MIC2875
4.8A I
SW
, Synchronous Boost Regulator
with Bi-Directional Load Disconnect
General Description
The MIC2875 is a compact and highly-efficient 2MHz
synchronous boost regulator with a 4.8A switch. It features
a bi-directional load disconnect function which prevents
any leakage current between the input and output when
the device is disabled. The MIC2875 operates in bypass
mode automatically when the input voltage is greater than
the target output voltage. At light loads, the boost
converter goes to the PFM mode to improve the efficiency.
To minimize switching artifacts in the audio band, the
MIC2875 is designed to operate with a minimum switching
frequency of 45kHz. The MIC2875 also features an
integrated anti-ringing switch to minimize EMI.
The MIC2875 is available in a 8-pin 2mm × 2mm Thin DFN
(TDFN) package, with a junction temperature range of
−40°C
to +125°C.
Datasheets and support documentation are available on
Micrel’s web site at:
www.micrel.com.
Features
•
Input voltage range: 2.5V to 5.5V
•
Fully-integrated, high-efficiency, 2MHz synchronous
boost regulator
•
Bi-directional true load disconnect
•
Integrated anti-ringing switch
•
Minimum switching frequency of 45kHz
•
Up to 95% efficiency
•
<1µA shutdown current
•
Bypass mode for V
IN
≥ V
OUT
•
Overcurrent protection and thermal shutdown
•
Fixed and adjustable output versions
•
8-pin 2mm × 2mm TDFN package
Applications
•
•
•
•
•
Tablet and smartphones
USB OTG and HDMI hosts
Portable power reserve supplies
Low-noise audio applications
Portable equipment
Simplified Application Schematics
MIC2875 (Adjustable Output)
MIC2875 (Fixed Output)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
January 19, 2015
Revision 1.1
Micrel, Inc.
MIC2875
Ordering Information
Part Number
MIC2875-4.75YMT
MIC2875-5.0YMT
MIC2875-5.25YMT
MIC2875-5.5YMT
MIC2875-AYMT
Notes:
1. TDFN is a RoHS-compliant package. Lead finish is Pb free and Matte Tin. Mold compound is Halogen free.
2. ▲ = TDFN Pin 1 identifier.
Mark Code
87F
87G
87H
87J
87A
Output Voltage
4.75V
5.00V
5.25V
5.50V
Adjustable
Temperature Range
−40°C
to +125°C
−40°C
to +125°C
−40°C
to +125°C
−40°C
to +125°C
−40°C
to +125°C
Package
(1,
2)
8-Pin 2mm × 2mm TDFN
8-Pin 2mm × 2mm TDFN
8-Pin 2mm × 2mm TDFN
8-Pin 2mm × 2mm TDFN
8-Pin 2mm × 2mm TDFN
Pin Configuration
8-Pin 2mm × 2mm TDFN (MT)
Fixed Output
(Top View)
8-Pin 2mm × 2mm TDFN (MT)
Adjustable Output
(Top View)
Pin Description
Pin Number
Fixed
Output
1
2
3
4
5
−
Pin Number
Adjustable
Output
1
2
3
4
−
5
Pin Name
SW
PGND
IN
AGND
OUTS
FB
Pin Function
Boost Converter Switch Node: Connect the inductor between IN and SW pins.
Power Ground: The power ground for the synchronous boost DC-to-DC
converter power stage.
Supply Input: Connect at least 1µF ceramic capacitor between IN and AGND
pins.
Analog Ground: The analog ground for the regulator control loop.
Output Voltage Sense Pin: For output voltage regulation in fixed voltage
version. Connect to the boost converter output.
Feedback Pin: For output voltage regulation in adjustable voltage version.
Connect to the feedback resistor divider.
Boost Converter Enable: When this pin is driven low, the IC enters shutdown
mode. The EN pin has an internal 2.5MΩ pull-down resistor. The output is
disabled when this pin is left floating.
6
6
EN
January 19, 2015
2
Revision 1.1
Micrel, Inc.
MIC2875
Pin Description (Continued)
Pin Number
Fixed
Output
Pin Number
Adjustable
Output
Pin Name
Pin Function
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
R
DS(ON)
= 90Ω and requires a pull up resistor of 1MΩ. Connect /PG pin to
AGND when the /PG signal is not used.
Boost Converter Output.
Exposed Heat Sink Pad. Connect to AGND for best thermal performance.
7
7
/PG
8
EP
8
EP
OUT
ePad
January 19, 2015
3
Revision 1.1
Micrel, Inc.
MIC2875
Absolute Maximum Ratings
(3)
IN, EN, OUT, FB, /PG to PGND ......................
−0.3V
to +6V
AGND to PGND. ..........................................
−0.3V
to +0.3V
Power Dissipation .................................. Internally Limited
(5)
Lead Temperature (soldering, 10s) ............................ 260°C
Storage Temperature (T
S
) .........................
−65°C
to +150°C
ESD Rating
(6)
Human Body Model .............................................. 1.5kV
Machine Model ...................................................... 200V
Operating Ratings
(4)
Supply Voltage (V
IN
) ..................................... +2.5V to +5.5V
Output Voltage (V
OUT
) ......................................... Up to 5.5V
Enable Voltage (V
EN
) .............................................. 0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Package Thermal Resistance
8-Pin 2mm × 2mm TDFN (θ
JA
) .......................... 90°C/W
Electrical Characteristics
(7)
V
IN
= 3.6V, V
OUT
= 5V, C
IN
= 4.7µF, C
OUT
= 22µF, L = 1µH T
A
= 25°C,
bold
values indicate
−40°C ≤
T
J
≤
+125°C, unless otherwise
noted.
Symbol Parameter
Power Supply
V
IN
V
UVLOR
V
UVLOH
I
VIN
I
VINSD
I
VOUTSD
V
OUT
V
FB
Supply Voltage Range
UVLO Rising Threshold
UVLO Hysteresis
Quiescent Current
V
IN
Shutdown Current
V
OUT
Shutdown Current
Output Voltage
Feedback Voltage
Voltage Accuracy
Line Regulation
Load Regulation
D
MAX
D
MIN
I
LS
PMOS
NMOS
I
SW
F
SWMIN
F
OSC
T
SD
Notes:
3. Exceeding the absolute maximum ratings may damage the device.
4. The device is not guaranteed to function outside its operating ratings.
5. The maximum allowable power dissipation of any T
A
(ambient temperature) is P
D(max)
= (T
J(max)
– T
A
) /
θ
JA
. Exceeding the maximum allowable power
dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown
6. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.
7. Specification for packaged product only.
8. Guaranteed by design and characterization.
Condition
Min.
Typ.
Max.
Unit
2.5
2.32
200
Operating at minimum switching frequency
V
EN
= 0V, V
IN
= 5.5V, V
OUT
= 0V
V
EN
= 0V, V
IN
= 0.3V, V
OUT
= 5.5V
V
IN
Adjustable version, I
OUT
= 0A
Fixed version, I
OUT
= 0A
2.5V < V
IN
< 4.5V, I
OUT
= 500mA
I
OUT
= 200mA to 1200mA
0.8865
−1.5
0.3
0.2
92
6.5
V
IN
= 2.5V
V
IN
= 3.0V, I
SW
= 200mA, V
OUT
= 5.0V
V
IN
= 3.0V, I
SW
= 200mA, V
OUT
= 5.0V
V
EN
= 0V, V
IN
= 5.5V
I
OUT
= 0mA
1.6
3.8
4.8
79
82
0.2
45
2
155
15
0.9
1
1
2
5.5
2.49
V
V
mV
mA
3
5
5.5
0.9135
+1.5
µA
µA
V
V
%
%/V
%/A
%
%
Maximum Duty Cycle
Minimum Duty Cycle
Low-Side Switch Current Limit
(8)
Switch On-Resistance
Switch Leakage Current
(8)
Minimum Switching Frequency
Oscillator Frequency
Overtemperature Shutdown Threshold
Overtemperature Shutdown Hysteresis
5.8
A
mΩ
5
µA
kHz
2.4
MHz
°C
January 19, 2015
4
Revision 1.1
Micrel, Inc.
MIC2875
Electrical Characteristics
(7)
(Continued)
V
IN
= 3.6V, V
OUT
= 5V, C
IN
= 4.7µF, C
OUT
= 22µF, L = 1µH T
A
= 25°C,
bold
values indicate
−40°C ≤
T
J
≤
+125°C, unless otherwise
noted.
Symbol Parameter
Soft-Start
T
SS
Soft-Start Time
V
OUT
= 5.0V
1.1
ms
Condition
Min.
Typ.
Max.
Unit
EN, /PG Control Pins
V
EN
EN Threshold Voltage
EN Pin Current
V
/PG-THR
V
/PG-THF
Power-Good Thershold (Rising)
Power-Good Thershold (Falling)
Boost converter and chip logic ON
Boost converter and chip logic OFF
V
IN
= V
EN
= 3.6V
1.5
0.90 × V
OUT
0.83 × V
OUT
1.5
0.4
3
V
µA
V
V
January 19, 2015
5
Revision 1.1
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