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MIC5212
Micrel
MIC5212
Dual 500mA LDO Regulator Final
General Description
The MIC5212 is a dual linear voltage regulator with very-low dropout voltage (typically 10mV at light loads and 350mV at 500mA), very-low ground current (225A at 10mA output), and better than 1% initial accuracy. Both regulator outputs can supply up to 500mA at the same time as long as each regulator's maximum junction temperature is not exceeded. Key features include current limiting, overtemperature shutdown, and protection against reversed battery. The MIC5212 is available in a fixed 3.3V/2.5V output voltage configuration. Other voltages are available; contact Micrel for details.
Features
* * * * * * * * * * * * * Fused lead frame SOIC-8 Up to 500mA per regulator output Low quiescent current Low dropout voltage Tight load and line regulation Low temperature coefficient Current and thermal limiting Reversed input polarity protection Hard disk drives CD R/W Bar code scanners SMPS post regulator/DC-to-DC modules High-efficiency linear power supplies
Applications
Ordering Information
Part Number MIC5212-SJBM Voltage 3.3V/2.5V Accuracy 1.0% Junction Temp. Range* -40C to +125C Package 8-lead SOIC
Other voltages available. Contact Micrel for details.
Typical Application
MIC5212-SJBM IN = 5V 4.7F INA OUTA INB OUTB GND VO2 = 2.5V 4.7F 4.7F VO1 = 3.3V
3.3V/2.5V Dual LDO
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
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MIC5212
MIC5212
Micrel
Pin Configuration
OUTA 1 INA 2 INB 3 OUTB 4
SOIC-8 (M)
8 GND 7 GND 6 GND 5 GND
Pin Description
Pin Number 1 2 3 4 5, 6, 7, 8 Pin Name OUTA INA INB OUTB GND Pin Function Regulator A Output Regulator A Input Regulator B Input Regulator B Output Ground
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Absolute Maximum Ratings (Note 1)
Supply Input Voltage (VIN A or B) ................. -20V to +20V Power Dissipation (PD) ............................ Internally Limited Storage Temperature Range ................... -60C to +150C Lead Temperature (soldering, 5 sec.) ....................... 260C
Operating Ratings (Note 2)
Supply Input Voltage (VIN) ............................... 2.5V to 16V Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance (JA)......................................... Note 3
Electrical Characteristics
Regulator A and B VIN = VOUT + 1V; IL = 100A; CL = 4.7F; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Symbol VO VO/T VO/VO VO/VO VIN - VO Parameter Output Voltage Accuracy Output Voltage Temperature Coefficient Line Regulation Load Regulation Dropout Voltage, Note 6 (per regulator) Conditions variation from specified VOUT Note 4 VIN = VOUT + 1V to 16V IL = 0.1mA to 500mA, Note 5 IL = 150mA IL = 500mA IGND Ground Pin Current, Note 7 (per regulator) IL = 150mA IL = 500mA PSRR ILIMIT Ripple Rejection Current Limit Spectral Noise Density
Note 1. Note 2. Note 3.
Min -1 -2
Typical
Max 1 2
Units % % ppm/C
40 0.009 0.05 175 350 1.5 12 75 750 500 1000 0.05 0.1 0.7 1.0 275 350 500 600 2.5 3.0 20 25
%/V %/V % % mV mV mV mV mA mA mA mA dB5 mA nV/Hz
f = 120Hz, IL = 150mA VOUT = 0V VOUT = 2.5V, IOUT = 50mA, COUT = 2.2F
Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max), the junction-to-ambient thermal resistance, JA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(max) = (TJ(max) - TA) / JA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The JA of the 8-lead SOIC (M) is 63C/W mounted on a PC board (see "Thermal Considerations" section for further details). Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 0.1mA to 500mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V differential. Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of the load current plus the ground pin current.
Note 4. Note 5. Note 6. Note 7.
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MIC5212
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Typical Characteristics
MIC5212-3.3 PSRR 150mA Load
90 80 70 PSRR (dB) PSRR (dB) 60 50 40 30 20 10
COUT = 10F Tantulum VIN = 4.3V VOUT = 3.3V VIN = VOUT + 1V
MIC5212 PSRR 500mA Load
90 80 70 50 40 30 20 10 1M
500mA COUT = 10F Tantulum VIN = 4.3V VOUT = 3.3V VIN = VOUT + 1V
MIC5212-2.5 PSRR 150mA Load
90 80 70 PSRR (dB) 60 50 40 30 20 10 1M
COUT = 10F Tantulum VIN = 4.3V VOUT = 3.3V VIN = VOUT + 1V
60
0 10
1k 100 10k 100k FREQUENCY (Hz)
0 10
100 1k 10k 100k FREQUENCY (Hz)
0 10
10k 100k 100 1k FREQUENCY (Hz)
1M
MIC5212-2.5 PSRR 500mA Load
90
GROUND CURRENT (mA) 14
Ground Current vs. Temperature
800 500mA LOAD CURRENT (mA) 700 600 500 400 300 200 100 12 10 8 6 300mA 4 150mA 100A 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 2
S/C Current vs. Temperature
80 70 PSRR (dB) 60 50 40 30 20 10
COUT = 10F Tantulum VIN = 4.3V VOUT = 3.3V VIN = VOUT + 1V
0 10
100 1k 10k 100k FREQUENCY (Hz)
1M
0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
Output Voltage vs. Temperature
3.320 DROPOUT VOLTAGE (mV) OUTPUT VOLTAGE (V) 3.315 3.310 3.305 3.300 3.295 3.290 3.285 3.280 3.275 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 500 450 400 350 300 250 200 150 100 50
Dropout Voltage vs. Temperature
350 DROPOUT VOLTAGE (mV) 300 250 200 150 100 50 0 50
Dropout Voltage vs. Load Current
500mA 300mA 150mA
0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C)
100 150
200 250
300 350
400 450
OUTPUT CURRENT (mA)
Ground Current vs. Load
14
GROUND CURRENT (mA)
12 10 8 6 4 2 0 0 100 200 300 400 500 OUTPUT CURRENT (mA)
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0
MIC5212
Micrel
Output 1 Load Transient Response
VIN = 3.3V VOUT = 2.5V COUT = 10 F Ceramic
Output 2 Load Transient Response
OUTPUT 2 OUTPUT 1 (20mV/div) (20mV/div)
VIN = 3.3V VOUT = 2.5V COUT = 10 F Ceramic
OUTPUT 1 OUTPUT 2 (20mV/div) (20mV/div)
OUTPUT CURRENT (500mA/div)
1000mA 500mA 10mA 10mA TIME (1ms/div.)
OUTPUT 2 CURRENT (200mA/div)
1000mA 500mA 10mA 10mA TIME (1ms/div.)
Output 1 Line Transient Response
VIN = 3.3V VOUT = 2.5V COUT = 10 F Ceramic 7V 4.3V
Line Transient Response
6V 3.5V
VIN (2V/div)
VOUT 1 VOUT 2 (10mV/div) (10mV/div)
1000mA
10mA
TIME (1ms/div.)
VOUT 1 (10mV/div)
VOUT 2 (10mV/div)
VIN (2V/div)
TIME (1ms/div.)
Turn-On Response
VSUPPLY (2V/div)
3.3V, 500mA
OUTPUT 1 (1V/div)
2.5V, 200mA
OUTPUT 2 (1V/div)
TIME (40s/div.)
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MIC5212
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Functional Diagram
INA OUTA
Bandgap Ref. VREF
Current Limit Thermal Shutdown
INB
OUTB
Bandgap Ref. VREF
Current Limit Thermal Shutdown
GND
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Lower thermal resistance is achieved by joining the four ground leads with the die attach paddle to create a singlepiece electrical and thermal conductor. This concept has been used by MOSFET manufacturers for years, proving very reliable and cost effective for the user. Thermal resistance consists of two main elements, JC (junction-to-case thermal resistance) and CA (case-to-ambient thermal resistance). See Figure 1. JC is the resistance from the die to the leads of the package. CA is the resistance from the leads to the ambient air and it includes CS (case-tosink thermal resistance) and SA (sink-to-ambient thermal resistance).
Applications Information
Input Capacitor A 1F capacitor should be placed from IN to GND if there is more than 10 inches of wire between the input and the AC filter capacitor or if a battery is used as the input. Output Capacitor An output capacitor is required between OUT and GND to prevent oscillation. 1.0F minimum is recommended. Larger values improve the regulator's transient response. The output capacitor value may be increased without limit. The output capacitor should have an ESR (Effective Series Resistance) of about 5 or less and a resonant frequency above 1MHz. Ultra-low-ESR capacitors may cause a lowamplitude oscillation and/or underdamped transient response. Most tantalum or aluminum electrolytic capacitors are adequate; film types will work, but are more expensive. Since many aluminum electrolytic capacitors have electrolytes that freeze at about -30C, solid tantalum capacitors are recommended for operation below -25C. At lower values of output current, less output capacitance is required for output stability. The capacitor can be reduced to 0.47F for current below 10mA or 0.33F for currents below 1mA. No-Load Stability The MIC5212 will remain stable and in regulation with no load (other than the internal voltage divider) unlike many other voltage regulators. This is especially important in CMOS RAM keep-alive applications. Dual-Supply Operation When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode clamped to ground.
Power SO-8 Thermal Characteristics
SO-8
JA JC CA
AMBIENT
ground plane heat sink area
printed circuit board
Figure 1. Thermal Resistance Using the power SO-8 reduces the JC dramatically and allows the user to reduce CA. The total thermal resistance, JA (junction-to-ambient thermal resistance) is the limiting factor in calculating the maximum power dissipation capability of the device. Typically, the power SO-8 has a JC of 20C/W, this is significantly lower than the standard SO-8 which is typically 75C/W. CA is reduced because pins 5 through 8 can now be soldered directly to a ground plane which significantly reduces the case-to-sink thermal resistance and sink to ambient thermal resistance.
One of the secrets of the MIC5212's performance is its power SO-8 package featuring half the thermal resistance of a standard SO-8 package. Lower thermal resistance means more output current or higher input voltage for a given package size.
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MIC5212
Low dropout linear regulators from Micrel are rated to a maximum junction temperature of 125C. It is important not to exceed this maximum junction temperature during operation of the device. To prevent this maximum junction temperature from being exceeded, the appropriate ground plane heat sink must be used.
900
Micrel
Quick Method
COPPER AREA (mm2)
700 600 500 400 300 200 100 0 0
40C 50C 55C 65C 75C 85C
800
Determine the power dissipation requirements for the design along with the maximum ambient temperature at which the device will be operated. Refer to Figure 3, which shows safe operating curves for three different ambient temperatures: 25C, 50C and 85C. From these curves, the minimum amount of copper can be determined by knowing the maximum power dissipation required. If the maximum ambient temperature is 50C and the power dissipation is as above, 920mW, the curve in Figure 3 shows that the required area of copper is 500mm2. The JA of this package is ideally 63C/W, but it will vary depending upon the availability of copper ground plane to which it is attached.
100C
0.25 0.50 0.75 1.00 1.25 1.50 POWER DISSIPATION (W)
COPPER AREA (mm2)
900 800 700 600 500 400 300 200 100 0 0 0.25 0.50 0.75 1.00 1.25 1.50 POWER DISSIPATION (W) T = 125C J 85C 50C 25C
Figure 2. Copper Area vs. Power-SO Power Dissipation ( JA) (T Figure 2 shows copper area versus power dissipation with each trace corresponding to a different temperature rise above ambient. From these curves, the minimum area of copper necessary for the part to operate safely can be determined. The maximum allowable temperature rise must be calculated to determine operation along which curve. T = TJ(max) - TA(max) TJ(max) = 125C TA(max) = maximum ambient operating temperature For example, the maximum ambient temperature is 50C, the T is determined as follows: T = 125C - 50C T = 75C Using Figure 2, the minimum amount of required copper can be determined based on the required power dissipation. Power dissipation in a linear regulator is calculated as follows: PD = (VIN1 - VOUT1) x IOUT1 + VIN1 x IGND1 + (VIN2 - VOUT2) x IOUT2 + VIN2 x IGND2 With a common 5V input, a 3.3V, 300mA output on LDO 1 and a 2.5V, 150mA output on LDO 2, power dissipation is as follows: PD = (5V - 3.3V) x 300mA + 5V x 5mA + (5V - 2.5V) x 150mA + 5V x 1.8mA PD = 0.919W From Figure 2, the minimum amount of copper required to operate this application at a T of 75C is 500mm2.
Figure 3. Copper Area vs. Power-SO Power Dissipation (TA)
MIC5212
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MIC5212
Micrel
Package Information
0.026 (0.65) MAX) PIN 1
0.157 (3.99) 0.150 (3.81)
DIMENSIONS: INCHES (MM)
0.050 (1.27) TYP
0.020 (0.51) 0.013 (0.33) 0.0098 (0.249) 0.0040 (0.102) 0-8 SEATING PLANE 45 0.010 (0.25) 0.007 (0.18)
0.064 (1.63) 0.045 (1.14)
0.197 (5.0) 0.189 (4.8)
0.050 (1.27) 0.016 (0.40) 0.244 (6.20) 0.228 (5.79)
8-Pin SOIC (M)
MICREL, INC.
TEL
1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
FAX
+ 1 (408) 944-0800
+ 1 (408) 944-0970
WEB
http://www.micrel.com
The information furnished by Micrel in this datasheet 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) 2003 Micrel, Incorporated.
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MIC5212

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