Micrel MIC2826 Quad output pmic with hyperlight loadâ ¢ dcdc, three ldos, and i2c control Datasheet

MIC2826
Quad Output PMIC with HyperLight Load™ DCDC, three LDOs, and I2C Control
General Description
The Micrel MIC2826 is a four output, programmable Power
Management IC, optimized for high efficiency power
support in Mobile Application Processors, Co-Processors,
DSPs, GPS and Media Player chipsets. The device
integrates a single 500mA PWM/PFM synchronous buck
(step-down) regulator with three Low Dropout Regulators
and a 400kHz I²C interface that provides programmable
Dynamic Voltage Scaling (DVS), Power Sequencing, and
individual output Enable/Disable controls allowing the user
to optimally control all four outputs.
The 4MHz synchronous buck regulator features a patented
HyperLight Load™ (HLL) architecture which minimizes
switching losses and provides low quiescent current
operation for high efficiency at light loads. Additional
benefits of this proprietary architecture are low output
ripple voltage and fast transient response throughout the
entire load range with the use of small output capacitors,
reducing the overall system size.
Three high performance LDOs are integrated into the
MIC2826 to provide additional system voltages for I/O,
memory and other analog functions. Each LDO is capable
of sourcing 150mA output current with high PSRR and low
output noise. A 2% output voltage accuracy, low dropout
voltage (150mV @ 150mA), and low ground current of
116µA (all three LDOs operating) makes this device ideally
suited for mobile applications.
The MIC2826 is available in a tiny 14-pin 2.5mm x 2.5mm
Thin MLF® with a junction operating range from -40°C to
+125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Applications
•
•
•
•
•
•
Application processors
GPS subsystems
General purpose PMIC
Mobile phones / PDAs
Portable media players
Mobile television receivers
Features
•
•
•
•
•
•
•
Fast-mode I2C control interface
Tiny 14-pin 2.5mm x 2.5mm MLF® package
Default start-up voltage states and sequencing
Fault indication processor flag - IRQb
-40°C to 125°C junction temperature range
Thermal shutdown and current-limit protection
Power On After Fault (POAF) function
DC-DC Synchronous Buck
• 2.7V to 5.5V input voltage range
• 500mA continuous output current
• HyperLight Load™ mode
– 25µA quiescent current
• 90% peak efficiency; 85% at 1mA
• Ultra-fast transient response
• Dynamic Voltage Scaling (DVS) range: 0.8V to 1.8V
– 0.8V to 1.2V in 25mV steps
– 1.2V to 1.8V in 50mV steps
• ±2% initial accuracy
• Low output voltage ripple: 20mVpp in HyperLight
Load™ mode, 3mV in full PWM mode
LDOs
• 1.8V to VDVIN input voltage range
• 150mA output current (each LDO)
• Dynamic Voltage Scaling (each LDO)
–
DVS range: 0.8V to 3.3V in 50mV steps
• ±2% initial accuracy
• Low quiescent current – 50µA (each LDO)
• Low dropout voltage – 50mV @ 50mA
• Low output noise - 45µVRMS
• Stable with ceramic output capacitors
• 65dB PSRR at 1kHz
HyperLight Load is a trademark of Micrel, Inc
MLF and MicroLeadFrame are registered 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
July 2009
M9999-071609-A
Micrel, Inc.
MIC2826
Typical Application
GPS Subsystem Application
July 2009
2
M9999-071609-A
Micrel, Inc.
MIC2826
Ordering Information
Default Start Up
Voltages (1)
Marking
Code (2)
Part Number
Default Start Up
Sequence (1)
Junction Temp.
Range
SW
LDO1
LDO2
LDO3
SW
LDO1
LDO2
LDO3
Package
(3)
MIC2826-A0YMT
826A0
1.2V
2.6V
1.2V
1.8.V
2
1
3
4
-40°C to +125°C
14-Pin 2.5x2.5mm
Thin MLF®
MIC2826-D9YMT
826D9
1.8V
2.5V
1.2V
1.2V
1
Off
Off
Off
-40°C to +125°C
14-Pin 2.5x2.5mm
Thin MLF®
Note:
1. Other Default voltages and sequences are available on request (Voltages: 0.8V to 3.3VOUT LDOs, and 0.8V to 1.8VOUT PWM).
Please contact Micrel Marketing for other voltage ranges.
®
2. Thin MLF Pin 1 Identifier symbol is “▲”.
®
3. Thin MLF is a Green RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
July 2009
3
M9999-071609-A
Micrel, Inc.
MIC2826
Pin Configuration
14-Pin 2.5mm x 2.5mm Thin MLF® (MT)
(Top View)
Pin Description
Pin Number
Pin Name
Pin Function
1
LDO1OUT
Output of LDO1: Requires a minimum 1µF ceramic capacitor-to-AGND.
2
LDO2OUT
Output of LDO2: Requires a minimum 1µF ceramic capacitor-to-AGND.
3
LDO23IN
External Input Supply Rail to LDO2 and LDO3. Requires a minimum 1µF ceramic
capacitor to AGND.
4
LDO3OUT
5
IRQb
6
SW
7
DGND
Switch Ground Pin.
8
DVIN
Input Voltage: Requires a close minimum 2.2µF ceramic capacitor to DGND.
9
SDA
Fast-mode 400kHz I²C Data Input/Output pin.
10
SCL
Fast-mode 400kHz I²C Clock Input pin.
July 2009
Output of LDO3: Connect a minimum 1µF ceramic capacitor to AGND.
Fault Output (open drain).
Switch (Output): Internal power MOSFET output switches.
11
FB
12
AGND
Feedback Pin Connected to VOUT to sense output voltage.
13
EN
Enable (Input): Executes default startup sequence. Active High. HIGH = ON,
LOW = OFF. Do not leave floating. The EN pin function is optional if I2C control
is used for startup and shutdown.
14
LDO1IN
External Input Supply Rail to LDO1. Requires a minimum 1µF ceramic capacitor
to AGND.
EP
HS PAD
Exposed Heat-Sink Pad.
Analog Ground. Must be connected externally to DGND.
4
M9999-071609-A
Micrel, Inc.
MIC2826
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VDVIN, VLDO1IN, VLDO23IN) .......... -0.3V to +6V
Enable Voltage (VEN) ....................................... -0.3V to +6V
I2C Voltage (VSDA, VSCL) ................................... -0.3V to +6V
Power Dissipation ................................. Internally Limited(3)
Lead Temperature (Soldering, 10 sec.) ..................... 260°C
Storage Temperature (TS)...................–65°C ≤ TJ ≤ +150°C
ESD Rating(4) ................................................................. 2kV
DVIN Supply voltage (VDVIN)......................... +2.7V to +5.5V
LDO Supply voltage (VLDO1IN, VLDO23IN)...........+1.8V to VDVIN
Enable Input Voltage (VEN)..................................0V to VDVIN
I2C Voltage (VSDA, VSCL) .................................... 0V to +5.5V
Junction Temperature Range (TJ)............. –40°C to +125°C
Junction Thermal Resistance
2.5mm x 2.5mm Thin MLF-14 (θJA) ...................89°C/W
Electrical Characteristics(5) – DC/DC Converter
DVIN = EN = 3.6V; LDO1, LDO2, LDO3 disabled; L=1µH, COUT =4.7µF, IOUT= 20mA, TA = 25°C, unless otherwise
specified. Bold values indicate -40°C≤TJ≤+125°C.
Parameter
Conditions
Min
2.7
Supply Voltage Range
Under-Voltage Lockout
Threshold
Rising
Switcher Quiescent Current,
HLL
IOUT = 0mA, FB > 1.2 * VOUT Nominal
Shutdown Current
EN = 0V, DVIN = 5.5V
Output Voltage Accuracy
DVIN = 3.6V; ILOAD = 20mA
Current Limit in PWM Mode
FB = 0.9* VOUT(NOM)
Output Voltage Line Regulation
Output Voltage Load Regulation
PWM Switch ON-Resistance
Typ
2.45
Units
5.5
V
2.55
2.65
V
25
35
µA
2
5
µA
+3
%
-3
0.55
Max
1
A
DVIN = 3.0V to 5.5V, ILOAD = 20mA
0.4
%/V
20mA < ILOAD < 500mA, DVIN = 3.6V
0.5
%
ISW = 100mA PMOS
0.55
Ω
ISW = -100mA NMOS
0.6
Ω
4
MHz
300
µs
Frequency
ILOAD = 120mA
SoftStart Time
VOUT = 90%
Enable Voltage
OFF
0.2
1.2
ON
2
V
Enable Input Current
0.1
Over-temperature Shutdown
160
°C
Over-temperature Shutdown
Hysteresis
20
°C
VOUT Ramping Up
91
%
VOUT Ramping Down
89
%
280
Ω
VPOR Threshold
% of VOUT below Nominal
Auto-Discharge NFET
resistance
µA
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. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
5. Specification for packaged product only.
July 2009
5
M9999-071609-A
Micrel, Inc.
MIC2826
Electrical Characteristics - LDO1, LDO2, and LDO3
DVIN = EN = LDO1IN = LDO23IN = 3.6V; DC-DC disabled; LDO COUT =1µF, LDO IOUT = 100µA, TA = 25°C, unless
otherwise specified. Bold values indicate -40°C≤TJ≤+125°C.
Parameter
Conditions
Min
Output Voltage Accuracy
Variation from nominal VOUT
-3.0
Input voltage
IOUT = 100µA to 150mA;
Typ
Max
Units
+3.0
%
2
V
IOUT = 100µA to 100mA; -20°C to +100°C
1.74
V
Output Voltage DVS Range
Adjustable through I²C Registers
0.8
Line Regulation
LDO1IN, LDO23IN = VOUT +1V to 5.5V; IOUT = 100µA
Load Regulation
IOUT = 100µA to 75mA
Dropout Voltage
IOUT = 50mA; VOUT = 2V
70
IOUT = 150mA; VOUT = 2V
200
IOUT = 50mA; VOUT = 3V
50
mV
IOUT = 150mA; VOUT = 3V
150
mV
1 LDO enabled
50
µA
2 LDOs enabled
83
µA
3 LDOs enabled
116
µA
f = up to 1kHz; COUT = 1µF; VOUT = 2.5V
65
dB
f = 1kHz - 10kHz; COUT = 1µF VOUT = 2.5V
45
dB
Ground Pin Current
Ripple Rejection
0.014
3.3
V
0.1
%/V
4
mV
mV
350
mV
EN = DVIN
Current Limit
VOUT = 0V
Output Voltage Noise
COUT = 1µF,10Hz to 100kHz
190
Auto-Discharge NFET
resistance
400
550
mA
45
µVRMS
280
Ω
Electrical Characteristics – I2C Interface
DVIN = EN = 3.6V, TA = 25°C, unless otherwise specified. Bold values indicate -40°C≤TJ≤+125°C.
Parameter
Conditions
Min
Typ
LOW-Level Input Voltage
1.2
HIGH-Level Input Voltage
Max
Units
0.2
V
V
SDA Pull-down resistance
Open drain pull-down on SDA during read back
80
Ω
IRQb Pull-down resistance
Open drain pull-down
55
Ω
July 2009
6
M9999-071609-A
Micrel, Inc.
MIC2826
Typical Characteristics
Enable Threshold
v s. Input Voltage
Enable Threshold
v s. Temperature
2.0
0.9
0.9
1.8
0.8
0.8
1.6
0.7
0.7
1.4
ENABLE THRESHOLD (V)
ENABLE THRESHOLD (V)
OUTPUT VOLTAGE (V)
Thermal Shutdown
0.6
1.2
0.5
1.0
0.4
0.8
0.3
0.6
0.2
DVIN = 3.6V
VIN = 3.6V
VOUT = 1.8V
0.4
0.2
0.1
0.6
0.5
0.4
0.3
0.2
0.1
DVIN = VIN = 3.6V
0
0
0.0
-40
0
40
80
120
160
T EM PERAT URE (°C)
-40
200
-20
0
20 40 60 80
T EM PERAT URE (°C)
2.7
100 120
3.1
LDO Output Noise
Spectral Density
LDO Input Voltage PSRR
5.1
5.5
Dropout Voltage
v s. Load Current
10
90
3.5
3.9 4.3
4.7
INPUT VO LT AGE (V)
250
80
70
NO ISE (µV/√Hz)
40
DVIN = 5.5V
VIN = 3.6V
VOUT = 1.2V
COUT = 1µF
Load = 150mA
20
10
0
0.01
DVIN = VIN = 5.5V
VOUT = 1.0V
COUT = 1µF
Load = 10mA
VLDO = 3V
100
0
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
FREQ UENCY (Hz)
FREQ UENCY (Hz)
0
Dropout Voltage
v s. Tem perature
L = 150mA
DRO POUT VOLTAGE (mV)
175
150
L = 100mA
100
75
50
L = 50mA
25
0
DVIN = 5.5V
VLDO = 2V
COUT = 1µF
-20
0
20 40 60 80
T EM PERAT URE (°C)
125
100
L = 100mA
75
50
25
DVIN = 5.5V
VLDO = 3V
COUT = 1µF
L = 50mA
1.8
1.230
1.6
OUTPUT VO LTAGE (V)
2.0
1.240
1.220
1.210
1.200
1.190
1.180
1.170
DVIN = 5.0
VIN = 3.6V
COUT = 1µF
1.160
1.150
0
July 2009
25
50
75
100 125
LOAD CURRENT (mA)
-20
0
20 40 60 80
T EM PERAT URE (°C)
1.22
1.21
1.20
1.19
1.18
DVIN = VIN = 3.6V
VOUT = 1.2V
COUT = 1µF
Load = 100µA
1.17
1.16
-40
100 120
1.4
1.2
1.0
0.8
0.6
DVIN = 5.5V
VLDO = 1.8V
COUT = 1µF
Load = 100µA
0.4
0.2
0.0
150
150
1.23
-20
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5
INPUT VO LT AG E (V)
7
0
20
40
60
80
100 120
TEM PERATURE (°C)
LDO Current Limit
v s. Input Voltage
LDO Output Voltage
v s. Input Voltage
1.250
125
1.15
-40
LDO Output Voltage
v s. Load Current
100
1.24
L = 150mA
150
100 120
75
LDO Output Voltage
v s. Temperature
0
-40
50
1.25
175
200
125
25
LO AD CURRENT (mA)
200
225
50
DVIN = 5.5V
COUT = 1µF
0.001
250
DROPOUT VOLTAG E (mV)
150
Noise = (10Hz to 100kHz)=44.77µVRMS
Dropout Voltage
v s. Temperature
OUTPUT VOLTAGE (V)
VLDO = 2V
LDO OUTPUT VOLTAGE (V)
30
0.1
200
CURRENT LIM IT (mA)
PSRR (dB)
50
DROPOUT VOLTAGE (mV)
1
60
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
DVIN =5.5V
COUT = 1µF
2
2.5
3
3.5
4
4.5
INPUT VOLT AGE (V)
5
5.5
M9999-071609-A
Micrel, Inc.
MIC2826
Typical Characteristics (continued)
55
440
53
430
51
420
410
400
390
380
370
0
20
40
60
80
TEM PERATURE (°C)
100
47
45
43
41
DVIN = VIN = 3.6V
VOUT = 1.2V
COUT = 1µF
Load = 150mA
39
35
350
-20
100
49
37
DVIN = VIN = 3.6V
-40
120
-40
120
LDO Ground Current
v s. Load Current
0
20 40 60 80
T EM PERAT URE (°C)
40
1 LDO
VOUT = 1.2V
COUT = 1µF
Load = 100µA
20
0
100 120
2.7
90
90
85
85
80
49.2
48.8
75
70
VIN=4.2V
60
DVIN = VIN = 3.6V
VOUT = 1.2V
COUT = 1µF
48.4
VIN=3.6V
65
L = 1µH
C = 4.7µF
50
75
100
125
LO AD CURRENT (mA)
150
1
DC-DC Efficiency VOUT=1.5V
VIN=2.7V
85
10
100
LO AD CURRENT (mA)
1000
DC-DC Switching Frequency
v s. Load Current
90
EFFICIENCY (%)
80
VIN=4.2V
70
60
50
L = 1µH
C = 4.7µF
55
10
100
LOAD CURRENT (mA)
10
SW FREQ UENCY (M Hz)
L=4.7µH
L=1µH
DVIN = 3.6V
VOUT = 1.8V
10
100
LOAD CURRENT (mA)
1
VOUT = 1.8V
L = 1µH
5.0
4.5
4.6
4.0
4.4
4.2
4.0
3.8
DVIN = 3.6V
VOUT = 1.8V
L = 1µH
C= 4.7µF
Load = 120mA
3.6
3.4
10
100
LOAD CURRENT (mA)
3.5
3.0
2.5
2.0
1.5
VOUT = 1.8V
L = 1µH
C= 4.7µF
Load = 120mA
1.0
0.5
0.0
-40
-20
0
20 40 60 80
T EM PERAT URE (°C)
8
100 120
1000
DC-DC Switching Frequency
v s. Input Voltage
4.8
3.0
1000
1000
5.0
3.2
0.01
10
100
LOAD CURRENT (mA)
VIN=4.2V
DC-DC Switching Frequency
v s. Temperature
DC-DC Switching Frequency
v s. Load Current
L=2.2µH
VIN=3.6V
0.1
0.01
1
1000
VIN=3.0V
1
L = 1µH
C = 4.7µF
40
50
July 2009
100
VIN=3.6V
60
1
10
10
VIN=2.7V
65
0.1
1
100
70
1
L = 1µH
C = 4.7µF
DC-DC Efficiency VOUT=1.8V
VIN=3.6V
VIN=4.2V
1
VIN=4.2V
65
LOAD CURRENT (mA)
80
75
70
1000
SW FREQUENCY (M Hz)
90
75
50
SW FREQUENCY (M Hz)
25
5.5
VIN=2.7V
55
50
0
5.1
60
55
48.0
3.5
3.9
4.3
4.7
INPUT VOLTAGE (V)
VIN=3.6V
80
VIN=2.7V
EFFICIENCY (%)
EFFICIENCY (%)
49.6
3.1
DC-DC Efficiency VOUT=1.2V
51.2
50.0
EFFICIENCY (%)
2 LDOs
60
51.6
50.4
SW FREQUENCY (M Hz)
3 LDOs
80
DC-DC Efficiency VOUT=1.0V
50.8
G ROUND CURRENT (µA)
-20
GROUND CURRENT (µA)
450
360
LDO Ground Current
v s. Input Voltage
LDO Ground Current
v s. Temperature
GROUND CURRENT (µA)
CURRENT LIMIT (mA)
LDO Current Limit
v s. Temperature
2.7
3.1
3.5
3.9
4.3
4.7
INPUT VOLT AGE (V)
5.1
5.5
M9999-071609-A
Micrel, Inc.
MIC2826
Typical Characteristics (continued)
DC-DC Output Voltage
v s. Load Current
DC-DC Output Voltage
v s. Input Voltage
DC-DC Output Voltage
v s. Tem perature
1.92
1.9
1.90
1.88
1.88
OUTPUT VOLTAGE (V)
O UTPUT VOLTAGE (V)
1.84
1.82
1.80
1.78
1.76
1.74
VIN = 3.6V
L = 1µH
C= 4.7µF
1.72
1.70
1.84
1.82
1.8
1.78
1.76
1.74
100
200
300
400
LOAD CURRENT (mA)
DVIN = 3.6V
VOUT = 1.8V
Load = 20mA
1.72
1.7
1.68
0
OUTPUT VOLTAGE (V)
1.86
1.86
-40
500
-20
DC-DC Current Lim it
v s. Input Voltage
0
20 40 60 80
T EM PERAT URE (°C)
2.10
2.06
2.02
1.98
1.94
1.90
1.86
1.82
1.78
1.74
1.70
1.66
1.62
1.58
1.54
1.50
100 120
L = 1µH
C= 4.7µF
Load = 20mA
2.7
3.1
5.1
5.5
RDSON (PMOS)
v s. Temperature
Current Limit
v s. Tem perature
1.2
3.5
3.9
4.3
4.7
INPUT VOLT AGE (V)
1.40
800
1.20
700
1.1
CURRENT LIM IT (A)
CURRENT LIM IT (A)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
VOUT = 1.8V
L = 1µH
C= 4.7µF
0.2
0.1
0.0
2.7
3.1
3.5
3.9 4.3 4.7
INPUT VO LT AGE (V)
5.1
600
1.00
RDS (mΩ)
1.0
0.80
0.60
0.40
DVIN = 3.6V
VOUT = 1.8V
300
100
0
0.00
-40
-20
RDSON (NMOS)
v s. Temperature
0
20 40 60 80
T EM PERAT URE (°C)
-40
100 120
800
700
700
600
600
500
500
RDS (mΩ)
500
400
300
RDS (mΩ)
800
800
600
400
300
300
200
200
100
100
100
0
0
-20
0
20 40 60 80
T EM PERAT URE (°C)
100 120
2.7
28
30
25
20
15
DVIN = 3.6V
VOUT = 1.8V
IOUT = 0mA
0
July 2009
-20
0
20 40 60 80
T EM PERAT URE (°C)
100 120
Q UIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
29
35
-40
3.5
3.9
4.3
4.7
5.1
5.5
2.7
3.1
3.5 3.9 4.3 4.7
INPUT VOLT AGE (V)
5.1
5.5
Quiescent Current
v s. Input Voltage
40
5
3.1
INPUT VOLTAGE (V)
Quiescent Current
v s. Tem perature
10
100 120
400
200
0
0
20 40 60 80
T EM PERAT URE (°C)
RDSON (NMOS)
v s. Input Voltage
900
-40
-20
RDSON (PMOS)
v s. Input Voltage
700
RDS (mΩ)
400
200
0.20
5.5
500
27
26
25
24
23
22
21
VOUT = 1.8V
IOUT = 0mA
20
19
2.7
3.1
3.5 3.9 4.3 4.7
INPUT VO LT AG E (V)
9
5.1
5.5
M9999-071609-A
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MIC2826
Functional Characteristics
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MIC2826
Functional Characteristics (continued)
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MIC2826
Functional Block Diagram
MIC2826 Block Diagram
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MIC2826
Power-Up via the EN Pin
The EN pin is transition sensitive and not level sensitive
(with the exception of hot enable—please see the
description below). If the EN pin is toggled low-to-high,
the MIC2826 will execute the default startup sequence.
During the startup sequence, the appropriate set of
supply enables is loaded into the Enable Register. This
allows the part to present a consistent interface to the
I²C host; if the host reads the Enable Control register, it
will see one or more enables on, which is consistent with
one or more active supplies.
Individual control of the supplies is now possible via the
I²C interface.
Functional Description – Power Control
and Sequencing
Two Types of Part: Sequence-Enabled and NoSequence
•
Sequence-Enabled
parts
support
automatic
sequencing of the four supplies. Sequence-Enabled
parts all have a default sequence (activated by
asserting the EN pin). These parts also allow
sequencing to be disabled.
While very flexible, sequence-enabled parts require
more care in operation. See the later section
“Ensuring Clean Switching in Sequence-Enabled
Parts”.
•
No-Sequence parts have no built-in sequencing
capability. Their default startup turns on only one
supply, which requires no sequencing. If the host
needs more supplies to come on, this can be
accomplished with I²C writes which allows a
sequence activated by software to be performed.
“Hot Enable” Startup
Some systems may choose to tie the EN pin to DVIN, so
that the MIC2826 registers an active EN pin as it
completes power-on. This is perfectly legal and
produces a default startup immediately after power is
applied. Depending on the rise time of the input power
being applied, the UVLO flag may be set.
Power-up State
When battery power is first applied to the MIC2826, all
I²C registers are loaded with their default (POR) values.
If EN is high, a default startup is executed; otherwise,
the part remains in a quiescent state waiting to be
started by EN or an I²C command.
Power-Down via the EN Pin
If the EN pin is toggled high-to-low, the MIC2826 will
shut down all outputs simultaneously. For reasons
similar to those above, at the conclusion of the shutdown
sequence, all four individual supply enables will be clear
in the Enable Control register and the bias will be
switched off.
If the MIC2826 startup is initiated by asserting EN and
later shutdown is initiated by clearing the Enable
Register bits, the part will be quiescent (with all bias
currents disabled) but EN will still be high. In this case,
de-asserting EN will have no effect, since the part has
already completed its shutdown.
Enable Pin-Initiated Default Startup
When EN is asserted, a default startup is executed. This
is defined below:
•
The voltage registers are loaded with their default
values.
•
In sequence-enabled parts, the Sequence Control
bit is set to low (to allow sequencing to occur). Nosequence parts always have zero for the Sequence
Control bit
•
The correct set of supply enable bits is loaded into
the Enable Register, and the appropriate sequence
is then executed.
•
The Power-On After Fault (POAF) bit is set to its
default state, high.
Power-Up and Power-Down via the Enable Register
The four individual power supply enable bits in the
Enable Register (LDO3-EN, LDO2-EN, LDO1-EN, and
DC-EN) may be used to enable and disable individual
supplies. If the part is sequenced-enabled, and
sequencing is permitted by the Sequence Control bit,
enabled supplies are turned on in sequence. Any
disabled outputs will not participate in the sequence and
will be ignored.
See also the “Ensuring Clean Switching in SequenceEnabled Parts” section.
Under no circumstances should the EN and I²C control
be used simultaneously. The results would not be
deterministic.
If a supply output is enabled and its Voltage Control
register is written with a new value, the output voltage
changes immediately at the I²C acknowledge.
Turning on the Power Supplies
After power is applied, the MIC2826 offers two methods
of turning the four supply outputs on and off:
1. Default startup sequencing or shutdown via the
EN pin;
2. Flexible startup sequencing or shutdown via the
I²C interface
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MIC2826
Interrupt Operation
If interrupts are enabled (INT-EN = 1), then the
MIC2826’s IRQb output will be asserted (driven low)
whenever either of the two fault bits, UVLO or TSD, are
asserted. Clearing the fault status bit by writing a one to
it will clear the interrupt if the fault condition is no longer
present. If the fault is still present, the status bit will be
asserted again, together with the IRQb output. This
operation does not depend on the state of the POAF bit.
The default state of the INT_EN bit is zero, so the
interrupt output is disabled. This is done so that the
interrupt pin does not transition in MIC2826 systems
which use only the EN pin and not the I²C interface.
Fault Handling
A fault is generated from either a thermal shutdown or
under-voltage lockout event. If a fault occurs, the
activation of the fault condition immediately turns off all
output supplies, sets the fault flag bit(s) in the Status
Register, and loads default values in the Enable and
Voltage Registers. The sequence Control bit SEQ CNT
is cleared to enable sequencing for sequence-enabled
parts. The POAF bit is unaffected.
The default state of the Enable Register’s POAF (Power
On After Fault) bit is high, indicating that the MIC2826
will perform a default start up when the fault goes away.
If the user instead prefers that the part does not
automatically attempt re-start after a fault, the POAF can
be programmed to a “0”.
The EN pin can be toggled high-to-low at any time to
clear the supply enables in the Enable Register and shut
down the part. The same can be achieved through I2C at
any time by disabling all enables in the enable register.
Either method can be used to shut down the part during
a fault.
Shutdown after a fault will maintain the fault flags in the
status register. Only Power-on-Reset or an echo reset of
the status register will clear these flags.
Ensuring Clean Switching in Sequence-Enabled
Parts
In no-sequence parts, no sequencing ever occurs, and
no special rules are required. However, in sequenceenabled parts, care must be taken when using automatic
supply startup sequencing.
The sequence-enabled MIC2826 accomplishes supply
sequencing by asynchronously using one supply’s power
good signal to enable the next supply in line. As a
consequence “downstream” supplies can momentarily
switch off their outputs when “upstream” supplies are
switched in and out of the sequencing chain.
Example:
Suppose the sequence [DC, 1, 2, 3] is enabled and
LDO1 is off, the others are enabled and their status is
valid. If LDO1 is now enabled through I²C, LDO2 and
LDO3 will turn momentarily off, until LDO1 is valid, which
then starts LDO2 first and then LDO3.
To avoid this, the following rules should be observed,
which apply only to sequence-enabled parts:
1. If all supplies are to be turned on, it is fine to use
sequencing. This is what happens naturally as part
of the EN-initiated default startup. It may also be
accomplished by setting all four supply enables
simultaneously in the Enable Register, and leaving
the Sequence Control bit low to permit
sequencing.
2. When starting from an all-off condition and a
subset of the supplies is to be turned on,
sequencing is permitted.
3. When one or more supplies are on, and a supply
is to be turned off or on, sequencing must be
disabled by setting SEQ CNT high.
4. When a subset of the supplies has been turned on
via the Enable Register, an active transition on the
EN pin must not be used to turn on the remaining
supplies.
Thermal Shutdown (TSD)
If the MIC2826’s on-chip thermal shutdown detects that
the die is too hot, the part will immediately turn off all
outputs but maintain the bias to internal circuitry. The
thermal event is logged in the Status register which can
be read via I²C. When the thermal shutdown event is
removed, a default startup is executed if POAF is high.
Under Voltage Lock Out (UVLO)
If the MIC2826’s on-chip voltage monitor detects a low
voltage on the DVIN supply, the part will immediately
turn off all outputs but maintain the bias to internal
circuitry. When the UVLO event is removed, the outputs
will turn on using the default startup if POAF is high.
The UVLO event is logged in the status register which
can be read via I²C.
If the power on DVIN drops too low, the MIC2826 will no
longer be able to function reliably and will enter its
power-on reset (POR) state. Any previously raised TSD
or UVLO flags will now be cleared at startup
Power Good Indication and Hysteresis
The status of all four outputs can be read via I²C in the
status register. A register flag is set for each output
when it reaches 90% of its regulated value and cleared
when the output falls to about 85%.
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MIC2826
Sequencing rules do not apply to the last supply in the
sequencing chain (the supply labeled “4th” in the
sequence table). The 4th supply may be turned on and
off at any time, since there are no downstream supplies
from the 4th.
Available Default Startup Sequences
The following table shows available default startup
sequences for the MIC2826. Please contact Micrel
factory to request customized default startup voltages
and sequences.
Sequence
Number
DCDC
LDO1
LDO2
LDO3
SequenceEnabled
Part?
Sequence 0
2nd
1st
3rd
4th
Yes
Sequence 2
1st
2nd
3rd
4th
Yes
Sequence 9
On
Off
Off
Off
No
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MIC2826
Functional Description – Fast-mode I²C
Interface
I²C Address
The seven-bit I²C address of the MIC2826 is set at the
factory to 1011010 binary, which would be identified as
B4h using standard I²C nomenclature, in which the
read/write bit takes the least significant position of the
eight-bit address. Other I²C base addresses are
available; please contact Micrel for details.
Electrical Characteristics – Serial Interface Timing
3.0V ≤ VDVIN ≤ 3.6V unless otherwise noted. Bold values indicate -40°C ≤ TA ≤ +125°C.
Symbol
Parameter
Conditions
Min
Typ
Max
Units
t1
SCL (clock) period
2.5
µs
t2
Data In Setup Time to SCL High
100
ns
t3
Data Out Stable After SCL Low
0
ns
t4
SDA Low Setup Time to SCL Low
Start
100
ns
t5
SDA High Hold Time after SCL High
Stop
100
ns
Serial Interface Timing
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MIC2826
the MIC2826, followed by a repeat of the device address
with the R/W bit (LSB) set to the high (read) state. The
data to be read from the part may then be clocked out.
These protocols are shown in Figure 1 and Figure 2.
The Register Address is eight bits (one byte) wide. This
byte carries the address of the MIC2826 register to be
operated upon. Only the lower three bits are used.
Serial Port Operation
The MIC2826 uses standard Write_Byte, Read_Byte,
and Read_Word operations for communication with its
host. The Write_Byte operation involves sending the
device’s address (with the R/W bit low to signal a write
operation), followed by the register address and the
command byte. The Read_Byte operation is a composite
write and read operation: the host first sends the
device’s address followed by the register address, as in
a write operation. A new start bit must then be sent to
Figure 1: Write_Byte protocol
Figure 2: Read_Byte protocol
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MIC2826
Enable/Startup Control Register (00h):
The Enable Register is used to allow control of the
MIC2826’s power supplies. It allows each supply to be
turned on and off, and whether sequencing is used.
When a default startup is executed as a result of the EN
pin being taken from low to high, the Sequence Control,
and Supply Enable bits are all set to their default values.
The Sequence Control bit, only implemented in
sequence-enabled parts, must be used carefully. See
the section on “Ensuring Clean Switching in SequenceEnabled Parts”.
Functional Description – I²C Control
Registers
Register
Address
Register
Name
Read/
Write
00h
Enable
R/W
Enable and startup control
register
01h
Status
R/W
Regulator output & fault
condition status register
02h
DC-DC
R/W
DC-DC regulator voltage
control register
03h
LDO1
R/W
LDO1 voltage control
register
04h
LDO2
R/W
LDO2 voltage control
register
05h
LDO3
R/W
LDO3 voltage control
register
D7
Description
D5
D4
D3
D2
D1
D0
Reserved
POAF
SEQ CNT
LDO3-EN
LDO2-EN
LDO1-EN
DC-EN
Access
N/A
R/W
R/W
R/W
R/W
R/W
R/W
POR Value
00
1
0
0
0
0
0
Data
00
0 = Remain off
after fault
0 = Sequencing
enabled
1 = Restore
power after fault
1 = Sequencing
disabled
0 = Disable
Yes
Yes
Yes
Yes
No
No
Yes
Yes, if POAF=1
Name
Set by Default
Startup?
Set by a
fault?
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18
1 = Enable
M9999-071609-A
Micrel, Inc.
MIC2826
Status Register (01h):
The Status Register allows the state of each supply to
be interrogated, supports flags that are set when fault
conditions occur, and controls the use of the MIC2826’s
interrupt pin.
D7
D6
D5
D4
D3
D2
D1
D0
Name
Reserved
INT-EN
UVLO
TSD
L3-Status
L2-Status
L1-Status
DC-Status
Access
RO
R/W
Echo
reset
Echo reset
RO
RO
RO
RO
POR
Value
0
0
0
0
0
0
0
0
Data
0
0: Interrupt
is disabled
0: Normal
0: Normal
1: DVIN
undervoltage
occurred
1: Thermal
shutdown
occurred
0 = LDO3
Not Valid
0 = LDO2
Not Valid
0 = LDO1
Not Valid
0 = DC-DC
Not Valid
1 = LDO3
Valid
1 = LDO2
Valid
1 = LDO1
Valid
1 = DC-DC
Valid
1: Interrupt
is enabled
Note:
“Echo reset” bits remain set until cleared. Clearing these bits is accomplished by writing a one to that bit location (“echo the one to reset”). If the fault
condition (UVLO or thermal shutdown) persists after the echo reset, the corresponding Status Register bit will be set high again immediately.
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MIC2826
DC-DC Regulator Voltage Control Register (02h)
This register controls the output voltage of the DC-DC
PWM/PFM Regulator. The DC-DC Regulator employs a
dual scale voltage step size to cover a wide range of
output voltages from 0.8V to 1.8V. From 0.8V to 1.2V a
step size of 25mV allows maximum power saving when
the Processor Core is placed into a light load state. From
1.2V to 1.8V, a step size of 50mV provides a wide range
of output voltages for power system flexibility.
DC-DC Regulator Voltage Control Register Table
DC-DC Regulator Voltage Control Register Address: 02h
Step Size
Register Value
Output Voltage
25mV
00h
0.800
01h
0.825
02h
0.850
03h
0.875
04h
0.900
05h
0.925
06h
0.950
07h
0.975
08h
1.000
09h
1.025
0Ah
1.050
0Bh
1.075
0Ch
1.100
0Dh
1.125
0Eh
1.150
0Fh
1.175
10h
1.200
11h
1.250
12h
1.300
13h
1.350
14h
1.400
15h
1.450
16h
1.500
17h
1.550
18h
1.600
19h
1.650
1Ah
1.700
1Bh
1.750
1Ch
1.800
50mV
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MIC2826
LDO1, LDO2, LDO3 Voltage Control Registers Table
LDO1 Regulator Voltage Control Register Address: 03h
LDO2 Regulator Voltage Control Register Address: 04h
LDO3 Regulator Voltage Control Register Address: 05h
Step Size
Register Value
Output Voltage
Step Size
Register Value
Output Voltage
50mV
00h
0.800
50mV
BAh
2.400
0Bh
0.850
BDh
2.450
14h
0.900
C1h
2.500
1Dh
0.950
C4h
2.550
25h
1.000
C7h
2.600
2Eh
1.050
C9h
2.650
37h
1.100
CCh
2.700
3Eh
1.150
CEh
2.750
45h
1.200
D1h
2.800
4Ch
1.250
D3h
2.850
52h
1.300
D6h
2.900
57h
1.350
D8h
2.950
5Ch
1.400
DAh
3.000
61h
1.450
DCh
3.050
65h
1.500
DEh
3.100
69h
1.550
E1h
3.150
6Dh
1.600
E3h
3.200
72h
1.650
E6h
3.250
79h
1.700
E8h
3.300
7Fh
1.750
85h
1.800
8Bh
1.850
91h
1.900
July 2009
96h
1.950
9Ah
2.000
9Fh
2.050
A4h
2.100
A8h
2.150
ACh
2.200
B0h
2.250
B4h
2.300
B7h
2.350
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MIC2826
LDO1OUT
The LDO1OUT pin provides the regulated output voltage
of LDO1. Power is provided by LDO1IN. LDO1OUT
voltage can be dynamically scaled through I2C control.
The recommended output capacitance is 1µF,
decoupled to AGND.
Functional Description
DVIN
The DVIN pin provides power to the source of the
internal switch P-channel MOSFET, I2C control and
voltage references for the MIC2826. The DVIN operating
voltage range is from 2.7V to 5.5V. In order for any
MIC2826 outputs to regulate, the appropriate input
voltage must be applied to the DVIN pin. Due to the
high switching speeds, a 4.7µF capacitor is
recommended as close as possible to the DVIN and
power ground (DGND) pin for bypassing. Please refer to
layout recommendations.
LDO2OUT
The LDO2OUT pin provides the regulated output voltage
of LDO2. Power is provided by LDO23IN. LDO2OUT
voltage can be dynamically scaled through I2C control.
The recommended output capacitance is 1µF,
decoupled to AGND.
LDO1IN
LDO1IN provides power to the source of LDO1 Pchannel MOSFET. The LDO1IN operating voltage range
is from 1.8V to VDVIN. The recommended bypass
capacitor is 1µF.
LDO3OUT
The LDO3OUT pin provides the regulated output voltage
of LDO3. Power is provided by LDO23IN. LDO3OUT
voltage can be dynamically scaled through I2C control.
The recommended output capacitance is 1µF,
decoupled to AGND.
LDO23IN
LDO23IN provides power to the source of the MIC2826
LDO2 and LDO3 P-channel MOSFET. The LDO23IN
operating voltage range is from 1.8V to VDVIN. The
recommended bypass capacitor is 1µF.
SCL
The I2C clock input pin provides a reference clock for
clocking in the data signal. This is a fast-mode 400kHz
input pin, and requires a 4.7kΩ pull-up resistor. Please
refer to “Serial Port Operation” for more details.
EN
The enable pin controls the ON and OFF state of all the
outputs of the MIC2826. The EN pin is transition
sensitive and not level sensitive. By toggling the enable
pin low-to-high, this activates the default startup
sequence of the part.
SDA
The I2C data bidirectional pin allows for data to be
written to and read from the MIC2826. This is a fastmode 400kHz I2C pin, and requires a 4.7kΩ pull-up
resistor. Please refer to “Serial Port Operation” for more
details.
SW
The switching pin connects directly to one end of the
inductor and provides the switching current during
switching cycles. The other end of the inductor is
connected to the load, output capacitor, and the FB pin.
Due to the high speed switching on this pin, the switch
node should be routed away from sensitive nodes.
IRQb
The IRQb (open drain) pin provides an interrupt for when
either the UVLO or TSD faults are asserted. When
enabled through I2C, the IRQb pin will assert together
with the corresponding fault condition. Please refer to
the “Interrupt Operation” for more details.
FB
The feedback pin provides the control path to control the
output. A recommended 4.7µF bypass capacitor should
be connected in shunt with the DC-DC output. It is good
practice to connect the output bypass capacitor to the
DGND and FB should be routed to the top of COUT.
DGND
Power ground (DGND) is the ground path for the DC-DC
MOSFET drive current. The current loop for the Power
ground should be as small as possible and separate
from the Analog ground (AGND) loop. Refer to the layout
consideration for more details.
AGND
Analog ground (AGND) is the ground path for the biasing
and control circuitry. The current loop for the Analog
ground should be separate from the Power ground
(AGND) loop. Refer to the layout consideration for more
details.
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MIC2826
The MIC2826 was designed for use with an inductance
range from 0.47µH to 4.7µH. Typically, a 1µH inductor is
recommended for a balance of transient response,
efficiency and output ripple. For faster transient
response a 0.47µH inductor may be used. For lower
output ripple, a 4.7µH is recommended.
Proper selection should ensure the inductor can handle
the maximum average and peak currents required by the
load. Maximum current ratings of the inductor are
generally given in two methods; permissible DC current
and saturation current. Permissible DC current can be
rated either for a 40°C temperature rise or a 10% to 20%
loss in inductance. Ensure the inductor selected can
handle the maximum operating current. When saturation
current is specified, make sure that there is enough
margin that the peak current will not saturate the
inductor. Peak current can be calculated as follows:
Application Information
The Micrel MIC2826 is a four output, programmable
Power Management IC, optimized for high efficiency
power support. The device integrates a single 500mA
PWM/PFM synchronous buck (step-down) regulator with
three Low Dropout Regulators and an I²C interface that
provides programmable Dynamic Voltage Scaling (DVS),
Power Sequencing, and individual output Enable/Disable
controls allowing the user to optimally control all four
outputs.
Input Capacitors
A 4.7µF ceramic capacitor is recommended on the DVIN
pin for bypassing. X5R or X7R dielectrics are
recommended for the input capacitor. Y5V dielectrics
lose most of their capacitance over temperature and are
therefore not recommended. Also, tantalum and
electrolytic capacitors alone are not recommended
because of their reduced RMS current handling,
reliability, and ESR increases.
An additional 0.1µF is recommended close to the DVIN
and DGND pins for high frequency filtering. Smaller case
size capacitors are recommended due to their lower
ESR and ESL.
Minimum 1.0µF ceramic capacitors are recommended
on the LDO1IN and LDO23IN pins for bypassing.
Please refer to layout recommendations for proper
layout of the input capacitors.
⎡
⎛ 1 − VOUT /VIN ⎞⎤
IPEAK = ⎢IOUT + VOUT ⎜
⎟⎥
⎝ 2 × f × L ⎠⎦
⎣
As shown by the previous calculation, the peak inductor
current is inversely proportional to the switching
frequency and the inductance; the lower the switching
frequency or the inductance the higher the peak current.
As input voltage increases, the peak current also
increases.
The size of the inductor depends on the requirements of
the application. Refer to the Application Circuit and Bill of
Material for details.
DC resistance (DCR) is also important. While DCR is
inversely proportional to size, DCR can represent a
significant efficiency loss. Refer to the Efficiency
Considerations.
Output Capacitors
The MIC2826 is designed for a 2.2µF or greater ceramic
output capacitor for the DC-DC converter and 1.0µF for
the LDO regulators. Increasing the output capacitance
will lower output ripple and improve load transient
response but could increase solution size or cost. A low
equivalent series resistance (ESR) ceramic output
capacitor such as the TDK C1608X5R0J475K, size
0603, 4.7µF ceramic capacitor is recommended based
upon performance, size and cost. X5R or X7R dielectrics
are recommended for the output capacitor. Y5V
dielectrics lose most of their capacitance over
temperature and are therefore not recommended.
In addition to a 4.7µF, a small 0.1µF is recommended
close to the load for high frequency filtering. Smaller
case size capacitors are recommended due to their
lower equivalent series ESR and ESL.
Efficiency Considerations
Efficiency is defined as the amount of useful output
power, divided by the amount of power supplied.
⎛V
×I
Efficiency % = ⎜⎜ OUT OUT
V
IN × IIN
⎝
Maintaining high efficiency serves two purposes. It
reduces power dissipation in the power supply, reducing
the need for heat sinks and thermal design
considerations and it reduces consumption of current for
battery powered applications. Reduced current draw
from a battery increases the devices operating time and
is critical in hand held devices.
There are two types of losses in switching converters;
DC losses and switching losses. DC losses are simply
the power dissipation of I2R. Power is dissipated in the
high side switch during the on cycle. Power loss is equal
to the high side MOSFET RDSON multiplied by the Switch
Current squared. During the off cycle, the low side Nchannel MOSFET conducts, also dissipating power.
Device operating current also reduces efficiency. The
Inductor
Inductor selection will be determined by the following
(not necessarily in the order of importance);
•
Inductance
•
Rated current value
•
Size requirements
•
DC resistance (DCR)
July 2009
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MIC2826
product of the quiescent (operating) current and the
supply voltage is another DC loss. The current required
driving the gates on and off at a constant 4MHz
frequency and the switching transitions make up the
switching losses.
PMOS on and keeps it on for the duration of the
minimum-on-time. This increases the output voltage. If
the output voltage is over the regulation threshold, then
the error comparator turns the PMOS off for a minimumoff-time until the output drops below the threshold. The
NMOS acts as an ideal rectifier that conducts when the
PMOS is off. Using a NMOS switch instead of a diode
allows for lower voltage drop across the switching device
when it is on. The asynchronous switching combination
between the PMOS and the NMOS allows the control
loop to work in discontinuous mode for light load
operations. In discontinuous mode, the MIC2826 works
in pulse frequency modulation (PFM) to regulate the
output. As the output current increases, the off-time
decreases, thus providing more energy to the output.
This switching scheme improves the efficiency of
MIC2826 during light load currents by only switching
when it is needed. As the load current increases, the
MIC2826 goes into continuous conduction mode (CCM)
and switches at a frequency centered at 4MHz. The
equation to calculate the load when the MIC2826 goes
into continuous conduction mode may be approximated
by the following formula:
Efficiency VOUT=1.8V
100
VIN=3.6V
90
EFFICIENCY (%)
80
70
VIN=2.7V
60
VIN=4.2V
50
40
30
20
10
0
1
10
100
LOAD CURRENT (mA)
1000
The Figure above shows an efficiency curve. From no
load to 100mA, efficiency losses are dominated by
quiescent current losses, gate drive and transition
losses. By using the HyperLight Load™ mode the
MIC2826 is able to maintain high efficiency at low output
currents.
Over 100mA, efficiency loss is dominated by MOSFET
RDSON and inductor losses. Higher input supply voltages
will increase the Gate-to-Source threshold on the
internal MOSFETs, thereby reducing the internal RDSON.
This improves efficiency by reducing DC losses in the
device. All but the inductor losses are inherent to the
device. In which case, inductor selection becomes
increasingly critical in efficiency calculations. As the
inductors are reduced in size, the DC resistance (DCR)
can become quite significant. The DCR losses can be
calculated as follows:
DCR Loss = IOUT2 × DCR
From that, the loss in efficiency due to inductor
resistance can be calculated as follows:
⎛ (V − VOUT ) × D ⎞
ILOAD > ⎜ IN
⎟
2L × f
⎝
⎠
As shown in the previous equation, the load at which
MIC2826 transitions from HyperLight Load™ mode to
PWM mode is a function of the input voltage (VIN), output
voltage (VOUT), duty cycle (D), inductance (L) and
frequency (f). This is illustrated in the graph below. Since
the inductance range of MIC2826 is from 0.47µH to
4.7µH, the device may then be tailored to enter
HyperLight Load™ mode or PWM mode at a specific
load current by selecting the appropriate inductance. For
example, in the graph below, when the inductance is
4.7µH the MIC2826 will transition into PWM mode at a
load of approximately 5mA. Under the same condition,
when the inductance is 1µH, the MIC2826 will transition
into PWM mode at approximately 70mA.
Switching Frequency
v s. Load Current
⎡ ⎛
⎞⎤
VOUT × IOUT
⎟⎟⎥ × 100
Efficiency Loss = ⎢1 − ⎜⎜
⎣⎢ ⎝ VOUT × IOUT + L_PD ⎠⎦⎥
10
L=4.7µH
SW FREQUENCY (M Hz)
Efficiency loss due to DCR is minimal at light loads and
gains significance as the load is increased. Inductor
selection becomes a trade-off between efficiency and
size in this case.
HyperLight Load Mode™
The MIC2826 uses a minimum on and off time
proprietary control loop (patented by Micrel). When the
output voltage falls below the regulation threshold, the
error comparator begins a switching cycle that turns the
July 2009
1
L=2.2µH
L=1µH
0.1
0.01
1
24
10
100
LO AD CURRENT (mA)
1000
M9999-071609-A
Micrel, Inc.
MIC2826
Recommended Schematic
Bill of Materials
Item
Part Number
Manufacturer
(1)
Description
C1, C2, C3,
C4, C5
GRM155R61A105KE15D
Murata
Capacitor, 1µF, 10V, X5R, 0402 size
C1005X5R0J105KT
TDK(2)
Capacitor, 1µF, 10V, X5R, 0402 size
C6, C7
GRM188R60J475K
Murata(1)
C1608X5R0J475M
R1, R4
R2, R3
JP1
L1
5
Capacitor, 4.7µF, 6.3V, X5R, 0603 size
2
Capacitor, 4.7µF, 6.3V, X5R, 0603 size
CRCW040210K0FKEA
Vishay(3)
Resistor, 10kΩ, 1%, 1/16W, 0402 size
2
CRCW04024K70FKEA
(3)
Resistor, 4.7kΩ, 1%, 1/16W, 0402 size
2
(4)
Connector, 2.54mm (0.1”) Pitch PCB Connector, 4 circuits
1
(1))
Inductor, 1.0µH, 0.8A, 2.0 x 1.25 x 0.5mm
0022152046
LQM21PN1R0MC0
MLP2520S1R0L
U1
TDK
(2)
Qty.
Vishay
Molex
Murata
TDK(2)
Inductor, 1.0µH, 1.5A, 2.5 x 2.0 x 1.0mm
(5
XPL2010-102ML
Coilcraft
CIG21W1R0MNE
Samsung
MIC2826-xxYMT
(6)
Micrel, Inc.(7)
1
Inductor, 1.0µH, 1.1A, 2.0 x 1.9 x 1.0mm
Inductor, 1.0µH, 1.05A, 2.0 x 1.25 x 1.0mm
Quad Output PMIC with HyperLight Load™ DC-DC,
Three LDOs, and I2C Control
1
Notes:
1. Murata Tel: www.murata.com.
2. TDK: www.tdk.com.
3. Vishay Tel: www.vishay.com.
4. Molex.: www.molex.com.
5. Coilcraft: www.coilcraft.com.
6. Samsung: www.sem.samsung.com.
7. Micrel, Inc.: www.micrel.com.
July 2009
25
M9999-071609-A
Micrel, Inc.
MIC2826
Recommended Layout
Top Layout
Bottom Layout
July 2009
26
M9999-071609-A
Micrel, Inc.
MIC2826
Package Information
14-Pin 2.5mm x 2.5mm Thin MLF® (MT)
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.
© 2009 Micrel, Incorporated.
July 2009
27
M9999-071609-A