MIC2876
4.8A ISW, Synchronous Boost Regulator
with Bi-Directional Load Disconnect
Features
General Description
• Up to 95% Efficiency
• Input Voltage Range from 2.5V to 5.5V
• Fully Integrated, High-Efficiency, 2 MHz
Synchronous Boost Regulator
• Bi-Directional True Load Disconnect
• Integrated Anti-Ringing Switch
• 5.0V.
Efficiency vs. Load Current
DS20005572B-page 2
2016 - 2022 Microchip Technology Inc.
MIC2876
Functional Block Diagrams
MIC2876 (Fixed Output)
EN
IN
SW
VIN
ANTIRINGING
BODY
DRIVER
REFERENCE
GENERATOR
OUT
HS
DRIVER
2MHz
OSCILLATOR
PWM
LOGIC
CONTROL
LS
DRIVER
OUTS
VIN
OC
4.8A
PWM
/PG
CURRENT
SENSE
+
SLOPE
COMPENSATION
VREF
SOFTSTART
PGND
AGND
MIC2876 (Adjustable Output)
EN
IN
SW
VIN
ANTIRINGING
BODY
DRIVER
REFERENCE
GENERATOR
OUT
HS
DRIVER
2MHz
OSCILLATOR
PWM
LOGIC
CONTROL
LS
DRIVER
PGL
/PG
PGH
OC
4.8A
PWM
CURRENT
SENSE
+
SLOPE
COMPENSATION
FB
VREF
SOFTSTART
PGND
2016 - 2022 Microchip Technology Inc.
AGND
DS20005572B-page 3
MIC2876
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings †
IN, EN, OUT, FB, /PG to PGND ................................................................................................................... –0.3V to +6V
AGND to PGND......................................................................................................................................... –0.3V to +0.3V
ESD Rating (HBM) (Note 1) ....................................................................................................................................1.5 kV
ESD Rating (MM) (Note 1) ........................................................................................................................................200V
Power Dissipation (Note 2).....................................................................................................................Internally Limited
Operating Ratings ‡
Supply Voltage (VIN).................................................................................................................................. +2.5V to +5.5V
Output Voltage (VOUT).................................................................................................................................... Up to +5.5V
Enable Voltage (VEN) ......................................................................................................................................... 0V to VIN
† Notice: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the device at those or any other conditions above those indicated
in the operational sections of this specification is not intended. Exposure to maximum rating conditions for extended
periods may affect device reliability.
‡ Notice: The device is not guaranteed to function outside its operating ratings.
Note 1: Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5 kΩ in series
with 100 pF.
2: The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA.
Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
DS20005572B-page 4
2016 - 2022 Microchip Technology Inc.
MIC2876
ELECTRICAL CHARACTERISTICS
Electrical Characteristics: VIN = 3.6V, VOUT = 5V, CIN = 4.7 µF, COUT = 22 µF, L = 1 µH, TA = 25°C, unless noted.
Bold values are valid for –40°C ≤ TJ ≤ +125°C. (Note 1).
Parameters
Sym.
Min.
Typ.
Max.
Units
Conditions
Power Supply
Supply Voltage Range
VIN
2.5
—
5.5
V
—
UVLO Rising Threshold
VUVLOR
—
2.32
2.49
V
—
UVLO Hysteresis
VUVLOH
—
200
—
mV
—
Quiescent Current
IVIN
—
109
—
µA
Non-switching
VIN Shutdown Current
IVINSD
—
1
3
µA
VEN = 0V, VIN = 5.5V,
VOUT = 0V
VOUT Shutdown Current
IVOUTSD
—
2
5
µA
VEN = 0V, VIN = 0.3V,
VOUT = 5.5V
Output Voltage
VOUT
VIN
—
5.5
V
—
Feedback Voltage
VFB
0.8865
0.9
0.9135
V
Adjustable version, IOUT = 0A
Voltage Accuracy
—
–1.5
—
+1.5
%
Fixed version, IOUT = 0A
Line Regulation
—
—
0.3
—
%/V
2.5V < VIN < 4.5V,
IOUT = 500 mA
Load Regulation
—
—
0.2
—
%/A
IOUT = 200 mA to 1200 mA
Maximum Duty Cycle
DMAX
—
92
—
%
—
Minimum Duty Cycle
DMIN
—
6.5
—
%
—
Low-Side Switch Current Limit
(Note 2)
ILS
3.8
4.8
5.8
A
VIN = 2.5V
Switch On-Resistance
PMOS
—
79
—
mΩ
VIN = 3.0V, ISW = 200 mA,
VOUT = 5.0V
NMOS
—
82
—
Switch Leakage Current
ISW
—
0.2
5
µA
VEN = 0V, VIN = 5.5V
Oscillator Frequency
FOSC
1.6
2
2.4
MHz
—
Overtemperature Shutdown
Threshold
TSD
—
155
—
°C
—
Overtemperature Shutdown
Hysteresis
—
—
15
—
°C
—
TSS
—
1.1
—
ms
VOUT = 5.0V
VEN
1.5
—
—
V
Boost converter and chip logic
ON
—
—
0.4
—
1.5
3
VIN = 3.0V, ISW = 200 mA,
VOUT = 5.0V
Soft-Start
Soft-Start Time
EN, /PG Control Pins
EN Threshold Voltage
EN Pin Current
Note 1:
2:
—
Boost converter and chip logic
OFF
µA
VIN = VEN = 3.6V
Specification for packaged product only.
Guaranteed by design and characterization.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 5
MIC2876
ELECTRICAL CHARACTERISTICS (CONTINUED)
Electrical Characteristics: VIN = 3.6V, VOUT = 5V, CIN = 4.7 µF, COUT = 22 µF, L = 1 µH, TA = 25°C, unless noted.
Bold values are valid for –40°C ≤ TJ ≤ +125°C. (Note 1).
Parameters
Sym.
Min.
Typ.
Max.
Units
Conditions
Power Good Threshold (Rising)
V/PG-THR
—
0.9 x
VOUT
—
V
—
Power Good Threshold (Falling)
V/PG-THF
—
0.83 x
VOUT
—
V
—
Note 1:
2:
Specification for packaged product only.
Guaranteed by design and characterization.
DS20005572B-page 6
2016 - 2022 Microchip Technology Inc.
MIC2876
TEMPERATURE SPECIFICATIONS
Parameters
Sym.
Min.
Typ.
Max.
Units
Conditions
Junction Operating Temperature
TJ
–40
—
+125
°C
Storage Temperature Range
TS
–65
—
+150
°C
—
Lead Temperature
—
—
—
+260
°C
Soldering, 10s
JA
—
90
—
°C/W
Temperature Ranges
Note 1
Package Thermal Resistances
Thermal Resistance, 8-Lead 2x2 UDFN
Note 1:
—
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., TA, TJ, JA). Exceeding the
maximum allowable power dissipation will cause the device operating junction temperature to exceed the
maximum +125°C rating. Sustained junction temperatures above +125°C can impact the device reliability.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 7
MIC2876
2.0
Note:
TYPICAL PERFORMANCE CURVES
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.
FIGURE 2-1:
Efficiency vs. Load Current.
FIGURE 2-4:
Temperature.
Oscillator Frequency vs.
FIGURE 2-2:
Current.
Output Voltage vs. Load
FIGURE 2-5:
vs. Temperature.
Output Shutdown Current
FIGURE 2-3:
Voltage.
Output Voltage vs. Input
FIGURE 2-6:
Temperature.
Feedback Voltage vs.
DS20005572B-page 8
2016 - 2022 Microchip Technology Inc.
MIC2876
VSW
(5V/div)
V/PG
(2V/div)
VOUT
(1V/div)
(AC-COUPLED)
VIN = 3.5V, VOUT = 5.0V
L = 1μH, IOUT = 0A TO 1.2A
IOUT
(1A/div)
Time (100μs/div)
FIGURE 2-7:
Temperature.
UVLO Threshold vs.
FIGURE 2-10:
Load Transient (0A to 1.2A).
VSW
(5V/div)
V/PG
(2V/div)
VOUT
(1V/div)
(AC-COUPLED)
VIN = 3.5V, VOUT = 5.0V
L = 1μH, IOUT = 1.2A TO 0A
IOUT
(1A/div)
Time (100μs/div)
FIGURE 2-8:
Temperature.
Enable Threshold vs.
FIGURE 2-11:
VIN
(2V/div)
VOUT
(500mV/div)
(AC-COUPLED)
Load Transient (1.2A to 0A).
VIN = 2.5V TO 3.5V, VOUT = 5.0V
L = 1μH, IOUT = 1A
VOUT
(5V/div)
IL
(2A/div)
Time (100μs/div)
FIGURE 2-9:
Temperature.
Power Good Threshold vs.
2016 - 2022 Microchip Technology Inc.
FIGURE 2-12:
3.5V).
Line Transient (2.5V to
DS20005572B-page 9
MIC2876
VIN
(2V/div)
VOUT
(500mV/div)
(AC-COUPLED)
VIN = 3.5V TO 2.5V, VOUT = 5.0V
L = 1μH, IOUT = 1A
VSW
(2V/div)
VOUT
(50mV/div)
(AC-COUPLED)
VOUT
(5V/div)
PULSE SKIPPING MODE
VIN = 3.5V, VOUT = 5.0V, IOUT = 50mA
IL
(200mA/div)
IL
(2A/div)
Time (100μs/div)
FIGURE 2-13:
2.5V).
VIN
(2V/div)
VOUT
(2V/div)
(AC-COUPLED)
Line Transient (3.5V to
VIN = 2.5V TO 5.5V
VOUT = 5.0V
L = 1μH
IOUT = 1A
Time (4μs/div)
FIGURE 2-16:
Skipping Mode).
Output Ripple (Pulse
VSW
(5V/div)
VOUT
(50mV/div)
(AC-COUPLED)
VOUT
(5V/div)
IL
(5A/div)
IL
(1A/div)
Time (200ns/div)
Time (100μs/div)
FIGURE 2-14:
5.5V).
Line Transient (2.5V to
VIN = 5.5V TO 2.5V
VOUT = 5.0V, L = 1μH
IOUT = 1A
VIN
(2V/div)
VOUT
(2V/div)
(AC-COUPLED)
FIGURE 2-17:
VEN
(2V/div)
V/PG
(2V/div)
IL
(5A/div)
BOOST MODE
VIN = 3.5V
VOUT = 5.0V
IOUT = 500mA
IL
(1A/div)
Time (400μs/div)
Time (100μs/div)
DS20005572B-page 10
Output Ripple (PWM Mode).
VOUT
(5V/div)
VOUT
(5V/div)
FIGURE 2-15:
2.5V).
PWM MODE
VIN = 3.5V, VOUT = 5.0V, IOUT = 1.2A
Line Transient (5.5V to
FIGURE 2-18:
Soft-Start (Boost Mode).
2016 - 2022 Microchip Technology Inc.
MIC2876
BYPASS MODE
VIN = 5.5V
VOUT = 5.0V
IOUT = 500mA
VEN
(2V/div)
V/PG
(5V/div)
VOUT
(5V/div)
IL
(1A/div)
Time (400μs/div)
FIGURE 2-19:
Soft-Start (Bypass Mode).
VOUT = 5.0V
VOUT = 5.0V
VOUT
(1V/div)
BYPASS MODE – VIN > 5.0V
VOUT = VIN
VIN
(1V/div)
IOUT = 0A
Time (1s/div)
FIGURE 2-20:
Bypass Mode.
VOUT = 5.0V
VOUT = 5.0V
VOUT
(1V/div)
BYPASS MODE – VIN > 5.0V
VOUT = VIN
VIN
(1V/div)
IOUT = 500mA
Time (1s/div)
FIGURE 2-21:
Bypass Mode.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 11
MIC2876
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
Pin Number
Fixed Output
Pin Number
Adj. Output
Pin Name
1
1
SW
2
2
PGND
3
3
IN
Description
Boost Converter Switch Node: Connect the inductor between IN
and SW pins.
Power Ground: The power ground for the synchronous boost
DC/DC converter power stage.
Supply Input: Connect at least 1 µF ceramic capacitor between IN
and AGND pins.
4
4
AGND
Analog Ground: The analog ground for the regulator control loop.
5
—
OUTS
Output Voltage Sense Pin: For output voltage regulation in fixed
voltage version. Connect to the boost converter output.
—
5
FB
Feedback Pin: For output voltage regulation in adjustable version.
Connect to the feedback resistor divider.
6
6
EN
Boost Converter Enable: When this pin is driven low, the IC enters
shutdown mode. The EN pin has an internal 2.5 MΩ pull-down
resistor. The output is disabled when this pin is left floating.
7
7
/PG
Open Drain Power Good Output (Active Low): The /PG pin is high
impedance when the output voltage is below the power good
threshold and becomes low once the output is above the power
good threshold. The /PG pin has a typical RDS(ON) = 90Ω and
requires a pull up resistor of 1 MΩ. Connect /PG pin to AGND when
the /PG signal is not used.
8
8
OUT
Boost Converter Output.
EP
EP
ePad
Exposed Heat Sink Pad. Connect to AGND for best thermal
performance.
DS20005572B-page 12
2016 - 2022 Microchip Technology Inc.
MIC2876
4.0
FUNCTIONAL DESCRIPTION
4.1
Input (IN)
The input supply provides power to the internal
MOSFET’s gate drivers and control circuitry for the
boost regulator. The operating input voltage range is
from 2.5V to 5.5V. A 1 µF low-ESR ceramic input
capacitor should be connected from IN to AGND as
close to MIC2876 as possible to ensure a clean supply
voltage for the device. A minimum voltage rating of 10V
is recommended for the input capacitor.
4.2
Switch Node (SW)
The MIC2876 has internal low-side and synchronous
MOSFET switches. The switch node (SW) between the
internal MOSFET switches connects directly to one
end of the inductor and provides the current path during
switching cycles. The other end of the inductor is
connected to the input supply voltage. Due to the
high-speed switching on this pin, the switch node
should be routed away from sensitive nodes wherever
possible.
4.3
4.7
Feedback/Output Voltage Sense
(FB/OUTS)
Feedback or output voltage sense pin for the boost
converter. For the fixed voltage version, this pin should
be connected to the OUT pin. For the adjustable
version, connect a resistor divider to set the output
voltage (see “Output Voltage Programming” for more
information).
4.8
Power Good Output (/PG)
The open-drain active-low power-good output (/PG) is
low when the output voltage is above the power-good
threshold. A pull-up resistor of 1 MΩ is recommended.
4.9
Exposed Heat Sink Pad (EP)
The exposed heat sink pad, or ePad (EP), should be
connected to AGND for best thermal performance.
Ground Path (AGND)
The ground path (AGND) is for the internal biasing and
control circuitry. AGND should be connected to the
PCB pad for the package exposed pad. The current
loop of the analog ground should be separated from
that of the power ground (PGND). AGND should be
connected to PGND at a single point.
4.4
Power Ground (PGND)
The power ground (PGND) is the ground path for the
high current in the boost switches. The current loop for
the power ground should be as short as possible and
separate from the AGND loop as applicable.
4.5
Boost Converter Output (OUT)
A low-ESR ceramic capacitor of 22 µF (for operation
with VIN ≤ 5.0V), or 66 µF (for operation with VIN >
5.0V) should be connected from VOUT and PGND as
close as possible to the MIC2876. A minimum voltage
rating of 10V is recommended for the output capacitor.
4.6
Enable (EN)
Enable pin of the MIC2876. A logic high on this pin
enables the MIC2876. When this pin is driven low, the
MIC2876 enters the shutdown mode. When the EN pin
is left floating, it is pulled-down internally by a built-in
2.5 MΩ resistor.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 13
MIC2876
5.0
APPLICATION INFORMATION
5.1
General Description
The MIC2876 is a 2 MHz, current-mode, PWM,
synchronous boost converter with an operating input
voltage range of 2.5V to 5.5V. At light load, the
converter enters pulse-skipping mode to maintain high
efficiency over a wide range of load current. The
maximum peak current in the boost switch is limited to
4.8A (typical).
5.2
Bi-Directional Output Disconnect
The power stage of the MIC2876 consists of a NMOS
transistor as the main switch and a PMOS transistor as
the synchronous rectifier. A control circuit turns off the
back gate diode of the PMOS to isolate the output from
the input supply when the chip is disabled (VEN = 0V).
An “always on” maximum supply selector switches the
cathode of the backgate diode to either the IN or the
OUT (whichever of the two has the higher voltage). As
a result, the output of the MIC2876 is bi-directionally
isolated from the input as long as the device is
disabled. The maximum supply selector and hence the
output disconnect function requires only 0.3V at the IN
pin to operate.
5.3
Integrated Anti-Ringing Switch
The MIC2876 includes an anti-ringing switch that
eliminates the ringing on the SW node of a
conventional boost converter operating in the
discontinuous conduction mode (DCM). At the end of a
switching cycle during DCM operation, both the NMOS
and PMOS are turned off. The anti-ringing switch in the
MIC2876 clamps the SW pin voltage to IN to dissipate
the remaining energy stored in the inductor and the
parasitic elements of the power switches.
5.4
5.6
Output Voltage Programming
The MIC2876 has an adjustable version that allows the
output voltage to be set by an external resistor divider
R2 and R3. The typical feedback voltage is 900 mV, the
recommended maximum and minimum output voltage
is 5.5V and 3.2V, respectively. The current through the
resistor divider should be significantly larger than the
current into the FB pin (typically 0.01 µA). It is
recommended that 0.1% tolerance feedback resistors
must be used and the total resistance of R2 + R3
should be around 1 MΩ. The appropriate R2 and R3
values for the desired output voltage are calculated as
in Equation 5-1:
EQUATION 5-1:
V OUT
R2 = R3 ------------–1
0.9V
Example 1:
With a VOUT of 3.3V and an R3 value of 281.2 kΩ
(standard value is 280 kΩ), R2 calculates out to
750 kΩ.
Example 2:
With a VOUT of 5V and an R3 value of 200 kΩ, R2
calculates out to 911.1 kΩ (standard value is 910 kΩ).
5.7
Current Limit Protection
The MIC2876 has a current limit feature to protect the
part against heavy load conditions. When the current
limit comparator determines that the NMOS switch has
a peak current higher than 4.8A, the NMOS is turned off
and the PMOS is turned on until the next switching
cycle. The current limit protection is reset cycle by
cycle.
Automatic Bypass Mode
The MIC2876 automatically operates in bypass mode
when the input voltage is higher than the target output
voltage. In bypass mode, the NMOS is turned off while
the PMOS is fully turned on to provide a very low
impedance path from IN to OUT.
5.5
Soft-Start
The MIC2876 integrates an internal soft-start circuit to
limit the inrush current during start-up. When the device
is enabled, the PMOS is turned-on slowly to charge the
output capacitor to a voltage close to the input voltage.
Then, the device begins boost switching cycles to
gradually charge up the output voltage to the target
VOUT.
DS20005572B-page 14
2016 - 2022 Microchip Technology Inc.
MIC2876
6.0
COMPONENT SELECTION
6.1
Inductor
Inductor selection is a trade-off between efficiency,
stability, cost, size, and rated current. Because the
boost converter is compensated internally, the
recommended inductance is limited from 1 µH to
2.2 µH to ensure system stability and presents a good
balance between these considerations.
A large inductance value reduces the peak-to-peak
inductor ripple current hence the output ripple voltage.
This also reduces both the DC loss and the transition
loss at the same inductor’s DC resistance (DCR).
However, the DCR of an inductor usually increases
with the inductance in the same package size. This is
due to the longer windings required for an increase in
inductance. Since the majority of the input current
passes through the inductor, the higher the DCR the
lower the efficiency is, and more significantly at higher
load currents. On the other hand, inductor with smaller
DCR but the same inductance usually has a larger size.
The saturation current rating of the selected inductor
must be higher than the maximum peak inductor
current to be encountered and should be at least 20%
to 30% higher than the average inductor current at
maximum output current.
6.2
Input Capacitor to the Device
Supply
A ceramic capacitor of 1 µF or larger with low ESR is
recommended to reduce the input voltage ripple to
ensure a clean supply voltage for the device. The input
capacitor should be placed as close as possible to the
MIC2876 IN and AGND pins with short traces to ensure
good noise performance. X5R or X7R type ceramic
capacitors are recommended for better tolerance over
temperature. The Y5V and Z5U type temperature
rating ceramic capacitors are not recommended due to
their large reduction in capacitance over temperature
and increased resistance at high frequencies. The use
of these reduces their ability to filter out high-frequency
noise. The rated voltage of the input capacitor should
be at least 20% higher than the maximum operating
input voltage over the operating temperature range.
6.3
The Y5V and Z5U type temperature rating ceramic
capacitors are not recommended due to their large
reduction in capacitance over temperature and
increased resistance at high frequencies. These
reduce their ability to filter out high-frequency noise.
The rated voltage of the input capacitor should be at
least 20% higher than the maximum operating input
voltage over the operating temperature range.
6.4
Output Capacitor
Output capacitor selection is also a trade-off between
performance, size, and cost. Increasing the output
capacitor will lead to an improved transient response;
however, the size and cost also increase. For operation
with VIN ≤ 5.0V, a minimum of 22 µF output capacitor
with ESR less than 10 mΩ is required. For operation
with VIN > 5.0V, a minimum of 66 µF output capacitor
with ESR less than 10 mΩ is required. X5R or X7R type
ceramic capacitors are recommended for better
tolerance over temperature. Additional capacitors can
be added to improve the transient response, and to
reduce the ripple of the output when the MIC2876
operates in and out of bypass mode.
The Y5V and Z5U type ceramic capacitors are not
recommended due to their wide variation in
capacitance over temperature and increased
resistance at high frequencies. The rated voltage of the
output capacitor should be at least 20% higher than the
maximum operating output voltage over the operating
temperature range. The 0805 size ceramic capacitor is
recommended for smaller ESL at output capacitor
which contributes to a smaller voltage spike value at
the output voltage of the high-frequency switching
boost converter.
Input Capacitor to the Power Path
A ceramic capacitor of a 4.7 µF of larger with low ESR
is recommended to reduce the input voltage fluctuation
at the voltage supply of the high-current power path. An
input capacitor should be placed close to the VIN supply
to the power inductor and PGND for good device
performance at heavy load condition. X5R- or
X7R-type ceramic capacitors are recommended for
better tolerance over temperature.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 15
MIC2876
7.0
POWER DISSIPATION
As with all power devices, the ultimate current rating of
the output is limited by the thermal properties of the
device package and the PCB on which the device is
mounted. There is a simple, Ohm’s law-type
relationship between thermal resistance, power
dissipation, and temperature which are analogous to
an electrical circuit (see Figure 7-1):
EQUATION 7-2:
T J = P DISS JC + CA + T A
As can be seen in the diagram, total thermal resistance
θJA = θJC + θCA. This can also be written as in
Equation 7-3:
EQUATION 7-3:
T J = P DISS JA + T A
FIGURE 7-1:
Circuit.
Series Electrical Resistance
From this simple circuit we can calculate VX if we know
ISOURCE, VZ, and the resistor values, RXY and RYZ
using Equation 7-1:
Given that all of the power losses (minus the inductor
losses) are effectively in the converter and dissipated
within the MIC2876 package, PDISS can be calculated
thusly:
EQUATION 7-4:
2
1
P DISS = P OUT --- – 1 – I OUT DCR
EQUATION 7-1:
V X = I SOURCE R XY + R YZ + V Z
Thermal circuits can be considered using this same
rule and can be drawn similarly by replacing current
sources with power dissipation (in watts), resistance
with thermal resistance (in °C/W) and voltage sources
with temperature (in °C).
For Linear Mode.
EQUATION 7-5:
I OUT
1
P DISS = P OUT --- – 1 – ------------- DCR
1 – D
2
For Boost Mode.
EQUATION 7-6:
V OUT – V IN
D = ---------------------------V OUT
Duty Cycle (Boost).
FIGURE 7-2:
Circuit.
Series Thermal Resistance
Now replacing the variables in the equation for VX, we
can find the junction temperature (TJ) from the power
dissipation, ambient temperature and the known
thermal resistance of the PCB (θCA) and the package
(θJC).
In the equations above, ƞ is the efficiency taken from
the efficiency curves and DCR represents the inductor
DCR. θJC and θJA are found in the temperature
specifications section of the data sheet.
Where the real board area differs from 1” square, θCA
(the PCB thermal resistance), values for various PCB
copper areas can be taken from Figure 7-3.
.
DS20005572B-page 16
2016 - 2022 Microchip Technology Inc.
MIC2876
FIGURE 7-3:
Determining PCB Area for a
Given PCB Thermal Resistance.
Figure 7-3 shows the total area of a round or square
pad, centered on the device. The solid trace represents
the area of a square, single-sided, horizontal, solder
masked, copper PC board trace heat sink, measured in
square millimeters. No airflow is assumed. The dashed
line shows the PC board’s trace heat sink covered in
black oil-based paint and with 1.3 m/sec (250 feet per
minute) airflow. This approaches a “best case” pad
heat sink. Conservative design dictates using the solid
trace data, which indicates that a maximum pad size of
5000 mm2 is needed. This is a pad 71 mm × 71 mm
(2.8 inches per side).
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 17
MIC2876
8.0
PCB LAYOUT GUIDELINES
PCB layout is critical to achieve reliable, stable and
efficient performance. A ground plane is required to
control EMI and minimize the inductance in power,
signal and return paths. The following guidelines
should be followed to ensure proper operation of the
device. Please refer to the MIC2876 evaluation board
document for the recommended placement and layout
of components.
8.1
8.5
Output Capacitor
• Use wide and short traces to connect the output
capacitor as close as possible to the OUT and
PGND pins without going through via holes to
minimize the switching current loop during the
main switch off cycle and the switching noise.
• Use either X5R or X7R temperature rating
ceramic capacitors. Do not use Y5V or Z5U type
ceramic capacitors.
Integrated Circuit (IC)
• Place the IC close to the point-of-load.
• Use fat traces to route the input and output power
lines.
• Analog grounds and power ground should be kept
separate and connected at a single location at the
PCB pad for exposed pad of the IC.
• Place as many thermal vias as possible on the
PCB pad for the exposed pad and connect it to
the ground plane to ensure a good PCB thermal
resistance.
8.2
IN Decoupling Capacitor
• The IN decoupling capacitor must be placed close
to the IN pin of the IC and preferably connected
directly to the pin and not through any via. The
capacitor must be located right at the IC.
• The IN decoupling capacitor should be connected
as close as possible to AGND.
• The IN terminal is noise sensitive and the
placement of capacitor is very critical.
8.3
VIN Power Path Bulk Capacitor
• The VIN power path bulk capacitor should be
placed and connected close to the VIN supply to
the power inductor and the PGND of the IC.
• Use either X5R or X7R temperature rating
ceramic capacitors. Do not use Y5V or Z5U type
ceramic capacitors.
8.4
Inductor
• Keep both the inductor connections to the switch
node (SW) and input power line short and wide
enough to handle the switching current. Keep the
areas of the switching current loops small to
minimize the EMI problem.
• Do not route any digital lines underneath or close
to the inductor.
• Keep the switch node (SW) away from the noise
sensitive pins.
• To minimize noise, place a ground plane
underneath the inductor.
DS20005572B-page 18
2016 - 2022 Microchip Technology Inc.
MIC2876
9.0
PACKAGING INFORMATION
9.1
Package Marking Information
8-Lead UDFN*
Example
XXX
NNNC
76F
812C
Legend: XX...X
Y
YY
WW
NNN
e3
*
Product code or customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC® designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
●, ▲, ▼ Pin one index is identified by a dot, delta up, or delta down (triangle
mark).
Note:
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information. Package may or may not include
the corporate logo.
Underbar (_) symbol may not be to scale.
Note:
If the full seven-character YYWWNNN code cannot fit on the package, the following truncated codes
are used based on the available marking space:
6 Characters = YWWNNN; 5 Characters = WWNNN; 4 Characters = WNNN; 3 Characters = NNN;
2 Characters = NN; 1 Character = N
Note:
The “C” on the package marking drawings above represents copper bonding wire.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 19
MIC2876
8-Lead UDFN 2 mm x 2 mm Package Outline and Recommended Land Pattern
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
D
A
B
N
(DATUM A)
(DATUM B)
E
NOTE 1
2X
0.05 C
2
1
2X
TOP VIEW
0.05 C
0.05 C
8X
0.08 C
(A3)
C
A
A1
SEATING
PLANE
SIDE VIEW
0.05
C A B
D2
1
2
NOTE 1
0.05
C A B
E2
R0.10
(K)
L
N
e
e
2
8X b
0.10
0.05
C A B
C
BOTTOM VIEW
DS20005572B-page 20
2016 - 2022 Microchip Technology Inc.
MIC2876
8-Lead UDFN 2 mm x 2 mm Package Outline and Recommended Land Pattern
Note:
Notes:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
Units
Dimension Limits
N
Number of Terminals
e
Pitch
Overall Height
A
Standoff
A1
Terminal Thickness
A3
Overall Length
D
Exposed Pad Length
D2
Overall Width
E
Exposed Pad Width
E2
Terminal Width
b
L
Terminal Length
Terminal-to-Exposed-Pad
K
MIN
0.50
0.00
1.10
0.50
0.20
0.30
MILLIMETERS
NOM
8
0.50 BSC
0.55
0.02
0.152 REF
2.00 BSC
1.20
2.00 BSC
0.60
0.25
0.35
0.35 REF
MAX
0.60
0.05
1.30
0.70
0.30
0.40
1. Pin 1 visual index feature may vary, but must be located within the hatched area.
2. Package is saw singulated
3. Dimensioning and tolerancing per ASME Y14.5M
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
REF: Reference Dimension, usually without tolerance, for information purposes only.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 21
MIC2876
8-Lead UDFN 2 mm x 2 mm Package Outline and Recommended Land Pattern
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
X2
8
ØV
C Y2
G1
Y1
1
2
SILK SCREEN
X1
E
RECOMMENDED LAND PATTERN
Units
Dimension Limits
E
Contact Pitch
Optional Center Pad Width
X2
Optional Center Pad Length
Y2
Contact Pad Spacing
C
Contact Pad Width (X8)
X1
Contact Pad Length (X8)
Y1
Contact Pad to Center Pad (X8)
G1
Thermal Via Diameter
V
MIN
MILLIMETERS
NOM
0.50 BSC
MAX
1.30
0.70
1.90
0.30
0.80
0.20
0.30
Notes:
1. Dimensioning and tolerancing per ASME Y14.5M
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
2. For best soldering results, thermal vias, if used, should be filled or tented to avoid solder loss during
reflow process
Mi
DS20005572B-page 22
hi T
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l
D
i
C04 3158 HZA R
B
2016 - 2022 Microchip Technology Inc.
MIC2876
APPENDIX A:
REVISION HISTORY
Revision A (July 2016)
• Converted Micrel document MIC2876 to Microchip data sheet DS20005572B.
• Minor text changes throughout.
• Updated TDFN package information to Microchipstandard UDFN.
Revision B (July 2022)
• Corrected package marking drawings and added
note below legend in Section 9.1, Package Marking Information.
• Removed incorrect TDFN package outline and
replaced with correct UDFN package outline.
• Minor text corrections where needed.
2016 - 2022 Microchip Technology Inc.
DS20005572B-page 23
MIC2876
NOTES:
DS20005572B-page 24
2016 - 2022 Microchip Technology Inc.
MIC2876
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, contact your local Microchip representative or sales office.
–
PART NO.
Device
XX
X
XX
–
Output Temperature Package
Voltage
Device:
MIC2876:
Output Voltage:
4.75
5.0
5.25
5.5
A
=
=
=
=
=
4.75V
5.00V
5.25V
5.50V
Adjustable
Y
Package:
MT =
8-Pin 2 mm x 2 mm UDFN (Note)
Media Type:
T5
TR
500/Reel
5,000/Reel
Note:
=
=
–40°C to +125°C
Ultra-Thin DFN is an RoHS-compliant package. Lead finish is Pbfree and Matte Tin. Mold compound is Halogen free.
▲ = UDFN Pin 1 identifier
2016 - 2022 Microchip Technology Inc.
Examples:
a)
MIC2876-4.75YMT-T5:
b)
MIC2876-4.75YMT-TR:
c)
MIC2876-5.0YMT-T5:
d)
MIC2876-5.0YMT-TR:
e)
MIC2876-5.25YMT-T5:
f)
MIC2876-5.25YMT-TR:
g)
MIC2876-5.5YMT-T5:
h)
MIC2876-5.5YMT-TR:
i)
MIC2876-AYMT-T5:
j)
MIC2876-AYMT-TR:
Media
Type
4.8A ISW, Synchronous Boost Regulator
with Bi-Directional Load Disconnect
Temperature:
=
XX
MIC2876, 4.75V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
500/Reel
MIC2876, 4.75V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
5,000/Reel
MIC2876, 5.00V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
500/Reel
MIC2876, 5.00V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
5,000/Reel
MIC2876, 5.25V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
500/Reel
MIC2876, 5.25V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
5,000/Reel
MIC2876, 5.50V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
500/Reel
MIC2876, 5.50V Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
5,000/Reel
MIC2876, Adjustable Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
500/Reel
MIC2876, Adjustable Output
Voltage, –40°C to +125°C
Temp. Range, 8-Pin UDFN,
5,000/Reel
DS20005572B-page 25
MIC2876
NOTES:
DS20005572B-page 26
2016 - 2022 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip products:
•
Microchip products meet the specifications contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is secure when used in the intended manner, within operating specifications, and
under normal conditions.
•
Microchip values and aggressively protects its intellectual property rights. Attempts to breach the code protection features of
Microchip product is strictly prohibited and may violate the Digital Millennium Copyright Act.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of its code. Code protection does not
mean that we are guaranteeing the product is "unbreakable" Code protection is constantly evolving. Microchip is committed to
continuously improving the code protection features of our products.
This publication and the information herein may be used only
with Microchip products, including to design, test, and integrate
Microchip products with your application. Use of this information in any other manner violates these terms. Information
regarding device applications is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your
specifications. Contact your local Microchip sales office for
additional support or, obtain additional support at https://
www.microchip.com/en-us/support/design-help/client-supportservices.
THIS INFORMATION IS PROVIDED BY MICROCHIP "AS IS".
MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED,
WRITTEN OR ORAL, STATUTORY OR OTHERWISE,
RELATED TO THE INFORMATION INCLUDING BUT NOT
LIMITED TO ANY IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTABILITY, AND FITNESS FOR A
PARTICULAR PURPOSE, OR WARRANTIES RELATED TO
ITS CONDITION, QUALITY, OR PERFORMANCE.
IN NO EVENT WILL MICROCHIP BE LIABLE FOR ANY INDIRECT, SPECIAL, PUNITIVE, INCIDENTAL, OR CONSEQUENTIAL LOSS, DAMAGE, COST, OR EXPENSE OF ANY
KIND WHATSOEVER RELATED TO THE INFORMATION OR
ITS USE, HOWEVER CAUSED, EVEN IF MICROCHIP HAS
BEEN ADVISED OF THE POSSIBILITY OR THE DAMAGES
ARE FORESEEABLE. TO THE FULLEST EXTENT
ALLOWED BY LAW, MICROCHIP'S TOTAL LIABILITY ON
ALL CLAIMS IN ANY WAY RELATED TO THE INFORMATION
OR ITS USE WILL NOT EXCEED THE AMOUNT OF FEES, IF
ANY, THAT YOU HAVE PAID DIRECTLY TO MICROCHIP
FOR THE INFORMATION.
Use of Microchip devices in life support and/or safety applications is entirely at the buyer's risk, and the buyer agrees to
defend, indemnify and hold harmless Microchip from any and
all damages, claims, suits, or expenses resulting from such
use. No licenses are conveyed, implicitly or otherwise, under
any Microchip intellectual property rights unless otherwise
stated.
Trademarks
The Microchip name and logo, the Microchip logo, Adaptec, AVR,
AVR logo, AVR Freaks, BesTime, BitCloud, CryptoMemory,
CryptoRF, dsPIC, flexPWR, HELDO, IGLOO, JukeBlox, KeeLoq,
Kleer, LANCheck, LinkMD, maXStylus, maXTouch, MediaLB,
megaAVR, Microsemi, Microsemi logo, MOST, MOST logo,
MPLAB, OptoLyzer, PIC, picoPower, PICSTART, PIC32 logo,
PolarFire, Prochip Designer, QTouch, SAM-BA, SenGenuity,
SpyNIC, SST, SST Logo, SuperFlash, Symmetricom, SyncServer,
Tachyon, TimeSource, tinyAVR, UNI/O, Vectron, and XMEGA are
registered trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
AgileSwitch, APT, ClockWorks, The Embedded Control Solutions
Company, EtherSynch, Flashtec, Hyper Speed Control, HyperLight
Load, Libero, motorBench, mTouch, Powermite 3, Precision Edge,
ProASIC, ProASIC Plus, ProASIC Plus logo, Quiet- Wire,
SmartFusion, SyncWorld, Temux, TimeCesium, TimeHub,
TimePictra, TimeProvider, TrueTime, and ZL are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any
Capacitor, AnyIn, AnyOut, Augmented Switching, BlueSky,
BodyCom, Clockstudio, CodeGuard, CryptoAuthentication,
CryptoAutomotive, CryptoCompanion, CryptoController,
dsPICDEM, dsPICDEM.net, Dynamic Average Matching, DAM,
ECAN, Espresso T1S, EtherGREEN, GridTime, IdealBridge, InCircuit Serial Programming, ICSP, INICnet, Intelligent Paralleling,
IntelliMOS, Inter-Chip Connectivity, JitterBlocker, Knob-on-Display,
KoD, maxCrypto, maxView, memBrain, Mindi, MiWi, MPASM, MPF,
MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK, NetDetach,
Omniscient Code Generation, PICDEM, PICDEM.net, PICkit,
PICtail, PowerSmart, PureSilicon, QMatrix, REAL ICE, Ripple
Blocker, RTAX, RTG4, SAM-ICE, Serial Quad I/O, simpleMAP,
SimpliPHY, SmartBuffer, SmartHLS, SMART-I.S., storClad, SQI,
SuperSwitcher, SuperSwitcher II, Switchtec, SynchroPHY, Total
Endurance, Trusted Time, TSHARC, USBCheck, VariSense,
VectorBlox, VeriPHY, ViewSpan, WiperLock, XpressConnect, and
ZENA are trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated in
the U.S.A.
The Adaptec logo, Frequency on Demand, Silicon Storage
Technology, and Symmcom are registered trademarks of Microchip
Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology Germany
II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in
other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2016 - 2022, Microchip Technology Incorporated and its subsidiaries.
All Rights Reserved.
For information regarding Microchip’s Quality Management Systems,
please visit www.microchip.com/quality.
2016 - 2022 Microchip Technology Inc. and its subsidiariesAdvance
ISBN:
Information
DS20005572B-page 27
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DS20005572B-page 28
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