MCP1804T-C002I/DB Microchip Technology, MCP1804T-C002I/DB Datasheet - Page 24

• Manufacturer Part Number: MCP1804T-C002I/DB
• Description: IC REG LDO 12V 150MA SOT223-3
• Manufacturer: Microchip Technology

Specifications of MCP1804T-C002I/DB

• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Regulator Topology: Positive Fixed
• Voltage - Output: 12V
• Voltage - Input: Up to 28V
• Voltage - Dropout (typical): 0.65V @ 100mA
• Number Of Regulators: 1
• Current - Output: 150mA (Min)
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Input Voltage Max: 28 V
• Output Voltage: 1.8 V
• Output Voltage Tolerance: +/- 2 %
• Dropout Voltage (max): 710 V
• Output Current: 150 mA
• Line Regulation: 0.05 %/V
• Load Regulation: 275 mV
• Maximum Power Dissipation: 300 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Limit (min): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: MCP1804T-C002I/DBTR

MCP1804
6.3
Internal power dissipation, junction temperature rise,
junction temperature and maximum power dissipation
are calculated in the following example. The power
dissipation, as a result of ground current, is small
enough to be neglected.
6.3.1
6.3.1.1
The internal junction temperature rise is a function of
internal power dissipation and the thermal resistance
from junction to ambient for the application. The thermal
resistance from junction to ambient (Rθ
from an EIA/JEDEC standard for measuring thermal
resistance for small surface mount packages. The EIA/
JEDEC specification is JESD51-7, “High
Thermal Conductivity Test Board for Leaded Surface
Mount Packages”. The standard describes the test
method and board specifications for measuring the
thermal resistance from junction to ambient. The actual
thermal resistance for a particular application can vary
depending on many factors, such as copper area and
thickness. Refer to AN792, “A Method to Determine
How Much Power a SOT23 Can Dissipate in an
Application” (DS00792), for more information regarding
this subject.
DS22200B-page 24
Package:
Input Voltage:
LDO Output Voltages and Currents:
Maximum Ambient Temperature:
Internal Power Dissipation:
Internal Power dissipation is the product of the LDO
output current times the voltage across the LDO
(V
IN
Package Type = SOT-23
to V
T
T
T
J(RISE)
P
JRISE
JRISE
LDO(MAX)
Voltage Regulator
OUT
T
A(MAX)
POWER DISSIPATION EXAMPLE
V
P
P
I
).
Device Junction Temperature Rise
OUT
OUT
= P
= 141.8 milli-Watts x 256.0
= 36.3
LDO
LDO
V
IN
TOTAL
= 3.8V to 4.6V
= 1.8V
= 50 mA
= +40°C
= (V
= (4.6V - (0.98 x 1.8V)) x 50 mA
= 141.8 milli-Watts
°
I
OUT(MAX)
C
IN(MAX)
x Rq
JA
- V
OUT(MIN)
JA
°
) x
C/Watt
) is derived
Effective
6.3.1.2
To estimate the internal junction temperature, the
calculated temperature rise is added to the ambient or
offset temperature. For this example, the worst-case
junction temperature is estimated below.
Maximum Package Power Dissipation at +25°C
Ambient Temperature (minimum PCB footprint)
6.4
The MCP1804 can be used not only as a regulator, but
also as a low quiescent current voltage reference. In
many microcontroller applications, the initial accuracy
of the reference can be calibrated using production test
equipment or by using a ratio measurement. When the
initial accuracy is calibrated, the thermal stability and
line regulation tolerance are the only errors introduced
by the MCP1804 LDO. The low-cost, low quiescent
current and small ceramic output capacitor are all
advantages when using the MCP1804 as a voltage
reference.
FIGURE 6-2:
Voltage Reference.
SOT-23 (256°C/Watt = Rθ
SOT-89 (180°C/Watt = Rθ
50 µA Bias
C
1 µF
IN
P
P
P
P
T
T
J
J
D(MAX)
D(MAX)
D(MAX)
D(MAX)
= T
= 76.3°C
Bridge Sensor
Voltage Reference
MCP1804
V
GND
JRISE
IN
Junction Temperature Estimate
= (85°C - 25°C) / 256°C/W
= 234 milli-Watts
= (85°C - 25°C) / 180°C/W
= 333 milli-Watts
Ratio Metric Reference
V
OUT
+ T
A(MAX)
C
1 µF
Using the MCP1804 as a
OUT
© 2009 Microchip Technology Inc.
JA
JA
):
):
V
ADO
AD1
Microcontroller
REF
PICmicro
®