MICREL MIC5312

MIC5312
LowQ™ Mode Dual 300mA LDO
with Integrated POR
General Description
Features
The MIC5312 is a high performance, dual µCap low
dropout regulator with integrated power-on reset
supervisor, offering ultra-low operating current and a
second, even lower operating current mode, LowQ™
mode, reducing operating current by 75%. Each
regulator can source up to 300mA of output current
maximum.
Ideal for battery operated applications, the MIC5312
offers 1% accuracy, extremely low dropout voltage
(60mV @ 150mA), and low ground current (typically
28µA total). When put into LowQ™ mode, the internal
current draw drops down to 7µA total. The MIC5312
also comes equipped with a TTL logic compatible
enable pin that allows the part to be put into a zero-offmode current state, drawing no current when disabled.
The Power-on Reset is active low and indicates an
output undervoltage condition on either regulator 1 or 2
when the regulator is enabled.
The MIC5312 is a µCap design, operating with very
small ceramic output capacitors for stability, reducing
required board space and component cost.
The MIC5312 is available in fixed output voltages in the
3mm x 3mm MLF-10 leadless package. Data sheets
and support documentation can be found on Micrel’s
web site at www.micrel.com.
• Input voltage range: 2.5V to 5.5V
• LowQ™ Mode
- 7µA total quiescent current
- 10mA output current capable LowQ™ mode
- Logic level control with external pin
• Stable with ceramic output capacitor
• 2 LDO Outputs – 300mA each
• Integrated Power-on Reset (POR) with adjustable
delay time
• Tiny 3mm x 3mm MLF™-10 package
• Low dropout voltage of 60mV @ 150mA
• Ultra-low quiescent current of 28µA total in Full
Current Mode
• High output accuracy
- ±1.0% initial accuracy
- ±2.0% over temperature
• Thermal Shutdown Protection
• Current Limit Protection
Applications
•
•
•
•
Cellular/PCS phones
Wireless modems
PDAs
MP3 Players
Typical Application
VIN
VOUT1
VCORE
EN1
VOUT2
VI/O
EN2
POR
LOWQ
BYP
Baseband
µProcessor
SET
GND
MIC5312-xxBML
MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February 2005
M9999-021105
(408) 955-1690
Micrel, Inc.
MIC5312
Ordering Information
Part Number
MIC5312-GMBML
MIC5312-DKBML
Output
Voltage*
Junction Temp. Range
Package
1.8V/2.8V
1.85V/2.6V
–40°C to +125°C
–40°C to +125°C
10-Pin 3×3 MLF™
10-Pin 3×3 MLF™
Note: *Other Voltage options available between 1.25V and 5V. Contact Micrel for details.
Pin Configuration
VIN 1
10 VOUT1
EN1 2
9 VOUT2
EN2 3
8 POR
LOWQ 4
7 SET
BYP 5
6 GND
MIC5312-xxBML (3x3)
Pin Description
Fixed
1
2
Pin Name
VIN
EN1
3
EN2
4
LowQ™
5
BYP
6
7
GND
SET
8
POR
9
10
EP
VOUT2
VOUT1
GND
February 2005
Pin Function
Supply Input. (VIN1 and VIN2 are internally tied together)
Enable Input (regulator 1). Active High Input. Logic High = On; Logic Low = Off;
Do not leave floating
Enable Input (regulator 2). Active High Input. Logic High = On; Logic Low = Off;
Do not leave floating
LowQ™ Mode. Active Low Input. Logic High = Full Power Mode; Logic Low = Light
Load Mode; Do not leave floating.
Reference Bypass: Connect external 0.01µF to GND to reduce output noise. May
be left open.
Ground.
Delay Set Input: Connect external capacitor to GND to set the internal delay for the
POR output. When left open, there is no delay. This pin cannot be grounded. Delay
= 1µs/1pF
Power-On Reset Output: Open-drain output. Active low indicates an output
undervoltage condition on either regulator 1 or regulator 2 when device is enabled.
Output of regulator 2
Output of regulator 1
Ground. Internally connected to the Exposed Pad.
2
M9999-021105
(408) 955-1690
Micrel, Inc.
MIC5312
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Input Voltage (VIN) .............................. 0V to 6V
Enable Input Voltage (VEN)............................. 0V to 6V
LowQ™ Input Voltage (VLowQ™)...................... 0V to 6V
Power Dissipation (PD) ..................Internally Limited (3)
Junction Temperature ....................... -40°C to +125°C
Lead Temperature (soldering, 5sec.) .................260°C
Storage Temperature (Ts) ................. -65°C to +150°C
Supply Input Voltage (VIN)..........................2.5V to 5.5V
Enable Input Voltage (EN1/EN2/LowQ™) ...... 0V to VIN
Junction Temperature (TJ) .................. -40°C to +125°C
Package Thermal Resistance
MLF-10 (θJA) ................................................. 63°C/W
Electrical Characteristics (Full Power Mode)
VIN = VOUT + 1.0V for higher output of the regulator pair; LowQ™ = VIN; COUT = 2.2µF, IOUT = 100µA; TJ = 25°C, bold
values indicate -40°C to +125, unless noted.
Parameter
Output Voltage Accuracy
Line Regulation
Load Regulation
Dropout Voltage
Ground Pin Current
Ground Pin Current in
Shutdown
Ripple Rejection
Conditions
Variation from nominal VOUT
Variation from nominal VOUT; -40°C to +125°C
VIN = VOUT +1V to 5.5V
February 2005
Typ
0.02
Max
+1.0
+2.0
0.3
0.6
1.0
1.5
Units
%
%
%/V
IOUT = 100µA to 150mA
IOUT = 100µA to 300mA
IOUT = 150mA
IOUT = 300mA
IOUT1 = IOUT2 = 100µA to 300mA
0.35
0.7
VEN < 0.2V
0.1
mV
mV
µA
µA
µA
65
35
450
45
dB
dB
mA
µVrms
60
120
28
f = up to 1kHz; COUT = 2.2µF ceramic; CBYP = 10nF
f = 1kHz – 20kHz; COUT = 2.2µF ceramic; CBYP = 10nF
Current Limit
VOUT = 0V (Both Regulators)
Output Voltage Noise
COUT = 2.2µF, CBYP = 0.01µF, 10Hz to 100kHz
Enable and LowQ™ Input (EN1/EN2/LowQ™)
Enable Input Voltage
Logic Low
Logic High
Enable Input Current
VIL < 0.2V
VIH > 1.0V
Turn-on Time
COUT = 2.2µF; CBYP = 0.01µF
Light Load Response
Response Time (4)
Into Light Load
Out of Light Load
POR Output
VTH
Low Threshold, % of VOUT(Flag ON)
High Threshold, % of VOUT (Flag OFF)
VOL
POR Output Logic Low Voltage; IL = 250µA
IPOR
Flag Leakage Current, Flag OFF
SET INPUT
SET Pin Current Source
SET Pin Threshold Voltage
Min
-1.0
-2.0
VSET = 0V
350
700
0.2
1.0
0.1
0.1
300
1
1
500
50
50
–1
0.01
0.01
1.25
1.25
V
V
µA
µA
µs
µs
µs
90
0.75
3
240
45
50
%
%
97
0.1
+1
1.75
%
%
V
µA
µA
V
M9999-021105
(408) 955-1690
Micrel, Inc.
MIC5312
Electrical Characteristics (LowQ™ Mode)
VIN = VOUT + 1.0V for higher output of the regulator pair; LowQ™ = 0V; COUT = 2.2µF, IOUT = 100µA; TJ = 25°C, bold
values indicate -40°C to +125°C, unless noted.
Parameter
Output Voltage Accuracy
Conditions
Variation from nominal VOUT
Line Regulation
Typ
Max
+2.0
+3.0
Units
%
%
VIN = VOUT +1V to 5.5V
0.02
%/V
Load Regulation
IOUT = 100µA to 10mA
0.1
0.3
0.6
0.5
%
Dropout Voltage
IOUT = 10mA
100
200
mV
Ground Pin Current
Both outputs enabled
7
Ground Pin Current in
Shutdown
Ripple Rejection
VEN < 0.2V
10
12
1.0
µA
µA
µA
150
dB
dB
mA
Current Limit
Min
-2.0
-3.0
0.01
f = up to 1kHz; COUT = 2.2µF ceramic; CBYP = 10nF
f = 1kHz – 20kHz; COUT = 2.2µF ceramic; CBYP = 10nF
VOUT = 0V (Both regulators)
40
45
30
75
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = TJ(max) – TA / θJA. Exceeding the maximum
allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4. Response time defined as the minimum hold-off time after the LowQ™ command before applying load transients.
February 2005
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Micrel, Inc.
MIC5312
Typical Characteristics
80
70
70
60
60
50
40
150mA
30 VOUT=1.85V
+1V
V =V
20 IN OUT
= 2.2µF
C
10 OUT
C
= 10nF
300mA
BYP
0
10
1k
100
10k 100k 1M
FREQUENCY (Hz)
40
.
30 VOUT=1.85V
VIN=VOUT+1V
20
=10mA
I
LOAD
10 C
= 2.2 µF Ceramic
1
0.5
VOUT=2.6V
0
0
1
35
2
3
4
5
SUPPLY VOLTAGE (V)
150mA
100mA
20
15
10
10mA LowQ™
5
0
1.3 1.8 2.3 2.8 3.3 3.8 4.3 4.8 5.3
SUPPLY VOLTAGE (V)
80
150mA
60
40
50mA
20
0
-40 -20 0
35
300mA
25
1
100
Ground Current
vs. Supply Voltage
30
300mA
120
6
2.5
2.45
2.4
2.35
2.3
0
30
25
50mA
150mA
20
15
10
5
0
-40 -20 0
20 40 60 80 100 120
75
100
125
10mA
120
100
80
6mA
60
3mA
40
20
0
-40 -20 0
20 40 60 80 100 120
Ground Current
vs. Temperature (LowQ Mode)
9
300mA
100mA
50
140
20 40 60 80 100 120
Ground Current
vs. Temperature
100µA
25
Dropout vs.
Temperature (LowQ Mode)
DROPOUT VOLTAGE (mV)
1.5
2.55
GROUND CURRENT (µA)
150mA
300mA
2.6
1k
100
10k 100k 1M
FREQUENCY (Hz)
140
Output Voltage
vs. Temperature
2.65
OUT
160
100mA
2
GROUND CURRENT (µA)
2.7
Dropout vs.
Temperature (Normal Mode)
Dropout Characteristics
2.5
NOISE (µV/rootHz)
50
0
10
DROPOUT VOLTAGE (mV)
3
OUTPUT VOLTAGE (V)
50mA
Ripple Rejection
LowQ Mode
OUTPUT VOLTAGE (V)
90
80
PSRR (dB)
90
GROUND CURRENT (µA)
PSRR (dB)
Ripple Rejection
vs. I LOAD (Normal Mode)
8
7
6
10mA
100µA
5
4
3
2
1
0
-40 -20 0
20 40 60 80 100 120
Output Noise
Spectral Density
0.1
0.01 VIN = 4.45V
COUT = 2.2 µF
CBYP = 0.01µF
VOUT = 1.8V
R
0.001 OUT
10 100 1k 10k 100k 1M 10M
FREQUENCY (Hz)
February 2005
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(408) 955-1690
Micrel, Inc.
MIC5312
Functional Characteristics
Enable Off - Normal
VEN
(500mV/div)
VEN
(500mV/div)
Enable On- Normal
ILOAD = 200mA
VOUT = 2.6V
VOUT
(1V/div)
VOUT
(1V/div)
ILOAD = 200mA
VOUT = 2.6V
Time (40µs/div)
Time (10µs/div)
Line Transient - Normal
VIN
(1V/div)
VIN
(1V/div)
Line Transient - LowQ
5.5V
5.5V
4V
VOUT
(20mV/div)
4V
VOUT
(50mV/div)
VOUT = 2.6V
VIN = VOUT + 1V
COUT = 2.2µF
LowQ = 0V
ILOAD = 10mA
ILOAD = 300mA
VOUT = 2.6V
COUT = 2.2µF
LowQ = 5.5V
Time (40µs/div)
Time (200µs/div)
IOUT
(100mA/div)
Load Transient - Normal
10mA
VOUT
(20mV/div)
100µA
VOUT = 2.6V
VIN = VOUT + 1V
COUT = 2.2µF
Time (200µs/div)
February 2005
300mA
0mA
VOUT
(10mV/div)
IOUT
(10mV/div)
Load Transient - LowQ
VOUT = 2.6V
VIN = VOUT + 1V
COUT = 2.2µF
Time (1ms/div)
6
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Micrel, Inc.
MIC5312
Functional Characteristics (cont.)
LowQTM
(1V/div)
LowQ
TM
LowQ
Normal
VOUT1
VOUT2
(500mV/div) (500mV/div)
Normal
LowQ to Normal Transien t
TM
VOUT2
VOUT1
(500mV/div) (500mV/div)
LowQTM
(1V/div)
Normal to LowQ Transien t
ILOAD = 10mA
Time (40µs/div)
Power-On Reset Characteristics
VOUT2
(2V/div)
VOUT1
(1V/div)
VEN = EN1 = EN2
(1V/div)
Time (40µs/div)
ILOAD = 10mA
POR
(2V/div)
COUT = 2.2µF
CSET = 0.01µF
CBYP = 0.01µF
VIN = 5.0V
ILOAD = 10mA
Time (2ms/div)
February 2005
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M9999-021105
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Micrel, Inc.
MIC5312
Functional Diagram
VIN
VOUT1
LDO1
EN1
LOWQ
LowQTM
VOUT2
LDO2
EN2
POR & Delay
POR
SET
BYP
Reference
GND
MIC5312 Block Diagram
February 2005
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Micrel, Inc.
MIC5312
Functional Description
The MIC5312 is a high performance, low quiescent
current power management IC consisting of two µCap
low dropout regulators with a LowQ™ mode featuring
lower operating current. Both regulators are capable of
sourcing 300mA. A POR circuit monitors both of the
outputs and indicates when the output voltage is within
5% of nominal. The POR offers a delay time that is
externally programmable with a single capacitor to
ground.
Enable 1 and 2
The enable inputs allow for logic control of both output
voltages with individual enable inputs. The enable input
is active high, requiring 1.0V for guaranteed operation.
The enable input is CMOS logic and cannot be left
floating.
There are two regulators in the MIC5312 that share a
common bias. Each regulator can be enabled
independently by setting the voltage on pins EN1 and
EN2 to either logic high or low to turn the channel on or
off. It is also possible to enable both channels by
applying a voltage above 1.0V to both enable pins.
Power-On Reset (POR)
The power-on reset output is an open-drain N-Channel
device, requiring a pull-up resistor to either the input
voltage or output voltage for proper voltage levels. The
POR output has a delay time that is programmable with
a capacitor from the SET pin to ground. The delay time
can be programmed to be as long as 1 second.
The SET pin is a current source output that charges a
capacitor that sets the delay time for the power-on reset
output. The current source is a 1.25uA current source
that charges a capacitor up from 0V. When the capacitor
reaches 1.25V, the output of the POR is allowed to go
high. The delay time in micro seconds is equal to the
Cset in picofarads.
POR Delay (µs) = CSET (pF)
LowQ™ Mode
The LowQ™ pin is logic level low, requiring <0.2V to
enter the LowQ™ mode. The LowQ™ pin cannot be left
floating. Features of the LowQ™ mode include lower
total quiescent current of typically 7uA.
LowQ Mode can be used in many portable electronics
applications where long battery life is crucial. These
include cell phones, mp3 players, digital cameras and
PDAs. The lower ground current will increase the life of
the battery and prolong the usage between charges.
Input Capacitor
Good bypassing is recommended from input to ground
to help improve AC performance. A 1µF capacitor or
greater located close to the IC is recommended. Larger
load currents may require larger capacitor values.
Bypass Capacitor
The internal reference voltage of the MIC5312 can be
bypassed with a capacitor to ground to reduce output
noise and increase input ripple rejection (PSRR). A
quick-start feature allows for quick turn-on of the output
voltage. The recommended nominal bypass capacitor is
0.01µF, but an increase will result in longer turn on
times ton.
Output Capacitor
Each regulator output requires a 2.2µF ceramic output
capacitor for stability. The output capacitor value can be
increased to improve transient response, but
performance has been optimized for a 2.2µF ceramic
type output capacitor. X7R/X5R dielectric-type ceramic
capacitors are recommended because of their
temperature performance. X7R-type 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% to 60% respectively over their
operating temperature ranges. To use a ceramic chip
capacitor with Y5V dielectric, the value must be much
higher than a X7R ceramic capacitor to ensure the same
minimum capacitance over the equivalent operating
temperature range.
Thermal Considerations
The MIC5312 is designed to provide 300mA of
continuous current per channel in a very small MLF
package. Maximum power dissipation can be calculated
based on the output current and the voltage drop across
the part. To determine the maximum power dissipation
of the package, use the junction-to-ambient thermal
resistance of the device and the following basic
equation:
PD (max) = (TJ (max) - TA) /θJA
TJ (max) is the maximum junction temperature of the
die, 125°C, and TA is the ambient operating
temperature. θJA is layout dependent; Table 1 shows
examples of the junction-to-ambient thermal resistance
for the MIC5312.
Package
3x3 MLF™-10
θJA Recommended
Minimum Footprint
63°C/W
θJC
2°C/W
Table 1. MLF™ Thermal Resistance
February 2005
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Micrel, Inc.
MIC5312
PD LDO2 = (VIN-VOUT2) x IOUT2
PD LDO1 = (4.2V-2.8V) x 100mA
PD LDO1 = 140mW
The actual power dissipation of the regulator circuit can
be determined using the equation:
PDTOTAL = PD LDO1 + PD LDO2
PD LDO1 = (VIN-VOUT1) x IOUT1
PD LDO2 = (VIN-VOUT2) x IOUT2
Substituting PD(max) for PD and solving for the operating
conditions that are critical to the application will give the
maximum operating conditions for the regulator circuit.
For example, when operating the MIC5312 at 60°C with
a minimum footprint layout, the maximum load currents
can be calculated as follows:
PD (max) = (TJ (max) - TA) /θJA
PD (max) = (125°C - 60°C) / 63°C /W
PD (max) = 1.03W
The junction-to-ambient thermal resistance for the
minimum footprint is 63°C/W, from Table 1. The
maximum power dissipation must not be exceeded for
proper operation. Using a lithium-ion battery as the
supply voltage of 4.2V, 1.8VOUT/150mA for channel 1
and 2.8VOUT/100mA for channel 2, power dissipation
can be calculated as follows:
PD LDO1 = (VIN-VOUT1) x IOUT1
PD LDO1 = (4.2V-1.8V) x 150mA
PD LDO1 = 360mW
February 2005
PDTOTAL = PD LDO1 + PD LDO2
PDTOTAL = 360mW + 140mW
PDTOTAL = 500mW
The calculation shows that we are well below the
maximum allowable power dissipation of 1.03W for a
60° ambient temperature.
After the maximum power dissipation has been
calculated, it is always a good idea to calculate the
maximum ambient temperature for a 125° junction
temperature. Calculating maximum ambient temperature
as follows:
TA(max) = TJ(max) – (PD x θJA)
TA(max) = 125°C – (500mW x 63°C/W)
TA(max) = 93.5°C
For a full discussion of heat sinking and thermal effects
on voltage regulators, refer to the “Regulator Thermals”
section of Micrel’s Designing with Low-Dropout Voltage
Regulators handbook.
This information can be found on Micrel's website at:
http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
10
M9999-021105
(408) 955-1690
Micrel, Inc.
MIC5312
Package Information
10-Pin 3x3 MLF (MLF)
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.
© 2004 Micrel, Incorporated.
February 2005
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