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MIC29311
Micrel
MIC29311
3A Fast-Response LDO Regulator for USB Preliminary Information
General Description
The MIC29311 is a 3A, fast response, low-dropout (LDO) voltage regulator. Using Micrel's proprietary Super eta PNPTM process, the MIC29311 offers exceptional dropout (600mV at 3A) and low ground current (60mA at 3A). Fast transient response allows it to recover quickly from large load changes while maintaining a steady output. The device can be sent into a "zero-current" off mode when the TTL compatible enable is brought low. Designed specifically for Universal Serial Bus (USB) applications, the MIC29311 works with USB power switches to provide an economical solution for self-powered hubs. The 5.1V output voltage is optimized to work with lower-cost high on-resistance USB power switches (300m) to provide a minimum of 4.75V at 500mA to downstream ports. Used with MIC2527 quad USB power switches, the MIC29311 can power up to 6 downstream ports. Features of the MIC29311 include thermal shutdown, current limit, reversed-battery and reversed-lead insertion protection. An overvoltage clamp is available to maintain a safe output when the input voltage exceeds 8V. An error flag is also available to indicate of the output falls out of regulation, or when an overcurrent condition occurs. The MIC29311 is available in a 5-pin TO-220 or TO-263 package with a fixed 5.1V output voltage. For other high current, low-dropout voltage regulators, please see the MIC29150/300/500/750 and the MIC29310, MIC29510, MIC29710.
Features
* * * * * * * * * * Fast transient response 3A output current over full temperature range 600mV dropout voltage at full load Low ground current 3% total accuracy "Zero" off-mode current Thermal Shutdown Current Limiting Reversed battery protection Fixed 5.1V Output
Applications
* * * * Self-powered USB hubs USB power switching High-efficiency linear power supplies High-efficiency switching supply post-regulator
Typical Application
MIC29311-5.1 LDO Regulator AC Line 6.3Vac 3A 47F MIC5207-3.3 100mA max. LDO Regulator IN OUT GND 4.7 F D+ D- 10k 0.01F 33F GND VBUS D+ D- GND Downstream USB Port 6 4.75V min 500mA max. 1.0 F 3.3V USB Controller V+ ON/OFF OVERCURRENT 33F 0.01F 5.8V @ 3A 10k IN EN OUT FLAG GND 33F 5.1V 0.01F 33F Ferrite Bead VBUS D+ D- GND Downstream USB Port 1 4.75V min 500mA max.
VBUS D+ D- GND Upstream USB Port
VBUS D+ D- GND Downstream USB Port 2 4.75V min 500mA max.
Bold lines indicate 0.1" wide, 1-oz. copper high-current traces.
Simple USB Stand-Alone 6-Port Self-Powered Hub
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
December 1998
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MIC29311
MIC29311
Micrel
Ordering Information
Part Number MIC29311-5.1BT MIC29311-5.1BU Voltage 5.1V 5.1V Temperature Range 0C to +125C 0C to +125C Package TO-220-5 TO-263-5
Pin Configuration
5 4 3 2 1
ERR OUT GND IN EN
5 4 3 2 1
ERR OUT GND IN EN
TAB
TO-220-5 (T)
TAB
TO-263-5 (U)
Pin Description
Pin Number 1 2 3, TAB 4 5 Pin Name EN IN GND OUT ERR Pin Function Enable (Input): Logic-level high enable/logic-level low shutdown control. Unregulated Input: +16V maximum supply. Ground: Ground pin and TAB are internally connected. Regulator Output Error Flag (Output): Open-collector (active-low) output. Active low indicates overcurrent or undervoltage output conditions.
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Absolute Maximum Ratings (Note 1)
Input Voltage (VIN) ........................................ -20V to +12V Enable Voltage (VEN) .................................... -20V to +12V Error Output Voltage (VERR) ............................. 0V to +12V Lead Temperature (soldering, 5 sec.) ....................... 260C ESD Rating, Note 3
Operating Ratings (Note 2)
Input Voltage (VIN) ........................................................ +8V Maximum Power Dissipation (PD(max))..................... Note 4 Junction Temperature (TJ) ........................... 0C to +125C Package Thermal Resistance TO-220-5 (JA) .................................................... 55C/W TO-220-5 (JC) ...................................................... 2C/W TO-263-5 (JC) ...................................................... 2C/W
Electrical Characteristics
TA = 25C, bold values indicate 0C TJ +125C; unless noted. Parameter Output Tolerange Line Regulation Load Regulation Output Voltage Temperature Coefficient Dropout Voltage, Note 6 Condition 10mA IOUT < 3A, (VOUT + 1V) VIN 8V IOUT = 10mA, (VOUT + 1V) VIN 8V VIN = VOUT + 1V, 10mA IOUT 3A Note 5 IOUT = 100mA IOUT = 750mA IOUT = 1.5A IOUT = 3A Ground Current, Note 7 VIN = 6.1V, IOUT = 750mA VIN = 6.1V, IOUT = 1.5A VIN = 6.1V, IOUT = 3A Dropout Ground Current Current Limit Minimum Load Current Output Noise Voltage CLOAD = 10F CLOAD = 33F Error Flag Output Output Leakage Current Output Low Voltage VIN = 6.1V, VERR = 8V VIN = 4.1V, IERR = 250A 0.1 220 1 2 300 400 A A mV mV VIN = 4.6V, IOUT = 10mA VIN = 3V, VOUT = 0V 3.0 Min -3 0.06 0.2 20 80 220 330 600 5 15 60 2 3.8 7 400 260 10 150 3 1000 20 Typ Max +3 0.5 1 100 200 Units % % % ppm/C mV mV mV mV mA mA mA mA A mA V(rms) V(rms)
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MIC29311
MIC29311
Parameter Enable Input Logic Low Voltage Logic High Voltage Enable Input Current regulator shutdown regulator enabled VEN = VIN VEN = 0.8V Regulator Output Current
Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. Note 7. Note 8.
Micrel
Condition Min Typ Max Units
0.8 2.4 15 30 75 2 4 10 20
V V A A A A A
VIN = 8V, VEN 0.8V (shutdown), VOUT = 0V, Note 8
Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. PD(max) = (TJ(max) - TA) / JA, where JA depends upon the printed curcuit board layout. See "Applications Information." Output voltage temperature coefficient is defined as the VOUT(worst case) / (TJ(max) - TJ(min)) where TJ(max) is +125C and TJ(min) is 0C. VDO = VIN - VOUT when VOUT decreases to 99% of its nominal output voltage with VIN = VOUT + 1V. IGND is the quiescent current. IIN = IGND + IOUT. VEN 0.8V and VIN 8V, VOUT = 0.
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Typical Characteristics
Dropout Voltage vs. Output Current
0.6 1.0
MIC2931x Dropout Voltage vs. Temperature
DROPOUT VOLTAGE (mV) OUTPUT VOLTAGE (V)
7 6 5 4 3 2 1 0 0
Dropout Characteristics
DROPOUT VOLTAGE (V)
0.5 0.4 0.3 0.2 0.1 0.0 0 1 2 OUTPUT CURRENT (A) 3
0.8 0.6 0.4 0.2 0 ILOAD = 3A
ILOAD = 10mA
Awaiting Further Characterization Data
ILOAD = 3A
0
30 60 90 120 TEMPERATURE (C)
150
2 4 INPUT VOLTAGE (V)
6
Ground Current vs. Input Voltage
2.0 200
Ground Current vs. Input Voltage
2.0 GROUND CURRENT (mA)
IOUT = 3A 150
Ground Current vs. Input Voltage
GROUND CURRENT (mA)
GROUND CURRENT (mA)
IOUT = 10mA 1.5
1.5 1.0 0.5 0.0
VOUT = 3.3V
1.0
100
0.5
50
RLOAD = 100 -0.5 -20 -10 0 10 INPUT VOLTAGE (V) 20
0.0
0
2 4 6 8 INPUT VOLTAGE (V)
10
0
0
2 4 6 8 INPUT VOLTAGE (V)
10
Ground Current vs. Temperature
6 20
Ground Current vs. Temperature
100
Ground Current vs. Temperature
GROUND CURRENT (mA)
GROUND CURRENT (mA)
5 4 3 2 1 0 0 30 60 90 120 TEMPERATURE (C) 150 IOUT = 750mA
GROUND CURRENT (mA)
15 IOUT = 1.5A
80 IOUT = 3A 60 40 20 0
10
5
0 0
30 60 90 120 TEMPERATURE (C)
150
0
30 60 90 120 TEMPERATURE (C)
150
Ground Current vs. Output Current
60
GROUND CURRENT (mA)
5.20 5.18 OUTPUT VOLTAGE (V) 5.16 5.14 5.12 5.10 5.08 5.06 5.04 5.02 5.00 0
Output Voltage vs. Temperature
6 5
Short Circuit Current vs. Temperature
50 40 30 20 10 0 0 1 2 OUTPUT CURRENT (A) 3
Awaiting Further Characterization Data
CURRENT (A)
4 3 2 1 VOUT = 0V
30 60 90 120 TEMPERATURE (C)
150
0
0
30 60 90 120 TEMPERATURE (C)
150
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MIC29311
MIC29311
Micrel
40 ENABLE CURRENT (A) 35 30 25 20 15 10 5 0 0
Enable Current vs. Temperaure
10
Output Impedance vs. Frequency
OUTPUT IMPEDANCE ()
1
VEN = 5V
0.1
VEN = 2V
0.01
10x100
100x100
1x103
10x103
100x103
FREQUENCY (Hz)
Load Transient Response (See Test Circuit Schematic)
OUTPUT VOLTAGE
MIC29311-5.1 EN VIN = VOUT + 1V 1F IN GND Error Output OUT 10k ERR
VOUT 5.1V nominal 330F AVX TPSE337M006R0100 tantalum 4
+20mV 5.1V -20mV 1ms/division
Load Transcient Response Test Circuit
LOAD CURRENT
IOUT switching between 200mA and 3A
3A
200mA 0mA
Line Transient Response with 3A Load, 10F Output Capacitance
Line Transient Response with 3A Load, 100F Output Capacitance
INPUT VOLTAGE
8.0V 6.0V
INPUT VOLTAGE
8.0V 6.0V
200s/division IOUT = 3A COUT =10F
200s/division IOUT = 3A COUT = 100F
OUTPUT VOLTAGE
+20mV 5.1V -20mV
OUTPUT VOLTAGE
+20mV 5.1V -20mV
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1x106
30 60 90 120 TEMPERATURE (C)
150
0.001
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MIC29311
Micrel
Functional Diagram
IN O.V. ILIMIT 1.180V FLAG 1.240V 18V R1*
OUT
Reference
EN Thermal Shutdown
R2*
GND
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MIC29311
MIC29311
Micrel
The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large compared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the regulator. The low dropout properties of Micrel Super eta PNP regulators allow very significant reductions in regulator power dissipation and the associated heat sink without compromising performance. When this technique is employed, a capacitor of at least 1F is needed directly between the input and regulator ground. Please refer to Application Note 9 for further details and examples on thermal design and heat sink specification. Capacitor Requirements For stability and minimum output noise, a capacitor on the regulator output is necessary. The value of this capacitor is dependent upon the output current; lower currents allow smaller capacitors. The MIC29311 regulator is stable with a minimum capacitor value of 10F at full load. This capacitor need not be an expensive low ESR type: aluminum electrolytics are adequate. In fact, extremely low ESR capacitors may contribute to instability. Tantalum capacitors are recommended for systems where fast load transient response is important. Where the regulator is powered from a source with a high AC impedance, a 0.1F capacitor connected between Input and GND is recommended. This capacitor should have good characteristics to above 250kHz. When the regulator is located more than 3 inches from the ac bulk supply capacitors, a 1F or greater input capacitor is recommended. Minimum Load Current The MIC29311 regulator is specified between finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. A 10mA minimum load current is necessary for proper regulation. Enable Input The MIC29311 version features an enable (EN) input that allows on-off control of the device. Special design allows "zero" current drain when the device is disabled--only microamperes of leakage current flows. The EN input has TTL/ CMOS compatible thresholds for simple interfacing with logic, or may be directly tied to VIN. Enabling the regulator requires approximately 20A of current into the EN pin. Error Flag The MIC29311 features an error flag which looks at the output voltage and signals an error condition when this voltage drops 5% below its expected value. The error flag is an opencollector output that pulls low under fault conditions. It may sink 10mA. Low output voltage signifies a number of possible problems, including an overcurrent fault (the device is in current limit) and low input voltage. The flag output is inoperative during overtemperature shutdown conditions. USB Applications The main application of the MIC29311 is to control power distribution in a self-powered Universal Serial Bus hub. For self-powered hubs, the MIC29311 provides 5.1V 3% to downstream ports from an unregulated supply voltage (see 8 December 1998
Applications Information
The MIC29311 is a high-performance low-dropout voltage regulator suitable for all moderate to high-current voltage regulator applications. The 600mV dropout voltage at full load makes it especially valuable in battery-powered systems and as high-efficiency noise filters in "post-regulator" applications. Its unique output voltage makes the MIC39311 ideal for Universal Serical Bus (USB) power switching applications. Unlike older NPN-pass transistor designs, where the minimum dropout voltage is limited by the base-emitter voltage drop and collector-emitter saturation voltage, dropout performance of the PNP output of these devices is limited merely by the low VCE saturation voltage. A trade-off for the low dropout voltage is a varying base drive requirement. But Micrel's Super eta PNPTM process reduces this drive requirement to merely 1% to 5% of the load current. The MIC29311 regulator is fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current under overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. Transient protection allows device (and load) survival even when the input voltage spikes above and below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. The MIC29311 version offers a logic level on-off control: when disabled, the device draws nearly zero current.
MIC29311-5.1 VIN
Enable Shutdown
IN EN
OUT FLG GND
VOUT Flag
Figure 1. Input and Output Capacitors Thermal Design Linear regulators are simple to use. The most complicated design parameters to consider are thermal characteristics. Thermal design requires the following application-specific parameters: Maximum ambient temperature, TA Output Current, IOUT Output Voltage, VOUT Input Voltage, VIN First, calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet.
PD = IOUT 1.02VIN - VOUT
(
)
Where the ground current is approximated by 2% of IOUT. Then the heat sink thermal resistance is determined by: SA = TJ(max) - TA PD - JC + CS
Where TJ (max) 125C and CS is between 0 and 2C/W. MIC29311
MIC29311
"Typical Application"). USB requires that the downstream voltage supplied to peripherals from a self-powered hub is between 4.75V and 5.25V. The MIC29311 provides regulation with this requirement. The enable pin input controls ganged power for up to seven downstream ports, each drawing up to 500mA. The device has an output current limiting circuit that linearly decreases the output voltage as the output current exceeds 3A. When the part is out of regulation by 5%, the error flag goes low and signals a fault condition to the microcontroller, allowing the system to be disabled. This provides the overcurrent protection that is required by USB. In Figure 2, the MIC29311 provides power to the MIC2527 quad power switches. The MIC2527 provides power switching to four independently controlled downstream ports. Two MIC2527s can be used to provide a 6-port, self-powered hub in conjunction with the MIC29311. The 5.1V output of the MIC29311 is optimized to ensure that under maximum load condition, the output voltage of each channel of the MIC2527 remains above 4.75V. This is the minimum voltage require-
Micrel
ment for self-powered USB hubs. The output voltage is a function of the minimum output voltage of the power supply, the PCB trace resistance and the on-resistance of the switch. Table 1 shows the maximum allowable on-resistance for a 5.1V power supply in a self-powered hub, assuming 30mV of voltage drop due to PCB trace resistance. The 5.1V of the MIC29311 and the 300m on-resistance of each MIC2527 switch provides an economical solution to power management of self-powered hubs.
Nominal Supply Minimum Maximum Maximum Voltage Tolerance Voltage Voltage RON 1% 5.05V 5.15V 540m 2% 5V 5.2V 440m 5.10V 3% 4.95V 5.25V 340m 4% 4.9V 5.3V -- 5% 4.85V 5.36V --
Table 1. Max. Allowable On-Resistance For further information concerning USB power management, refer to Application Note 17 and Application Hint 30.
5.7V
MIC29311-5.1 LDO Regulator IN EN OUT ERR GND
5.1V 3%
Ferrite Bead 10k 47k
4.75V min. at 500mA
VBUS MIC2527 ENA FLGA ENB FLGB ENC FLGC IN IN OUTA OUTB OUTC OUTD GND GND 33F* 0.01F 0.1 F 33F* 0.01F 33F* 0.01F D+ D- GND Downstream USB Port 1 500mA max.
3.3V USB Controller MIC5207-3.3 LDO Regulator 4.7 F IN OUT 1F GND D+ D- GND V+ ON/OFF OVERCURRENT
VBUS D+ D- GND Downstream USB Port 2 500mA max.
END FLGD
Bold lines indicate 0.1" wide, 1-oz. copper high-current traces. * 33F, 16V tantalum or 100F, 10V electrolytic per port
VBUS D+ D- GND Downstream USB Port 3 500mA max.
VBUS 33F* 0.01F D+ D- GND Downstream USB Port 4 500mA max.
Figure 2. 4-Port Self-Powered Hub
December 1998
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MIC29311
MIC29311
Micrel
Package Information
0.150 D 0.005 (3.81 D 0.13) 0.400 0.015 (10.16 0.38) 0.108 0.005 (2.74 0.13) 0.241 0.017 (6.12 0.43) 0.177 0.008 (4.50 0.20) 0.050 0.005 (1.27 0.13)
0.578 0.018 (14.68 0.46)
SEATING PLANE
7 Typ. 0.550 0.010 (13.97 0.25)
0.067 0.005 (1.70 0.127) 0.268 REF (6.81 REF)
0.032 0.005 (0.81 0.13)
0.018 0.008 (0.46 0.20)
0.103 0.013 (2.620.33)
Dimensions: inch (mm)
TO-220-5 (T)
0.4050.005 0.065 0.010 202 0.0500.005
0.176 0.005 0.060 0.005
0.3600.005 0.6000.025 SEATING PLANE 0.004 +0.004 -0.008
0.0670.005 DIM. = INCH
0.032 0.003
8 MAX 0.015 0.002
0.100 0.01
TO-263-5 (U)
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Micrel
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MIC29311
Micrel
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. (c) 1998 Micrel Incorporated
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