MIC2545A/2549A Programmable Current-Limit High-Side Switch
General Description
The MIC2545A and MIC2549A are integrated high-side power switches optimized for low-loss DC power switching and other power-management applications, including advanced configuration and power interface (ACPI). The MIC2545A/49A is a cost-effective, highly-integrated solution that requires few external components to satisfy USB and ACPI requirements.
Load current management features include a precision, resistor-programmable output current-limit and a soft-start circuit, which minimizes inrush current when the switch is enabled. Thermal shutdown, along with adjustable current-limit, protects the switch and the attached device.
The MIC2545A/49A’s open-drain flag output is ud to indicate current-limiting or thermal shutdown to a local controller. The MIC2549A has an additional internal latch which turns the output off upon thermal shutdown, providing robust fault control. The enable signal is compatible with both 3V and 5V logic, and is also ud as the thermal shutdown latch ret for the MIC2549A.
The MIC2545A and MIC2549A are available in active-high and active-low enable versions in 8-pin DIP, SOIC, and TSSOP packages.
Data sheets and support documentation can be found on Micrel’s web site at: Features
• 2.7V to 5.5V inputmidway
•Adjustable current-limit up to 3A
•Rever current flow blocking
• 90µA typical on-state supply current
•1µA typical off-state supply current
• 50mΩ maximum on-resistance
•Open-drain fault flagcowbone
•Thermal shutdown
•Thermal-shutdown output latch (MIC2549A) •2ms (slow) soft-start turn-on, fast turnoff •Available with active-high or active-low enable
Applications
•USB power distribution
•PCI Bus Power Switching
• Notebook PC
• ACPI power distribution
•PC card hot swap applications
• Inrush current-limiting
_________________________________________________________________________________________________________________________ Typical Application
Micrel Inc. • 2180 Fortune Drive • San Jo, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
Ordering Information伯明翰大学学院
Part Number
Enable
Temperature Range Latch
Pb-Free
Package
MIC2545A-1BM Active HIGH –40°C to +85°C No No 8-Pin SOP
MIC2545A-1BN Active HIGH –40°C to +85°C No No 8-Pin DIP
MIC2545A-1BTS Active HIGH –40°C to +85°C No No 14-Pin TSSOP
MIC2545A-2BM Active LOW –40°C to +85°C No No 8-Pin SOP
MIC2545A-2BN Active LOW –40°C to +85°C No No 8-Pin DIP
MIC2545A-2BTS Active LOW –40°C to +85°C No No 14-Pin TSSOP
MIC2545A-1YM Active HIGH –40°C to +85°C No Yes 8-Pin SOP
MIC2545A-1YN Active HIGH –40°C to +85°C No Yes 8-Pin DIP
MIC2545A-1YTS Active HIGH –40°C to +85°C No Yes 14-Pin TSSOP
MIC2545A-2YM Active LOW –40°C to +85°C No Yes 8-Pin SOP
MIC2545A-2YN Active LOW –40°C to +85°C No Yes 8-Pin DIP
MIC2545A-2YTS Active LOW –40°C to +85°C No Yes 14-Pin TSSOP
MIC2549A-1BM Active HIGH –40°C to +85°C Yes No 8-Pin SOP
MIC2549A-1BN Active HIGH –40°C to +85°C Yes No 8-Pin DIP
MIC2549A-1BTS Active HIGH –40°C to +85°C Yes No 14-Pin TSSOP
MIC2549A-2BM Active LOW –40°C to +85°C Yes No 8-Pin SOP
MIC2549A-2BN Active LOW –40°C to +85°C Yes No 8-Pin DIP
MIC2549A-2BTS Active LOW –40°C to +85°C Yes No 14-Pin TSSOP MIC2549A-1YM Active HIGH –40°C to +85°C Yes Yes 8-Pin SOP
MIC2549A-1YN Active HIGH –40°C to +85°C Yes Yes 8-Pin DIP
MIC2549A-1YTS Active HIGH –40°C to +85°C Yes Yes 14-Pin TSSOP MIC2549A-2YM Active LOW –40°C to +85°C Yes Yes 8-Pin SOP
MIC2549A-2YN Active LOW –40°C to +85°C Yes Yes 8-Pin DIP
MIC2549A-2YTS Active LOW
–40°C to +85°C
Yes Yes 14-Pin TSSOP
Pin Configuration
8-Pin SOP (M) 8-Pin DIP (N)
14-Pin TSSOP (TS)
Pin Description
Pin Number SOP, DIP
Pin Number TSSOP
Pin Name
Pin Function
1 1 EN Enable (Input): Logic-compatible enable input (−1 version is active high, −2
version is active low). High input >1.8V typical; low input <1.4V typical. Do not
float. MIC2549A only: Also rets thermal-shutdown latch. 2 3 FLG
Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent or
thermal shutdown. MIC2549A only: Latched low on thermal shutdown. 3
nosmoking
5
GND
Ground: supply return.
4 7 ILIM
Current Limit: Sets current-limit threshold using an external resistor (R SET )
connected to ground. 76.8Ω < R SET < 459Ω. 5, 7 8, 12 IN Supply Input: Output MOSFET drain. Also powers internal circuitry. Both IN pins must be externally connected together.
6, 8 10, 14 OUT Switch Output: Output MOSFET source. Both OUT pins must be externally connected together.
2, 4, 6, 9, 11, 13
NC奖牌英文
Not internally connected.
Absolute Maximum Ratings (1)
Supply Voltage (V IN )....................................................+7.0V Output Voltage (V OUT ).................................................+7.0V Output Current (I OUT ).................................Internally Limited Enable Input (V EN )...........................................−0.3V to +7V Fault Flag Voltage (V FLG ).............................................+7.0V Fault Flag Current (I FLG )..............................................50mA Storage Temperature (Ts).........................–65°C to +150°C Junction Temperature (T J )........................Internally Limited Lead Temperature (soldering, 5c.).........................260°C ESD Rating (3)..............................................................1500V
Operating Ratings (2)
Supply Voltage (V IN ).....................................+2.7V to +5.5V Ambient Temperature (T A )..........................–40°C to +85°C Package Thermal Resistance PDIP (θJA )........................................................130°C/W SOIC (θJA )........................................................160°C/W
TSSOP (θJA )(4)..................................................100°C/W Current-Limit Set Range (5)..................................0.5A to 3A
Electrical Characteristics (4)
V IN = +5V; T A = 25°C, bold values indicate –40°C to +85°C, unless noted. Symbol Parameter Condition
Min. Typ. Max. Units Switch Off, OUT = Open (6) 0.75 5 µA
90 125
Supply Current
Switch On, OUT = Open (6)
150
µA
V EN Enable High Transition (6) 2.4 1.6
Enable Input Voltage Enable Low Transition (6) 1.5 0.8 V
V EN = V OH(MIN) = 2.4V 0.01 1 Enable Input Current V EN = V OL(MAX) = 0.8V 0.01 1 µA
Enable Input Capacitance Note 7 1 pF
R DS(ON) Switch Resistance
I OUT = 500mA
35
50
m Ω
fuchengI LIMIT = 0.5A to 3A, V OUT = 1V to 4V (5) 184 230 276
Current-Limit Factor I LIMIT = 1A to 2.5A, V OUT = 1V to 4V (5) 195 230 264 V
Output Leakage Current Switch Off, V OUT = 0V
eli
1
10
µA
t ON Output Turn-On Delay R L = 10Ω, C L = 1µF, Figures 1a, 1b 1 2 5 ms t R Output Turn-On Ri Time R L = 10Ω, C L = 1µF, Figures 1a, 1b 0.75 1.8 4.9 ms t OFF
Output Turn-Off Delay
R L = 10Ω, C L = 1µF, Figures 1a, 1b
25 µs
Notes:
机械工程专业1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD nsitive. Handling precautions recommended. Human body model, 1.5k in ries with 100pF.
4. Assumes 4-layer PCB is ud.
5.
Current limit is determined by I LIMIT =
SET
R 230, where R SET is in Ωs, and 230 is typical current-limit factor in volts.
6. Off is
≤ 0.8V and on is ≥ 2.4V for the MIC2545A-1 and MIC2549A-1. Off is ≥ 2.4V and on is ≤ 9.8V for the MIC2545A-2 and MIC2549A-2. The enable input has about 100mV of hysteresis.
7. Guaranteed by design but not production tested.
Electrical Characteristics (4) (Continued)
V IN = +5V; T A = 25°C, bold values indicate –40°C to +85°C, unless noted. Symbol Parameter Condition
正立
Min. Typ. Max.
Units t F Output Turn-Off Fall Time R L = 10Ω, C L = 1µF, Figures 1a, 1b 23 µs T J Increasing 135 Overtemperature Threshold Shutdown
T J Decreasing 120 °C Error Flag Off Current V FLG = 5V
0.01
1
µA
EN Pul Ret Width MIC2549A Thermal-Shutdown Latch (7) 1 µs
t SU V IN to EN Set-Up
MIC2549(7), Figure 1c 0 µs Current-Limit Respon Time V OUT = 0V to I OUT = 2A, I SET = 1A (7) 40 µs
V OL
Error Flag Output Resistance
I FLG = 10mA
4
2015年高考试卷
15
Ω
Test Circuit
Functional Characteristics Test Circuit
Timing Diagrams
Figure 1a. MIC2545A/49A-2
Figure 1b. MIC2545A/49A-1
Figure 1c. Input-to-Enable Setup Timing
