MICREL MIC5166YML

MIC5166
3A High-Speed Low VIN DDR Terminator
General Description
Features
The MIC5166 is a 3A, high-speed, linear, low VIN, double
data rate (DDR), memory terminator power supply. The
part is small and requires small output capacitors making it
a tiny overall solution. This allows it to be conveniently
placed close to the DDR memory, minimizing circuit board
layout inductance which may cause excessive voltage
ripple at the DDR memory.
The MIC5166 contains a precision voltage divider network
in order to take in the VDDQ voltage as a reference voltage
and conveniently output the terminator voltage (VTT) at one
half of the VDDQ input voltage.
The MIC5166 is capable of sinking and sourcing up to 3A.
It is stable with only two 10µF ceramic output capacitors.
The part is available in a small 3mm × 3mm MLF®
thermally-enhanced package.
The MIC5166 has a high-side NMOS output stage offering
very-low output impedance, and very-high bandwidth. The
NMOS output stage offers a unique ability to respond very
quickly to sudden load changes such as is required for
DDR memory termination power supply applications.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
• Operating voltage range:
• VDDQ Supply: 0.9V to 3.6V
• Bias Supply: 2.5V to 5.5V
• High bandwidth – very fast transient response
• Stable with two 10µF ceramic output capacitors
• Two 10µF output capacitors used in most applications
• High output voltage accuracy:
• 0.015% line regulation
• 1.5% load regulation
• Logic level enable input
• Power Good (PG)
• Thermally-enhanced 3mm × 3mm MLF®
• Junction temperature range –40°C to +125°C
Applications
•
•
•
•
•
Desktop computers
Notebook computers
Datacom systems
Servers
Video cards
_________________________________________________________________________________________________________________________
Typical Application
Ramp Control 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
June 2012
M9999-060612-A
Micrel, Inc.
MIC5166
Ordering Information
Part Number
MIC5166YML
Output Voltage
Junction Temperature Range(1)
½VDDQ
Package
10-Pin 3mm × 3mm MLF
–40°C to +125°C
Lead Finish
®
Pb-Free
Note:
1.
®
MLF is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free..
Pin Configuration
10-Pin 3mm × 3mm MLF® (ML)
Pin Description
Pin Number
Pin Name
Description
1
VREF
Reference Voltage. This output provides an output of the internal reference voltage VDDQ/2. The VREF
output is used to provide the reference voltage for the memory chip. Connect a 1.0µF capacitor to
ground at this pin. This pin can sink and source 10mA.
2
BIAS
BIAS Supply Voltage. The BIAS supply is the power MOSFET gate drive supply voltage and the
supply bus for the IC. The BIAS voltage must be greater than (VTT + 2.2V). A 1.0µF ceramic capacitor
from the BIAS pin to PGND must be placed next to the IC.
3
AGND
Analog Ground. Internal signal ground for all low-power circuits.
4
VDDQ
Input Supply. VDDQ is connected to an internal precision divider which provides the VREF. Connect a
4.7µF capacitor to ground at this pin.
5
PG
Power Good. This is an open drain output that indicates when the output voltage is within ±10% of the
reference voltage. The PG flag is asserted typically with 65µs delay when the enable is set low or
when the output goes outside ±10% the window threshold.
6
SNS
Feedback. Input to the error amplifier.
Enable. Logic level control of the output. Logic HIGH enables the MIC5166 and a logic LOW shuts
down the MIC5166. In the off state, supply current of the device is greatly reduced (typically 0.2µA).
The EN pin should not be left open.
Power Ground. Internal ground connection to the source of the internal, low-side drive, N-channel
MOSFET.
7
EN
8
PGND
9
VTT
Power Output. This is the connection to the source of the internal high-side N-channel MOSFET and
drain of the low-side N-channel MOSFET. This is a high-frequency, high-power connection, therefore
two 10µF output capacitors must be placed as close to the IC as possible.
10
VIN
High-Side N-Channel MOSFET Drain Connection. The VIN operating voltage range is from 0.9V to
3.6V. An input capacitor between the VIN pin and the PGND is required as close to the chip as
possible.
EP
ePad
June 2012
Exposed Pad. Must be connected to a GND plane for best thermal performance.
2
M9999-060612-A
Micrel, Inc.
MIC5166
Absolute Maximum Ratings(1)
Operating Ratings(3)
VBIAS .................................................................. –0.3V to 6V
VIN ................................................................. –0.3V to VBIAS
VDDQ ................................................................... –0.3V to VIN
VTT ................................................................... –0.3V to VIN
VEN ................................................................. –0.3V to VBIAS
VPG ................................................................. –0.3V to VBIAS
PGND to AGND ............................................. –0.3V to 0.3V
Junction Temperature ................................................ 150°C
Storage Temperature Range ....................–65°C to +150°C
Lead Temperature (soldering, 10s)............................ 260°C
Continuous Power Dissipation (TA = 25°C)
(De-rated 16.4mW/°C above 25°C) .....................1.64W
Continuous Power Dissipation (TA = 85°C) .............656mW
(2)
ESD ....……………………………………..........2kV(HBM)
Supply Voltage (VBIAS)...................................... 2.5V to 5.5V
(4)
Supply Voltage (VIN)......................................0.9V to 3.6V
(5)
Supply Voltage (VDDQ) .................................... 0.9V to VIN
Power Good Voltage (VPG).................................. 0V to VBIAS
Enable Input (VEN) ............................................... 0V to VBIAS
Junction Temperature (TJ) ..................–40°C ≤ TJ ≤ +125°C
Package Thermal Resistance
3mm x 3mm MLF®-10 (θJC).............................28.7°C/W
3mm x 3mm MLF®-10 (θJA).............................60.7°C/W
Electrical Characteristics(6)
VIN = 1.5V, VBIAS = 3.3V, VDDQ = 1.5V, TA = 25°C, unless noted. Bold values indicate –40°C ≤ TJ ≤ +125°C.
Parameter
Condition
Min.
VIN Rising
0.625
Typ.
Max.
Units
3.6
V
0.9
V
Power Input Supply
0.9
Input Voltage Range (VIN)
Undervoltage Lockout Trip Level
UVLO Hysteresis
0.8
150
mV
Quiescent Supply Current (IIN)
IOUT = 0A
0.1
10
µA
Shutdown Current (IIN)
VEN = 0V
0.1
5
µA
5.5
V
2.23
2.33
V
Bias Supply
2.5
Bias Voltage Range (VBIAS)
Undervoltage Lockout Trip Level
1.9
VBIAS Rising
UVLO Hysteresis
Quiescent Supply Current (IBIAS)
Shutdown Current (IBIAS)
70
mV
IOUT = 1mA
1.6
3
IOUT = 1A
1.6
3
VEN = 0V
0.1
5
µA
40
mV
1.5
2.1
mA
VTT Output
VTT Accuracy
Load Regulation
Line Regulation
June 2012
Variation from VREF, IOUT = -3A to 3A
−40
VSNS =0.75V, IOUT = 10mA to +3A
VSNS =0.75V, IOUT = -10mA to -3A
−1.8
VIN = 1.5V to 3.6V, VBIAS = 5.5V, IOUT = 100mA
−0.05
0.005
0.05
VIN = 1.5V, VBIAS = 2.5V to 5.5V, IOUT = 100mA
−0.1
0.015
0.17
3
−1.4
%
%/V
M9999-060612-A
Micrel, Inc.
MIC5166
Electrical Characteristics(6) (Continued)
VIN = 1.5V, VBIAS = 3.3V, VDDQ = 1.5V, TA = 25°C, unless noted. Bold values indicate –40°C ≤ TJ ≤ +125°C.
Parameter
Condition
Min.
Typ.
Max.
Units
1
%
VREF Output
VREF Voltage Accuracy
Variation from (VDDQ/2), IREF = -10mA to 10mA
−1
Bias Supply Dropout Voltage
Dropout Voltage (VBIAS – VTT)
IOUT = 100mA
1.15
V
Dropout Voltage (VBIAS – VTT)
IOUT = 500mA
1.25
V
Dropout Voltage (VBIAS – VTT)
IOUT = 3.0A
1.65
2.2
V
Enable Control
EN Logic High Level
EN Logic Low Level
EN Current
Start-Up Time
1.2
Logic High
V
0.2
Logic Low
VEN = 0.2V
1.0
VEN = 1.2V
6.0
From EN pin going high to VTT 90% of VREF
55
V
µA
µs
Short-Current Protection
Sourcing Current Limit
VIN = 2.7V, VTT = 0V
3.1
4.9
7.8
A
Sinking Current Limit
VIN = 2.7V, VTT = VIN
−3.1
−4.9
−7.8
A
Internal FETs
Top-MOSFET RDS(ON)
Source, IOUT = 3A (VTT to PGND)
130
190
mΩ
Bottom-MOSFET RDS(ON)
Sink, IOUT = -3A (VIN to VTT)
130
190
mΩ
≤110
%
Power Good (PG)
PG Window
≥90
Threshold % of VTT from VREF
Hysteresis
PG Output Low Voltage
IPG = 4mA (sinking)
PG Leakage Current
VPG = 5.5V, VSNS = VREF
2
%
430
mV
1.0
μA
Thermal Protection
Over-Temperature Shutdown
TJ Rising
Over-Temperature Shutdown
Hysteresis
150
°C
10
°C
Notes:
1.
Exceeding the absolute maximum rating may damage the device.
2.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
3.
The device is not guaranteed to function outside its operating rating.
4.
If VBIAS ≤ 3.6V, then VIN(MAX) = VBIAS.
5.
If VBIAS ≤ 4V, then VDDQ(MAX) = 2 × (VBIAS − 2.2V). If VBIAS > 4V, then VDDQ(MAX) = 3.6V.
6.
Specification for packaged product only.
June 2012
4
M9999-060612-A
Micrel, Inc.
MIC5166
Typical Characteristics
VIN Operating Supply Current
vs. Input Voltage
0.20
0.15
0.10
VDDQ = 1.2V
VBIAS = 5V
0.05
VTT = 0.6V
IOUT = 0A
0.52
0.16
0.12
0.08
1.2
1.6
2.0
2.4
2.8
3.2
1.2
1.6
2.0
2.4
2.8
3.2
3.6
0.8
1.2
1.6
INPUT VOLTAGE (V)
2.0
1.5
VIN = 1.5V
VTT = 0.3V
2.4
2.8
0.54
VDDQ = 0.6V
0.52
VEN = 0V
0.180
0.120
0.50
0.48
VIN = 1.5V
0.060
VDDQ = 0.6V
0.46
IOUT = 0A
VEN = VBIAS
0.44
0.000
0.0
3.0
3.5
4.0
4.5
2.5
5.0
3.5
4.0
4.5
2.5
5.0
1.000
VTT = 0.6V
IOUT = 0A
0.800
0.700
FALLING
0.600
1.8
2.7
INPUT VOLTAGE (V)
June 2012
3.6
5.0
VTT RISING
8.0
6.0
4.0
VDDQ = 1.2V
VBIAS = 5.5V
2.0
VTT = 0.6V
105%
VTT FALLING
100%
95%
VTT FALLING
VTT RISING
90%
VDDQ = 1.2V
85%
VBIAS = 5V
IOUT = 0A
80%
0.0
0.9
4.5
110%
VEN = VIN
0.500
4.0
115%
VPG WINDOW/VTT (%)
ENABLE PIN CURRENT (µA)
VBIAS = 5V
3.5
Power Good Window/VTT Ratio
vs. Input Voltage
10.0
VDDQ = 1.2V
RISING
3.0
BIAS VOLTAGE (V)
Enable Pin Current
vs. Input Voltage
Enable Threshold
vs. Input Voltage
ENABLE THRESHOLD (V)
3.0
BIAS VOLTAGE (V)
BIAS VOLTAGE (V)
0.900
3.6
VREF/VDDQ Tracking Ratio
vs. BIAS Voltage
VEN = VBIAS
2.5
3.2
VIN = 1.5V
VREF/VDDQ
2.5
2.0
VDDQ VOLTAGE (V)
VBIAS Shutdown Current
vs. BIAS Voltage
SHUTDOWN CURRENT (µA)
SUPPLY CURRENT (mA)
VEN = VBIAS
0.240
0.5
IOUT = 0A
0.44
0.8
3.6
3.0
IOUT = 0A
VTT = 0.6V
VEN = 0V
VBIAS Operating Supply Current
vs. BIAS Voltage
VDDQ = 0.6V
VDDQ = 1.2V
0.46
VBIAS = 5V
INPUT VOLTAGE (V)
1.0
0.48
VBIAS = 5V
0.00
0.8
0.50
VDDQ = 1.2V
0.04
VEN = VBIAS
0.00
VREF/VDDQ Tracking Ratio
vs. VDDQ Voltage
0.54
VREF/VDDQ
SHUTDOWN CURRENT (µA)
SUPPLY CURRENT (µA)
0.20
VIN Shutdown Current
vs. Input Voltage
VEN = V BIAS
75%
0.9
1.8
2.7
INPUT VOLTAGE (V)
5
3.6
0.9
1.8
2.7
INPUT VOLTAGE (V)
M9999-060612-A
3.6
Micrel, Inc.
MIC5166
Typical Characteristics (Continued)
Top MOSFET On-Resistance
vs. Input Voltage
Bottom MOSFET On-Resistance
vs. Input Voltage
150
Current Limit
vs. Input Voltage
150
5.0
130
VIN = 1.5V
VDDQ = 1.2V
120
VBIAS = 5V
VSNS = OPEN
110
ISINK = 3A
140
130
VIN = 1.5V
120
VDDQ = 1.2V
VBIAS = 5V
VTT = 0.6V
110
1.0
1.3
1.6
1.9
2.2
2.5
VEN = VBIAS
2.8
1.0
V DDQ = 1.2V
V BIAS = 5.0V
-2.0
1.3
1.6
1.9
2.2
2.5
1.2
2.8
1.6
IOUT = 0A to 3A
0.0000
0.5950
V BIAS = 5V
VEN = VBIAS
1.8
2.1
2.4
2.7
3.0
3.3
-0.0150
-3.00
VDDQ=1.2V
0.5900
V TT = 0.6V
-2.00
INPUT VOLTAGE (V)
VTT = 0.6V
VEN = V BIAS
-1.00
0.00
1.00
2.00
0.5850
-3.00
3.00
VREF/VDDQ vs. I_Load
VIN = 1.5V
SUPPLY CURRENT (uA)
V DDQ=1.2V
VTT/VDDQ
0.5050
0.5000
V IN = 0.6V
V EN = VBIAS
0.5000
VBIAS = 5V
VIN = 1.5V
0.4950
VDDQ=1.2V
1.00
0.4
V IN = 1.5V
0.5050
0.00
VIN Operating Supply Current
vs. Temperature
VTT/VDDQ vs. I_Load
V BIAS = 5V
VREF/VDDQ
-1.00
I_LOAD (A)
0.5100
0.4950
-2.00
I_LOAD (A)
0.5100
3.00
VIN = 1.5V
V DDQ=1.2V
3.6
2.00
VBIAS = 5V
V EN = VBIAS
1.5
3.6
0.6000
V IN = 1.5V
-0.0100
1.2
3.2
0.6050
-0.0050
-2.0%
2.8
0.0050
VTT (V)
VREF-VTT (V)
VTT = 0.6V
2.4
0.6100
0.0100
VDDQ = 1.2V
0.9
2.0
VTT vs. I_Load
1.0%
VBIAS = 5.0V
V EN = VBIAS
INPUT VOLTAGE (V)
0.0150
SOURCING
V TT = 0.6V
SINKING
VREF-VTT vs. I_Load
2.0%
SINKING
0.0
-1.0
INPUT VOLTAGE (V)
Load Regulation
vs. Input Voltage
-1.0%
1.0
-5.0
0.7
INPUT VOLTAGE (V)
0.0%
2.0
-4.0
100
0.7
SOURCING
3.0
-3.0
ISINK = -3A
VEN = VBIAS
100
TOTAL REGULATION (%)
CURRENT LIMIT (A)
ON-RESISTANCE (mΩ)
ON-RESISTANCE (mΩ)
4.0
140
VBIAS = 5V
VDDQ = 1.2V
0.3
VTT = 0.6V
IOUT = 0A
VEN = VBIAS
0.2
0.1
VTT = 0.6V
VEN = VBIAS
0.4900
-3.00
-2.00
-1.00
0.00
1.00
I_LOAD (A)
June 2012
2.00
3.00
0.4900
-3.00
0.0
-2.00
-1.00
0.00
1.00
I_LOAD (A)
6
2.00
3.00
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
M9999-060612-A
Micrel, Inc.
MIC5166
Typical Characteristics (Continued)
1.0000
1.0
VIN = 1.5V
UVLO THRESHOLD (V)
VBIAS =5V
0.4
Enable Threshold
vs. Temperature
VDDQ = 1.2V
VEN = 0V
0.3
0.2
0.1
VV
5.0V
BIAS
BIAS==5.0V
= 1.2V
VVDDQ
DDQ = 1.2V
= 0.6V
VVTT
TT = 0.6V
IOUT = 0A
= 0A
IOUT
0.9
RISING
ENABLE THRESHOLD (V)
0.5
SHUTDOWN CURRENT (uA)
VIN UVLO Threshold
vs. Temperature
VIN Shutdown Current
vs. Temperature
VEN = VBIAS
0.8
0.7
FALLING
0.6
0.0
-50
-25
0
25
50
75
100
-25
0
25
50
75
100
TEMPERATURE (°C)
TEMPERATURE (°C)
Sourcing Load Regulation
vs. Temperature
Sinking Load Regulation
vs. Temperature
1.0%
0.8000
RISING
0.7000
VIN = 1.5V
VBIAS = 5V
0.6000
FALLING
VDDQ = 1.2V
VTT = 0.6V
0.5000
-50
125
0.9000
125
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
VREF/VDDQ Tracking Ratio
vs. Temperature
0.601
1.0%
0.0%
-0.5%
VIN = 1.5V
VBIAS = 5V
-1.0%
VDDQ = 1.2V
VTT = 0.6V
-1.5%
IOUT = 0A to 3A
VBIAS = 5.5V
0.5%
VDDQ = 1.2V
0.600
VTT = 0.6V
0.0%
VREF/VDDQ
LOAD REGULATION (%)
LOAD REGULATION (%)
VIN = 1.5V
0.5%
IOUT = 0A to -3A
VEN = VBIAS
-0.5%
-1.0%
25
50
75
0.597
100
-50
-50
125
-25
0
25
50
75
100
5.5
CURRENT LIMIT (A)
OUTPUT VOLTAGE (V)
0.6000
VIN = 1.5V
VBIAS = 5V
VDDQ = 1.2V
VTT = 0.6V
VBIAS = 5V
5.3
VDDQ = 1.2V
VTT = 0.6V
SOURCING
VEN = VBIAS
5.0
SINKING
4.8
IOUT = 0A
VEN = VBIAS
-50
-25
0
25
50
75
TEMPERATURE (°C)
June 2012
100
125
50
75
100
125
100
125
VIN = 1.5V
VBIAS = 5V
2
VDDQ = 1.2V
VEN = VIN
1
0
4.5
0.5970
25
Enable Pin Current
vs. Temperature
VIN = 1.5V
0.5980
0
TEMPERATURE (°C)
Current Limit
vs. Temperature
Output Voltage
vs. Temperature
0.5990
-25
125
TEMPERATURE (°C)
TEMPERATURE (°C)
0.6010
IOUT = 0A
V EN = V BIAS
-1.5%
ENABLE PIN CURRENT (µA)
0
V TT = 0.6V
0.598
-2.0%
-25
V BIAS = 5V
V DDQ = 1.2V
VEN = VBIAS
-2.0%
-50
V IN = 1.5V
0.599
-50
-25
0
25
50
75
TEMPERATURE (°C)
7
100
125
-50
-25
0
25
50
75
TEMPERATURE (°C)
M9999-060612-A
Micrel, Inc.
MIC5166
Typical Characteristics (Continued)
Top MOSFET On-Resistance
vs. Temperature
Bottom MOSFET On-Resistance
vs. Temperature
175
160
VIN = 1.5V
ON-RESISTANCE (mΩ)
ON-RESISTANCE (mΩ)
VIN = 1.5V
VBIAS = 5V
160
VDDQ = 1.2V
VTT = 0.6V
145
ISOURCE = +3A
VEN = VBIAS
130
115
VBIAS = 5V
150
VDDQ = 1.2V
VTT = 0.6V
140
ISINK = -3A
VEN = VBIAS
130
120
110
100
-50
-25
0
25
50
75
TEMPERATURE (°C)
June 2012
100
125
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
8
M9999-060612-A
Micrel, Inc.
MIC5166
Functional Characteristics
June 2012
9
M9999-060612-A
Micrel, Inc.
MIC5166
Functional Characteristics (Continued)
June 2012
10
M9999-060612-A
Micrel, Inc.
MIC5166
Functional Diagram
Figure 1. MIC5166 Block Diagram
June 2012
11
M9999-060612-A
Micrel, Inc.
MIC5166
The memory bits are not usually all at a logic high or
logic low at the same time so the VTT supply is usually
not sinking or sourcing −3A or +3A current continuously.
Application Information
DDR memory requires two power supplies, one for the
memory chip, referred to as VDDQ and the other for a
termination supply VTT, which is one-half VDDQ. With
memory speeds in excess of 300MHz, the memory
system bus must be treated as a transmission line. To
maintain good signal integrity the memory bus must be
terminated to minimize signal reflections. Figure 2 shows
the simplified termination circuit. Each control, address
and data lines have these termination resistors RS and
RT connected to them.
VTT
VTT is regulated to VREF. Due to high-speed signaling, the
load current seen by VTT is constantly changing. To
maintain adequate transient response, two 10µF ceramic
capacitors are required. The proper placement of
ceramic capacitors is important to reduce both ESR and
ESL such that high-current and high-speed transients do
not exceed the dynamic voltage tolerance requirement of
VTT. The ceramic capacitors provide current during the
fast edges of the bus transition. Using several smaller
ceramic capacitors distributed near the termination
resistors is important to reduce the effects of PCB trace
inductance.
VDDQ
The VDDQ input on the MIC5166 is used to create the
internal reference voltage for VTT. The reference voltage
is generated from an internal resistor divider network of
two 500kΩ resistors, generating a reference voltage VREF
that is VDDQ/2. The VDDQ input should be Kelvin
connected as close as possible to the memory supply
voltage.
Since the reference is simply VDDQ/2, any perturbations
on VDDQ will also appear at half the amplitude on the
reference. For this reason a 4.7µF ceramic capacitor is
required on the VDDQ supply. This will aid performance
by improving the source impedance over a wide
frequency range.
Sense
The sense (SNS) pin provides the path for the error
amplifier to regulate VTT. The SNS input must also be
Kelvin connected to the VTT bypass capacitors. If the
SNS input is connected to close to the MIC5166, the IR
drop of the PCB trace can cause the VTT voltage at the
memory chip to be too low. Placing the MIC5166 as
close as possible to the DDR memory will improve the
load regulation performance.
Figure 2. DDR Memory Termination Circuit
Bus termination provides a means to increase signaling
speed while maintaining good signal integrity. The
termination network consists of a series resistor (RS) and
a terminating resistor (RT). Values of RS range between
10Ω to 30Ω with a typical of 22Ω, while RT ranges from
22Ω to 28Ω with a typical value of 25Ω. VREF must
maintain half VDDQ with a ±1% tolerance, while VTT will
dynamically sink and source current to maintain a
termination voltage of ±40mV from the VREF line under all
conditions. This method of bus termination reduces
common-mode noise, settling time, voltage swings,
EMI/RFI and improves slew rates.
VDDQ powers all the memory ICs, memory drivers and
receivers for all the memory bits in the DDR memory
system. The MIC5166 regulates VTT to VDDQ/2 during
sourcing or sinking current.
June 2012
Enable
The MIC5166 features an active-high enable input (EN)
that allows on-off control of the regulator. The current
through the device reduces to near “zero” when the
device is shutdown, with only <0.2µA of leakage current.
The EN input may be directly tied to VBIAS. The active
high enable pin uses CMOS technology and the enable
pin cannot be left floating; a floating enable pin may
cause an indeterminate state on the output.
12
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Micrel, Inc.
MIC5166
Power Good (PG)
The power-good (PG) output provides an under and over
voltage fault flag for the VTT output. The PG output
remains high as long as VTT is within ±10% range of VREF
and goes low if the output moves beyond this range.
Component Selection
Input Capacitor
A 10µF ceramic input capacitor is all that is required for
most applications if it is close to a bulk capacitance.
The input capacitor must be placed on the same side of
the board and next to the MIC5166 to minimize the
dropout voltage and voltage ringing during transient and
short circuit conditions. It is also recommended that each
capacitor to be connected to the PGND directly, not
through vias. X7R or X5R dielectric 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% and 60% respectively over their operating
temperature ranges. To use a ceramic chip capacitor
with Y5V dielectric, the value must be much higher than
an X7R ceramic.
Figure 3. Power Good Threshold
Output Capacitor
As part of the frequency compensation, the MIC5166
requires two 10µF ceramic output capacitors for best
transient performance. To improve transient response,
any other type of capacitor can be placed in parallel as
long as the two 10µF ceramic output capacitors are
placed next to the MIC5166.
The output capacitor type and placement criteria are the
same as the input capacitor. See the input capacitor
section for a detailed description.
The PG has an open-drain output. A pull-up resistor
must be connected to VIBIAS, VIN or an external source.
The external source voltage must not exceed the
maximum rating of the pin. The PG pin can be
connected to another regulator’s enable pin for
sequencing of the outputs.
VBIAS Requirement
A 1µF ceramic input capacitor is required on VBIAS pin.
To achieve the ultra-fast transient response, the
MIC5166 uses an all N-channel power output stage as
shown in the Functional Diagram. The high-side Nchannel MOSFET requires the VBIAS voltage to be 2.2V
higher than the VTT to be able to fully enhance the highside MOSFET.
Thermal Considerations
The MIC5166 is packaged in the 3mm x 3mm MLF®, a
package that has excellent thermal performance. This
maximizes heat transfer from the junction to the exposed
pad (ePad) which connects to the ground plane. The
size of the ground plane attached to the exposed pad
determines the overall thermal resistance from the
junction to the ambient air surrounding the printed circuit
board.
VIN Requirement
VIN is used to supply the rail voltage for the high-side Nchannel power output stage. It is normally connected to
VDDQ, but it can be connected to a lower voltage to
reduce power dissipation. In this case, the input voltage
must be higher than the VTT voltage to ensure that the
output stage is not operating in dropout.
June 2012
Thermal Design
The most complicated design parameters to consider
are thermal characteristics. Thermal design requires the
following application-specific parameters:
13
•
Maximum ambient temperature (TA)
•
Output current (IOUT)
•
Output voltage (VOUT)
•
Input voltage (VIN)
•
Ground current (IGND)
M9999-060612-A
Micrel, Inc.
MIC5166
There are two suggested methods for measuring the IC
case temperature: a thermocouple or an infrared
thermometer. If a thermocouple is used, it must be
constructed of 36 gauge wire or higher to minimize the
wire heatsinking effect. In addition, the thermocouple tip
must be covered in either thermal grease or thermal glue
to make sure that the thermocouple junction is making
good contact to the case of the IC. This thermocouple
from Omega (5SC-TT-K-36-36) is adequate for most
applications.
To avoid this messy thermocouple grease or glue, an
infrared thermometer is recommended. Most infrared
thermometers’ spot size is too large for an accurate
reading on small form factor ICs. However, an IR
thermometer from Optris has a 1mm spot size, which
makes it ideal for the 3mm x 3mm MLF® package.
First, calculate the power dissipation of the regulator
from these numbers and the device parameters from this
datasheet.
PD = (VIN – VTT) × IOUT + (VBIAS × IGND)
Eq. 1
where the ground current is approximated by using
numbers from the “Electrical Characteristics” or “Typical
Characteristics.”
For example, given an expected maximum ambient
temperature (TA) of 70°C with VIN = 1.2V, VBIAS = 3.3V,
VTT = 0.9V, and IOUT = 3A, first calculate the expected PD
using Equation 1:
PD = (1.2V – 0.9V) × 3A + 3.3V × 0.0016A
= 0.90528W
Eq. 2
Next, determine the junction temperature for the
expected power dissipation above using the thermal
resistance (θJA) of the 10-pin 3mm × 3mm MLF® (YML)
adhering to the following criteria for the PCB design
(1oz. copper and 100mm2 copper area for
the MIC5166):
TJ = (θJA × PD) + TA = (60.7°C/W × 0.90528W) + 70°C
= 124.95°C
Eq. 3
To determine the maximum power dissipation allowed
that would not exceed the IC’s maximum junction
temperature (125°C) when operating at a maximum
ambient temperature of 70°C:
PD(MAX) = (TJ(MAX) – TA)/θJA = (125°C – 70°C)/(60.7°C/W)
= 0.9061W
Eq. 4
Thermal Measurements
It is always wise to measure the IC’s case temperature
to make sure that it is within its operating limits. Although
this might seem like a very elementary task, it is very
easy to get erroneous results. The most common
mistake is to use the standard thermocouple that comes
with the thermal voltage meter. This thermocouple wire
gauge is large, typically 22 gauge, and behaves like a
heatsink, resulting in a lower case measurement.
June 2012
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Micrel, Inc.
MIC5166
Sequencing
The following diagrams illustrate methods for connecting
MIC5166’s to achieve sequencing requirements:
Figure 6. Turn-On Sequence with Soft-Start
(RC = 3.3nF)
June 2012
Figure 7. Turn-On Sequence with No Soft-Start
(RC = Open)
15
M9999-060612-A
Micrel, Inc.
MIC5166
PCB Layout Guidelines
Warning!!! To minimize EMI and output noise, follow
these layout recommendations
PCB Layout is critical to achieve reliable, stable and
efficient performance. A ground plane is required to
control EMI and minimize the inductance in power,
signal and return paths.
The following guidelines should be followed to insure
proper operation of the MIC5166 converter.
Output Capacitor
•
Use a wide trace to connect the output capacitor
ground terminal to the input capacitor ground
terminal.
•
Phase margin will change as the output capacitor
value and ESR changes. Contact the factory if the
output capacitor is different from what is shown in
the BOM.
•
The feedback divider network must be place close to
the IC with the bottom of R2 connected to AGND.
•
The feedback trace should be separate from the
power trace and connected as close as possible to
the output capacitor. Sensing a long high current
load trace can degrade the DC load regulation.
IC
•
The 10µF ceramic capacitor, which is connected to
the VIN pin, must be located right at the IC. The
VDDQ pin is very noise sensitive and placement of
the capacitor is very critical. Use wide traces to
connect to the VDDQ and AGND pins.
•
The signal ground pin (AGND) must be connected
directly to the ground planes. Do not route the
AGND pin to the PGND Pad on the top layer.
•
Place the IC close to the point-of-load (POL).
•
Use wide traces to route the input and output power
lines.
•
Signal and power grounds should be kept separate
and connected at only one location.
Input Capacitor
•
A 10µF X5R or X7R dielectric ceramic capacitor is
recommended on each of the VIN pins for
bypassing.
•
Place the input capacitors on the same side of the
board and as close to the IC as possible.
•
Keep both the VIN pin and PGND connections short.
•
Place several vias to the ground plane close to the
input capacitor ground terminal.
•
Use either X7R or X5R dielectric input capacitors.
Do not use Y5V or Z5U type capacitors.
•
Do not replace the ceramic input capacitor with any
other type of capacitor. Any type of capacitor can be
placed in parallel with the input capacitor.
•
If a Tantalum input capacitor is placed in parallel
with the input capacitor, it must be recommended for
switching regulator applications and the operating
voltage must be derated by 50%.
•
In “Hot-Plug” applications, a Tantalum or Electrolytic
bypass capacitor must be used to limit the overvoltage spike seen on the input supply with power is
suddenly applied.
June 2012
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Micrel, Inc.
MIC5166
Evaluation Board Schematics
June 2012
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M9999-060612-A
Micrel, Inc.
MIC5166
Evaluation Board Schematics (Continued)
June 2012
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M9999-060612-A
Micrel, Inc.
MIC5166
Bill of Materials
Item
C1, C2, C19
Part Number
AVX
C2012X5R0J226K
TDK(2)
C4, C6, C12
C7
C2012X5R0J225K
TDK(2)
C8
C9
C1608X7R1H102K
TDK(2)
C10, C11
C14
C1608C0G1H390J
TDK(2)
C15, C20, C24
C16, C18, C21, C23
C1608C0G1H391J
TDK(2)
C17
June 2012
390pF, 50V, ceramic capacitor, NPO, 0603
1
100pF, 50V, ceramic capacitor, NPO, 0603
1
47µF, 6.3V, ceramic capacitor, X5R,1206
2
100µF, 6.3V, ceramic capacitor, X5R, 1210
1
10µF, 6.3V, ceramic capacitor, X5R, 0603
3
1µF, 6.3V, ceramic capacitor, X5R, 0603
4
4.7µF, 6.3V, ceramic capacitor, X5R, 0603
1
Murata
AVX(3)
C1608C0G1H101J
TDK(2)
(1)
Murata
12066D476MAT2A
AVX(3)
C3216X5R0J476M
TDK(2)
Murata(1)
12106D107MAT2A
AVX(3)
C3225X5R0J107M
TDK(2)
(1)
Murata
06036D106MAT
AVX(3)
FP3-1R0-R
TDK(2)
(1)
Murata
06036D105KAT2A
AVX(3)
C1608X5R0J105K
TDK(2)
(1)
Murata
06036D475KAT2A
AVX(3)
C1608X5R0J475M
TDK(2)
C1608X5R0J475M
1
(1)
06035A101JAT2A
GRM188R60J105KA01D
39pF, 50V, ceramic capacitor, NPO, 0603
Murata
AVX(3)
GRM188R60J106ME47D
3
(1)
06035A391JAT2A
GRM32ER60J107ME20L
1nF, 50V, ceramic capacitor, X7R, 0603
Murata
AVX(3)
GRM31CR60J476ME19L
1
(1)
06035A390JAT2A
GRM1885C1H101JA01D
2.2µF, 6.3V, ceramic capacitor, X5R, 0805
Murata
AVX(3)
GRM188R71H391KA01D
3
(1)
06035C102KAT
GRM1885C1H390JA01D
22µF, 6.3V, ceramic capacitor, X5R, 0805
(3)
AVX
GRM188R71H102KA01D
Qty.
Murata(1)
08056D225KAT2A
GRM21BR60J225KA01L
Description
(3)
08056D226MAT
GRM21BR60J226ME39L
C3
Manufacturer
(1)
Murata
19
M9999-060612-A
Micrel, Inc.
MIC5166
Bill of Materials (Continued)
Item
Part Number
Manufacturer
C5
C22
C13
AVX
C1608X7R1H104K
TDK(2)
EEU-FC1A471
N.U. 0603 ceramic capacitor
1
0.1µF, 50V, ceramic capacitor, X7R, 0603
1
470µF/10V, Elect., 20%, 8x11.5, Radial
1
(1)
Murata
Panasonic(4)
(5)
L1
FP3-1R0-R
Cooper
Q3, Q4
NDS8425
Fairchild(7)
R1A
CRCW0603300RFKEA
Vishay Dale(6)
300Ω, resistor, 1%, 0603
R1B
CRCW06031101FKEA
(6)
Vishay Dale
510Ω, resistor, 1%, 0603
R1C
CRCW0603806RFKEA
Vishay Dale(6)
806Ω, resistor, 1%, 0603
R1D
CRCW06031K10FKEA
Vishay Dale(6)
1.1K, resistor, 1%, 0603
CRCW0603698RFKEA
(6)
698Ω, resistor, 1%, 0603
(6)
R2
Qty.
(3)
06035C104KAT2A
GRM188R71H104KA93D
Description
Vishay Dale
1µH,6.26A Inductor
1
MOSFET, N-CH 20V 7.4A 8-SOIC
2
1
1
R3
CRCW06032002FKEA
Vishay Dale
20K, resistor, 1%, 0603
1
R4
CRCW06034752FKEA
Vishay Dale(6)
47.5K, resistor, 1%, 0603
1
R6, R8, R11,
R17, R21
CRCW06032R20RFKEA
Vishay Dale(6)
2.2Ω, resistor, 1%, 0603
5
R7
CRCW060349R9RFKEA
Vishay Dale(6)
R9
CRCW06031002FKEA
49.9Ω, resistor, 1%, 0603
1
(6)
10K, resistor, 1%, 0603
1
(6)
Vishay Dale
R10, R19
CRCW06031K00FKEA
Vishay Dale
1K, resistor, 1%, 0603
2
R12
CRCW0603000RFKEA
Vishay Dale(6)
0Ω, resistor, 1%, 0603
1
(6)
1Ω, resistor, 1.5W, 1%, 2512
3
(6)
2Ω, resistor, 1.5W, 1%, 2512
1
(6)
R13, R14, R24
R15
CRCW25121R00FKEGHP
CRCW25122R00JNEG
Vishay Dale
Vishay Dale
R16, R18, R20
CRCW06031003FKEA
Vishay Dale
100K, resistor, 1%, 0603
3
R22, R23
LR2512-R50FW
Vishay Dale(6)
0.5Ω, resistor, 1.5W, 1%, 2512
2
RV1
PV36W103C01B00
Pot, 10KΩ, 0.5W, 9.6x5xx10
1
Murata(1)
(9)
U1
MIC22405YML
Micrel
U2
MIC5166YMM
Micrel(9)
U3
SN74AHCT00RGYR
U4
U5
MIC1557YM5
MIC4425
TI(8)
4A, Synchronous Buck Regulator
1
3A High-Speed Low VIN DDR Terminator
1
Quad, 2IN Pos-NAND Gate, 14-pin, QFN
1
Micrel
(9)
5MHz RC Timer Oscillator
1
Micrel
(9)
3A Dual Inverting and Non-Inverting MOSFET Driver
1
Notes:
1. Murata Tel: www.murata.com.
2. TDK: www.tdk.com.
3. AVX: www.avx.com.
4. Panasonic: www.panasonic.com.
5. Cooper: www.cooper.com
6. Vishay Dale: www.vishay.com.
7. Fairchild: www.fairchildsemi.com.
8. TI: www.ti.com
9. Micrel, Inc.: www.micrel.com.
June 2012
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Micrel, Inc.
MIC5166
PCB Layout Recommendations
Top Silk
Copper Layer 1
June 2012
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MIC5166
PCB Layout Recommendations (Continued)
Copper Layer 2
Copper Layer 3
June 2012
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Micrel, Inc.
MIC5166
PCB Layout Recommendations (Continued)
Copper Layer 4
Bottom Silk
June 2012
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Micrel, Inc.
MIC5166
Package Information
10-Pin 3mm × 3mm MLF® (ML)
June 2012
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M9999-060612-A
Micrel, Inc.
MIC5166
Recommended Landing Pattern
10-Pin 3mm × 3mm MLF® Land Pattern
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
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
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.
© 2012 Micrel, Incorporated.
June 2012
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