TC1054/TC1055/TC1186 Data Sheet

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 2002-2012 Microchip Technology Inc.

DS21350E-page 1

TC1054/TC1055/TC1186

Features

• Low Ground Current for Longer Battery Life
• Low Dropout Voltage
• Choice of 50 mA (TC1054), 100 mA (TC1055) 

and 150 mA (TC1186) Output

• High Output Voltage Accuracy
• Standard or Custom Output Voltages: 

- 1.8V, 2.5V, 2.6V, 2.7V, 2.8V, 2.85V, 3.0V, 

3.3V, 3.6V, 4.0V, 5.0V

• Power-Saving Shutdown Mode
• ERROR Output Can Be Used as a Low-Battery 

Detector or Microcontroller-Reset Generator

• Overcurrent and Overtemperature Protection
• 5-Pin SOT-23 Package
• Pin-Compatible Upgrades for Bipolar Regulators

Applications

• Battery Operated Systems
• Portable Computers
• Medical Instruments
• Instrumentation
• Cellular/GSM/PHS Phones
• Linear Post-Regulators for SMPS
• Pagers

Typical Application

General Description

The TC1054, TC1055 and TC1186 are high accuracy
(typically ±0.5%) CMOS upgrades for older (bipolar)
low dropout regulators. Designed specifically for
battery-operated systems, the devices’ CMOS
construction minimizes ground current, extending
battery life. Total supply current is typically 50 µA at full
load (20 to 60 times lower than in bipolar regulators).
The devices’ key features include low noise operation,
low dropout voltage – typically 85 mV (TC1054),
180 mV (TC1055) and 270 mV (TC1186) at full load —
and fast response to step changes in load. An error
output (ERROR) is asserted when the devices are
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 0.5 µA (maximum), with both
V

OUT

 and ERROR disabled when the shutdown input is

low. The devices incorporate both overtemperature
and over-current protection.

The TC1054, TC1055 and TC1186 are stable with an
output capacitor of only 1 µF, and have a maximum
output current of 50 mA, 100 mA and 150 mA,
respectively. For higher output current regulators,
please refer to the TC1173 (I

OUT

 = 300 mA) data sheet

(DS21632).

Package Type

V

OUT

GND

1 µF

+

V

IN

V

IN

V

OUT

1

5

2

4

3

SHDN

Shutdown Control

(from Power Control Logic)

ERROR

ERROR

1 M

TC1054
TC1055
TC1186

Note:

 5-Pin SOT-23 is equivalent to the EIAJ (SC-74A)

5

1

4

2

3

5-Pin SOT-23

TC1054
TC1055
TC1186

V

OUT

ERROR

SHDN

GND

V

IN

50 mA, 100 mA and 150 mA CMOS LDOs with Shutdown and ERROR Output

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TC1054/TC1055/TC1186

DS21350E-page 2

 2002-2012 Microchip Technology Inc.

1.0

ELECTRICAL 
CHARACTERISTICS

Absolute Maximum Ratings †

Input Voltage ..................................................................6.75V
Output Voltage ..................................... (-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 Junction Temperature Range ..-40°C <T

J

< +125°C

Storage Temperature.....................................-65°C to +150°C

† Notice:

 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.

DC CHARACTERISTICS

Electrical Specifications:

 Unless otherwise noted, V

IN

= V

OUT

+ 1V,  I

L

= 100 µA,  C

L

= 3.3 µF, SHDN > V

IH

, T

A

 = +25°C. Boldface 

type specifications apply for junction temperatures of -40°C to +125°C.

Parameters

Sym

Min

Typ

Max

Units

Conditions

Input Operating Voltage

V

IN

2.7

6.50

V

Note 8

Maximum Output Current

I

OUT

MAX

50

mA

TC1054

100

TC1055

150

TC1186

Output Voltage

V

OUT

V

R

 – 2.5%

  V

R

 ±0.5% V

R

 + 2.5%

V

Note 1

V

OUT

 Temperature 

Coefficient

TCV

OUT

20

ppm/°C

Note 2

40

Line Regulation

V

OUT

/

V

IN

0.05

0.35

%

(V

R

 + 1V) 

V

IN

6V

Load Regulation

TC1054; TC1055

V

OUT

/V

OUT

0.5

2

%

(

Note 3

)

I

L

 = 0.1 mA to I

OUT

MAX

TC1186

0.5

3

Note 1:

V

R

 is the regulator output voltage setting. For example: V

R

 = 1.8V, 2.5V, 2.7V, 2.85V, 3.0V, 3.3V, 3.6V, 

4.0V, 5.0V.

2:

3:

Regulation is measured at a constant junction temperature using low-duty-cycle pulse testing. Load regu-
lation is tested over a load range from 0.1 mA 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.

5:

Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipa-
tion 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 ms.

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

JA

). Exceeding the 

maximum allowable power dissipation causes the device to initiate thermal shutdown. See Section 5.0 
“Thermal Considerations”

 for more details.

7:

Hysteresis voltage is referenced by V

R

.

8:

The minimum V

IN

 has to justify the conditions: V

IN

 

 V

R

 + V

DROPOUT

 and V

IN

 

 2.7V for I

L

 = 0.1 mA to 

I

OUT

MAX

.

9:

Apply for junction temperatures of -40°C to +85°C.

TC V

OUT

 = (V

OUT

MAX

 – V

OUT

MIN

)x 10

6

V

OUT 

T

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 2002-2012 Microchip Technology Inc.

DS21350E-page 3

TC1054/TC1055/TC1186

Dropout Voltage

V

IN

– V

OUT

2

mV

I

L

 = 100 µA

65

I

L

 = 20 mA

85

120

I

L

 = 50 m

TC1055; TC1186

180

250

I

L

 = 100 mA

TC1186

270

400

I

L

 = 150 mA (

Note 4

)

Supply Current

I

IN

50

80

µA

SHDN = V

IH

I

L

 = 0 µA (

Note 9

)

Shutdown Supply Current

I

INSD

0.05

0.5

µA

SHDN = 0V

Power Supply Rejection Ratio

PSRR

64

dB

1 kHz

Output Short Circuit Current

I

OUT

SC

300

450

mA

V

OUT

 = 0V

Thermal Regulation

V

OUT

/

P

D

0.04

V/W

Notes 5

,

6

Thermal Shutdown 
Die Temperature

T

SD

160

°C

Thermal Shutdown Hysteresis

T

SD

10

°C

Output Noise

eN

260

nV/

Hz I

L

 = I

OUT

MAX

SHDN Input
SHDN Input High Threshold

V

IH

45

%V

IN

V

IN

 = 2.5V to 6.5V

SHDN Input Low Threshold

V

IL

15

%V

IN

V

IN

 = 2.5V to 6.5V

ERROR Output
Minimum V

IN

 Operating Voltage

V

IN

MIN

1.0

V

Output Logic Low Voltage

V

OL

400

mV

1 mA Flows to ERROR

ERROR Threshold Voltage

V

TH

0.95  x  V

R

V

See 

Figure 4-2

ERROR Positive Hysteresis

V

HYS

50

mV

Note 7

V

OUT

 to ERROR Delay

 t

DELAY

2.5

ms

V

OUT

 falling from 

V

R

 to V

R

 – 10%

DC CHARACTERISTICS (CONTINUED)

Electrical Specifications:

 Unless otherwise noted, V

IN

= V

OUT

+ 1V,  I

L

= 100 µA,  C

L

= 3.3 µF, SHDN > V

IH

, T

A

 = +25°C. Boldface 

type specifications apply for junction temperatures of -40°C to +125°C.

Parameters

Sym

Min

Typ

Max

Units

Conditions

Note 1:

V

R

 is the regulator output voltage setting. For example: V

R

 = 1.8V, 2.5V, 2.7V, 2.85V, 3.0V, 3.3V, 3.6V, 

4.0V, 5.0V.

2:

3:

Regulation is measured at a constant junction temperature using low-duty-cycle pulse testing. Load regu-
lation is tested over a load range from 0.1 mA 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.

5:

Thermal Regulation is defined as the change in output voltage at a time T after a change in power dissipa-
tion 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 ms.

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

JA

). Exceeding the 

maximum allowable power dissipation causes the device to initiate thermal shutdown. See Section 5.0 
“Thermal Considerations”

 for more details.

7:

Hysteresis voltage is referenced by V

R

.

8:

The minimum V

IN

 has to justify the conditions: V

IN

 

 V

R

 + V

DROPOUT

 and V

IN

 

 2.7V for I

L

 = 0.1 mA to 

I

OUT

MAX

.

9:

Apply for junction temperatures of -40°C to +85°C.

TC V

OUT

 = (V

OUT

MAX

 – V

OUT

MIN

)x 10

6

V

OUT 

T

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TC1054/TC1055/TC1186

DS21350E-page 4

 2002-2012 Microchip Technology Inc.

2.0

TYPICAL PERFORMANCE CURVES

Note:

 Unless otherwise indicated, V

IN

 = V

OUT

 + 1V, I

L

 = 100 µA, C

L

 = 3.3 µF, SHDN > V

IH

, T

A

 = +25°C.

FIGURE 2-1:

Dropout Voltage vs. 

Temperature (I

LOAD

 = 10 mA).

FIGURE 2-2:

Dropout Voltage vs. 

Temperature (I

LOAD

 = 100 mA).

FIGURE 2-3:

Ground Current vs. V

IN

 

(I

LOAD

 = 10 mA).

FIGURE 2-4:

Dropout Voltage vs. 

Temperature (I

LOAD

 = 50 mA).

FIGURE 2-5:

Dropout Voltage vs. 

Temperature (I

LOAD

 = 150 mA).

FIGURE 2-6:

Ground Current vs. V

IN

 

(I

LOAD

 = 100 mA).

Note:

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.

0.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

0.016

0.018

0.020

-40

-20

0

20

50

70

125

DROPOUT VOLTAGE (V)

I

LOAD

 = 10 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

0.000

0.020

0.040

0.060

0.080

0.100

0.120

0.140

0.160

0.180

0.200

-40

-20

0

20

50

70

125

DROPOUT VOLTAGE (V)

I

LOAD

 = 100 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

0

10

20

30

40

50

60

70

80

90

GND CURRENT (

μ

A)

0  0.5   1 1.5   2   2.5  3   3.5   4  4.5 5   5.5  6   6.5  7   7.5

I

LOAD

 = 10 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

V

IN

 (V)

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

-40

-20

0

20

50

70

125

DROPOUT VOLTAGE (V)

I

LOAD

 = 50 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

0.000

0.050

0.100

0.150

0.200

0.250

0.300

-40

-20

0

20

50

70

125

DROPOUT VOLTAGE (V)

I

LOAD

 = 150 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

0

10

20

30

40

50

60

70

80

90

GND CURRENT (

μ

A)

0   0.5  1  1.5   2   2.5   3   3.5   4  4.5    5   5.5  6   6.5   7   7.5

I

LOAD

 = 100 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

V

IN

 (V)

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DS21350E-page 5

TC1054/TC1055/TC1186

Note:

 Unless otherwise indicated, V

IN

 = V

OUT

 + 1V, I

L

 = 100 µA, C

L

 = 3.3 µF, SHDN > V

IH

, T

A

 = +25°C.

FIGURE 2-7:

Ground Current vs. V

IN

 

(I

LOAD

 = 150 mA).

FIGURE 2-8:

V

OUT

 vs. V

IN

 

(I

LOAD

= 100 mA).

FIGURE 2-9:

V

OUT

 vs. V

IN

 

(I

LOAD

= 150 mA).

FIGURE 2-10:

V

OUT

 vs. V

IN

 

(I

LOAD

= 0 mA).

FIGURE 2-11:

Output Voltage (3.3V) vs. 

Temperature (I

LOAD

 = 10 mA).

FIGURE 2-12:

Output Voltage (5V) vs. 

Temperature (I

LOAD

 = 10 mA).

0

10

20

30

40

50

60

70

80

GND CURRENT (

μ

A)

 

0  0.5   1 1.5   2   2.5  3   3.5  4   4.5 5   5.5  6   6.5  7   7.5

I

LOAD

 = 150 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

V

IN

 (V)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

I

LOAD

 = 100 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

0    0.5   1   1.5   2   2.5   3   3.5   4   4.5   5   5.5   6   6.5   7

V

IN

 (V)

 

V

OUT

 (V)

 

 

3.274

3.276

3.278

3.280

3.282

3.284

3.286

3.288

3.290

-40

-20

-10

0

20

40

85

125

I

LOAD

 = 150 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

V

IN

 = 4.3V

TEMPERATURE (

°C)

V

OUT

 (V)

 

0

0.5

1

1.5

2

2.5

3

3.5

 0    0.5   1  1.5    2   2.5   3   3.5    4   4.5   5    5.5   6   6.5   7

I

LOAD

 = 0

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

V

IN

 (V)

 

V

OUT

 (V)

 

3.275

3.280

3.285

3.290

3.295

3.300

3.305

3.310

3.315

3.320

-40

-20

-10

0

20

40

85

125

I

LOAD

 = 10 mA

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

V

IN

 = 4.3V

TEMPERATURE (

°C)

V

OUT

 (V)

 

4.985

4.990

4.995

5.000

5.005

5.010

5.015

5.020

5.025

-40

-20

-10

0

20

40

85

125

I

LOAD

 = 10 mA

V

IN

 

= 6V

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

V

OUT

 (V)

 

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TC1054/TC1055/TC1186

DS21350E-page 6

 2002-2012 Microchip Technology Inc.

Note:

 Unless otherwise indicated, V

IN

 = V

OUT

 + 1V, I

L

 = 100 µA, C

L

 = 3.3 µF, SHDN > V

IH

, T

A

 = +25°C.

FIGURE 2-13:

Output Voltage (5V) vs. 

Temperature (I

LOAD

 = 10 mA).

FIGURE 2-14:

GND Current vs. 

Temperature (I

LOAD

 = 10 mA).

FIGURE 2-15:

GND Current vs. 

Temperature (I

LOAD

 = 150 mA).

FIGURE 2-16:

Output Noise vs. Frequency.

FIGURE 2-17:

Stability Region vs. Load 

Current.

FIGURE 2-18:

Measure Rise Time of 3.3V 

LDO.

4.974

4.976

4.978

4.980

4.982

4.984

4.986

4.988

4.990

4.992

4.994

-40

-20

-10

0

20

40

85

125

I

LOAD

 = 150 mA

V

IN

 

= 6V

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

V

OUT

 (V)

 

                                                                    

   

0

10

20

30

40

50

60

70

-40

-20

-10

0

20

40

85

125

GND CURRENT (

μ

A)

I

LOAD

 = 10 mA

V

IN

 

= 6V

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

0

10

20

30

40

50

60

70

80

-40

-20

-10

0

20

40

85

125

GND CURRENT (

μ

A) 

I

LOAD

 = 150 mA

V

IN

 

= 6V

C

IN

 

= 1 

μF

C

OUT

 

= 1 

μF

TEMPERATURE (

°C)

10.0

1.0

0.1

0.0

0.01K 0.1K

1K

10K

100K

1000K

FREQUENCY (Hz)

NOISE (

μ

V/

Hz)

R

LOAD

 = 50 

Ω 

C

OUT 

= 1 

μF

C

IN

 = 1 

μF

1000

100

10

1

0.1

0.01

0

10 20 30 40 50 60 70 80 90 100

LOAD CURRENT (mA)

C

OUT 

ESR

 

(Ω

)

C

OUT

 = 1 

μ

to 10 

μF

Stable Region

V

SHDN

V

OUT

Conditions:

 C

IN

 = 1 µF, C

OUT

 = 1 µF,

I

LOAD

 = 100 mA, V

IN

 = 4.3V, Temperature = +25°C,

Fall Time = 184 µs

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DS21350E-page 7

TC1054/TC1055/TC1186

Note:

 Unless otherwise indicated, V

IN

 = V

OUT

 + 1V, I

L

 = 100 µA, C

L

 = 3.3 µF, SHDN > V

IH

, T

A

 = +25°C.

FIGURE 2-19:

Measure Rise Time of 5.0V 

LDO.

FIGURE 2-20:

Thermal Shutdown 

Response of 5.0V LDO.

FIGURE 2-21:

Measure Fall Time of 3.3V 

LDO.

FIGURE 2-22:

Measure Fall Time of 5.0V 

LDO.

V

SHDN

V

OUT

Conditions:

 C

IN

 = 1 µF, C

OUT

 = 1 µF,

I

LOAD

 = 100 mA, V

IN

 = 6V, Temperature = +25°C,

Fall Time = 192 µs

V

OUT

Conditions:

 V

IN

 = 6V, C

IN

 = 0 µF, C

OUT

 = 1 µF

I

LOAD

 was increased until temperature of die

reached about +160°C, at which time integrated ther-
mal protection circuitry shuts the regulator off when
die temperature exceeds approximately +160°C.
The regulator remains off until die temperature drops
to approximately +150°C.

V

SHDN

V

OUT

Conditions:

 C

IN

 = 1 µF, C

OUT

 = 1 µF,

I

LOAD

 = 100 mA, V

IN

 = 4.3V, Temperature = +25°C,

Fall Time = 52 µs

V

SHDN

V

OUT

Conditions: 

C

IN

 = 1 µF, C

OUT

 = 1 µF,

I

LOAD

 = 100 mA, V

IN

 = 6V, Temperature = +25°C,

Fall Time = 88 µs

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TC1054/TC1055/TC1186

DS21350E-page 8

 2002-2012 Microchip Technology Inc.

3.0

PIN DESCRIPTIONS

The descriptions of the pins are listed in 

Table 3-1

.

3.1

Unregulated Supply Input (V

IN

)

Connect unregulated input supply to the V

IN

 pin. If

there is a large distance between the input supply and
the LDO regulator, some input capacitance is
necessary for proper operation. A 1 µF capacitor
connected from V

IN

 to ground is recommended for

most applications.

3.2

Ground Terminal (GND)

Connect the unregulated input supply ground return to
GND. Also connect the negative side of the 1 µF typical
input decoupling capacitor close to GND and the
negative side of the output capacitor C

OUT

 to GND.

3.3

Shutdown Control Input (SHDN)

The regulator is fully enabled when a logic-high is
applied to SHDN. The regulator enters shutdown when
a logic-low is applied to SHDN. During shutdown,
output voltage falls to zero, ERROR is open-circuited
and supply current is reduced to 0.5 µA (maximum).

3.4

Out Of Regulation Flag (ERROR)

ERROR goes low when V

OUT

 is out-of-tolerance by

approximately -5%.

3.5

Regulated Voltage Output (V

OUT

)

Connect the output load to V

OUT

 of the LDO. Also

connect the positive side of the LDO output capacitor
as close as possible to the V

OUT

 pin.

TABLE 3-1:

PIN FUNCTION TABLE

Pin No.
SOT-23

Symbol

Description

1

V

IN

Unregulated supply input

2

GND

Ground terminal

3

SHDN

Shutdown control input

4

ERROR

Out-of-Regulation Flag (Open-drain output)

5

V

OUT

Regulated voltage output

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 2002-2012 Microchip Technology Inc.

DS21350E-page 9

TC1054/TC1055/TC1186

4.0

DETAILED DESCRIPTION

The TC1054, TC1055 and TC1186 are precision fixed
output voltage regulators (If an adjustable version is
desired, please see the TC1070/TC1071/TC1187 data
sheet (DS21353)). Unlike bipolar regulators, the
TC1054, TC1055 and TC1186 supply current does not
increase with load current.

Figure 4-1

 shows a typical application circuit, where the

regulator is enabled any time the shutdown input
(SHDN) is at or above V

IH

, and shutdown (disabled)

when SHDN is at or below V

IL

. 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 0.05 µA
(typical), V

OUT

 falls to zero volts, and ERROR is open-

circuited.

FIGURE 4-1:

Typical Application Circuit.

4.1

ERROR Open-Drain Output 

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

(typical) for a 5.0V regulator and 2.85V (typical) for a
3.0V regulator). ERROR output operation is shown in

Figure 4-2

Note that ERROR is active when V

OUT

 falls to V

TH

 and

inactive when V

OUT

 rises above V

TH

 by V

HYS

.

As shown in 

Figure 4-1

, ERROR can be used either as

a battery low flag or as a processor RESET signal (with
the addition of timing capacitor C

2

). R

1

x C

2

 should be

chosen to maintain ERROR below V

IH

 of the processor

RESET input for at least 200 ms to allow time for the
system to stabilize. Pull-up resistor R

1

 can be tied to

V

OUT

, V

IN

 or any other voltage less than (V

IN

+ 0.3V).

FIGURE 4-2:

Error Output Operation.

4.2

Output Capacitor

A 1 µF (minimum) capacitor from V

OUT

 to ground is

recommended. The output capacitor should have an
effective series resistance greater than 0.1

 and less

than 10.0

, with a resonant frequency above 1 MHz. A

1 µF 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 approxi-
mately -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.

or RESET

V

OUT

SHDN

GND

ERROR

+

V

IN

V

OUT

1 µF

+

Battery

+

0.2 µF

C

2

R

1

 

1 MΩ

V+

BATTLOW 

1 µF

C

1

TC1054
TC1055
TC1186

C

2

 Required Only if 

ERROR is used as a 
Processor RESET 
Signal (see Text)

Shutdown 
Control (to 
CMOS Logic or 
Tie to V

IN

 if 

unused)

V

TH

V

OUT

ERROR

V

IH

V

OL

HYSTERESIS 

(V

H

)

t

DELAY

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TC1054/TC1055/TC1186

DS21350E-page 10

 2002-2012 Microchip Technology Inc.

5.0

THERMAL CONSIDERATIONS

5.1

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.

5.2

Power Dissipation 

The amount of power the regulator dissipates is
primarily a function of input voltage, output voltage and
output current. The following equation is used to
calculate worst-case actual power dissipation:

EQUATION 5-1:

The maximum allowable power dissipation
(

Equation 5-2

) 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 (

JA

). The 5-Pin SOT-23 package has a

JA

 of approximately 220°C/Watt.

EQUATION 5-2:

Equation 5-1

 can be used in conjunction with

Equation 5-2

 to ensure regulator thermal operation is

within limits.
For example:

Actual power dissipation:

Maximum allowable power dissipation:

In this example, the TC1054 dissipates a maximum of
20.7 mW; below the allowable limit of 318 mW. In a
similar manner, 

Equation 5-1

 and 

Equation 5-2

 can be

used to calculate maximum current and/or input
voltage limits.

5.3

Layout Considerations

The primary path of heat conduction out of the package
is via the package leads. Layouts having a ground
plane, wide traces at the pads and wide power supply
bus lines, combine to lower θJA and increase the max-
imum allowable power dissipation limit.

P

D

V

INMAX

V

OUTMIN

I

LOADMAX

Where:

P

D

= Worst-case actual power dissipation

V

INmax

= Maximum voltage on V

IN

V

OUTmin

= Minimum regulator output voltage

I

LOADmax

= Maximum output (load) current

Where all terms are previously defined.

P

DMAX

T

J MAX

T

AMAX

JA

--------------------------------------------

=

Given:
V

IN

MAX

= 3.0V +5%

V

OUT

MIN

= 2.7V – 2.5%

I

LOAD

MAX

= 40 mA

T

J

MAX

= +125°C

T

A

MAX

= +55°C

Find:

1.

Actual power dissipation

2.

Maximum allowable dissipation

P

D

V

INMAX

V

OUTMIN

I

LOADMAX

3.0

1.05

2.7

0.975

40 10

-3

=

20.7mW

=

P

DMAX

T

JMAX

T

AMAX

J A

--------------------------------------------

=

125

55

220

-------------------------

=

318mW

=

Maker
Microchip Technology Inc.
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