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MIC49500
5A Dual Supply, Low Voltage, High Bandwidth LDO
General Description
The MIC49500 is an ultra-high-bandwidth, lowdropout, 5.0A voltage regulator ideal for powering core voltages of low-voltage microprocessors. The MIC49500 implements a dual supply configuration allowing for very low output impedance and very fast transient response. The MIC49500 requires a bias input supply and a main input supply, allowing for ultra-low input voltages on the main supply rail. The input supply operates from 1.4V to 6V and the bias supply requires between 3V and 6V for proper operation. The MIC49500 can regulate to an output voltage as low as 0.7V, making it an ideal product for low-voltage to low-voltage conversion. The MIC49500 requires a minimum of output capacitance for stability, working optimally with any type of capacitor, including small ceramic capacitors. Available in fixed output voltages from 0.9V to 1.8V and adjustable output voltages down to 0.7V, the MIC49500 comes in both 7-pin S-Pak and TO-263 packages. The MIC49500 is rated to the full operating temperature range of -40C to 125C junction temperature.
Features
* Input voltage range: - VIN: 1.4V to 6V - VBIAS: 3.0V to 6V * Stable with 10F ceramic output capacitor * +1.0% initial output tolerance * Maximum dropout (VIN - VOUT) is 500mV over temperature * Adjustable output voltage down to 0.7V * Ultra Fast Transient Response (Up to 10MHz bandwidth) * Excellent line and load regulation specifications * Logic controlled shutdown option * Thermal shutdown and current limit protection * Thin 7-pin S-Pak package * TO-263 7-pin package * -40C to +125C operating junction temperature range
Applications
* * * * ASIC Core Voltage Regulator PLD/FPGA Core Power Supply Linear Point-of-Load Conversion High Speed Post-Regulator
Typical Application
VIN = 2.0V
OFF ON
MIC49500WR IN EN BIAS GND ADJ OUT
VOUT = 1.0V R1 COUT = 10F Ceramic
Output Voltage (50mV/div)
Load Transient
VBIAS = 3.1V CBIAS = 1F Ceramic CIN = 1F Ceramic
VOUT = 1.8V VIN = 2.8V VBIAS = 3.9V 5A COUT = CBIAS = 10F
R2
Output Current (2A/div)
0A
Low Voltage, Fast Transient Response Regulator
Time (10s/div)
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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MIC49500
Block Diagram
VBIAS VIN Ilimit
EN
Enable
Bandgap
ADJ SNS / ADJ FIX (SNS) VOUT ADJ
FIX
GND
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Ordering Information
Part Number* MIC49500-0.9WR MIC49500-1.2WR MIC49500WR MIC49500-0.9WU MIC49500-1.2WU MIC49500WU Voltage 0.9V 1.2V ADJ 0.9V 1.2V ADJ Junction Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package S-Pak-7 S-Pak-7 S-Pak-7 TO-263 TO-263 TO-263 Lead Finish* RoHS Compliant RoHS Compliant RoHS Compliant RoHS Compliant RoHS Compliant RoHS Compliant
Other Voltage available. Contact Micrel for details. * RoHS compliant with `high-melting solder' exemption.
Pin Configuration
7 6 5 4 3 2 1 VSNS/ADJ NC VOUT GND VIN VBIAS EN 7 6 5 4 3 2 1 VSNS/ADJ NC VOUT GND VIN VBIAS EN
MIC49500WR (S-Pak-7)
MIC49500WU (TO263-7)
Pin Description
Pin Number S-Pak-7
1 2 3 4 5 6 7 7
Pin Name (Fixed)
EN VBIAS VIN GND VOUT NC VSNS -
Pin Name (Adj)
EN VBIAS VIN GND VOUT ADJ
Pin Function
Enable: TTL/CMOS compatible input. Logic high = enable, logic low or open = shutdown. Bias Supply: Bias supply input for powering all internal circuitry of the device, except the main current path. Input Voltage: Main Power Input Supply. Supplies main current to output device. Ground (TAB is connected to Ground). Output Voltage: Regulator Output. No Connect Remote Voltage Sense: Connect direct the load to improve regulation. Connect direct to pin 5 if not used. Adjust Input. Connect external resistor divider to program output voltage.
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Absolute Maximum Ratings(1)
Supply Voltage (VIN) ............................................. 6.5V Bias Supply Voltage (VBIAS) .................................. 6.5V Enable Input Voltage (VEN)................................... 6.5V Power Dissipation............................. Internally Limited Junction Temperature ................. -40C TJ +125C Storage Temperature (TS) ........... -65C TJ 150C Lead Temperature (soldering, 5 sec.) ................260C ESD Rating(3) .........................................................3kV
Operating Ratings(2)
Supply voltage (VIN).......................................1.4V to 6V Bias Supply Voltage (VBIAS)..............................3V to 6V Enable Input Voltage (VEN)........................... 0V to VBIAS Junction Temperature Range........-40C TJ +125C Package Thermal Resistance S-Pak (JC) ................................................. 2C/W TO-263 (JC) ............................................... 2C/W
Electrical Characteristics(4)
VIN = VOUT + 1.0V; VBIAS = VOUT + 2.1V; COUT = 10F; IOUT = 10mA; TJ = 25C, bold values indicate -40C to +125C, unless noted.
Parameter Output Voltage Accuracy
Output Voltage Line Regulation Output Voltage Load Regulation VIN - VO; Dropout Voltage VBIAS - VO; Dropout Voltage Ground Pin Current
Conditions At 25C, fixed voltage options Over temperature range
VIN = VOUT + 1V to 6V IL = 10mA to 5A IL = 2.5A IL = 5.0A IL = 2.5A IL = 5.0A VOUT = 1.2V; IL = 0mA VOUT = 1.2V; IL = 5.0A 0.7V VOUT 1.8V 1.8V < VOUT 3.3V VIL < 0.6V IL = 0mA IL = 5.0A VOUT = 0V
Min -1 -2 -0.1
Typ
Max +1 +2 +0.1
Units % %
%/V % mV mV V V mA mA mA mA A mA mA A nA V V mV A s V V
0.2 145 290 1.5 1.7 55 55 55 75 0.1 30 70 7.5 50 1.2 1.15 50 0.1 10 0.7
1.0 300 500 2.0 2.1 90 90 130 5 50 150 9.5 1000
Ground Pin Current in Shutdown Current thru VBIAS Current Limit Feedback Current Enable Input Enable Input Threshold
5.5
Regulator enable Regulator shutdown
1.6 20
Enable Hysteresis Enable Pin Input Current COUT = 10F; Note 5 Turn-on Time Reference Voltage (Adjustable Output Only) VREF TA = 25C -40C < TA < 125C
Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating.
0.6 150 5 45
0.707 0.714
0.693 0.686
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 4. Specification for packaged product only. 5. Turn-on time is measured from 10% of the positive edge of the enable signal to 90% of the rising edge of the output voltage of the regulator.
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Typical Characteristics
60 55 50 45 40 35 30 25 VIN = VOUT + 1V VOUT = 1.2V VEN = VIN VBIAS = 3.3V COUT = 10F
Ground Current vs. Load Current
1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0
Output Voltage vs. Input Voltage
50mA 2.5A
1.6 1.4 1.2 1.0 0.8 0.6
Output Voltage vs. Bias Voltage
50mA 2.5A
5A
5A
20 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 LOAD CURRENT (A)
VOUT = 1.5V VBIAS = 3.3V COUT = 10F 1 2 3 4 INPUT VOLTAGE (V) 5
0.4 0.2 0 0 1
VIN = VOUT + 1V VOUT = 1.5V COUT = CIN = 10F 2 3 4 BIAS VOLTAGE (V) 5
80 70 60 50 40 30 20 10 0 0
Bias Current vs. Output Current
60 50 40
Ground Current vs. Temperature
2.5A 1A 100A 5A
1.70 1.65 1.60 1.55
Output Voltage vs. Temperature
30 500mA VIN = VOUT + 1V VOUT = 1.8V VBIAS = 3.3V COUT = CBIAS = 10F 1 2 3 4 OUTPUT CURRENT (A) 5 20 10 0
0
1.50 1.45
VIN = VOUT + 1V VOUT = 3V COUT = 10F 20 40 60 80 TEMPERATURE (C)
1.40 1.35 1.30
VIN = VOUT = 1V VOUT = 1.5V COUT = 10F 20 40 60 80 TEMPERATURE (C)
60 50 40 30 20 10 0 0
Bias Current vs. Temperature
800 780 760 740
Output Voltage vs. Temperature
350 300 250 200 150
Dropout Voltage vs. Output Current
1A 2.5A 100A 500mA VIN = 4V VOUT = 3V COUT = 10F 20 40 60 80 TEMPERATURE (C) 5A
720 700 680 660 640 620 600
VIN = VOUT + 1V VOUT = 1.5V VBIAS = 3.3V COUT = 10F IOUT = 100A 20 40 60 80 TEMPERATURE (C)
100 50 0 0
VIN = VOUT + 1V VOUT = 1.5V VBIAS = 3.3V COUT = 10F 1 2 3 4 OUTPUT CURRENT (I) 5
1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0
V BIAS Dropout Voltage vs. Output Current
Enable Threshold
2.5 2.0 1.5 1.0 Hot 10 9 8 7 6 5 4 3 2 1 0 2.5
Current Limit vs. Input Voltage
Room Cold
VIN = VOUT + 1V VOUT = 1.5V VBIAS = 3.3V COUT = 10F 1 2 3 4 OUTPUT CURRENT (A) 5
0.5 0 0
VIN = 2.5V VOUT = 0V VBIAS = 3.3V COUT = 10F 3 3.5 4 4.5 5 INPUT VOLTAGE (V) 5.5
0.5 1 1.5 2 2.5 ENABLE VOLTAGE (V)
3
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Typical Characteristics (continued)
10
Output Noise Spectral Density
100 RIPPLE REJECTION (dB) 90 80 70 60 50 40 30 20 10 0 10
MIC49500 VBIAS PSRR
RIPPLE REJECTION (dB)
90 80 70 60 50 40 30 20 10 0 10
MIC49500 VIN PSRR
1
0.1 VIN = 3.8V VOUT = 2.8V COUT = 10F IOUT = 10mA 0.01 0.01 0.1 1 10 100 1,000 10,000 FREQUENCY (kHz)
100 1k 10k 100k FREQUENCY (Hz)
1M
100 1k 10k 100k FREQUENCY (Hz)
1M
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Functional Characteristics
Enable Turn-On
Enable Voltage (1V/div)
Load Transient
Output Voltage (50mV/div)
VOUT = 1.8V VIN = 2.8V VBIAS = 3.9V COUT = CBIAS = 10F
Output Voltage (500mV/div)
5A
VOUT = 1.8V VIN = VBIAS = 5V IOUT = 10mA COUT = CBIAS = 10F CFEEDFORWARD = 47pF Time (2s/div)
Output Current (2A/div)
0A
Time (10s/div)
Line Transient (VIN)
Input Voltage (1V/div) 5V 4V
Bias Voltage (1V/div)
Line Transient (VBIAS)
5V 4V
VOUT = 1.5V VBIAS = 3.6V Output Voltage (10mV/div)
Output Voltage (20mV/div)
VOUT = 1.5V VIN = 2.5V COUT = 10F IOUT = 1A
COUT = 10F IOUT = 1A
Time (100s/div)
Time (100s/div)
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MIC49500 capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% and 60%, respectively, over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic or a tantalum capacitor to ensure the same capacitance value over the operating temperature range. Tantalum capacitors have a very stable dielectric (10% over their operating temperature range) and can also be used with this device.
Input Capacitor An input capacitor of 1F or greater is recommended when the device is more than 4 inches away from the bulk supply capacitance, or when the supply is a battery. Small, surface mount, ceramic chip capacitors can be used for the bypassing. The capacitor should be placed within 1" of the device for optimal performance. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage. 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:
Applications Information
The MIC49500 is an ultra-high performance, low dropout linear regulator designed for high current applications requiring fast transient response. The MIC49500 utilizes two input supplies, significantly reducing dropout voltage, perfect for low-voltage, DCto-DC conversion. The MIC49500 requires a minimum of external components and obtains a bandwidth of up to 10MHz. As a Cap regulator, the output is tolerant of virtually any type of capacitor including ceramic and tantalum. The MIC49500 regulator is fully protected from damage due to fault conditions, offering constant current limiting and thermal shutdown.
Bias Supply Voltage VBIAS, requiring relatively light current, provides power to the control portion of the MIC49500. VBIAS requires approximately 70mA for 5A load current. Most of the biasing current is used to supply the base current to the pass transistor. This allows the pass element to be driven into saturation, reducing the dropout to 290mV at a 5A load current. Bypassing on the bias pin is recommended to improve performance of the regulator during line and load transients. Small ceramic capacitors from VBIAS to ground help reduce high frequency noise from being injected into the control circuitry from the bias rail and are good design practice. Good bypass techniques typically include one larger capacitor such as 1F ceramic and smaller valued capacitors such as 0.01F or 0.001F in parallel with that larger capacitor to decouple the bias supply. The VBIAS input voltage must be 2.1V above the output voltage with a minimum VBIAS input voltage of 3.0V. Input Supply Voltage VIN provides the high current to the collector of the pass transistor. The minimum input voltage is 1.4V, allowing conversion from low voltage supplies. Output Capacitor The MIC49500 requires a minimum of output capacitance to maintain stability. However, proper capacitor selection is important to ensure desired transient response. The MIC49500 is specifically designed to be stable with a wide range of capacitance values and ESR. A 10F ceramic chip capacitor should satisfy most applications. Output capacitance can be increased without bound. See typical characteristics for examples of load transient response. X7R dielectric ceramic capacitors are recommended because of their temperature performance. X7R-type
* * * *
Maximum ambient temperature (TA) Output Current (IOUT) Output Voltage (VOUT) Input Voltage (VIN)
* Ground Current (IGND) First, calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet. PD = VIN x IIN + VBIAS x IBIAS - VOUT x IOUT The input current will be less than the output current as the output load increases. The bias current is a sum of base drive and ground current. Ground current is constant over load current. Then the heat sink thermal resistance is determined with this formula:
SA
=
TJ(MAX) TA PD JC CS)
The heat sink may be significantly reduced in applications where the maximum input voltage is known and large compared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the
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Micrel, Inc. regulator. The low dropout properties of the MIC49500 allow 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. Refer to Application Note 9 for further details and examples on thermal design and heat sink specification.
MIC49500
Adjustable Regulator Design The MIC49500 adjustable version allows programming the output voltage anywhere between 0.7Vand 6V. Two resistors are used. The resistor value between VOUT and the adjust pin should not exceed 10k. Larger values can cause instability. The resistor values are calculated by:
Minimum Load Current The MIC49500, unlike most other high current regulators, does not require a minimum load to maintain output voltage regulation. Power Sequencing There is no power sequencing requirement for VIN and VBIAS, giving more flexibility to the user.
R1 = R2 x
VOUT 0.7
-1
Where VOUT is the desired output voltage. Enable The fixed output voltage versions of the MIC49500 feature an active high enable input (EN) that allows on-off control of the regulator. Current drain reduces to "zero" when the device is shutdown, with only microamperes of leakage current. The EN input has TTL/CMOS compatible thresholds for simple logic interfacing. EN may be directly tied to VIN and pulled up to the maximum supply voltage.
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Package Information
7-Pin SPAK (R)
7-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 a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2005 Micrel, Inc.
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