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MIC5250
Micrel
MIC5250
Dual 150mA Cap CMOS LDO Regulator Preliminary Information
General Description
The MIC5250 is an efficient, precise dual CMOS voltage regulator optimized for ultra-low-noise applications. The MIC5250 offers better than 1% initial accuracy, extremely low dropout voltage (typically 150mV at 150mA) and constant ground current over load (typically 100A). The MIC5250 provides a very-low-noise output, ideal for RF applications where quiet voltage sources are required. A noise bypass pin is also available for further reduction of output noise. Designed specifically for hand-held and battery-powered devices, the MIC5250 provides TTL logic compatible enable pins. When disabled, power consumption drops nearly to zero. The MIC5250 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in hand-held wireless devices. Key features include current limit, thermal shutdown, pushpull outputs for faster transient response, and active clamps to speed up device turnoff. Available in the 10-lead MSOP (micro-shrink-outline package), the MIC5250 also offers a range of fixed output voltages.
Features
* Ultralow dropout--100mV @ 100mA * Ultralow noise--30V(rms) * Stability with ceramic, tantalum, or aluminum electrolytic capacitors * Load independent, ultralow ground current * 150mA output current * Current limiting * Thermal Shutdown * Tight load and line regulation * "Zero" off-mode current * Fast transient response * TTL-Logic-controlled enable input
Applications
* * * * * * * * Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers PCMCIA VCC and VPP regulation/switching Consumer/personal electronics SMPS post-regulator/dc-to-dc modules High-efficiency linear power supplies
Ordering Information
Part Number MIC5250-2.7BMM MIC5250-2.8BMM MIC5250-3.0BMM MIC5250-3.3BMM Voltage 2.7V 2.8V 3.0V 3.3V Junction Temp. Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package 10-lead MSOP 10-lead MSOP 10-lead MSOP 10-lead MSOP
Other voltages available. Contact Micrel for details.
Typical Application
MIC5250-3.3BMM VINA
ENABLE SHUTDOWN 9 2
INA ENA INB ENB
OUTA BYPA GNDA OUTB BYPB GNDB
10 1 3
3.3V CBYPA (optional) COUTA
VINB
ENABLE SHUTDOWN
7 5
8 4 6
3.3V CBYPB (optional) COUTB
ENA may be connected directly to INA. ENB may be connected directly to INB. GNDA and GND B may be connected to isolated grounds or the same ground.
Dual Ultra-Low-Noise Regulator Circuit
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
March 2000
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MIC5250
MIC5250
Micrel
Pin Configuration
BYPA 1 ENA 2 GNDA 3 BYPB 4 ENB 5
10 OUTA 9 INA 8 OUTB 7 INB 6 GNDB
MIC5250-x.xBMM
Pin Description
Pin Number 9/7 3/6 2/4 1/4 10 / 8 Pin Name INA / B GNDA / B ENA / B BYPA / B OUTA / B Pin Function Supply Input* Ground* Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. Reference Bypass: Connect external 0.01F capacitor to GND to reduce output noise. May be left open. Regulator Output
* Supply inputs and grounds are fully isolated.
Absolute Maximum Ratings (Note 1)
Supply Input Voltage (VIN) .................................. 0V to +7V Enable Input Voltage (VEN) ................................. 0V to +7V Junction Temperature (TJ) ...................................... +150C Storage Temperature ............................... -65C to +150C Lead Temperature (soldering, 5 sec.) ....................... 260C ESD, Note 3
Operating Ratings (Note 2)
Input Voltage (VIN) ......................................... +2.7V to +6V Enable Input Voltage (VEN) .................................. 0V to VIN Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance (JA)...................................... 200C/W
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Electrical Characteristics
Each regulator: VIN = VOUT + 1V, VEN = VIN; IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Symbol VO VLNR VLDR VIN - VOUT Parameter Output Voltage Accuracy Line Regulation Load Regulation Dropout Voltage, Note 5 Conditions IOUT = 0mA VIN = VOUT + 0.1V to 6V IOUT = 0.1mA to 150mA, Note 4 IOUT = 100A IOUT = 50mA IOUT = 100mA IOUT = 150mA IQ IGND PSRR ILIM en Enable Input VIL VIH IEN Enable Input Logic-Low Voltage Enable Input Logic-High Voltage Enable Input Current VIN = 2.7V to 5.5V, regulator shutdown VIN = 2.7V to 5.5V, regulator enabled VIL 0.4V VIH 2.0V Shutdown Resistance Discharge Thermal Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis
Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. 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. 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 150mA. 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. The total current drawn from the supply is the sum of the load current plus the ground pin current.
Min -1 -2 -0.3
Typical
Max 1 2
Units % % %/V % mV mV mV mV mV A A A dB mA V(rms)
0 2.0 1.5 50 100 150 0.2 100 100 50
0.3 3.0 5 85 150 200 250 1 150
Quiescent Current Ground Pin Current, Note 6
VEN 0.4V (shutdown) IOUT = 0mA IOUT = 150mA f = 120Hz, COUT = 10F, CBYP = 0.01F VOUT = 0V COUT = 10F, CBYP = 0.01F, f = 10Hz to 100kHz 160
Power Supply Rejection Current Limit Output Voltage Noise
300 30
0.8 2.0 1 0.17 1.5 500
0.4
V V A A C C
150 10
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MIC5250
MIC5250
Micrel
Typical Characteristics
Power Supply Rejection Ratio
100 IOUT = 100A 80 COUT = 1F tant PSRR (dB) 60 40 20 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz) VIN = 4V VOUT = 3V PSRR (dB) 100 IOUT = 10mA 80 COUT = 1F tant 60 40 20 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz) VIN = 4V VOUT = 3V
Power Supply Rejection Ratio
100
Power Supply Rejection Ratio
IOUT = 100mA 80 COUT = 1F tant PSRR (dB) 60 40 20 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz) VIN = 4V VOUT = 3V
Power Supply Rejection Ratio
100 IOUT = 150mA 80 COUT = 1F tant PSRR (dB) 60 40 20 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz) VIN = 4V VOUT = 3V PSRR (dB) 100 80
Power Supply Rejection Ratio
100 80 PSRR (dB) 60 40 20
Power Supply Rejection Ratio
VIN = 4V VOUT = 3V
60 40 20 V = 4V IN VOUT = 3V 0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz) IOUT = 100A COUT = 10F cer. CBYP = 0.01F
IOUT = 10mA COUT = 10F cer. CBYP = 0.01F
0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
Power Supply Rejection Ratio
100 80 PSRR (dB) 60 40 20 IOUT = 100mA COUT = 10F cer. CBYP = 0.01F VIN = 4V VOUT = 3V PSRR (dB)
100 80 60 40 20
Power Supply Rejection Ratio
RIPPLE REJECTION (dB)
VIN = 4V VOUT = 3V
Power Supply Ripple Rejection vs. Voltage Drop
80 70 60 50 40 30 20 10 0 0 150mA IOUT = 100mA COUT = 1F 200 400 600 800 1000 VOLTAGE DROP (mV) 100A 10mA
IOUT = 150mA COUT = 10F cer. CBYP = 0.01
0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
0 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 10M 10 100 1k 10k 100k 1M 1E+7 FREQUENCY (Hz)
Power Supply Ripple Rejection vs. Voltage Drop
80 RIPPLE REJECTION (dB) 70 60 50 40 30 20 10 0 0 100A COUT = 10F cer. CBYP = 0.01F 200 400 600 800 1000 VOLTAGE DROP (mV) 10mA 100mA IOUT = 100mA
Noise Performance
10 IL = 100A NOISE (V/Hz) 1 NOISE (V/Hz) 1 10
Noise Performance
IL = 100A
VIN = 4V 0.1 V OUT = 3V COUT = 1F cer. CBYP = 0.01F 0.01 10 100 1k 10k 1E+5 1M 1E+1 1E+2 1E+3 1E+4 100k 1E+6 FREQUENCY (Hz)
VIN = 4V 0.1 VOUT = 3V COUT = 10F cer. CBYP = 0.01F 0.01 1k 10k 100k 1M 10 100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 FREQUENCY (Hz)
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Ground Pin Current
95 QUIESCENT CURRENT (A) VIN = 4V VOUT = 3V QUIESCENT CURRENT (A) 200
Ground Pin Current
VIN = 4V VOUT = 3V
150
90
100
50 IOUT = 100A 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
85 0.1
1 10 100 LOAD CURRENT (mA)
500
Ground Pin Current
150 QUIESCENT CURRENT (A) VIN = 4V VOUT = 3V QUIESCENT CURRENT (A) 100
Ground Pin Current
100 VOUT = 3V 75 QUIESCENT CURRENT (A)
Ground Pin Current
VOUT = 3V 75
125
100
50
50
75 IOUT = 150mA 50 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
25 IOUT = 100A 0 0 1 2 3 4 INPUT VOLTAGE (V) 5
25
IOUT = 150mA 1 2 3 4 INPUT VOLTAGE (V) 5
0 0
Dropout Characteristics
3.5 DROPOUT VOLTAGE (mV) OUTPUT VOLTAGE (V) 3.0 2.5 2.0 1.5 1.0 0.5 0 0 1 2 3 4 INPUT VOLTAGE (V) 5 VOUT = 3V RL = 30k RL = 30 8
Dropout Voltage
300 ILOAD = 100A 6 DROPOUT VOLTAGE (mV) 250 200 150 100 50
Dropout Voltage
IL = 150mA
4
2
0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
Dropout Voltage
300 DROPOUT VOLTAGE (mV) 250 200 150 100 50 0 0 TA = -40C 25 50 75 100 125 150 OUTPUT CURRENT (mA) TA = 125C TA = 25C OUTPUT CURRENT (mA) 600 500 400 300 200 100
Short Circuit Current
3.05 OUTPUT VOLTAGE (V)
Output Voltage vs. Temperature
VIN = 4V
TYPICAL 3V DEVICE
3.00
VIN = 3.5V VEN = 3V
2.95
2.90 ILOAD = 100A 2.85 -50 0 50 100 TEMPERATURE (C) 150
0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
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MIC5250
MIC5250
Micrel
Enable Pin Bias Current
2.0 ENABLE PIN CURRENT (A) THRESHOLD VOLTAGE (V)
4
Enable Threshold Voltage
1.5 VIN = 4.0V 1.0
3
2
VIN = 4.0V
0.5
VEN = 100mV
1
0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
Functional Characteristics
Line Transient Response
OUTPUT VOLTAGE (50mV/div.)
OUTPUT VOLTAGE (100mV/div.)
Load Transient Response
6V VOUT = 3V COUT = 10F CBYP = 0.01F IOUT = 100A 4V
OUTPUT CURRENT
INPUT VOLTAGE (2V/div.)
150mA VIN = 4V VOUT = 3V COUT = 10F cer. CBYP = 0.01F
100A
TIME (10ms/div.)
TIME (100s/div.)
Enable Pin Delay
ENABLE VOLTAGE (1V/div.) ENABLE VOLTAGE (2V/div.)
Shutdown Delay
OUTPUT VOLTAGE (1V/div.)
VIN = 4V VOUT = 3V COUT = 10F CBYP = 0.01F IOUT = no load TIME (20s/div.)
OUTPUT VOLTAGE (1V/div.)
VOUT = 3V COUT = 10F CBYP = 0.01F IOUT = no load
TIME (1ms/div.)
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Crosstalk Characteristics
OUTPUT VOLTAGE A OUTPUT VOLTAGE B (100mV/div.) (20mV/div.) OUTPUT VOLTAGE A OUTPUT VOLTAGE B (100mV/div.) (20mV/div.)
Crosstalk Characteristics
VOUTB = 3.3V COUTB = 10F CBYPB = 0 ILOAD = 100A
VOUTB = 3.3V COUTB = 10F CBYPB = 0 ILOAD = 100A
VIN = 4.3V separate supplies
VOUTA = 3.3V COUTA = 10F CBYPA = 0
VIN = 4.3V common supply
VOUTA = 3.3V COUTA = 10F CBYPA = 0
ILOAD = 100A
ILOAD = 150mA
ILOAD = 100A
ILOAD = 150mA
TIME (25s/div.)
TIME (25s/div.)
Block Diagrams
INA Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation BYPA
PULL UP
ENA
Thermal Sensor Undervoltage Lockout
FAULT
Error Amplifier
Current Amplifier
PULL DOWN
OUTA
ACTIVE SHUTDOWN
GNDA INB Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation BYPB
PULL UP
ENB
Thermal Sensor Undervoltage Lockout
FAULT
Error Amplifier
Current Amplifier
PULL DOWN
OUTB
ACTIVE SHUTDOWN
GNDB
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MIC5250
MIC5250
Micrel
Thermal Considerations The MIC5250 is a dual LDO voltage regulator designed to provide two output voltages from one package. Both regulator outputs are capable of sourcing 150mA of output current. Proper thermal evaluation needs to be done to ensure that the junction temperature does not exceed it's maximum value, 125C. Maximum power dissipation can be calculated based on the output current and the voltage drop across each regulator. The sum of the power dissipation of each regulator determines the total power dissipation. The maximum power dissipation that this package is capable of handling can be determined using thermal resistance, junction to ambient, and the following basic equation: TJ (max ) - TA PD(max ) = JA
Applications Information
Enable/Shutdown The MIC5250 comes with active-high enable pins that allows either regulator to be disabled. Forcing an enable pin low disables the respective regulator and places it into a "zero" off-mode-current state. In this state, current consumed by the regulator goes nearly to zero. Forcing an enable pin high enables the output voltage. This part is CMOS therefore the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor Input capacitors are not required for stability. A 1F input capacitor is recommended for either regulator when the bulk ac supply capacitance is more than 10 inches away from the device, or when the supply is a battery. Output Capacitor The MIC5250 requires output capacitors for stability. The design requires 1F or greater on each output to maintain stability. Capacitors can be low-ESR ceramic chip capacitors. The MIC5250 has been designed to work specifically with low-cost, small chip capacitors. Tantalum capacitors can also be used for improved capacitance over the operating temperature range. The value of the capacitor can be increased without bounds. Bypass Capacitor Capacitors can be placed from each noise bypass pin to their respective ground to reduce output voltage noise. These capacitors bypass the internal references. A 0.01F capacitor is recommended for applications that require low-noise outputs. Transient Response The MIC5250 implements a unique output stage design which dramatically improves transient response recovery time. The output is a totem-pole configuration with a Pchannel MOSFET pass device and an N-channel MOSFET clamp. The N-channel clamp is a significantly smaller device that prevents the output voltage from overshooting when a heavy load is removed. This feature helps to speed up the transient response by significantly decreasing transient response recovery time during the transition from heavy load (100mA) to light load (100A). Active Shutdown Each regulator also features an active shutdown clamp, which is an N-channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. Cross Talk When a load transient occurs on one output of the MIC5250, the second output may couple a small amount of ripple to its output. This typically comes from a common input source or from poor grounding. Using proper grounding techniques such as star grounding as well as good bypassing directly at the inputs of each regulator will help to reduce the magnitude of the cross talk. See "Functional Characteristics" for an example of cross talk performance.
TJ(max) is the maximum junction temperature of the die, 125C and TA is the ambient operating temperature of the die. JA is layout dependent. Table 1 shows the typical thermal resistance for a minimum footprint layout for the MIC5250.
Package MSOP-10 JA at Recommended Minimum Footprint 200 C/W
Table 1. Thermal Resistance The actual power dissipation of each regulator output can be calculated using the following simple equation:
PD = VIN - VOUT IOUT + VIN IGND
(
)
Each regulator contributes power dissipation to the overall power dissipation of the package.
PD (total ) = PD (reg1) + PD (reg 2)
Each output is rated for 150mA of output current, but the application may limit the amount of output current based on the total power dissipation and the ambient temperature. A typical application may call for two 3.0V outputs from a single Li-ion battery input. This input can be as high as 4.2V. When operating at high ambient temperatures, the output current may be limited. When operating at an ambient of 60C, the maximum power dissipation of the package is calculated as follows: 125C - 60C PD(max) = 200C/W PD(max) = 325mW For the application mentioned above, if regulator 1 is sourcing 150mA, it contributes the following to the overall power dissipation: PD(reg1) = VIN - VOUT IOUT + VIN IGND
PD(reg1) = (4.2V - 3.0V) 150mA + 4.2V x 100A
(
)
PD(reg1) = 180.4mW
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MIC5250
Since the total power dissipation allowable is 325mW, the maximum power dissipation of the second regulator is limited to: Fixed Regulator Applications
MIC5250-3.3BMM 10 OUTA VINA
9 2
Micrel
PD(max) = PD(reg1) + PD(reg2) 325mW = 180.4mW + PD (reg 2) PD (reg 2) = 144.6mW
The maximum output current of the second regulator can be calculated using the same equations but solving for the output current (ground current is constant over load and simplifies the equation): PD (reg 2) = VIN - VOUT IOUT + VIN IGND 144.6mW = (4.2V - 3.0V) IOUT + 4.2V x 100A
IOUT = 120.5mA
3.3V 0.01F 1F
INA ENA INB ENB
BYPA GNDA OUTB BYPB GNDB
1 3
VINB
7 5
8 4 6
3.3V 0.01F 1F
Figure 1. Ultra-Low-Noise Dual 3.3V Application Figure 1 includes 0.01F capacitors for low-noise operation and shows EN (pin 3) connected to IN (pin 1) for an applications where enable/shutdown is not required. COUT = 1F minimum.
MIC5250-3.3BMM 10 OUTA VINA
9 2
(
)
The second output is limited to 120mA due to the total power dissipation of the system when operating at 60C ambient temperature.
INA ENA INB ENB
BYPA GNDA OUTB BYPB GNDB
1 3
3.3V 1F
VINB
7 5
8 4 6
3.3V 1F
Figure 2. Low-Noise Fixed Voltage Application Figure 2 is an example of a low-noise configuration where CBYP is not required. COUT = 1F minimum. 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.
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MIC5250
MIC5250
Micrel
Package Information
3.15 (0.122) 2.85 (0.114)
4.90 BSC (0.193)
DIMENSIONS: MM (INCH)
3.10 (0.122) 2.90 (0.114) 1.10 (0.043) 0.94 (0.037)
0.26 (0.010) 0.10 (0.004)
0.30 (0.012) 0.15 (0.006) 0.50 BSC (0.020)
0.15 (0.006) 0.05 (0.002)
6 MAX 0 MIN
0.70 (0.028) 0.40 (0.016)
10-Lead MSOP (MM)
MIC5250
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MIC5250
Micrel
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MIC5250
MIC5250
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) 2000 Micrel Incorporated
MIC5250
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March 2000

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