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MIC2044/2045
General Description
The MIC2044 and MIC2045 are high-side MOSFET switches
optimized for general purpose power distribution applications
that require circuit protection. These devices switch up to
5.5V and as low as 0.8V while offering both programmable
current limiting and thermal shutdown to protect the device
and the load. A fault status output is provided to indicate
overcurrent and thermal shutdown fault conditions. Both
devices employ soft-start circuitry to minimize the inrush
current in applications that employ highly capacitive loads.
Additionally, for tighter control over inrush current during start
up, the output slew-rate may be adjusted by an external
capacitor.
The MIC2045 features a auto-reset circuit breaker that latches
the output OFF upon detecting an overcurrent condition
lasting more than 32ms. The output is reset by removing or
reducing the load.
Data sheets and support documentation can be found on
Micrel's web site at www.micrel.com.
Typical Application
+3.3V
Power
Supply
OUT1
OUT2
ON/OFF
Logic
IN
Controller
OVERCURRENT
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
January 2005
C2
m
0.1
F
C1
m
0.1
F
13, 16
C3
R1
m
W
4.7
F
20k
C4*
m
0.022
F
R
100
MIC2044/2045
Single Channel, High Current, Low Voltage,
Protected Power Distribution Switch
Features
• 30mΩ maximum on-resistance
• 0.8V to 5.5V operating range
• Adjustable current limit
• Up to 6A continuous output current
• Short circuit protection
• Very fast reaction to short circuits
• Thermal shutdown
• Adjustable slew-rate control
• Circuit breaker mode (MIC2045)
• Fault status flag
• Power-Good detection
• Undervoltage lockout
• No reverse current flow through the switching MOSFET
when OFF or disabled
• Low quiescent current
Applications
• Docking stations
• LAN servers
• WAN switches
• Hot swap board insertions
• Notebook PCs
• PDAs
• Base stations
• RAID controllers
• USB hosts
MIC2044-1BTS
8
9,12,14
VBIAS
VOUT
7, 11,
15
VIN
PGREF
2
EN
R4
W
20k
3
/FAULT
4
1
SLEW
PWRGD
6
5
ILIM
UVLOIN
(OPEN)
GND
SET
W
10
Note:
All V
pins (7, 11, 13, 16) must be externally tied together.
IN
All V
pins (9, 12, 14) must be externally tied together.
OUT
I
= 4A.
LIMIT
Output Power-Good = 3.0V.
*C4 is optional. See
1
V
OUT
3.3V@ 3.5A
R2
C
W
LOAD
m
294k
33
F
1%
R3
W
24.3k
1%
MIC39100-2.5BS
IN
2.5V
EN
OUT
GND
"Applications Information."
MIC2044/2045
Micrel
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Related Manuals for Micrel MIC2044
Summary of Contents for Micrel MIC2044
- Page 1 Output Power-Good = 3.0V. *C4 is optional. See "Applications Information." Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com January 2005 MIC2044/2045...
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Page 2: Ordering Information
MIC2044/2045 Micrel Ordering Information Part Number Standard Pb-Free Enable Circuit Breaker Package MIC2044-1BTS MIC2044-1YTS Active-High 16-Pin TSSOP MIC2044-2BTS MIC2044-2YTS Active-Low 16-Pin TSSOP MIC2045-1BTS MIC2045-1YTS Active-High 16-Pin TSSOP MIC2045-2BTS MIC2045-2YTS Active-Low 16-Pin TSSOP Pin Configuration PWRGD 16 VIN PGREF /FAULT VOUT... -
Page 3: Pin Description
= CLF/R . CLF is the current limit LIMIT factor specified in the “Electrical Characteristics” table. For the MIC2044/45, the continuous output current range is 1A to 6A. UVLOIN Undervoltage Lockout Adjust (Input): With this pin left open, the UVLO threshold is internally set to 1.45V. -
Page 4: Absolute Maximum Ratings
MIC2044/2045 Micrel Absolute Maximum Ratings Operating Ratings (Note 1) (Note 2) and V Supply Voltage BIAS ..............................0.8V to 5.5V /FAULT, PWRGD Output Voltage ........6V ............1.6V to 5.5V /FAULT, PWRGD Output Current ......25mA BIAS Continuous Output Current ........1A to 6A ESD Rating, Note 3 Human Body Model ........... -
Page 5: Timing Diagrams
Specification for packaged product only. Note 5. OFF is V < 1.0V for MIC2044/MIC2045–1 and V > 4.0V for MIC2044/MIC2045 –2. ON is V > 4.0V for MIC2044/MIC2045–1 and < 1.0V for MIC2044/MIC2045 –2. Note 6. The current limit is determined as follows: I... -
Page 6: Test Circuit
MIC2044/2045 Micrel Test Circuit 0.1µF MIC2044/45-xBTS LOAD 0.1µF 9,12,14 VBIAS VOUT 20kΩ 260kΩ LOAD 7, 11, 47µF 13, 16 PGREF 24kΩ 10µF 20kΩ 20kΩ /FAULT 75kΩ UVLOIN PWRGD SLEW ILIM 68kΩ SLEW and C use multiple values SLEW (See specific response plots) -
Page 7: Typical Characteristics
MIC2044/2045 Micrel Typical Characteristics Enable Input Threshold Enable Input Threshold (Falling) Supply Current (Rising) vs. Temperature vs. Temperature vs. Temperature = 5.5V BIAS = 5.5V BIAS = 5.5V BIAS = 3V BIAS = 3V BIAS = 3V BIAS = 1.6V = 1.6V... -
Page 8: Functional Characteristics
MIC2044/2045 Micrel Functional Characteristics 5V Turn-On 5V Turn-Off = 5.0V BIAS = 1.65V LOAD = 47 = 5.0V BIAS LOAD = 100 = 1.65 LOAD = 47 LOAD = 100 TIME (1ms/div.) TIME (500 s/div.) Latched Output Latched Output Reset... - Page 9 MIC2044/2045 Micrel Functional Characteristics (continued) Output Slew Response Thermal Shutdown Response = 5.0V = 5Ω 5.0V LOAD BIAS = 47µF = 2Ω LOAD LOAD = 0.033µF = 47µF SLEW LOAD = 220Ω = 220Ω TIME (2.5ms/div.) TIME (100ms/div.) January 2005...
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Page 10: Functional Diagram
MIC2044/2045 Micrel Functional Diagram = 230mV PWRGD Bandgap VBIAS Reference 7,11,13,16 Power-Off Reset Thermal Shutdown PGREF 9,12,14 VOUT 5.3x Gate Replica UVLO Control UVLOIN Current SLEW Limit ILIM Delay Charge (32ms) Pump Input Power-On Latch Open Logic Reset (MIC2045) Load... -
Page 11: Functional Description
32ms, then the /FAULT output asserts level, nominally set at 1.45V. The UVLO threshold is adjust- low. At this point, the MIC2044 will continue to supply current able and can be varied by applying an external resistor divider... - Page 12 supplying current to the load when the die temperature drops to 120°C. If the fault is still present, the MIC2044 will quickly In substituting the resistor values of the circuit and the typical re-heat and shut down again. This process of turning...
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Page 13: Applications Information
120°C and then rises above 140°C in a continuous cycle. that switches 0.8V while the device is powered from a With VOUT cycling on and off, the MIC2044 will reset the separate 2.5V power supply. The UVLO threshold is set by /FAULT while in an overtemperature fault condition if V the following equation. - Page 14 The following list contains some useful suggestions for PCB layout design of the MIC2044/45 in order to prevent the die from overheating under normal operating conditions. Micrel Semiconductor does not assume responsibility for the use of...
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Page 15: Package Information
(b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.