TC59
Low Dropout, Negative Output Voltage Regulator
Features
• Low Dropout Voltage
- Typically 120mV @ 50mA; 380mV @ 100mA
for -5.0V Output Part
• Tight Output Voltage Tolerance: ±2% Max
• Low Supply Current: 3.5µA, Typ
• Small Package: 3-Pin SOT-23A
General Description
The TC59 is a low dropout, negative output voltage
regulator designed specifically for battery-operated
systems. Its full CMOS construction eliminates the
wasted ground current typical of bipolar LDOs. This
reduced supply current significantly extends battery
life, particularly when the TC59 is operated in dropout.
Other TC59 key features include low supply current
(typically 3.0µA) and low dropout operation (typically
120mV at 50mA). The TC59 is packaged in a small
3-Pin SOT-23A package.
Applications
•
•
•
•
Cellular Phones
Battery Operated Systems
Palmtops
Portable Cameras
Functional Block Diagram
Device Selection Table
Output
Part Number
Voltage
TC593002ECB
TC595002ECB
3.0V
5.0V
Package
Temperature
Range
-V
OUT
1
-V
OUT
1µF
3
V
SS
TC59
-V
IN
2
-V
IN
1µF
3-Pin SOT-23A -40°C to +85°C
3-Pin SOT-23A -40°C to +85°C
Other output voltages are available. Please contact Microchip
Technology Inc. for details.
_
+
_
+
Package Type
3-Pin SOT-23A
V
SS
4
TC59
1
-V
OUT
2
-V
IN
NOTE:
3-Pin SOT-23A is equivalent to the EIAJ SC59
2002 Microchip Technology Inc.
DS21438B-page 1
©
TC59
1.0
ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings*
Input Voltage .........................................................-12V
Output Current .................................................. 200mA
Output Voltage..................... -V
DD
– 0.3V to V
IN
+ 0.3V
Power Dissipation.............................................150mW
Operating Temperature Range............. -40°C to +85°C
Storage Temperature Range .............. -40°C to +125°C
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.
TC59 ELECTRICAL SPECIFICATIONS
Electrical Characteristics:
V
IN
= V
R
– 1.0V
(Note 1),
C
L
= 10µF, T
A
= 25°C unless otherwise noted.
Symbol
V
IN
I
DD
I
OUT(MAX)
Parameter
Input Voltage
Supply Current
Maximum Output Current
Min
—
—
100
80
60
1.02
X
V
R
—
—
Typ
—
3
—
—
—
—
±100
0.1
Max
-10
7
—
—
—
0.98 x V
R
—
0.3
Units
V
µA
mA
mA
mA
V
V
IN
= -6.0V; V
R
= -5.0V, V
OUT
≤
-4.5V
V
IN
= -5.0V; V
R
= -4.0V, V
OUT
≤
-3.6V
V
IN
= -4.0V; V
R
= -3.0V, V
OUT
≤
-2.7V
I
OUT
= 20mA
I
OUT
= 20mA
Test Conditions
V
OUT
TC V
OUT
∆V
OUT
/
(∆V
IN X
V
OUT
)
∆V
OUT
Output Voltage
Output Voltage
Temperature Coefficient
Line Regulation
ppm/°C I
OUT
= 20mA
%/V
I
OUT
= 20mA; V
R
= -5.0V; -6.0 < V
IN
< -10.0V
V
R
= -4.0V; -5.0 < V
IN
< -10.0V
V
R
= -3.0V; -4.0 < V
IN
< -10.0V
V
R
= -5.0V; 1mA < I
OUT
< 50mA
V
R
= -4.0V; 1mA < I
OUT
< 45mA
V
R
= -3.0V; 1mA < I
OUT
< 40mA
V
R
= -5.0V;
V
R
= -4.0V;
V
R
= -3.0V;
I
OUT
= 50mA
I
OUT
= 100mA
I
OUT
= 45mA
I
OUT
= 90mA
I
OUT
= 40mA
I
OUT
= 80mA
Load Regulation
—
40
80
mV
V
IN
- V
OUT
Dropout Voltage
—
—
—
—
—
—
120
380
120
380
120
380
300
600
300
600
300
600
mV
mV
mV
mV
mV
mV
Note
1:
V
R
is the regulator output voltage setting. For example: V
R
= -2.5V, -2.7V, -3.0V, -3.3V, -3.6V, -4.0V, -5.0V.
©
DS21438B-page 2
2002 Microchip Technology Inc.
TC59
2.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1:
Pin No.
(3-Pin SOT-23A)
1
2
3
PIN FUNCTION TABLE
Symbol
V
OUT
V
IN
V
SS
Regulated voltage output.
Supply voltage input.
Ground.
Description
3.0
DETAILED DESCRIPTION
3.2
Input Capacitor
The TC59 is a low quiescent current, precision fixed
negative output voltage LDO. Unlike bipolar linear
regulators, the TC59 supply current does not increase
proportionally with load current.
3.1
Output Capacitor
A minimum of 1µF tantalum output capacitor is
required. The requirements for the output capacitor are
an equivalent series resistance (esr) greater than 0.1Ω
and less than 5Ω, with a self-resonant frequency
greater than 1MHz. To improve supply noise rejection
and transient response, larger output capacitors can be
used. Care should be taken when increasing C
OUT
, that
the input impedance is not high enough to cause high
input impedance oscillation.
A 1µF input capacitor is recommended for most
applications when the input impedance is on the order
of 10Ω. When operating off of a battery input, or there
is a large distance from the input source to the LDO,
larger input capacitance may be required for stability.
When large values of output capacitance are used, the
input capacitance should be increased to prevent high
source impedance oscillations.
2002 Microchip Technology Inc.
DS21438B-page 3
©
TC59
4.0
4.1
THERMAL CONSIDERATIONS
Power Dissipation
EQUATION 4-3:
P
TOTAL
= P
D
(Pass Device) + P
D
(Bias)
For the TC59, the internal quiescent bias current is so
low (3µA typical), the P
D
(Bias) term of the power
dissipation equation can be ignored. The maximum
power dissipation can be estimated by using the
maximum input voltage and the minimum output
voltage to obtain a maximum voltage differential
between input and output and multiplying the maximum
voltage differential by the maximum output current.
The amount of power dissipated internal to the low drop
out linear regulator is the sum of the power dissipation
within the linear pass device (P-Channel MOSFET),
and the quiescent current required to bias the internal
reference and error amplifier. The internal linear pass
device power dissipation is calculated multiplying the
voltage across the linear device times the current
through the device. The input and output voltages are
negative for the TC59. The power dissipation is
calculated using the absolute value of the voltage
difference between the input and output voltage.
EQUATION 4-4:
P
MAX
= (V
IN (MAX)
– V
OUT (MIN)
) X I
OUT (MAX)
TABLE 4-1:
MAXIMUM POWER
DISSIPATION
Maximum Power
Dissipation
150mW
For example, given the following conditions:
V
IN
V
OUT
I
OUT
P
MAX
P
MAX
= -7.0V ±5%
= -5.0V ±2%
= 1mA to 40mA
= (7V X (1.05) – (5.0V X 0.98)) X 40mA
= 98.0 milli-Watts
Package Type
SOT-23-3
T
AMBIENT (MAX)
= 55°C
EQUATION 4-1:
P
D
(Pass Device) = (V
IN
– V
OUT
) X I
OUT
The internal power dissipation as a result of the bias
current for the LDO internal reference and error
amplifier is calculated by multiplying the ground or
quiescent current times the input voltage.
To determine the junction temperature of the device,
the thermal resistance from junction to air must be
known. The SOT-23-3 R
θJA
is estimated to be
approximately 359°C/W when mounted on a 4-layer
board. The R
θJA
will vary with physical layout, airflow
and other application specific conditions.
The device junction temperature is determined by
calculating the junction temperature rise above
ambient, then adding the rise to the ambient
temperature.
EQUATION 4-2:
P
D
(Bias) = V
IN
X I
GND
The total internal power dissipation is the sum of
Equation 4-1 and Equation 4-2.
EQUATION 4-5:
JUNCTION
TEMPERATURE
(SOT-23 EXAMPLE)
T
JUNCTION
= P
D (MAX)
X R
θJA
+ T
AMBIENT
T
JUNCTION
= 98.0 milli-Watts X 359°C/W + 55°C
T
JUNCTION
= 90.2°C
©
DS21438B-page 4
2002 Microchip Technology Inc.
TC59
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.
1. OUTPUT VOLTAGE vs. OUTPUT CURRENT
TC595002 (-5V)
-5.10
V
IN
= -6.0V
-6
TC595002 (-5V)
V
IN
= -6.0V
T
OPR
= -40°C
C
-5
-4
-3
-2
-1
0
0
50
100
150
200
OUTPUT CURRENT I
OUT
(mA)
250
OUTPUT VOLTAGE V
OUT
(V)
-5.05
-5.00
-4.95
-4.90
-4.85
-4.80
25°C
T
OPR
= -40°C
C
80°C
OUTPUT VOLTAGE V
OUT
(V)
25°C
80°C
0
20
40
60
80
100
OUTPUT CURRENT I
OUT
(mA)
TC594002 (-4V)
-4.10
TC594002 (-4V)
-5
OUTPUT VOLTAGE V
OUT
(V)
V
IN
= -5.0V
V
IN
= -5.0V
T
OPR
= -40°C
C
OUTPUT VOLTAGE V
OUT
(V)
-4.05
-4
-3
25°C
-4.00
-3.95
-3.90
-3.85
-3.80
0
T
OPR
= -40°C
80°C
25°C
-2
-1
80°C
0
0
200
50
100
150
OUTPUT CURRENT I
OUT
(mA)
250
20
40
60
80
100
OUTPUT CURRENT I
OUT
(mA)
TC593002 (-3V)
-3.10
TC593002 (-3V)
-4
V
IN
= -4.0V
V
IN
= -4.0V
OUTPUT VOLTAGE V
OUT
(V)
-3.05
OUTPUT VOLTAGE V
OUT
(V)
T
OPR
= -40°C
C
-3
T
OPR
= -40°C
C
-3.00
-2.95
-2.90
-2.85
-2.80
25°C
80°C
-2
25°C
-1
80°C
0
0
50
200
250
100
150
OUTPUT CURRENT I
OUT
(mA)
0
20
40
60
80
100
OUTPUT CURRENT I
OUT
(mA)
2002 Microchip Technology Inc.
DS21438B-page 5
©
