS:
V
IN
= V
+ 1V, IL = 0.1µA, CL = 3.3µF, SHDN > VIH, T
OUT
= 25°C, unless otherwise noted.
A
Symbol Parameter Test Conditions Min Typ Max Units
ERROR Open Drain Output
V
MIN
V
OL
V
TH
V
HYS
NOTES: 1. VR is the regulator output voltage setting. VR = 2.5V, 2.7V, 3.0V, 3.3V, 5.0V.
2. TC V
3. Regulation is measured at a constant junction temperature using low duty cycle pulse testing. Load regulation is tested over a load
4. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value.
5. Ground pin current is the regulator pass transistor gate current. The total current drawn from the input supply is the sum of the load
6. Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load
7. The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction temperature and the
8. Hysteresis voltage is referenced by VR.
9. Boldface type specifications apply for junction temperatures of – 40°C to +125°C.
Minimum Operating Voltage 1.0 — — V
Output Logic Low Voltage 1mA Flows to ERROR — — 400 mV
ERROR Threshold Voltage See Figure 2 — 0.95 x V
R
—V
ERROR Positive Hysteresis Note 8 — 50 — mV
= (V
OUT
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.
current, ground current and supply current (i.e. IIN = I
or line regulation effects. Specifications are for a current pulse equal to I
thermal resistance from junction-to-air (i.e. TA, TJ, qJA). Exceeding the maximum allowable power dissipation causes the device to
initiate thermal shutdown. Please see
OUT
V
MAX –
OUT
V
OUT
x ∆T
MIN)
6
x 10
Thermal Considerations
SUPPLY
+ I
+ I
GND
section of this data sheet for more details.
).
LOAD
at VIN = 6V for T = 10msec.
LMAX
PIN DESCRIPTION
Pin No.
(SOT-23A-5) Symbol Description
1VINUnregulated supply input.
2 GND Ground terminal.
3 SHDN 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, ERROR is open circuited and supply current is reduced to 0.05 microamp
(typical).
4 ERROR Out-of-Regulation Flag. (Open drain output). This output goes low when V
by approximately – 5%.
5V
OUT
Regulated voltage output.
is out-of-tolerance
OUT
TC1055-01 6/5/97
3
Page 10
PRELIMINARY INFORMATION
TC1055
100mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
DETAILED DESCRIPTION
The TC1055 is a precision fixed output voltage regulator. (If an adjustable version is desired, please see the
TC1070 or TC1071 data sheets.) Unlike the bipolar regulators, the TC1055 supply current does not increase with load
current. In addition, V
tion at very low load currents (an important consideration in
RTC and CMOS RAM battery back-up applications).
Figure 1 shows a typical application circuit. The regulator is enabled any time the shutdown input (SHDN) is at or
above VIH, and shutdown (disabled) when SHDN is at or
below VIL. SHDN may be controlled by a CMOS logic gate,
or I/O port of a microcontroller. If the SHDN input is not
required, it should be connected directly to the input supply.
While in shutdown, supply current decreases to 0.05µA
(typical) and V
OUT
circuited.
1µF
BATTERY
Shutdown Control
(to CMOS Logic or Tie
to V
if unused)
IN
Figure 1. Typical Application Circuit
remains stable and within regula-
OUT
falls to zero volts and ERROR is open
1µF
C1
+
R1
1M
0.2µF
C2
V
OUT
BATTLOW
or RESET
V
IN
GND
TC1055VCT
C2 Requires Only
if ERROR is used as a
Processor RESET Signal
(See Text)
V
OUT
ERRORSHDN
V
Pull-up resistor R1 can be tied to V
, VIN or any other
OUT
voltage less than (VIN + 0.3V).
V
OUT
HYSTERESIS (V
HYS
ERROR
V
TH
V
IH
V
OL
Figure 2. ERROR Output Operation
Output Capacitor
A 1µF(min) capacitor from V
mended. The output capacitor should have an effective
series resistance of 5Ω or less, and a resonant frequency
above 1MHz. A 1µF capacitor should be connected from
VIN 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.
to ground is recom-
OUT
)
ERROR Open Drain Output
ERROR is driven low whenever V
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
regardless of the programmed output voltage value
OUT
(e.g. ERROR = VOL at 4.75 (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
inactive when V
rises above VTH by V
OUT
As shown in Figure 1, ERROR can be used as a battery
low flag, or as a processor RESET signal (with the addition
of timing capacitor C2). R1 x C2 should be chosen to
maintain ERROR below VIH of the processor RESET input
for at least 200msec to allow time for the system to stabilize.
TC1055-01 6/5/97
falls out of regu-
OUT
falls to VTH, and
OUT
.
HYS
Thermal Considerations
Thermal Shutdown
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.
Power Dissipation
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:
4
Page 11
100mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
P
D ≈ (VIN
Where:
PD= Worst case actual power dissipation
V
V
OUT
I
LOAD
The maximum
= Maximum voltage on V
IN
MAX
= Minimum regulator output voltage
MIN
= Maximum output (load) current
MAX
allowable
is a function of the maximum ambient temperature (T
the maximum allowable die temperature (125°C) and the
thermal resistance from junction-to-air (θJA). SOT-23A-5
package has a θJA of approximately
mounted on a single layer FR4 dielectric copper clad PC
board.
–
MAX
Equation 1.
V
OUT
MIN
I
LOAD
)
IN
MAX
power dissipation (Equation 2)
220°C/Watt
A
MAX
when
PRELIMINARY INFORMATION
In this example, the TC1055 dissipates a maximum of
only 60mW; far below the allowable limit of 318mW. 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 VIN is found by substituting the maximum allowable power dissipation of 318mW
into Equation 1, from which V
Layout Considerations
The primary path of heat conduction out of the package
is via the package leads. Therefore, layouts having a
ground plane, wide traces at the pads, and wide power
),
supply bus lines combine to lower θJA and therefore increase the maximum allowable power dissipation limit.
IN
MAX
= 5.9V.
TC1055
P
D
MAX
=
(T
J
MAX
– T
J
)
MAX
θ
JA
Where all terms are previously defined.
Equation 2.
Equation 1 can be used in conjunction with Equation 2
to ensure regulator thermal operation is within limits. For
example:
Given:
V
V
OUT
I
T
IN
MAX
LOAD
AMAX
MIN
= 3.0V ±5%
= 2.7V ±0.5V
= 40mA
= 55°C
Find: 1. Actual power dissipation
2. Maximum allowable dissipation
Actual power dissipation:
P
D ≈ (VIN
= [(3.0 x 1.05) – (2.7 x .995)]40 x 10
MAX
–
V
OUT
MIN
I
LOAD
)
MAX
–3
= 18.5mW
Maximum allowable power dissipation:
P
θ
DMAX
= (T
J
MAX
– T
JA
A
= (125 – 55)
220
= 318mW
TC1055-01 6/5/97
MAX
)
5
Page 12
PRELIMINARY INFORMATION
TC1055
100mA CMOS LDO WITH SHUTDOWN
AND ERROR OUTPUT
MARKINGS
SOT-23A-5
PACKAGE DIMENSIONS
a & b = part number code + temperature range and voltage
TC1055 (V) Code
2.5 D1
2.7 D2
3.0 D3
3.3 D4
5.0 D6
c represents year and quarter code
d represents lot ID number
SOT-23A-5*
0.75 (1.90)
REFERENCE
.122 (3.10)
.098 (2.50)
.020 (0.50)
.012 (0.30)
.057 (1.45)
.035 (0.90)
.006 (0.15)
.000 (0.00)
NOTE: *SOT-23A-5 is equivalent to the EIAJ (SC-74A)
Sales Offices
TelCom Semiconductor
1300 Terra Bella Avenue
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TEL: 415-968-9241
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TC1055-01 6/5/97
.071 (1.80)
.059 (1.50)
.037 (0.95)
REFERENCE
.122 (3.10)
.106 (2.70)
10° MAX.
TelCom Semiconductor
Austin Product Center
9101 Burnet Rd. Suite 214
Austin, TX 78758
TEL: 512-873-7100
FAX: 512-873-8236
6
.010 (0.25)
.004 (0.09)
.022 (0.55)
.008 (0.20)
Dimensions: inches (mm)
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Hong Kong
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