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MIC29310/29312
Micrel
MIC29310/29312
3A Fast-Response LDO Regulator
General Description
The MIC29310 and MIC29312 are low cost versions of MIC29300 family low-dropout (LDO) regulators. Manufactured on Micrel's proprietary Super beta PNPTM process, the MIC29310/2 is a 3A LDO regulator with very low-dropout voltage (600mV over the full load) and low ground current. Along with a total accuracy of 2% (over temperature, line and load regulation) these regulators feature very fast transient recovery from input voltage surges and output load current changes. The MIC29310 is available in fixed 3.3V and 5V outputs voltages; the MIC29312 has an adjustable output which can be set by two external resistors to a voltage between 1.24V to 15V. In addition, all versions are fully protected against overcurrent faults, reversed input polarity, reversed lead insertion, and overtemperature operation. A TTL logic enable (EN) pin is available in the MIC29312 to shutdown the regulator. When not used, the device can be set to continuous operation by connecting EN to the input (IN). The MIC29310/2 is available in the standard 3- and 5-pin TO-220 and TO-263 packages with an operating junction temperature range of 0C to +125C. For applications requiring even lower dropout voltage, input voltage greater than 16V, or an error flag, see the MIC29300/29301/29302/ 29303.
Features
* * * * * * * * * * * * * * Low cost versions of MIC29300 family Fast transient response 3A current over full temperature range 600mV dropout voltage at full load Low ground current Accurate 1% guaranteed tolerance "Zero" current shutdown mode (MIC29312) Fixed voltage and adjustable versions Processor peripheral and I/O supplies PC add-in cards High-efficiency "green" computer systems High-efficiency linear power supplies High-efficiency switching supply post regulator Battery-powered equipment
Applications
Typical Application
On Off
MIC29312 EN IN GND OUT R1* ADJ R2* VOUT
VIN
MIC29310-x.x IN OUT GND
VOUT
VIN
V OUT = 1.240
R1 +1 R2
* For best performance, total series resistance (R1 + R2) should be small enough to pass the minimum regulator load current of 10mA.
Fixed Regulator Configuration
Adjustable Regulator Configuration
Micrel, Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
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Micrel
Ordering Information
Part Number Standard MIC29310-3.3BT MIC29310-3.3BU MIC29310-5.0BT MIC29310-5.0BU MIC29312BT MIC29312BU
Note: 1. RoHS compliant with "high-melting solder" exemption.
RoHS Compliant(1) MIC29310-3.3WT MIC29310-3.3WU MIC29310-5.0WT MIC29310-5.0WU MIC29312WT MIC29312WU
Voltage 3.3V 3.3V 5.0V 5.0V Adj. Adj.
Junction Temperature Range 0C to +125C 0C to +125C 0C to +125C 0C to +125C 0C to +125C 0C to +125C
Package TO-220 TO-263 TO-220 TO-263 TO-220 TO-263
Pin Configuration
3 OUT
TAB
3
TAB
OUT GND IN
2 GND 1 IN
2 1
MIC29310-x.xBT/WT TO-220-3 (T)
MIC29310-x.xBU/WU TO-263-3 (U)
5 ADJ 4 OUT 3 GND 2 IN 1 EN
5 4 3 2 1
ADJ OUT GND IN EN
TAB
TAB
MIC29312-x.xBT/WT TO-220-5 (T)
MIC29312-x.xBU/WU TO-263-5 (U)
Pin Function Enable (Input): Active-high, logic-level enable/shutdown control. Unregulated Input: +16V maximum supply. Ground: Ground pin and TAB are internally connected. Regulator Output Ouput Voltage Adjust: 1.24V feedback from external resistive divider.
Pin Description
Pin Number MIC29310 1 2, TAB 3 Pin Number MIC29312 1 2 3, TAB 4 5 Pin Name EN IN GND OUT ADJ
Absolute Maximum Ratings (Note 1)
Input Voltage (VIN) ..........................................-20V to +20V Power Dissipation (PD) ............................. Internally Limited Storage Temperature Range (TS) ............. -65C to +150C Lead Temperature (soldering, 5 sec.) ........................ 260C ESD, Note 3 MIC29310/29312 2
Operating Ratings (Note 2)
Input Voltage (VIN) ........................................ +2.3V to +16V Junction Temperature (TJ) ............................ 0C to +125C Package Thermal Resistance TO-263 (JC) ......................................................... 2C/W TO-220 (JC) ......................................................... 2C/W TO-220 (JA) ....................................................... 55C/W November 2006
MIC29310/29312
Micrel
Electrical Characteristics(Note 11)
TJ = 25C, bold values indicate 0C TJ +125C; unless noted Parameter Output Voltage Line Regulation Load Regulation VO / T ppm/C Dropout Voltage Condition 10mA IO IFL, (VOUT + 1V) VIN 8V, Note 4 IO = 10mA, (VOUT + 1V) VIN 16V VIN = VOUT + 1V, 10mA IOUT IFULL LOAD, Notes 4, 8 Output Voltage Temperature Coefficient, Note 8 VOUT = -1%, Note 5 IO = 100mA IO = 750mA IO = 1.5A IO = 3A IO = 750mA, VIN = VOUT + 1V IO = 1.5A IO = 3A VIN = 0.5V less than specified VOUT. IOUT = 10mA VOUT = 0V, Note 6 CL = 10F CL = 33F 10mA IO IFL, VOUT + 1V VIN 8V, Note 4 1.215 40 Note 9 20 0.1 nA/C 3.0 Min -2 0.06 0.2 20 Typ Max 2 0.5 1 100 Units % % %
80 220 330 600 5 15 60 2 3.8 7 400 260
200
1000 20 150 3
mV mV mV mV mA mA mA mA A
Ground Current
IGNDDO Ground Pin Current at Dropout Current Limit Minimum Load Current en, Output Noise Voltage (10Hz to 100kHz) IL = 100mA Reference (MIC29312 only) Reference Voltage Adjust Pin Bias Current Reference Voltage ppm/C Temperature Coefficient Adjust Pin Bias Current Temperature Coefficient Enable Input (MIC29312 only) Input Logic Voltage Enable Pin Input Current
10
mA VRMS VRMS
1.265 80 120
VMAX nA nA
low (off) high (on) VEN = VIN VEN = 0.8V
0.8 2.4 15 - 10 20 30 75 2 4
V V A A A A A A
Regulator Output Current in Shutdown
Note 1. Note 2. Note 3. Note 4: Note 5: Note 6: Note 7: Note 8: Note 9:
Note 10
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. Full Load current is defined as 3A for the MIC29310/29312. For testing, VOUT is programmed to 5V. Dropout voltage is defined as the input-to-output differential when the output voltage drops to 99% of its nominal value with VOUT + 1V applied to VIN. For this test, VIN is the larger of 8V or VOUT + 3V. Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground pin current. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. VREF VOUT (VIN - 1V), 2.4V VIN 16V, 10mA < IL IFL, TJ TJ(max).
Note 10: VEN 0.8V and VIN 8V, VOUT = 0. Note 11: Specification for packaged product only.
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Block Diagram
IN *EN On/Off Bias O.V. ILIMIT 16V Reference OUT
Feedback Thermal Shutdown
ADJ*
GND MIC29310/29312 * MIC29312 only.
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Typical Characteristics
MIC29312 Line Transient Response with 3A Load, 100F Output Capacitance
MIC29312 EN VIN = VOUT + 1V IN GND OUT ADJ 49.9k 1% 0.1F 93.1k 1%
INPUT VOLTAGE
VOUT 3.525V nominal 4 x 330F AVX TPSE337M006R0100 tantalum
6.525V 4.525V
200s/division
VOUT load (not shown):Intel(R) Power Validato r
OUTPUT VOLTAGE
MIC29312 Load Transient Response Test Circuit
+20mV 3.525V -20mV
IOUT = 3A COUT = 100F
MIC29312 Line Transient Response with 3A Load, 10F Output Capacitance
MIC29312 Load Transient Response (See Test Circuit Schematic)
INPUT VOLTAGE
6.525V 4.525V
OUTPUT VOLTAGE
+20mV 3.525V -20mV 1ms/division
200s/division IOUT = 3A COUT =10F
OUTPUT VOLTAGE
3.525V -20mV
LOAD CURRENT
+20mV
3A
200mA 0mA
0.60
DROPOUT VOLTAGE (V)
MIC2931x Dropout Voltage vs. Output Current
DROPOUT VOLTAGE (mV)
1 0.8 0.6 0.4 0.2
MIC2931x Dropout Voltage vs. Temperature
OUTPUT VOLTAGE (V)
5.0 4.0
MIC29310-3.3 Dropout Characteristics
0.50 0.40 0.30 0.20 0.10 0.00 0 1 2 OUTPUT CURRENT (A) 3
ILOAD = 10mA 3.0 2.0 ILOAD = 3A 1.0 0.0
ILOAD = 3A
0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
0
2 4 INPUT VOLTAGE (V)
6
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2.0
GROUND CURRENT (mA)
MIC2931x Ground Current vs. Input Voltage
GROUND CURRENT (mA)
200
MIC2931x Ground Current vs. Input Voltage
GROUND CURRENT (mA)
2.0 1.5 1.0 0.5 0.0
MIC2931x Ground Current vs. Input Voltage
VOUT = 3.3V
IOUT = 10mA 1.5
IOUT = 3A 150
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
6.0
GROUND CURRENT (mA)
MIC2931x Ground Current vs. Temperature
GROUND CURRENT (mA)
20
MIC2931x Ground Current vs. Temperature
GROUND CURRENT (mA)
100 80
MIC2931x Ground Current vs. Temperature
5.0 4.0 3.0 2.0 1.0 0.0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C) IOUT = 750mA
15 IOUT = 1.5A
IOUT = 3A 60 40 20 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
10
5
0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
60
GROUND CURRENT (mA)
MIC2931x Ground Current vs. Output Current
OUTPUT VOLTAGE (V)
MIC29310-3.3 Output Voltage vs. Temperature
3.40 3.38 3.36 3.34 3.32 3.30 3.28 3.26 3 DEVICES 3.24 3.22 3.20 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
6 5 CURRENT (A) 4 3 2 1
MIC2931x Short Circuit Current vs. Temperature
50 40 30 20 10 0 0 1 2 OUTPUT CURRENT (A) 3
VOUT = 0V
0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
40 ENABLE CURRENT (A) 35 30 25 20 15 10 5
MIC29312 Enable Current vs. Temperaure
ADJUST PIN CURRENT (nA)
50 40 30
MIC29312 Adjust Pin Current vs. Temperature
10
OUTPUT IMPEDANCE ()
MIC2931x Output Impedance vs. Frequency
1
VEN = 5V
ILOAD = 10mA 20 10 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
0.1
VEN = 2V
0.01
100x100
1x103
100x103
10x100
FREQUENCY (Hz)
MIC29310/29312
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10x103
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1x106
0 -60 -30 0 30 60 90 120 150 TEMPERATURE (C)
0.001
MIC29310/29312
Micrel PD = IOUT x (1.02VIN - VOUT) Where the ground current is approximated by 2% of IOUT. Then the heat sink thermal resistance is determined with this formula: TJ MAX - TA SA = ------------ - (JC + CS) PD Where TJ MAX 125C and CS is between 0 and 2C/W. 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 0.1F 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. MIC29310/2 regulators are 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. Transient Response and 5V to 3.3V Conversion The MIC29310/2 have excellent response to variations in input voltage and load current. By virtue of their low dropout voltage, these devices do not saturate into dropout as readily as similar NPN-based designs. A 3.3V output Micrel LDO will maintain full speed and performance with an input supply as low as 4.2V, and will still provide some regulation with supplies down to 3.8V, unlike NPN devices that require 5.1V or more for good performance and become nothing more than a resistor under 4.6V of input. Micrel's PNP regulators provide superior performance in "5V to 3.3V" conversion applications than NPN regulators, especially when all tolerances are considered. Minimum Load Current The MIC29310/2 regulators are specified between finite loads. If the output current is too small, leakage currents dominate
Applications Information
The MIC29310 and MIC29312 are high performance low-dropout voltage regulators suitable for all moderate to high-current voltage regulator applications. Their 600mV of dropout voltage at full load make them especially valuable in battery powered systems and as high efficiency noise filters in "post-regulator" 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 2% to 5% of the load current. MIC29310/312 regulators are 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 spike 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 MIC29312 version offers a logic level ON/OFF control: when disabled, the devices draw nearly zero current. An additional feature of this regulator family is a common pinout: a design's current requirement may change up or down yet use the same board layout, as all of Micrel's high-current Super eta PNPTM regulators have identical pinouts.
VOUT
IN OUT GND
Figure 3. The MIC29310 regulator requires only two capacitors for operation. 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, we calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet.
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MIC29310/29312
MIC29310/29312 and the output voltage rises. A 10mA minimum load current is necessary for proper regulation. Adjustable Regulator Design VOUT R1 = R2 x ( ----- - 1 ) 1.240
Micrel
Where VO is the desired output voltage. Figure 4 shows component definition. Applications with widely varying load currents may scale the resistors to draw the minimum load current required for proper operation (see the table below). Enable Input The MIC29312 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. Figure 4. Adjustable Regulator with Resistors The adjustable regulator version, MIC29312, allows programming the output voltage anywhere between 1.25V and the 15V maximum operating rating of the family. Two resistors are used. Resistors can be quite large, up to 1M, because of the very high input impedance and low bias current of the sense comparator. The resistor values are calculated by:
Resistor Value Table for the MIC29312 Adjustable Regulator
Voltage
2.85 2.9 3.0 3.1 3.15 3.3 3.45 3.6 3.8 4.0 4.1
Standard ()
R1 100k 100k 100k 100k 100k 100k 100k 100k 100k 100k 100k R2 76.8k 75.0k 69.8k 66.5k 64.9k 60.4k 56.2k 52.3k 48.7k 45.3k 43.2k
Min. Load ()
R1 162 165 174 187 191 205 221 237 255 274 287 R2 124 124 124 124 124 124 124 124 124 124 124
Note: This regulator has a minimum load requirement. "Standard" values assume the load meets this requirement. "Minimum Load" values are calculated to draw 10mA and allow regulation with an open load (the minimum current drawn from the load may be zero).
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Package Information
3-Pin TO-220 (T)
3-Pin TO-263 (U)
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5-Pin TO-220 (T)
5-Pin TO-263 (U)
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MICREL, INC.
2180 FORTUNE DRIVE
SAN JOSE, CA 95131
USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (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. (c) 2005 Micrel, Incorporated.
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