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OKDx-T/25-W12-xxx-C
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25A Digital PoL DC-DC Converter Series
Typical units
FEATURES
PRODUCT OVERVIEW

Small package: 25.65 x 13.8 x 8.2 mm (1.01 x
0.543 x 0.323 in) SIP: 26.3 x 7.6 x 15.6 mm (1.035
x 0.30 x 0.614 in)
The OKDx-T/25-W12 series are high efﬁciency,
digital point-of-Load (PoL) DC-DC power converters
capable of delivering 25A/82.5W. Available in three
different package formats, through-hole, single-inline, and surface mount, these converters have a
typical efﬁciency of 97.1%. PMBus™ compatibility
allows monitoring and conﬁguration of critical
system-level performance requirements. Apart from

0.6 V - 3.3 V output voltage range

High efﬁciency, typ. 97.1% at 5Vin, 3.3Vout half load

Conﬁguration and Monitoring via PMBus™

Adaptive compensation of PWM control loop & fast
loop transient response
standard PoL performance and safety features like
OVP, OCP, OTP, and UVLO, these digital converters
have advanced features: digital current sharing (full
power, no derating), non-linear transient response,
optimized dead time control, synchronization, and
phase spreading. These converters are ideal for use
in telecommunications, networking, and distributed
power applications.

Synchonization & phase spreading

Current sharing, Voltage Tracking & Voltage
margining

MTBF 20.2 Mh

Non-Linear Response for reduction of decoupling capacitor

Remote control & power good

Output short-circuit, output over voltage, & over
temperature protection

Certiﬁed to UL/IEC 60950-1
Power Management via PMBus™
Applications

Conﬁgurable soft-start/stop

Distributed power architectures

Conﬁgurable output voltage (Vout) and voltage
margins (Margin low and Margin high)

Intermediate bus voltage applications

Conﬁgurable protection limits for OVP, input over
voltage, input under voltage, over current, on/off,
and temperature

Network equipment

Servers and storage applications

Status monitor Vout, Iout, Vin, Temp, Power
good, and On/Off
PART NUMBER STRUCTURE
OKD x - T / 25 - W12 E - xxx - C
Digital Non-isolated PoL
Y = Surface Mount
H = Horizontal Mount Through-Hole
X = SIP
Trimmable Output
Voltage Range
0.6 - 3.3Vdc
RoHS Hazardous
Substance Compliance
C = RoHS-6 (does not claim EU RoHS exemption
7b – lead in solder)
Software Conﬁguration Digits
(001 is positive turn-on logic)
(002 is negative turn-on logic)*
Long pin length (5.5mm)
Maximum Rated Output
Current in Amps
Input Voltage Range
4.5-14Vdc
*Special quantity order is required;
contact Murata Power Solutions for
MOQ and lead times.
PM
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 1 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
ORDERING GUIDE
Model Number
OKDY-T/25-W12-001-C
OKDH-T/25-W12-001-C
OKDX-T/25-W12-001-C
OKDX-T/25-W12E-001-C
Output
0.6-3.3 V, 25 A/ 82.5 W
Absolute Maximum Ratings
Characteristics
TP1, TP2
Operating temperature (see Thermal Consideration section)
TS
Storage temperature
VI
Input voltage (See Operating Information Section for input and output voltage relations)
Logic I/O voltage
CTRL, SA0, SA1, SALERT, SCL, SDA, VSET, SYNC, GCB, PG
Ground voltage differential -S, PREF, GND
Analog pin voltage
VO, +S, VTRK
General and Safety
Safety
Calculated MTBF
Min
-40
-40
-0.3
-0.3
-0.3
-0.3
Conditions
Designed for UL/IEC/EN 60950 1
Telcordia SR-332, Issue 2 Method 1
Stress in excess of Absolute Maximum Ratings may cause permanent
damage. Absolute Maximum Ratings, sometimes referred to as no destruction
limits, are normally tested with one parameter at a time exceeding the limits
in the Electrical Speciﬁcation. If exposed to stress above these limits, function
and performance may degrade in an unspeciﬁed manner.
Conﬁguration File
This product is designed with a digital control circuit. The control circuit uses
a conﬁguration ﬁle which determines the functionality and performance of the
product. The Electrical Speciﬁcation table shows parameter values of func-
Min
Typ
Typ
20.2
Max
125
125
16
6.5
0.3
6.5
Max
Unit
°C
°C
V
V
V
V
Unit
Mhrs
tionality and performance with the default conﬁguration ﬁle, unless otherwise
speciﬁed. The default conﬁguration ﬁle is designed to ﬁt most application
needs with focus on high efﬁciency. If different characteristics are required it
is possible to change the conﬁguration ﬁle to optimize certain performance
characteristics. Note that current sharing operation requires changed conﬁguration ﬁle.
In this Technical speciﬁcation examples are included to show the possibilities with digital control. See Operating Information section for information
about trade offs when optimizing certain key performance characteristics.
VIN
VOUT
CI
CO
GND
+Sense
-Sense
(PGOOD)
(SA1)
SALERT
CTRL
VSET
Controller and digital interface
SYNC
SCL
SDA
SA0
GCB
VTRK
PREF
Fundamental Circuit Diagram
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 2 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Electrical Speciﬁcations, OKDY-T/25-W12-xxx-C and OKDH-T/25-W12-xxx-C
TP1 = -30 to +95°C, VIN = 4.5 to 14 V, VIN > VOUT + 1.0 V
Typical values given at: TP1 = +25 °C, VIN = 12.0 V, max IOUT, unless otherwise speciﬁed under Conditions.
Default conﬁguration ﬁle, 190 10-CDA 102 0206/001.
External CIN = 470 μF/10 mΩ, COUT = 470 μF/10 mΩ. See Operating Information section for selection of capacitor types.
Sense pins are connected to the output pins.
Characteristics
VI
Input voltage rise time
Conditions
monotonic
Output voltage without pin strap
Output voltage adjustment range
Output voltage adjustment including margining
Output voltage set-point resolution
VO
Load regulation; IO = 0 - 100%
VOac
Output ripple & noise
CO = 470 μF (minimum external capacitance). See Note 11
IO
Output current
IS
Static input current at max IO
Ilim
Current limit threshold
Isc
Short circuit current
RMS, hiccup mode, See Note 3
Efﬁciency
max IO
Pd
Power dissipation at max IO
Pli
Input idling power
(no load)
Default conﬁguration: Continues
Conduction Mode, CCM
PCTRL
Input standby power
Turned off with
CTRL-pin
Ci
Internal input capacitance
Max
2.4
Unit
V/ms
3.3
3.63
V
V
V
% Vo
1
%
2
%
±0.025
-1
-2
47
2
2
2
3
2
2
2
3
20
30
40
60
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
See Note 18
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
0.001
Ω
mV
mV
mVp-p
25
1.58
2.43
4.13
7.32
27
50% of max IO
See Note 17
0.60
0.54
Internal resistance +S/-S to VOUT/GND
Line regulation
Typ
1.2
Including line, load, temp.
See Note 14
Current sharing operation
See Note 15
Output voltage accuracy
Min
A
37.5
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
8
6
5
4
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
84.4
89.4
93.1
95.2
79.2
85.7
90.8
93.9
3.93
4.17
4.55
5.34
0.56
0.57
0.67
0.92
Default conﬁguration:
Monitoring enabled,
Precise timing enabled
170
70
A
A
A
%
%
W
W
mW
μF
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 3 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Characteristics
Co
Internal output capacitance
Total external output capacitance
COUT
ESR range of capacitors
(per single capacitor)
Vtr1
ttr1
fs
Load transient peak
voltage deviation
(H to L)
Load step 25-75-25%
of max IO
Default conﬁguration
di/dt = 2 A/μs
CO = 470 μF (minimum external
capacitance) see Note 12
Load transient recovery
time, Note 5
(H to L)
Load step 25-75-25%
of max IO
Default conﬁguration
di/dt = 2 A/μs
CO = 470 μF (minimum external
capacitance) see Note 12
Switching frequency
Switching frequency range
Switching frequency set-point accuracy
Control Circuit PWM Duty Cycle
Minimum Sync Pulse Width
Input Clock Frequency Drift Tolerance
Input Under Voltage Lockout,
UVLO
Input Over Voltage Protection,
IOVP
Power Good, PG,
See Note 2
Output voltage
Over/Under Voltage Protection,
OVP/UVP
Over Current Protection,
OCP
UVLO threshold
UVLO threshold range
Set point accuracy
UVLO hysteresis
UVLO hysteresis range
Delay
Fault response
IOVP threshold
IOVP threshold range
Set point accuracy
IOVP hysteresis
IOVP hysteresis range
Delay
Fault response
PG threshold
PG hysteresis
PG delay
PG delay range
UVP threshold
UVP threshold range
UVP hysteresis
OVP threshold
OVP threshold range
UVP/OVP response time
UVP/OVP
response time range
Fault response
OCP threshold
OCP threshold range
Protection delay,
Protection delay range
Fault response
Conditions
Min
Typ
200
See Note 9
300
15 000
Unit
μF
μF
See Note 9
5
30
mΩ
VO = 0.6 V
95
VO = 1.0 V
105
VO = 1.8 V
115
VO = 3.3 V
168
VO = 0.6 V
74
VO = 1.0 V
85
VO = 1.8 V
122
VO = 3.3 V
140
mV
μs
320
200-640
PMBus conﬁgurable
External clock source
-5
5
150
-13
5
95
13
3.85
3.85-14
PMBus conﬁgurable
-150
150
0.35
0-10.15
2.5
Automatic restart, 70 ms
16
4.2-16
PMBus conﬁgurable
See Note 3
PMBus conﬁgurable
-150
PMBus conﬁgurable
See Note 3
See Note 19
PMBus conﬁgurable
PMBus conﬁgurable
PMBus conﬁgurable
PMBus conﬁgurable
See Note 3
PMBus conﬁgurable
See Note 4
PMBus conﬁgurable
See Note 3
Max
150
1
0-11.8
2.5
Automatic restart, 70 ms
90
5
Direct after DLC
0-500
85
0-100
5
115
100-115
25
kHz
kHz
%
%
ns
%
V
V
mV
V
V
μs
V
V
mV
V
V
μs
% VO
% VO
s
% VO
% VO
% VO
% VO
% VO
μs
5-60
μs
Automatic restart, 70 ms
32
0-32
32
1-32
Automatic restart, 70 ms
A
A
Tsw
Tsw
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 4 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Characteristics
Over Temperature Protection,
OTP at P2
See Note 8
VIL
VIH
IIL
VOL
VOH
IOL
IOH
tset
thold
tfree
Cp
Conditions
OTP threshold
OTP threshold range
OTP hysteresis
OTP hysteresis range
Fault response
Logic input low threshold
Logic input high threshold
Logic input low sink current
Logic output low signal level
Logic output high signal level
Logic output low sink current
Logic output high source current
Setup time, SMBus
Hold time, SMBus
Bus free time, SMBus
Internal capacitance on logic pins
Initialization time
Output Voltage
Delay Time
See Note 6
Output Voltage
Ramp Time
See Note 13
Delay duration
Delay duration range
Delay accuracy
turn-on
Delay accuracy
turn-off
Ramp duration
Ramp duration range
Ramp time accuracy
VTRK Input Bias Current
VTRK Tracking Ramp Accuracy (VO - VVTRK)
VTRK Regulation Accuracy (VO - VVTRK)
Current difference between products in a current sharing group
Min
PMBus conﬁgurable
PMBus conﬁgurable
See Note 3
SYNC, SA0, SA1, SCL, SDA, GCB, CTRL,
VSET
CTRL
SYNC, SCL, SDA, SALERT, GCB, PG
See Note 1
See Note 1
See Note 1
READ_IOUT vs IO
0.8
V
V
mA
V
V
mA
mA
ns
ns
ms
pF
2
0.6
0.4
2.25
4
2
10
See Note 10
See Note 16
PMBus conﬁgurable
40
10
5-500000
Current sharing operation
VVTRK = 5.5 V
100% tracking, see Note 7
Current sharing operation
2 phases, 100% tracking
VO = 1.0 V, 10 ms ramp
100% Tracking
Current sharing operation
100% Tracking
Steady state operation
Ramp-up
IO = 0-25 A, TP1 = 0 to +95 °C
VI = 4.5-14 V, VO = 1.0 V
IO = 0-25 A, TP1 = 0 to +95 °C
VI = 4.5-14 V, VO = 0.6-3.3 V
Note 1: See section I2C/SMBus Setup and Hold Times – Deﬁnitions.
Note 2: Monitorable over PMBus Interface.
Note 3: Automatic restart ~70 or 240 ms after fault if the fault is no longer present. Continuous restart attempts if the
fault reappear after restart. See Operating Information and AN302 for other fault response options.
Note 4: Tsw is the switching period.
Note 5: Within +/-3% of VO
Note 6: See section Soft-start Power Up.
Note 7: Tracking functionality is designed to follow a VTRK signal with slew rate < 2.4 V/ms. For faster VTRK signals
accuracy will depend on the regulator bandwidth.
Note 8: See section Over Temperature Protection (OTP).
Note 9: See section External Capacitors.
ms
ms
-0.25/+4
ms
-0.25/+4
ms
10
0-200
100
20
PMBus conﬁgurable
READ_VIN vs VI
READ_VOUT vs VO
READ_IOUT vs IO
Unit
C
C
C
C
300
250
2
Number of products in a current sharing group
Monitoring accuracy
Typ
Max
120
-40…+125
25
0-165
Automatic restart, 240 ms
110
-100
ms
μs
%
200
100
±100
μA
mV
mV
-1
1
%
-2
2
%
Max 2 x READ_IOUT monitoring accuracy
2
7
A
3
1
%
%
±1.7
A
±3.0
A
Note 10: See section Initialization Procedure.
Note 11: See graph Output Ripple vs External Capacitance and Operating information section Output Ripple and Noise.
Note 12: See graph Load Transient vs. External Capacitance and Operating information section External Capacitors.
Note 13: Time for reaching 100% of nominal Vout.
Note 14: For Vout < 1.0 V accuracy is +/-10 mV. For further deviations see section Output Voltage Adjust using PMBus™.
Note 15: Accuracy here means deviation from ideal output voltage level given by conﬁgured droop and actual load.
Includes line, load and temperature variations.
Note 16: For current sharing the Output Voltage Delay Time must be reconﬁgured to minimum 15 ms.
Note 17: For steady state operation above 1.05 x 3.3 V, please contact your local Murata sales representative.
Note 18: A minimum load current is not required if Low Power mode is used (monitoring disabled).
Note 19: See sections Dynamic Loop Compensation and Power Good.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 5 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Efficiency and Power Dissipation
Efficiency vs. Output Current, VI = 5 V
Power Dissipation vs. Output Current, VI = 5 V
[%]
[W]
100
6
95
5
4
90
0.6 V
1.0 V
85
80
0.6 V
3
1.0 V
1.8 V
2
1.8 V
3.3 V
1
3.3 V
75
0
0
5
10
15
20
0
25 [A]
5
10
15
20
25 [A]
Efficiency vs. load current and output voltage:
TP1 = +25 °C, VI = 5 V, fsw = 320 kHz, CO = 470 μF/10 m.
Dissipated power vs. load current and output voltage:
TP1 = +25 °C, VI = 5 V, fsw = 320 kHz, CO = 470 μF/10 m.
Efficiency vs. Output Current, VI = 12 V
Power Dissipation vs. Output Current, VI = 12 V
[%]
[W]
100
6
5
95
4
90
0.6 V
1.0 V
85
80
0.6 V
3
1.0 V
1.8 V
2
1.8 V
3.3 V
1
3.3 V
75
0
0
5
10
15
20
25 [A]
0
5
10
15
20
25 [A]
Efficiency vs. load current and output voltage at
TP1 = +25 °C, VI = 12 V, fsw = 320 kHz, CO = 470 μF/10 m.
Dissipated power vs. load current and output voltage:
TP1 = +25 °C, VI = 12 V, fsw = 320 kHz, CO = 470 μF/10 m.
Efficiency vs. Output Current and
Switching Frequency
Power Dissipation vs. Output Current and
Switching frequency
[%]
[W]
95
6
5
90
200
kHz
85
200
kHz
4
320
kHz
3
320
kHz
80
480
kHz
2
480
kHz
75
640
kHz
1
640
kHz
70
0
0
5
10
15
20
Efficiency vs. load current and switch frequency at
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m.
Default configuration except changed frequency
25 [A]
0
5
10
15
20
25 [A]
Dissipated power vs. load current and switch frequency at
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m.
Default configuration except changed frequency
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 6 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Load Transient
Load Transient vs. External Capacitance, VO = 1.0 V
[mV]
400
Universal PID,
No NLR
DLC,
No NLR
300
Universal PID,
Default NLR
200
Load Transient vs. External Capacitance, VO = 3.3 V
[mV]
400
Universal PID,
No NLR
DLC,
No NLR
300
Universal PID,
Default NLR
200
DLC,
Default NLR
DLC,
Default NLR
Universal PID,
Opt. NLR
100
DLC,
Opt. NLR
0
0
1
2
3
4
Universal PID,
Opt. NLR
100
DLC,
Opt. NLR
0
0
5 [mF]
1
2
3
4
5 [mF]
Load transient peak voltage deviation vs. external capacitance.
Step (6.25-18.75-6.25 A). Parallel coupling of capacitors with 470 μF/10 m,
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, fsw = 320 kHz, di/dt = 2 A/μs
Load transient peak voltage deviation vs. external capacitance.
Step (6.25-18.75-6.25 A). Parallel coupling of capacitors with 470 μF/10 m,
TP1 = +25 °C, VI = 12 V, VO = 3.3 V, fsw = 320 kHz, di/dt = 2 A/μs
Load transient vs. Switch Frequency
Output Load Transient Response, Default Configuration
[mV]
400
Universal PID,
No NLR
DLC,
No NLR
300
Universal PID,
Default NLR
200
DLC,
Default NLR
Universal PID,
Opt. NLR
100
DLC,
Opt. NLR
0
200
300
400
500
600 [kHz]
Load transient peak voltage deviation vs. frequency.
Step-change (6.25-18.75-6.25 A).
TP1 = +25 °C. VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m
Output voltage response to load current
Step-change (6.25-18.75-6.25 A) at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
di/dt = 2 A/μs, fsw = 320 kHz
CO = 470 μF/10 m
Top trace: output voltage (200
mV/div.).
Bottom trace: load current (5
A/div.).
Time scale: (0.1 ms/div.).
Note: For Universal PID, see section Dynamic Loop Compensation (DLC).
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 7 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Output Current Characteristic
Output Current Derating, VO = 0.6 V
Output Current Derating, VO = 1.0 V
[A]
[A]
30
30
3.0 m/s
25
3.0 m/s
25
2.0 m/s
20
2.0 m/s
20
1.0 m/s
15
1.0 m/s
15
0.5 m/s
10
0.5 m/s
10
Nat. Conv.
5
Nat. Conv.
5
0
0
60
70
80
90
100
110
120 [°C]
60
70
80
90
100
110
120 [°C]
Available load current vs. ambient air temperature and airflow at
VO = 0.6 V, VI = 12 V. See Thermal Consideration section.
Available load current vs. ambient air temperature and airflow at
VO = 1.0 V, VI = 12 V. See Thermal Consideration section.
Output Current Derating, VO = 1.8 V
Output Current Derating, VO = 3.3 V
[A]
[A]
30
30
3.0 m/s
3.0 m/s
25
25
2.0 m/s
2.0 m/s
20
20
1.0 m/s
1.0 m/s
15
15
0.5 m/s
0.5 m/s
10
10
Nat. Conv.
5
Nat. Conv.
5
0
0
50
60
70
80
90
100
110
50
120 [°C]
Available load current vs. ambient air temperature and airflow at
VO = 1.8 V, VI = 12 V. See Thermal Consideration section.
60
70
80
90
100
110
120 [°C]
Available load current vs. ambient air temperature and airflow at
VO = 3.3 V, VI = 12 V. See Thermal Consideration section.
Current Limit Characteristics, VO = 1.0 V
Current Limit Characteristics, VO = 3.3 V
[V]
[V]
1,2
4,0
1,0
3,0
0,8
4.5 V
0,6
5.0 V
VI = 4.5 V
VI = 5.0, 12, 14 V
0,4
4.5 V
5.0 V
2,0
12 V
12 V
14 V
VI = 12, 14 V
VI = 4.5, 5.0 V
14 V
1,0
0,2
0,0
0,0
25
27
29
31
33
35 [A]
Output voltage vs. load current at TP1 = +25 °C, VO = 1.0 V.
Note: Output enters hiccup mode at current limit.
25
27
29
31
33
35 [A]
Output voltage vs. load current at TP1 = +25 °C, VO = 3.3 V.
Note: Output enters hiccup mode at current limit.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 8 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Output Voltage
Output Ripple & Noise, VO = 1.0 V
Output Ripple & Noise, VO = 3.3 V
Output voltage ripple at: TP1 = +25 °C, Trace: output voltage (20 mV/div.).
Time scale: (2 μs/div.).
VI = 12 V, CO = 470 μF/10 m
IO = 25 A
Output voltage ripple at: TP1 = +25 °C, Trace: output voltage (20 mV/div.).
Time scale: (2 μs/div.).
VI = 12 V, CO = 470 μF/10 m
IO = 25 A
Output Ripple vs. Input Voltage
Output Ripple vs. Frequency
[mVpk-pk]
[mVpk-pk]
70
150
60
120
50
0.6 V
0.6 V
40
1.0 V
30
1.8 V
20
3.3 V
90
1.0 V
1.8 V
60
3.3 V
30
10
0
5
7
9
11
0
[V]
13
200
300
400
500
600
[kHz]
Output voltage ripple Vpk-pk at: TP1 = +25 °C, CO = 470 μF/10 m, IO = 25 A
Output voltage ripple Vpk-pk at: TP1 = +25 °C, VI = 12 V, CO = 470 μF/10 m,
IO = 25 A. Default configuration except changed frequency.
Output Ripple vs. External Capacitance
Load regulation, VO = 1.0 V
[mV]
[V]
70
1,010
60
50
0.6V
40
1.0 V
30
1.8 V
20
3.3 V
1,005
4.5 V
5.0 V
1,000
12 V
14 V
0,995
10
0
0
1
2
3
4
5 [mF]
Output voltage ripple Vpk-pk at: TP1 = +25 °C, VI = 12 V. IO = 25 A.
Parallel coupling of capacitors with 470 μF/10 m
0,990
0
5
10
15
20
25 [A]
Load regulation at Vo = 1.0 V, TP1 = +25 °C, CO = 470 μF/10 m
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 9 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Start-up and shut-down
Start-up by input source
Start-up enabled by connecting VI at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Shut-down by input source
Top trace: output voltage (0.5 V/div.).
Bottom trace: input voltage (5 V/div.).
Time scale: (20 ms/div.).
Start-up by CTRL signal
Start-up by enabling CTRL signal at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Shut-down enabled by disconnecting
VI at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Top trace: output voltage (0.5 V/div.).
Bottom trace: input voltage (5 V/div.).
Time scale: (2 ms/div.).
Shut-down by CTRL signal
Top trace: output voltage (0.5 V/div.).
Bottom trace: CTRL signal (2 V/div.).
Time scale: (20 ms/div.).
Shut-down enabled by disconnecting
VI at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Top trace: output voltage (0.5 V/div).
Bottom trace: CTRL signal (2 V/div.).
Time scale: (2 ms/div.).
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 10 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Electrical Speciﬁcations, OKDX-T/25-W12-xxx-C
TP1 = -30 to +95 °C, VI = 4.5 to 14 V, VI > VO + 1.0 V
Typical values given at: TP1 = +25 °C, VI = 12.0 V, max IO, unless otherwise speciﬁed under Conditions.
Default conﬁguration ﬁle, 190 10-CDA 102 0259/001.
External CIN = 470 μF/10 mΩ, COUT = 470 μF/10 mΩ. See Operating Information section for selection of capacitor types.
Sense pins are connected to the output pins.
Characteristics
VI
Input voltage rise time
Conditions
monotonic
Output voltage without pin strap
Output voltage adjustment range
Output voltage adjustment including margining
Output voltage set-point resolution
VO
Load regulation; IO = 0 - 100%
VOac
Output ripple & noise
CO = 470 μF (minimum external capacitance). See Note 11
IO
Output current
IS
Static input current at max IO
Ilim
Current limit threshold
Isc
Unit
V/ms
3.3
3.63
V
V
V
% Vo
See Note 17
-1
1
%
-2
2
%
0.60
0.54
±0.025
Short circuit current
47
2
2
2
3
2
2
2
3
20
30
40
60
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
See Note 18
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
0.001
RMS, hiccup mode, See Note 3
Efﬁciency
max IO
Pd
Power dissipation at max IO
Pli
Input idling power
(no load)
Default conﬁguration: Continues
Conduction Mode, CCM
PCTRL
Input standby power
Turned off with
CTRL-pin
Ci
Internal input capacitance
Ω
mV
mV
mVp-p
25
1.61
2.46
4.17
7.35
27
50% of max IO
Max
2.4
Internal resistance +S/-S to VOUT/GND
Line regulation
Typ
1.2
Including line, load, temp.
See Note 14
Current sharing operation
See Note 15
Output voltage accuracy
Min
A
37.5
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
8
6
5
4
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
83.6
89.0
92.8
95.1
77.4
84.6
90.0
93.5
4.37
4.54
5.01
5.77
0.56
0.57
0.67
0.92
Default conﬁguration:
Monitoring enabled,
Precise timing enabled
170
70
A
A
A
%
%
W
W
mW
μF
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 11 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Characteristics
Co
Internal output capacitance
Total external output capacitance
COUT
ESR range of capacitors
(per single capacitor)
Vtr1
ttr1
fs
Load transient peak
voltage deviation
(H to L)
Load step 25-75-25%
of max IO
Default conﬁguration
di/dt = 2 A/μs
CO = 470 μF (minimum external
capacitance) see Note 12
Load transient recovery
time, Note 5
(H to L)
Load step 25-75-25%
of max IO
Default conﬁguration
di/dt = 2 A/μs
CO = 470 μF (minimum external
capacitance) see Note 12
Switching frequency
Switching frequency range
Switching frequency set-point accuracy
Control Circuit PWM Duty Cycle
Minimum Sync Pulse Width
Input Clock Frequency Drift Tolerance
Input Under Voltage Lockout,
UVLO
Input Over Voltage Protection,
IOVP
Power Good, PG,
See Note 2
Output voltage
Over/Under Voltage Protection,
OVP/UVP
Over Current Protection,
OCP
UVLO threshold
UVLO threshold range
Set point accuracy
UVLO hysteresis
UVLO hysteresis range
Delay
Fault response
IOVP threshold
IOVP threshold range
Set point accuracy
IOVP hysteresis
IOVP hysteresis range
Delay
Fault response
PG threshold
PG hysteresis
PG delay
PG delay range
UVP threshold
UVP threshold range
UVP hysteresis
OVP threshold
OVP threshold range
UVP/OVP response time
UVP/OVP
response time range
Fault response
OCP threshold
OCP threshold range
Protection delay,
Protection delay range
Fault response
Conditions
Min
Typ
200
See Note 9
300
15 000
Unit
μF
μF
See Note 9
5
30
mΩ
VO = 0.6 V
115
VO = 1.0 V
122
VO = 1.8 V
143
VO = 3.3 V
174
VO = 0.6 V
60
VO = 1.0 V
65
VO = 1.8 V
115
VO = 3.3 V
130
mV
μs
320
200-640
PMBus conﬁgurable
External clock source
-5
5
150
-13
5
95
13
3.85
3.85-14
PMBus conﬁgurable
-150
150
0.35
0-10.15
2.5
Automatic restart, 70 ms
16
4.2-16
PMBus conﬁgurable
See Note 3
PMBus conﬁgurable
-150
PMBus conﬁgurable
See Note 3
See Note 19
PMBus conﬁgurable
PMBus conﬁgurable
PMBus conﬁgurable
PMBus conﬁgurable
See Note 3
PMBus conﬁgurable
See Note 4
PMBus conﬁgurable
See Note 3
Max
150
kHz
kHz
%
%
ns
%
V
V
mV
V
V
μs
V
V
mV
V
V
μs
1
0-11.8
2.5
Automatic restart, 70 ms
90
5
Direct after DLC
0-500
85
0-100
5
115
100-115
25
% VO
% VO
ms
s
% VO
% VO
% VO
% VO
% VO
μs
5-60
μs
Automatic restart, 70 ms
32
0-32
32
1-32
Automatic restart, 70 ms
A
A
Tsw
Tsw
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 12 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Characteristics
Over Temperature Protection,
OTP at P2
See Note 8
VIL
VIH
IIL
VOL
VOH
IOL
IOH
tset
thold
tfree
Cp
Conditions
OTP threshold
OTP threshold range
OTP hysteresis
OTP hysteresis range
Fault response
Logic input low threshold
Logic input high threshold
Logic input low sink current
Logic output low signal level
Logic output high signal level
Logic output low sink current
Logic output high source current
Setup time, SMBus
Hold time, SMBus
Bus free time, SMBus
Internal capacitance on logic pins
Initialization time
Output Voltage
Delay Time
See Note 6
Output Voltage
Ramp Time
See Note 13
Delay duration
Delay duration range
Delay accuracy
turn-on
Delay accuracy
turn-off
Ramp duration
Ramp duration range
Ramp time accuracy
VTRK Input Bias Current
VTRK Tracking Ramp Accuracy (VO - VVTRK)
VTRK Regulation Accuracy (VO - VVTRK)
Current difference between products in a current sharing group
Min
PMBus conﬁgurable
PMBus conﬁgurable
See Note 3
SYNC, SA0, SA1, SCL, SDA, GCB, CTRL,
VSET
CTRL
SYNC, SCL, SDA, SALERT, GCB, PG
See Note 1
See Note 1
See Note 1
READ_IOUT vs IO
0.8
V
V
mA
V
V
mA
mA
ns
ns
ms
pF
2
0.6
0.4
2.25
4
2
10
See Note 10
See Note 16
PMBus conﬁgurable
40
10
5-500000
Current sharing operation
VVTRK = 5.5 V
100% tracking, see Note 7
Current sharing operation
2 phases, 100% tracking
VO = 1.0 V, 10 ms ramp
100% Tracking
Current sharing operation
100% Tracking
Steady state operation
Ramp-up
IO = 0-25 A, TP1 = 0 to +95 °C
VI = 4.5-14 V, VO = 1.0 V
IO = 0-25 A, TP1 = 0 to +95 °C
VI = 4.5-14 V, VO = 0.6-3.3 V
Note 1: See section I2C/SMBus Setup and Hold Times – Deﬁnitions.
Note 2: Monitorable over PMBus Interface.
Note 3: Automatic restart ~70 or 240 ms after fault if the fault is no longer present. Continuous restart attempts if the
fault reappear after restart. See Operating Information and AN302 for other fault response options.
Note 4: Tsw is the switching period.
Note 5: Within +/-3% of VO
Note 6: See section Soft-start Power Up.
Note 7: Tracking functionality is designed to follow a VTRK signal with slew rate < 2.4 V/ms. For faster VTRK signals
accuracy will depend on the regulator bandwidth.
Note 8: See section Over Temperature Protection (OTP).
Note 9: See section External Capacitors.
ms
ms
-0.25/+4
ms
-0.25/+4
ms
10
0-200
100
20
PMBus conﬁgurable
READ_VIN vs VI
READ_VOUT vs VO
READ_IOUT vs IO
Unit
C
C
C
C
300
250
2
Number of products in a current sharing group
Monitoring accuracy
Typ
Max
120
-40…+125
25
0-165
Automatic restart, 240 ms
110
-100
ms
μs
%
200
100
±100
μA
mV
mV
-1
1
%
-2
2
%
Max 2 x READ_IOUT monitoring accuracy
2
7
A
3
1
%
%
±1.7
A
±3.0
A
Note 10: See section Initialization Procedure.
Note 11: See graph Output Ripple vs External Capacitance and Operating information section Output Ripple and Noise.
Note 12: See graph Load Transient vs. External Capacitance and Operating information section External Capacitors.
Note 13: Time for reaching 100% of nominal Vout.
Note 14: For Vout < 1.0 V accuracy is +/-10 mV. For further deviations see section Output Voltage Adjust using PMBus™.
Note 15: Accuracy here means deviation from ideal output voltage level given by conﬁgured droop and actual load.
Includes line, load and temperature variations.
Note 16: For current sharing the Output Voltage Delay Time must be reconﬁgured to minimum 15 ms.
Note 17: For steady state operation above 1.05 x 3.3 V, please contact your local Murata sales representative.
Note 18: A minimum load current is not required if Low Power mode is used (monitoring disabled).
Note 19: See sections Dynamic Loop Compensation and Power Good.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 13 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Efficiency and Power Dissipation
Efficiency vs. Output Current, VI = 5 V
Power Dissipation vs. Output Current, VI = 5 V
[%]
[W]
100
6
5
95
4
90
0.6 V
1.0 V
85
80
0.6 V
3
1.0 V
1.8 V
2
1.8 V
3.3 V
1
3.3 V
75
0
0
5
10
15
20
25 [A]
0
5
10
15
20
25 [A]
Efficiency vs. load current and output voltage:
TP1 = +25 °C, VI = 5 V, fsw = 320 kHz, CO = 470 μF/10 m.
Dissipated power vs. load current and output voltage:
TP1 = +25 °C, VI = 5 V, fsw = 320 kHz, CO = 470 μF/10 m.
Efficiency vs. Output Current, VI = 12 V
Power Dissipation vs. Output Current, VI = 12 V
[%]
[W]
100
6
5
95
4
90
0.6 V
1.0 V
85
80
0.6 V
3
1.0 V
1.8 V
2
1.8 V
3.3 V
1
3.3 V
75
0
0
5
10
15
20
25 [A]
0
5
10
15
20
25 [A]
Efficiency vs. load current and output voltage at
TP1 = +25 °C, VI=12 V, fsw = 320 kHz, CO = 470 μF/10 m.
Dissipated power vs. load current and output voltage:
TP1 = +25 °C, VI=12 V, fsw = 320 kHz, CO = 470 μF/10 m.
Efficiency vs. Output Current and
Switching Frequency
Power Dissipation vs. Output Current and
Switching frequency
[%]
[W]
95
6
5
90
200
kHz
85
200
kHz
4
320
kHz
3
320
kHz
80
480
kHz
2
480
kHz
75
640
kHz
1
640
kHz
70
0
0
5
10
15
20
Efficiency vs. load current and switch frequency at
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m.
Default configuration except changed frequency
25 [A]
0
5
10
15
20
25 [A]
Dissipated power vs. load current and switch frequency at
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m.
Default configuration except changed frequency
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 14 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Load Transient
Load Transient vs. External Capacitance, VO = 1.0 V
[mV]
350
280
Universal PID,
No NLR
Load Transient vs. External Capacitance, VO = 3.3 V
[mV]
350
Universal PID,
No NLR
DLC,
No NLR
280
DLC,
No NLR
210
Universal PID,
Default NLR
210
Universal PID,
Default NLR
140
DLC,
Default NLR
140
DLC,
Default NLR
Universal PID,
Opt. NLR
70
DLC,
Opt. NLR
0
0
1
2
3
4
5 [mF]
Universal PID,
Opt. NLR
70
DLC,
Opt. NLR
0
0
1
2
3
4
5 [mF]
Load transient peak voltage deviation vs. external capacitance.
Step (6.25-18.75-6.25 A). Parallel coupling of capacitors with 470 μF/10 m,
TP1 = +25 °C. VI = 12 V, VO = 1.0 V, fsw = 320 kHz, di/dt = 2 A/μs
Load transient peak voltage deviation vs. external capacitance.
Step (6.25-18.75-6.25 A). Parallel coupling of capacitors with 470 μF/10 m,
TP1 = +25 °C. VI = 12 V, VO = 3.3 V, fsw = 320 kHz, di/dt = 2 A/μs
Load transient vs. Switch Frequency
Output Load Transient Response, Default Configuration
[mV]
350
Universal PID,
No NLR
280
DLC,
No NLR
210
Universal PID,
Default NLR
140
DLC,
Default NLR
Universal PID,
Opt. NLR
70
DLC,
Opt. NLR
0
200
300
400
500
600 [kHz]
Load transient peak voltage deviation vs. frequency.
Step-change (6.25-18.75-6.25 A).
TP1 = +25 °C. VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m
Output voltage response to load
Top trace: output voltage (200 mV/div.).
Step-change (6.25-18.75-6.25 A) at: Bottom trace: load current (5 A/div.).
TP1 = +25 °C, VI = 12 V, VO = 1.0 V Time scale: (0.1 ms/div.).
di/dt = 2 A/μs, fsw = 320 kHz
CO = 470 μF/10 m
Note: For Universal PID, see section Dynamic Loop Compensation (DLC).
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 15 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Output Current Characteristic
Output Current Derating, VO = 0.6 V
Output Current Derating, VO = 1.0 V
[A]
[A]
30
30
3.0 m/s
3.0 m/s
25
25
2.0 m/s
2.0 m/s
20
20
1.0 m/s
1.0 m/s
15
15
0.5 m/s
0.5 m/s
10
10
Nat. Conv.
Nat. Conv.
5
5
0
0
50
60
70
80
90
100
110
120 [°C]
50
60
70
80
90
100
110
120 [°C]
Available load current vs. ambient air temperature and airflow at
VO = 0.6 V, VI = 12 V. See Thermal Consideration section.
Available load current vs. ambient air temperature and airflow at
VO = 1.0 V, VI = 12 V. See Thermal Consideration section.
Output Current Derating, VO = 1.8 V
Output Current Derating, VO = 3.3 V
[A]
[A]
30
30
3.0 m/s
3.0 m/s
25
25
2.0 m/s
2.0 m/s
20
20
1.0 m/s
1.0 m/s
15
15
0.5 m/s
0.5 m/s
10
10
Nat. Conv.
Nat. Conv.
5
5
0
0
30
40
50
60
70
80
90
100 110 120 [°C]
30
Available load current vs. ambient air temperature and airflow at
VO = 1.8 V, VI = 12 V. See Thermal Consideration section.
40
50
60
70
80
90
100 110 120 [°C]
Available load current vs. ambient air temperature and airflow at
VO = 3.3 V, VI = 12 V. See Thermal Consideration section.
Current Limit Characteristics, VO = 1.0 V
Current Limit Characteristics, VO = 3.3 V
[V]
[V]
1,2
4,0
1,0
3,0
0,8
4.5 V
0,6
5.0 V
VI = 4.5 V
VI = 5.0, 12, 14 V
0,4
4.5 V
5.0 V
2,0
12 V
12 V
14 V
VI = 12, 14 V
VI = 4.5, 5.0 V
14 V
1,0
0,2
0,0
0,0
25
27
29
31
33
35 [A]
Output voltage vs. load current at TP1 = +25 °C, VO = 1.0 V.
Note: Output enters hiccup mode at current limit.
25
27
29
31
33
35 [A]
Output voltage vs. load current at TP1 = +25 °C, VO = 3.3 V.
Note: Output enters hiccup mode at current limit.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 16 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Output Voltage
Output Ripple & Noise, VO = 1.0 V
Output Ripple & Noise, VO = 3.3 V
Output voltage ripple at: TP1 = +25 °C, Trace: output voltage (20 mV/div.).
Time scale: (2 μs/div.).
VI = 12 V, CO = 470 μF/10 m
IO = 25 A
Output voltage ripple at: TP1 = +25 °C, Trace: output voltage (20 mV/div.).
Time scale: (2 μs/div.).
VI = 12 V, CO = 470 μF/10 m
IO = 25 A
Output Ripple vs. Input Voltage
Output Ripple vs. Frequency
[mVpk-pk]
[mVpk-pk]
50
100
40
80
0.6 V
0.6 V
30
1.0 V
1.8 V
20
60
1.0 V
1.8 V
40
3.3 V
3.3 V
10
20
0
5
7
9
11
0
[V]
13
200
300
400
500
600
[kHz]
Output voltage ripple Vpk-pk at: TP1 = +25 °C, CO = 470 μF/10 m, IO = 25 A.
Output voltage ripple Vpk-pk at: TP1 = +25 °C, VI = 12 V, CO = 470 μF/10 m,
IO = 25 A. Default configuration except changed frequency.
Output Ripple vs. External Capacitance
Load regulation, VO = 1.0 V
[mV]
[V]
50
1,010
40
0.6V
30
1,005
4.5 V
1.0 V
1.8 V
20
3.3 V
10
0
0
1
2
3
4
5 [mF]
Output voltage ripple Vpk-pk at: TP1 = +25 °C, VI = 12 V. IO = 25 A.
Parallel coupling of capacitors with 470 μF/10 m
5.0 V
1,000
12 V
14 V
0,995
0,990
0
5
10
15
20
25 [A]
Load regulation at Vo=1.0 V, TP1 = +25 °C, CO = 470 μF/10 m
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 17 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Characteristics
Start-up and shut-down
Start-up by input source
Start-up enabled by connecting VI at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Shut-down by input source
Top trace: output voltage (0.5 V/div.).
Bottom trace: input voltage (5 V/div.).
Time scale: (20 ms/div.).
Start-up by CTRL signal
Start-up by enabling CTRL signal at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Shut-down enabled by disconnecting
VI at:
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
CO = 470 μF/10 m, IO = 25 A
Top trace: output voltage (0.5 V/div).
Bottom trace: input voltage (5 V/div.).
Time scale: (2 ms/div.).
Shut-down by CTRL signal
Top trace: output voltage (0.5 V/div.).
Bottom trace: CTRL signal (2 V/div.).
Time scale: (20 ms/div.).
Shut-down enabled by disconnecting VI Top trace: output voltage (0.5 V/div).
at:
Bottom trace: CTRL signal (2 V/div.).
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
Time scale: (2 ms/div.).
CO = 470 μF/10 m, IO = 25 A
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OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
EMC Speciﬁcation
Output Ripple and Noise
Conducted EMI measured according to test set-up below. The fundamental
switching frequency is 320 kHz at VI = 12 V, max IO.
Output ripple and noise is measured according to ﬁgure below.
50 mm conductor
Vout
Tantalum
Capacitor
Output
10 μ F
Capacitor
470 μ F/10 m Ω
+S
–S
GND
Ceramic
Capacitor
0.1 μ F
Load
Conducted EMI Input terminal value (typical for default conﬁguration)
A 50 mm conductor works as a small inductor forming together with the
two capacitors as a damped ﬁlter.
50 mm conductor
BNC-contact to
oscilloscope
Output ripple and noise test set-up.
Operating information
Power Management Overview
EMI without ﬁlter
To spectrum
analyzer
RF Current probe
1kHz – 50MHz
Battery
supply
Resistive
load
C1
POL
50mm
C1 = 10uF / 600VDC
Feed- Thru RF capacitor
This product is equipped with a PMBus™ interface. The product incorporates
a wide range of readable and conﬁgurable power management features that
are simple to implement with a minimum of external components. Additionally, the product includes protection features that continuously safeguard the
load from damage due to unexpected system faults. A fault is also shown as
an alert on the SALERT pin. The following product parameters can continuously be monitored by a host: Input voltage, output voltage/current, and
internal temperature. If the monitoring is not needed it can be disabled and
the product enters a low power mode reducing the power consumption. The
protection features are not affected.
The product is delivered with a default conﬁguration suitable for a wide
range operation in terms of input voltage, output voltage, and load. The
conﬁguration is stored in an internal Non-Volatile Memory (NVM). All power
management functions can be reconﬁgured using the PMBus™ interface.
Please contact your local Murata Power Solutions representative for design
support of custom conﬁgurations or appropriate SW tools for design and
download of your own conﬁgurations.
Input Voltage
200mm
800mm
Conducted EMI test set-up
The input voltage range, 4.5 - 14 V, makes the product easy to use in intermediate bus applications when powered by a non-regulated bus converter or a
regulated bus converter. See Ordering Information for input voltage range.
Layout Recommendations
The radiated EMI performance of the product will depend on the PWB layout and
ground layer design. It is also important to consider the stand-off of the product. If
a ground layer is used, it should be connected to the output of the product and the
equipment ground or chassis.
A ground layer will increase the stray capacitance in the PWB
and improve the high frequency EMC performance.
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OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Input Under Voltage Lockout, UVLO
The product monitors the input voltage and will turn-on and turn-off at conﬁgured levels. The default turn-on input voltage level setting is 4.20 V, whereas
the corresponding turn-off input voltage level is 3.85 V. Hence, the default
hysteresis between turn-on and turn-off input voltage is 0.35 V. Once an input
turn-off condition occurs, the device can respond in a number of ways as
follows:
1. Continue operating without interruption. The unit will continue to operate
as long as the input voltage can be supported. If the input voltage continues to fall, there will come a point where the unit will cease to operate.
2. Continue operating for a given delay period, followed by shutdown if the
fault still exists. The device will remain in shutdown until instructed to
restart.
3. Initiate an immediate shutdown until the fault has been cleared. The user
can select a speciﬁc number of retry attempts.
The default response from a turn-off is an immediate shutdown of the device.
The device will continuously check for the presence of the fault condition.
If the fault condition is no longer present, the product will be re-enabled.
The turn-on and turn-off levels and response can be reconﬁgured using the
PMBus™ interface.
Remote Control
Vext
CTRL
GND
The product is equipped with a remote
control function, i.e., the CTRL pin. The
remote control can be connected to
either the primary negative input connection (GND) or an external voltage (Vext),
which is a 3 - 5 V positive supply voltage
in accordance to the SMBus Speciﬁcation
version 2.0.
The CTRL function allows the product
to be turned on/off by an external device like a semiconductor or mechanical
switch. By default the product will turn on when the CTRL pin is left open and
turn off when the CTRL pin is applied to GND. The CTRL pin has an internal
pull-up resistor. When the CTRL pin is left open, the voltage generated on the
CTRL pin is max 5.5 V.
If the device is to be synchronized to an external clock source, the clock
frequency must be stable prior to asserting the CTRL pin.
The product can also be conﬁgured using the PMBus™ interface to be
“Always on,” or turn on/off can be performed with PMBus™ commands.
Input and Output Impedance
The impedance of both the input source and the load will interact with the
impedance of the product. It is important that the input source has low characteristic impedance. The performance in some applications can be enhanced
by addition of external capacitance as described under External Decoupling
Capacitors. If the input voltage source contains signiﬁcant inductance, the
addition a capacitor with low ESR at the input of the product will ensure
stable operation.
External Capacitors
Input capacitors:
The input ripple RMS current in a buck converter is equal to
Eq. 1.
I inputRMS
I load D 1 D ,
where I load is the output load current and D is the duty cycle. The
maximum load ripple current becomes I load 2 . The ripple current is
divided into three parts, i.e., currents in the input source, external input
capacitor, and internal input capacitor. How the current is divided depends
on the impedance of the input source, ESR and capacitance values in the
capacitors. A minimum capacitance of 300 μF with low ESR is
recommended. The ripple current rating of the capacitors must follow
Eq. 1. For high-performance/transient applications or wherever the input
source performance is degraded, additional low ESR ceramic type
capacitors at the input is recommended. The additional input low ESR
capacitance above the minimum level insures an optimized performance.
Output capacitors:
When powering loads with significant dynamic current requirements, the
voltage regulation at the point of load can be improved by addition of
decoupling capacitors at the load.
The most effective technique is to locate low ESR ceramic and electrolytic
capacitors as close to the load as possible, using several capacitors in
parallel to lower the effective ESR. The ceramic capacitors will handle highfrequency dynamic load changes while the electrolytic capacitors are used
to handle low frequency dynamic load changes. Ceramic capacitors will
also reduce high frequency noise at the load.
It is equally important to use low resistance and low inductance PWB
layouts and cabling.
External decoupling capacitors are a part of the control loop of the product
and may affect the stability margins.
Stable operation is guaranteed for the following total capacitance CO in
the output decoupling capacitor bank where
Eq. 2.
>Cmin , Cmax @ >300, 15000@ μF.
CO
The decoupling capacitor bank should consist of capacitors which has a
capacitance value larger than C t C min and has an ESR range of
Eq. 3.
ESR
>ESRmin , ESRmax @ >5, 30@ mΩ
The control loop stability margins are limited by the minimum time constant
W min of the capacitors. Hence, the time constant of the capacitors should
follow Eq. 4.
Eq. 4. W t W min Cmin ESRmin 1.5 Ps
This relation can be used if your preferred capacitors have parameters
outside the above stated ranges in Eq. 2 and Eq.3.
x If the capacitors capacitance value is C C min one must use at least
N capacitors where
C
ªC º
N t « min » and ESR t ESRmin min .
C
C
«
»
x If the ESR value is ESR ! ESR max one must use at least N capacitors
of that type where
ª ESR º
C min
N t«
.
» and C t
ESR
N
max »
«
x If the ESR value is ESR ESR min the capacitance value should be
C t C min
ESRmin
.
ESR
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 20 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
For a total capacitance outside the above stated range or capacitors that do
not follow the stated above requirements above a re-design of the control
loop parameters will be necessary for robust dynamic operation and stability.
Control Loop
The product uses a voltage-mode synchronous buck controller with a ﬁxed
frequency PWM scheme. Although the product uses a digital control loop,
it operates much like a traditional analog PWM controller. As in the analog
controller case, the control loop compares the output voltage to the desired
voltage reference and compensation is added to keep the loop stable and
fast. The resulting error signal is used to drive the PWM logic. Instead of
using external resistors and capacitors required with traditional analog
control loops, the product uses a digital Proportional-Integral-Derivative (PID)
compensator in the control loop. The characteristics of the control loop is
conﬁgured by setting PID compensation parameters. These PID settings can
be reconﬁgured using the PMBus™ interface.
The DLC algorithm can also be initiated manually by sending the AUTO_
COMP_CONTROL command.
The DLC can also be conﬁgured with Auto Comp Gain Control. This scales
the DLC results to allow a trade-off between transient response and steadystate duty cycle jitter. A setting of 100% will provide the fastest transient
response while a setting of 10% will produce the lowest jitter. The default is
50%.
Changing DLC and PID Setting
Some caution must be considered while DLC is enabled and when it is
changed from enabled or disabled.
When operating, the controller IC uses the settings loaded in its (volatile)
RAM memory. When the input power is applied the RAM settings are retrieved
from the pin-strap resistors and the two non-volatile memories (DEFAULT and
USER). The sequence is described in the “Initialization Procedure” section.
Control Loop Compensation Setting
When DLC is enabled:
The products without DLC are by default conﬁgured with a robust control loop
compensation setting (PID setting) which allows for a wide range operation
of input and output voltages and capacitive loads as deﬁned in the section
External Decoupling Capacitors. For an application with a speciﬁc input voltage, output voltage, and capacitive load, the control loop can be optimized for
a robust and stable operation and with an improved load transient response.
This optimization will minimize the amount of required output decoupling
capacitors for a given load transient requirement yielding an optimized cost
and minimized board space. The optimization together with load step simulations can be made using the Murata Power Designer software.
When DLC is enabled, the normal sequence (after input power has been
applied) that a value stored in the user non-volatile memory overwrites any
previously loaded value does not apply for the PID setting (stored in the
PID_TAPS register). The PID setting in the user non-volatile memory is ignored
and a non-conﬁgurable default PID setting is loaded to RAM to act as a safe
starting value for the DLC. Once the output has been enabled and the DLC
algorithm has found a new optimized PID setting it will be loaded in RAM and
used by the control loop.
Dynamic Loop Compensation (DLC)
Only some of the products that this specification covers have this feature (see
section Ordering Information).
The DLC feature might in some documents be referred to as “Auto Compensation” or “Auto Tuning” feature.
When saving changes to the user non-volatile memory, all changes made
to the content of RAM will be saved. This also includes the default PID setting
(loaded to RAM to act as a safe starting value) or the PID setting changed
by the DLC algorithm after enabling output. The result is that as long as DLC
is enabled the PID setting in the user non-volatile memory is ignored, but it
might accidentally get overwritten.
When changing DLC from disabled to enabled:
The DLC feature measures the characteristics of the power train and calculates the proper compensator PID coefﬁcients.
A non-conﬁgurable default PID setting is loaded to RAM to act as a safe starting value for the DLC (same as above).
The default conﬁguration is that once the output voltage ramp up has
completed, the DLC algorithm will begin and a new optimized compensator
solution (PID setting) will be found and implemented. The DLC algorithm typically takes between 50 ms and 200 ms to complete.
When changing DLC from enabled to disabled:
By the PMBus™ command AUTO_COMP_CONFIG the user may select
between several different modes of operation:
When DLC is disabled:
Disable
Autocomp
once, will run DLC algorithm each time the output is enabled
(default conﬁguration)
Autocomp
every second will initiate a new DLC algorithm each 1 second
Autocomp
every minute will initiate a new DLC algorithm every minute.
The DLC can also be conﬁgured to run once only after the ﬁrst ramp up (after
input power have been applied) and to use that temporary stored PID settings
in all subsequent ramps. If input power is cycled a new DLC algorithm will be
performed after the ﬁrst ramp up. The default setting is however to run the DLC
algorithm after every ramp up.
When changing DLC from enabled to disabled, the PID setting in the user nonvolatile memory will be loaded to RAM. Any new optimized PID setting in RAM
will be lost, if not ﬁrst stored to the user non-volatile memory.
When DLC is disabled and input power has been applied, the PID setting in
the user non-volatile memory will be loaded to RAM and used in the control
loop.
The original PID setting in the user non-volatile memory is quite slow and not
recommended for optimal performance. If DLC is disabled it is recommended
to either:
1. Use the DLC to ﬁnd optimized PID setting.
2. Use Murata Power Designer to ﬁnd appropriate PID setting.
3. Use Universal PID as deﬁned below.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 21 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
The Universal PID setting (taps) is:
VO [V]
0.60
A = 4580.75,
B = -8544.00,
C = 3972.81
Write 0x7CF84DFE85807D8F26 to PID_TAPS register and write command STORE_USER_ALL
Note that if DLC is enabled, for best results VI must be stable before DLC
algorithm begins.
Load Transient Response Optimization
The product incorporates a Non-Linear transient Response, NLR, loop that
decreases the response time and the output voltage deviation during a load
transient. The NLR results in a higher equivalent loop bandwidth than is possible using a traditional linear control loop. The product is pre-conﬁgured with
appropriate NLR settings for robust and stable operation for a wide range of
input voltage and a capacitive load range as deﬁned in the section External
Decoupling Capacitors. For an application with a speciﬁc input voltage, output
voltage, and capacitive load, the NLR conﬁguration can be optimized for a
robust and stable operation and with an improved load transient response.
This will also reduce the amount of output decoupling capacitors and yield
a reduced cost. However, the NLR slightly reduces the efﬁciency. In order to
obtain maximal energy efﬁciency the load transient requirement has to be met
by the standard control loop compensation and the decoupling capacitors. The
NLR settings can be reconﬁgured using the PMBus™ interface.
Remote Sense
The product has remote sense that can be used to compensate for voltage
drops between the output and the point of load. The sense traces should be
located close to the PWB ground layer to reduce noise susceptibility. Due to
derating of internal output capacitance the voltage drop should be kept below
VDROPMAX = (5.25 – VOUT) / 2. A large voltage drop will impact the electrical
performance of the regulator. If the remote sense is not needed, +S should be
connected to VOUT and −S should be connected to GND.
Output Voltage Adjust using Pin-strap Resistor
VSET
R SET
PREF
Using an external Pin-strap resistor,
RSET, the output voltage can be set in
the range 0.6 V to 3.3 V at 28 different
levels shown in the table below. The
resistor should be applied between
the VSET pin and the PREF pin.
RSET also sets the maximum
output voltage, see section “Output
Voltage Range Limitation.” The resistor is sensed only during product start-up. Changing the resistor value during
normal operation will not change the output voltage. The input voltage must
be at least 1 V larger than the output voltage in order to deliver the correct
output voltage. See Ordering Information for output voltage range.
The following table shows recommended resistor values for RSET. Maximum 1% tolerance resistors are required.
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
RSET[kΩ]
10
11
12.1
13.3
14.7
16.2
17.8
19.6
21.5
23.7
26.1
28.7
31.6
1.25
1.30
1.40
34.8
38.3
42.2
VO [V]
1.50
1.60
1.70
1.80
1.90
2.00
2.10
2.20
2.30
2.50
3.00
3.30
RSET[kΩ]
46.4
51.1
56.2
61.9
68.1
75
82.5
90.9
100
110
121
133
The output voltage and the maximum output voltage can be pin strapped to
three ﬁxed values by connecting the VSET pin according to the table below.
VSET
VO [V]
0.60
1.2
2.5
Shorted to PREF
Open “high impedance”
Logic High, GND as reference
Output Voltage Adjust using PMBus™
The output voltage set by pin-strap can be overridden by conﬁguration ﬁle or
by using a PMBus™ command. See Electrical Speciﬁcation for adjustment
range.
When setting the output voltage by conﬁguration ﬁle or by a PMBus™
command, the speciﬁed output voltage accuracy is valid only when the set
output voltage level falls within the same bin range as the voltage level
deﬁned by the pin-strap resistor RSET. The applicable bin ranges are deﬁned
in the table below. Valid accuracy for voltage levels outside the applicable bin
range is two times the speciﬁed.
Example:
Nominal VO is set to 1.10 V by RSET = 26.1 kΩ. 1.10 V falls within the bin
range 0.988-1.383 V, thus speciﬁed accuracy is valid when adjusting VO
within 0.988-1.383V.
VO bin ranges [V]
0.600 – 0.988
0.988 – 1.383
1.383 – 1.975
1.975 – 2.398
2.398 – 2.963
2.963 – 3.753
Output Voltage Range Limitation
The output voltage range that is possible to set by conﬁguration or by the
PMBus™ interface is limited by the pin-strap resistor RSET. The maximum
output voltage is set to 110% of the nominal output value deﬁned by RSET,
VO,MAX = 1.1 x VO,RSET. This protects the load from an over voltage due to an
accidental wrong PMBus™ command.
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25A Digital PoL DC-DC Converter Series
Output Voltage Adjust Limitation using PMBus™
Switching Frequency
In addition to the maximum output voltage limitation by the pin-strap resistor RSET, there is also a limitation in how much the output voltage can be
increased while the output is enabled. If output is disabled then RSET resistor
is the only limitation.
The fundamental switching frequency is 320 kHz, which yields optimal power
efﬁciency. The switching frequency can be set to any value between 200
kHz and 640 kHz using the PMBus™ interface. The switching frequency will
change the efﬁciency/power dissipation, load transient response and output
ripple. For optimal control loop performance in a product without DLC, the
control loop must be re-optimized when changing the switching frequency.
Example:
If the output is enabled with output voltage set to 1.0 V, then it is only possible
to adjust/change the output voltage up to 1.7- V as long as the output is
enabled.
VO setting
when enabled [V]
0.000 – 0.988
0.988 – 1.383
1.383 – 1.975
1.975 – 2.398
2.398 – 2.963
2.963 – 3.753
VO set range
while enabled [V]
~0.2 to >1.2
~0.2 to >1.7
~0.2 to >2.5
~0.2 to >2.97
~0.2 to >3.68
~0.2 to >4.65
Over Voltage Protection (OVP)
The product includes over voltage limiting circuitry for protection of the load.
The default OVP limit is 15% above the nominal output voltage. If the output
voltage exceeds the OVP limit, the product can respond in different ways:
1. Initiate an immediate shutdown until the fault has been cleared. The user
can select a speciﬁc number of retry attempts.
2. Turn off the high-side MOSFET and turn on the low-side MOSFET. The
low-side MOSFET remains ON until the device attempts a restart, i.e. the
output voltage is pulled to ground level (crowbar function).
The default response from an overvoltage fault is to immediately shut down
as in 2. The device will continuously check for the presence of the fault
condition, and when the fault condition no longer exists the device will be reenabled. For continuous OVP when operating from an external clock for synchronization, the only allowed response is an immediate shutdown. The OVP
limit and fault response can be reconﬁgured using the PMBus™ interface.
Under Voltage Protection (UVP)
The product includes output under voltage limiting circuitry for protection of
the load. The default UVP limit is 15% below the nominal output voltage. The
UVP limit can be reconﬁgured using the PMBus™ interface.
Power Good
The product provides a Power Good (PG) ﬂag in the Status Word register
that indicates the output voltage is within a speciﬁed tolerance of its target
level and no fault condition exists. If speciﬁed in section Connections, the
product also provides a PG signal output. The PG pin is active high and by
default open-drain but may also be conﬁgured as push-pull via the PMBus™
interface.
By default, the PG signal will be asserted when the output reaches above
90% of the nominal voltage, and de-asserted when the output falls below
85% of the nominal voltage. These limits may be changed via the PMBus™
interface. A PG delay period is deﬁned as the time from when all conditions
within the product for asserting PG are met to when the PG signal is actually
asserted. The default PG delay is set to 10 ms. This value can be reconﬁgured
using the PMBus™ interface.
For products with DLC the PG signal is by default asserted directly after
the DLC operation have been completed. If DLC is disabled the conﬁgured PG
delay will be used. This can be reconﬁgured using the PMBus™ interface.
Synchronization
Synchronization is a feature that allows multiple products to be synchronized
to a common frequency. Synchronized products powered from the same
bus eliminate beat frequencies reﬂected back to the input supply, and also
reduces EMI ﬁltering requirements. Eliminating the slow beat frequencies
(usually <10 kHz) allows the EMI ﬁlter to be designed to attenuate only the
synchronization frequency. Synchronization can also be utilized for phase
spreading, described in section Phase Spreading.
The products can be synchronized with an external oscillator or one
product can be conﬁgured with the SYNC pin as a SYNC Output working as
a master driving the synchronization. All others on the same synchronization
bus must be conﬁgured with SYNC Input. Default conﬁguration is using the
internal clock, independently of signal at the SYNC pin.
Phase Spreading
When multiple products share a common DC input supply, spreading of the
switching clock phase between the products can be utilized. This dramatically
reduces input capacitance requirements and efﬁciency losses, since the peak
current drawn from the input supply is effectively spread out over the whole
switch period. This requires that the products are synchronized. Up to 16 different phases can be used.
The phase spreading of the product can be conﬁgured using the PMBus™
interface.
Parallel Operation (Current Sharing)
Paralleling multiple products can be used to increase the output current
capability of a single power rail. By connecting the GCB pins of each device
and conﬁguring the devices as a current sharing rail, the units will share the
current equally, enabling up to 100% utilization of the current capability for
each device in the current sharing rail. The product uses a low-bandwidth,
ﬁrst-order digital current sharing by aligning the output voltage of the slave
devices to deliver the same current as the master device. Artiﬁcial droop
resistance is added to the output voltage path to control the slope of the load
line curve, calibrating out the physical parasitic mismatches due to power
train components and PWB layout. Up to 7 devices can be conﬁgured in a
given current sharing group.
In order to avoid interference with other algorithms executing during
parallel operation, the dead-time algorithm should be turned off and ﬁxed
dead-times be used.
Phase Adding and Shedding for Parallel Operation
During periods of light loading, it may be beneﬁcial to disable one or more
phases (modules) in order to eliminate the current drain and switching losses
associated with those phases, resulting in higher efﬁciency. The product offers
the ability to add and drop phases (modules) using a PMBus™ command
in response to an observed load current change. All phases (modules) in a
current share rail are considered active prior to the current sharing rail ramp
to power-good. Phases can be dropped after power-good is reached. Any
member of the current sharing rail can be dropped. If the reference module is
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OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
dropped, the remaining active module with the lowest member position will
become the new reference. Additionally, any change to the number of members of a current sharing rail will precipitate autonomous phase distribution
within the rail where all active phases realign their phase position based on
their order within the number of active members. If the members of a current
sharing rail are forced to shut down due to an observed fault, all members of
the rail will attempt to re-start simultaneously after the fault has cleared.
Efﬁciency Optimized Dead Time Control
The product utilizes a closed loop algorithm to optimize the dead-time applied
between the gate drive signals for the switch and synch FETs. The algorithm
constantly adjusts the deadtime non-overlap to minimize the duty cycle, thus
maximizing efﬁciency. This algorithm will null out deadtime differences due to
component variation, temperature and loading effects. The algorithm can be
conﬁgured via the PMBus™ interface.
Over Current Protection (OCP)
The product includes current limiting circuitry for protection at continuous
overload. The following OCP response options are available:
1. Initiate a shutdown and attempt to restart an inﬁnite number of times with
a preset delay period between attempts.
The default settings for the soft-start delay period and the soft-start ramp
time is 10 ms. Hence, power-up is completed within 20 ms in default conﬁguration using remote control. When the soft-start delay time is set to 0 ms,
the module will begin its ramp-up after the internal circuitry has initialized
(approximately 2 ms). It is generally recommended to set the soft-start rampup time to a value greater than 500 μs to prevent inadvertent fault conditions due to excessive inrush current. The acctual minimum ramp-up time
will however normally be limited by the control loop settings and ramp-up
times of internal interface voltages in the controller circuit to approximately
2 ms. The soft-start power up of the product can be reconﬁgured using the
PMBus™ interface.
VIN
CTRL
VOUT
Initialization
time
2. Initiate a shutdown and attempt to restart a preset number of times with a
preset delay period between attempts.
3. Continue operating for a given delay period, followed by shutdown if the
fault still exists.
4. Continue operating through the fault (this could result in permanent
damage to the power supply).
5. Initiate an immediate shutdown.
The default response from an over current fault is an immediate shutdown
of the device. The device will continuously check for the presence of the
fault condition, and if the fault condition no longer exists the device will be
re-enabled. The load distribution should be designed for the maximum output
short circuit current speciﬁed. The OCP limit and response of the product can
be reconﬁgured using the PMBus™ interface.
Delay
time
Ramp
time
Illustration of Power Up Procedure
Output Voltage Sequencing
A group of products may be conﬁgured to power up in a predetermined
sequence. This feature is especially useful when powering advanced processors, FPGAs, and ASICs that require one supply to reach its operating voltage
prior to another. Multi-product sequencing can be achieved by conﬁguring the
start delay and rise time of each device through the PMBus™ interface and by
using the CTRL start signal.
VOUT
V1
Initialization Procedure
V2
The product follows a speciﬁc internal initialization procedure after power is
applied to the VIN pin:
1. Status of the address and output voltage pin-strap pins are checked and
values associated with the pin settings are loaded to RAM.
2. Values stored in the Murata default non-volatile memory are loaded to
RAM. This overwrites any previously loaded values.
3. Values stored in the user non-volatile memory are loaded to RAM. This
overwrites any previously loaded values.
Once the initialization process is completed, the product is ready to be
enabled using the CTRL pin. The product is also ready to accept commands
via the PMBus™ interface, which will overwrite any values loaded during the
initialization procedure.
Soft-start Power Up
The soft-start control introduces a time-delay before allowing the output
voltage to rise. Once the initialization time has passed the device will wait for
the conﬁgured delay period prior to starting to ramp its output. After the delay
period has expired, the output will begin to ramp towards its target voltage
according to the conﬁgured soft-start ramp time.
t
Illustration of Output Voltage Sequencing.
Voltage Tracking
The product integrates a lossless tracking scheme that allows its output to
track a voltage that is applied to the VTRK pin with no external components
required. During ramp-up, the output voltage follows the VTRK voltage until
the preset output voltage level is met. The product offers two modes of tracking as follows:
1. Coincident. This mode conﬁgures the product to ramp its output voltage at
the same rate as the voltage applied to the VTRK pin.
2. Ratiometric. This mode conﬁgures the product to ramp its output voltage
at a rate that is a percentage of the voltage applied to the VTRK pin. The
default setting is 50%, but a different tracking ratio may be set by an
external resistive voltage divider or through the PMBus™ interface.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 24 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
VOUT
MASTER
SLAVE
t
Illustration of Coincident Voltage Tracking.
VOUT
MASTER
SLAVE
t
Illustration of Ratiometric Voltage Tracking
where RGCB is the pull up resistor value and CGCB is the bus loading. The
pull-up resistor should be tied to an external supply voltage in range from 3.3
to 5 V, which should be present priorμ to or during power-up.
If exploring untested compensation or deadtime conﬁgurations, it is recommended that 27 Ω series resistors are placed between the GCB pin of each
product and the common GCB connection. This will avoid propagation of faults
between products potentially caused by hazardous conﬁguration settings.
When the conﬁgurations of the products are settled the series resistors can
be removed.
The GCB is an internal bus, such that it is only connected across the modules and not the PMBus™ system host. GCB addresses are assigned on a rail
level, i.e. modules within the same current sharing group share the same GCB
address. Addressing rails across the GCB is done with a 5 bit GCB ID, yielding
a theoretical total of 32 rails that can be shared with a single GCB bus.
Fault Spreading
The product can be conﬁgured to broadcast a fault event over the GCB bus to
the other devices in the group. When a non-destructive fault occurs and the
device is conﬁgured to shut down on a fault, the device will shut down and
broadcast the fault event over the GCB bus. The other devices on the GCB bus
will shut down together if conﬁgured to do so, and will attempt to re-start in
their prescribed order if conﬁgured to do so.
Over Temperature Protection (OTP)
The master device in a tracking group is deﬁned as the device that has the
highest target output voltage within the group. This master device will control
the ramp rate of all tracking devices and is not conﬁgured for tracking mode.
All of the CTRL pins in the tracking group must be connected and driven by
a single logic source. It should be noted that current sharing groups that are
also conﬁgured to track another voltage do not offer pre-bias protection; a
minimum load should therefore be enforced to avoid the output voltage from
being held up by an outside force.
The products are protected from thermal overload by an internal over temperature shutdown function in the controller circuit N1, located at position P2 (see
section Thermal Consideration). Some of the products that this speciﬁcation
covers use the temperature at position P2 (TP2) as a reference for speciﬁed
OTP threshold and some use position P1 (TP1) as a reference for speciﬁed OTP
threshold. See the Over Temperature Protection section in the electrical speciﬁcation for each product.
Voltage Margining Up/Down
When TP1 as deﬁned in thermal consideration section exceeds approximately 120 °C the product will shut down. The speciﬁed OTP threshold and
hysteresis are valid for worst case operation regarding cooling conditions,
input voltage and output voltage. The actually conﬁgured default value in the
controller circuit in position P2 is 110 °C, but at worst case operation the
temperature is approximately 10 °C higher at position P1. At light load the
temperature is approximately the same in position P1 and P2. This means the
OTP threshold and hysteresis will be lower at light load conditions when P1 is
used as a reference for OTP.
The product can adjust its output higher or lower than its nominal voltage
setting in order to determine whether the load device is capable of operating
over its speciﬁed supply voltage range. This provides a convenient method for
dynamically testing the operation of the load circuit over its supply margin or
range. It can also be used to verify the function of supply voltage supervisors.
Margin limits of the nominal output voltage ±5% are default, but the margin
limits can be reconﬁgured using the PMBus™ interface.
Pre-Bias Startup Capability
Pre-bias startup often occurs in complex digital systems when current from
another power source is fed back through a dual-supply logic component,
such as FPGAs or ASICs. The product family incorporates synchronous rectiﬁers, but will not sink current during startup, or turn off, or whenever a fault
shuts down the product in a pre-bias condition. Pre-bias protection is not
offered for current sharing groups that also have voltage tracking enabled.
Group Communication Bus
The Group Communication Bus, GCB, is used to communicate between
products. This dedicated bus provides the communication channel between
devices for features such as sequencing, fault spreading, and current sharing.
The GCB solves the PMBus™ data rate limitation. The GCB pin on all devices
in an application should be connected together. A pull-up resistor is required
on the common GCB in order to guarantee the rise time as follows:
Eq. 5.
Products with P1 as reference for OTP:
Products with P2 as reference OTP:
When TP2 as deﬁned in thermal consideration section exceeds 120°C the
product will shut down. For products with P2 as a reference for OTP the conﬁgured default value in the controller circuit in position P2 is 120°C.
The OTP threshold, hysteresis, and fault response of the product can be
reconﬁgured using the PMBus™ interface. The fault response can be conﬁgured as follows:
1. Initiate a shutdown and attempt to restart an inﬁnite number of times with
a preset delay period between attempts (default conﬁguration).
2. Initiate a shutdown and attempt to restart a preset number of times with a
preset delay period between attempts.
3. Continue operating for a given delay period, followed by shutdown if the
fault still exists.
 = RGCB CGCB ≤ 1μs,
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 25 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
4. Continue operating through the fault (this could result in permanent
damage to the power supply).
Default conﬁguration:
Continues Conduction Mode,
CCM
5. Initiate an immediate shutdown.
Optimization examples
This product is designed with a digital control circuit. The control circuit uses
a conﬁguration ﬁle which determines the functionality and performance of
the product. It is possible to change the conﬁguration ﬁle to optimize certain
performance characteristics. In the table below is a schematic view on how to
change different conﬁguration parameters in order to achieve an optimization
towards a wanted performance.



Input idling
power
(no load)
Pli
DCM, Discontinues
Conduction Mode
(diode emulation)
DCM with Minimum Pulse
Enabled
Increase
No change
Decrease
Control
Diode
Switching
NLR
Min.
loop
emulation pulse
frequency
threshold
bandwidth
(DCM)
Config.
parameters
Optimized performance
Maximize
efﬁciency



Enable
Disable
Minimize
ripple ampl.



Enable
or
disable
Enable or
disable
Improve load transient
response
Minimize
idle power loss



Disable
Disable



Enable
Enable
Input standby
power
PCTRL
Load transient Default conﬁguration
di/dt = 2 A/μs
peak voltage
CO = 470 μF
deviation
Vtr1
DLC and Optimized NLR
Load step
25-75-25% of conﬁguration
di/dt = 2 A/μs
max IO
CO = 470 μF
Note 1: The following table, graphs and waveforms are only examples and valid for OKDY-T/25-W12-001-C and
OKDH-T/25-W12-001-C.
Note 2: In the following table and graphs, the worst-case scenario (load step 18.75-6.25 A) has been considered for
load transient.
Default conﬁguration
Load transient di/dt = 2 A/μs
recovery time CO=470 μF
ttr1
Efficiency vs. Output Current and Switching frequency
Turned off with CTRL-pin
Load step
DLC and Optimized NLR
25-75-25% of conﬁguration
max IO
di/dt = 2 A/μs
CO = 470 μF
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
Default conﬁguration:
Monitoring enabled
Pulse monitor mode:
Monitoring disabled
Low power mode:
Monitoring disabled
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
VO = 0.6 V
VO = 1.0 V
VO = 1.8 V
VO = 3.3 V
[mV]
400
95
200
kHz
85
320
kHz
80
480
kHz
75
640
kHz
0
5
10
15
20
Efficiency vs. load current and switching frequency at
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m
Default configuration except changed frequency
25 [A]
108 mW
84 mW
95
105
mV
115
168
63
71
mV
79
108
74
85
122
140
μs
40
40
50
50
Universal PID,
No NLR
DLC,
NLR
300
No
Universal PID,
Default NLR
200
DLC,
Default NLR
Universal PID,
Opt. NLR
100
DLC,
Opt. NLR
0
70
170 mW
Load transient vs. Switching frequency
[%]
90
0.56
0.57
W
0.67
0.92
0.20
0.20
W
0.20
0.20
0.32
0.33
W
0.35
0.43
200
300
400
500
600 [kHz]
Load transient peak voltage deviation vs. frequency.
Step-change (6.25-18.75-6.25 A).
TP1 = +25 °C, VI = 12 V, VO =1.0 V, CO = 470 μF/10 m
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 26 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Power Dissipation vs. Output Current and Switching frequency
[W]
Load Transient vs. Decoupling Capacitance, VO = 1.0 V
[mV]
400
6
Universal PID,
No NLR
5
200
kHz
4
3
320
kHz
2
480
kHz
1
640
kHz
0
DLC,
NLR
300
Universal PID,
Default NLR
200
DLC,
Default NLR
Universal PID,
Opt. NLR
100
DLC,
NLR
0
0
5
10
15
20
25 [A]
No
0
1
2
3
4
Opt.
5 [mF]
Dissipated power vs. load current and switching frequency at
TP1 = +25 °C, VI = 12 V, VO = 1.0 V, CO = 470 μF/10 m
Default configuration except changed frequency
Load transient peak voltage deviation vs. decoupling capacitance.
Step (6.25-18.75-6.25 A). Parallel coupling of capacitors with 470 μF/10 m,
TP1 = +25 °C. VI = 12 V, VO = 1.0 V, fsw = 320 kHz, di/dt = 2 A/μs
Output Ripple vs. Switching frequency
Load Transient vs. Decoupling Capacitance, VO = 3.3 V
[mVpk-pk]
[mV]
400
150
120
0.6 V
90
1.0 V
Universal PID,
No NLR
DLC,
NLR
300
Universal PID,
Default NLR
200
DLC,
Default NLR
1.8 V
60
3.3 V
Universal PID,
Opt. NLR
100
30
DLC,
NLR
0
0
0
200
300
400
500
600
[kHz]
Output voltage ripple Vpk-pk at: TP1 = +25 °C, VI = 12 V, CO = 470 μF/10 m,
IO = 25 A resistive load. Default configuration except changed frequency.
No
1
2
3
4
Opt.
5 [mF]
Load transient peak voltage deviation vs. decoupling capacitance.
Step (6.25-18.75-6.25 A). Parallel coupling of capacitors with 470 μF/10 m,
TP1 = +25 °C. VI = 12 V, VO = 3.3 V, fsw = 320 kHz, di/dt = 2 A/μs
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 27 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Output Load Transient Response, Default Configuration
Output voltage response to load current step- Top trace: output voltage (200 mV/div.).
change (6.25-18.75-6.25 A) at:
Bottom trace: load current (5 A/div.).
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
Time scale: (0.1 ms/div.).
di/dt=2 A/μs, fsw = 320 kHz, CO = 470 μF/10 m
Default configuration (DLC and default NLR)
Output Load Transient Response, DLC and No NLR
Output voltage response to load current step- Top trace: output voltage (200 mV/div.).
change (6.25-18.75-6.25 A) at:
Bottom trace: load current (5 A/div.).
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
Time scale: (0.1 ms/div.).
di/dt=2 A/μs, fsw = 320 kHz, CO = 470 μF/10 m
DLC and no NLR
Output Load Transient Response, DLC and Optimized NLR
Output voltage response to load current step- Top trace: output voltage (200 mV/div.).
change (6.25-18.75-6.25 A) at:
Bottom trace: load current (5 A/div.).
TP1 = +25 °C, VI = 12 V, VO = 1.0 V
Time scale: (0.1 ms/div.).
di/dt=2 A/μs, fsw = 320 kHz, CO = 470 μF/10 m
DLC and optimized NLR
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 28 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Thermal Consideration
General
The product is designed to operate in different thermal environments and sufﬁcient cooling must be provided to ensure reliable operation.
Cooling is achieved mainly by conduction, from the pins to the host board,
and convection, which is dependent on the airﬂow across the product.
Increased airﬂow enhances the cooling of the product.
The Output Current Derating graph found in the Output section for each
model provides the available output current vs. ambient air temperature and
air velocity at speciﬁed VI.
AIR FLOW
P2
P1
Temperature positions and air ﬂow direction.
The product is tested on a 254 x 254 mm, 35 μm (1 oz), test board
mounted vertically in a wind tunnel with a cross-section of 608 x 203 mm.
The test board has 8 layers.
Proper cooling of the product can be veriﬁed by measuring the temperature
at positions P1 and P2. The temperature at these positions should not exceed
the max values provided in the table below.
Bottom view
Top view
AIR
FLOW
P1
P2
Note that the max value is the absolute maximum rating (non destruction)
and that the electrical Output data is guaranteed up to TP1 +95°C.
Definition of product operating temperature
The product operating temperatures are used to monitor the temperature
of the product, and proper thermal conditions can be veriﬁed by measuring
the temperature at positions P1 and P2. The temperature at these positions
(TP1, TP2) should not exceed the maximum temperatures in the table below.
The number of measurement points may vary with different thermal design
and topology. Temperatures above maximum TP1, measured at the reference
point P1 are not allowed and may cause permanent damage. It should also
be noted that depending on setting of the over temperature protection (OTP)
and operating conditions, the product may shut down before the maximum
allowed temperature at TP1 is reached.
SIP Version:Temperature positions and air ﬂow direction.
Definition of reference temperature TP1
The reference temperature is used to monitor the temperature limits of the
product. Temperature above maximum TP1, measured at the reference point
P1 is not allowed and may cause degradation or permanent damage to the
product. TP1 is also used to deﬁne the temperature range for normal operating conditions. TP1 is deﬁned by the design and used to guarantee safety
margins, proper operation and high reliability of the product.
Position
Description
Max Temp.
P1
Reference point, L1, inductor 125°C*
P2
N1, control circuit
125°C*
* A guard band of 5 °C is applied to the maximum recorded component temperatures
when calculating output current derating curves.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 29 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Pin layout, top view (component placement for illustration only).
Pin
1A
2A
3A
4A
4B
5A
5B
6A
6B
7A
7B
8A
8B
9A
9B
Designation
VIN
GND
VOUT
VTRK or PG*
PREF
+S
−S
SA0
GCB
SCL
SDA
VSET
SYNC
SALERT
CTRL
Function
Input Voltage
Power Ground
Output Voltage
Voltage Tracking input or Power Good
Pin-strap reference
Positive sense
Negative sense
PMBus address pin-strap
Group Communication Bus
PMBus Clock
PMBus Data
Output voltage pin-strap
Synchronization I/O
PMBus Alert
Remote Control
* OKDH-T/25-W12-001-C, OKDY-T/25-W12-001-C, OKDH-T/25-W12-001-C, OKDY-T/25-W12-001-C:
Pin 4A = VTRK pin.
SIP Version: Pin layout, top view (component placement for illustration only).
Pin
1A
2A
3A
4A
4B
5A
5B
6A
6B
7A
7B
8A
8B
9A
9B
10A
10B
Designation
VIN
GND
VOUT
+S
−S
VSET
VTRK
SALERT
SDA
SCL
SA1
SA0
SYNC
PG
CTRL
GCB
PREF
Function
Input Voltage
Power Ground
Output Voltage
Positive sense
Negative sense
Output voltage pin-strap
Voltage Tracking input
PMBus Alert
PMBus Data
PMBus Clock
PMBus address pin-strap 1
PMBus address pin-strap 0
Synchronization I/O
Power Good
Remote Control
Group Communication Bus
Pin-strap reference
OKDH-T/25-W12G-001-C, OKDY-T/25-W12G-001-C, OKDH-T/25-W12G-001-C, OKDY-T/25-W12G-001-C:
Pin 4A = PG pin.
For these products the PG pin is internally tied to the VTRK input of the products’ controller. Typically the VTRK
input bias current will be equivalent to a 50 kΩ pull-down resistor. This should be considered when choosing
pull-up resistor for the PG signal.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 30 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Unused input pins
Unused SDA, SCL and GCB pins should still have pull-up resistors as
speciﬁed.
Unused VTRK or SYNC pins should be left open or connected to the PREF pin.
Unused CTRL pin can be left open due to internal pull-up.
VSET and SA0/SA1 pins must be used. These pins must have pin-strap
resistors or strapping settings as speciﬁed.
PWB layout considerations
The pin-strap resistors, RSET, and RSA0/RSA1 should be placed as close to
the product as possible to minimize loops that may pick up noise.
Avoid current carrying planes under the pin-strap resistors and the
PMBus™ signals.
The capacitor CI (or capacitors implementing it) should be placed as close
to the input pins as possible.
Capacitor CO (or capacitors implementing it) should be placed close to the
load.
Care should be taken in the routing of the connections from the sensed
output voltage to the S+ and S– terminals. These sensing connections should
be routed as a differential pair, preferably between ground planes which are
not carrying high currents. The routing should avoid areas of high electric or
magnetic ﬁelds.
Typical Application Circuit
Standalone operation with PMBus™ communication. Top view of product footprint.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 31 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Typical Application Circuit (SIP version)
Standalone operation with PMBus™ communication. Top view of product footprint.
Typical Application Circuit (Parallel Operation)
Parallel operation.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 32 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
PMBus™ interface
This product provides a PMBus™ digital interface that enables the user to
conﬁgure many aspects of the device operation as well as to monitor the
input and output voltages, output current and device temperature. The product
can be used with any standard two-wire I2C or SMBus host device. In addition,
the product is compatible with PMBus™ version 1.1 and includes an SALERT
line to help mitigate bandwidth limitations related to continuous fault monitoring. The product supports 100 kHz bus clock frequency only. The PMBus™
signals, SCL, SDA and SALERT require passive pull-up resistors as stated in
the SMBus Speciﬁcation. Pull-up resistors are required to guarantee the rise
time as follows:
Eq. 6.  = Rp Cp ≤ 1μs,
where Rp is the pull-up resistor value and Cp is the bus loading, the
maximum allowed bus load is 400 pF. The pull-up resistor should be tied to
an external supply voltage in range from 2.7 to 5.5 V, which should be present
prior to or during power-up. If the proper power supply is not available,
voltage dividers may be applied. Note that in this case, the resistance in the
equation above corresponds to parallel connection of the resistors forming the
voltage divider.
Monitoring via PMBus™
It is possible to monitor a wide variety of parameters through the PMBus™
interface. Fault conditions can be monitored using the SALERT pin, which will
be asserted when any number of pre-conﬁgured fault or warning conditions
occurs. It is also possible to continuously monitor one or more of the power
conversion parameters including but not limited to the following:
Input
voltage (READ_VOUT)
Output
current (READ_IOUT)
Internal
junction temperature (READ_TEMPERATURE_1)
Switching
cycle (READ_DUTY_CYCLE)
Snap shot parameter capture
This product offers a special feature that enables the user to capture
parametric data during normal operation or following a fault. The following
parameters are stored:
voltage
Output
voltage
Output
current
Internal
junction temperature
Switching
Duty
The product incorporates two Non-Volatile Memory areas for storage of the supported PMBus™ commands; the Default NVM and the User NVM.
The Default NVM is pre-loaded with Murata factory default values. The
Default NVM is write-protected and can be used to restore the Murata factory
default values through the command RESTORE_DEFAULT_ALL.
The User NVM is pre-loaded with Murata factory default values. The User
NVM is writable and open for customization. The values in NVM are loaded
into operational RAM during initialization according to section “Initialization
Procedure”, where after commands can be changed through the PMBus™
Interface. The STORE_USER_ALL command will store the changed parameters to the User NVM.
INITIALIZATION
User NVM
Factory default
Customizable
STORE_USER_ALL
RESTORE USER ALL
Factory default
Write-protected
RAM
RESTORE_DEFAULT_ALL
WRITE
PMBus interface
READ
Software tools for design and production
Murata provides software tools for conﬁguration and monitoring of this product via the PMBus™ interface. For more information please contact your local
Murata sales representative.
PMBus™ addressing
The PMBus™ address should be conﬁgured with resistors connected
between the SA0/SA1 pins and the PREF pin, as shown in the ﬁgure below.
Recommended resistor values for hard-wiring PMBus™ addresses are shown
in the table. 1% tolerance resistors are required.
frequency
cycle
Status
INITIALIZATION
Default NVM
frequency (READ_FREQUENCY)
In the default conﬁguration monitoring is enabled also when the output
voltage is disabled. This can be changed in order to reduce standby power
consumption.
Input
Non-Volatile Memory (NVM)
voltage (READ_VIN)
Output
Duty
fault has occurred. Automatic store to Flash memory following a fault is triggered when any fault threshold level is exceeded, provided that the speciﬁc
fault response is to shut down. Writing to Flash memory is not allowed if the
device is conﬁgured to restart following the speciﬁc fault condition. It should
also be noted that the device supply voltage must be maintained during the
time the device is writing data to Flash memory; a process that requires
between 700-1400 μs depending on whether the data is set up for a block
write. Undesirable results may be observed if the input voltage of the product
drops below 3.0 V during this process.
SA0
SA1
registers
The Snapshot feature enables the user to read the parameters via the
PMBus™ interface during normal operation, although it should be noted that
reading the 22 bytes will occupy the bus for some time. The Snapshot enables
the user to store the snapshot parameters to Flash memory in response to a
pending fault as well as to read the stored data from Flash memory after a
R SA1
R SA0
PREF
Schematic of connection of address resistor.
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 33 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Index
0
1
2
3
4
5
6
7
8
9
10
11
12
RSA [kΩ]
10
11
12.1
13.3
14.7
16.2
17.8
19.6
21.5
23.7
26.1
28.7
31.6
Index
13
14
15
16
17
18
19
20
21
22
23
24
RSA [kΩ]
34.8
38.3
42.2
46.4
51.1
56.2
61.9
68.1
75
82.5
90.9
100
Address (decimal)
72-75
97
120-123
124-127
Comment
Unrestricted addresses
SMBus Device Default Address
10-bit slave addressing
Reserved for future use
I2C/SMBus – Timing
The PMBus™ address follows the equation below:
Eq. 7. PMBus™ Address (decimal) = 25 x (SA1 index) + (SA0 index)
The user can theoretically conﬁgure up to 625 unique PMBus™ addresses,
however the PMBus™ address range is inherently limited to 128. Therefore,
the user should use index values 0 - 4 on the SA1 pin and the full range of
index values on the SA0 pin, which will provide 125 device address combinations. The user shall also be aware of further limitations of the address space
as stated in the SMBus Speciﬁcation. Note that address 0x4B is allocated for
production needs and cannot be used.
Products with no SA1 pin have an internally deﬁned SA1 index as follows.
Product
OKDX-T/25-W12 (non SIP)
SA1 index
3
Optional PMBus™ Addressing
Alternatively the PMBus™ address can be deﬁned by connecting the SA0/SA1
pins according to the table below. SA1 = open for products with no SA1 pin.
SA1
low
open
high
low
20h
23h
26h
SA0
open
21h
24h
27h
high
22h
25h
Reserved
Low = Shorted to PREF
Open = High impedance
High = Logic high, GND as reference,
Logic High definitions see Electrical Specification
Reserved Addresses
Address 4Bh is allocated for production needs and cannot be used.
Addresses listed in the table below are reserved or assigned according to
the SMBus speciﬁcation and may not be usable. Refer to the SMBus speciﬁcation for further information.
Address (decimal)
0
1
2
3-7
8
9-11
12
40
44-45
55
64-68
Comment
General Call Address / START byte
CBUS address
Address reserved for different bus format
Reserved for future use
SMBus Host
Assigned for Smart Battery
SMBus Alert Response Address
Reserved for ACCESS.bus host
Reserved by previous versions of the SMBus speciﬁcation
Reserved for ACCESS.bus default address
Reserved by previous versions of the SMBus speciﬁcation
Setup and hold times timing diagram
The setup time, tset, is the time data, SDA, must be stable before the rising
edge of the clock signal, SCL. The hold time thold, is the time data, SDA, must
be stable after the rising edge of the clock signal, SCL. If these times are violated incorrect data may be captured or meta-stability may occur and the bus
communication may fail. When conﬁguring the product, all standard SMBus
protocols must be followed, including clock stretching. Refer to the SMBus
speciﬁcation, for SMBus electrical and timing requirements.
This product does not support the BUSY ﬂag in the status commands to
indicate product being too busy for SMBus response. Instead a bus-free time
delay according to this speciﬁcation must occur between every SMBus transmission (between every stop & start condition). In case of storing the RAM
content into the internal non-volatile memory (commands STORE_USER_ALL
and STORE_DEFAULT_ALL) an additional delay of 100 ms has to be inserted.
A 100 ms delay should be inserted after a restore from internal non-volatile
memory (commands RESTORE_DEFAULT_ALL and RESTORE_USER_ALL).
PMBus™ Commands
The products are PMBus™ compliant. The following table lists the implemented PMBus™ read commands. For more detailed information see
PMBus™ Power System Management Protocol Speciﬁcation; Part I – General
Requirements, Transport and Electrical Interface and PMBus™ Power System
Management Protocol; Part II – Command Language.
Designation
Standard PMBus™ Commands
Control Commands
PAGE
OPERATION
ON_OFF_CONFIG
WRITE_PROTECT
Output Commands
VOUT_MODE (Read Only)
VOUT_COMMAND
VOUT_TRIM
VOUT_CAL_OFFSET
VOUT_MAX
VOUT_MARGIN_HIGH
VOUT_MARGIN_LOW
VOUT_TRANSITION_RATE
VOUT_DROOP
MAX_DUTY
Cmd
Impl
00h
01h
02h
10h
No
Yes
Yes
No
20h
21h
22h
23h
24h
25h
26h
27h
28h
32h
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 34 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Designation
FREQUENCY_SWITCH
VIN_ON
VIN_OFF
IOUT_CAL_GAIN
IOUT_CAL_OFFSET
VOUT_SCALE_LOOP
VOUT_SCALE_MONITOR
COEFFICIENTS
Fault Limit Commands
POWER_GOOD_ON
POWER_GOOD_OFF
VOUT_OV_FAULT_LIMIT
VOUT_OV_WARN_LIMIT
VOUT_UV_WARN_LIMIT
VOUT_UV_FAULT_LIMIT
IOUT_OC_FAULT_LIMIT
IOUT_OC_WARN_LIMIT
IOUT_UC_FAULT_LIMIT
OT_FAULT_LIMIT
OT_WARN_LIMIT
UT_WARN_LIMIT
UT_FAULT_LIMIT
VIN_OV_FAULT_LIMIT
VIN_OV_WARN_LIMIT
VIN_UV_WARN_LIMIT
VIN_UV_FAULT_LIMIT
Fault Response Commands
VOUT_OV_FAULT_RESPONSE
VOUT_UV_FAULT_RESPONSE
OT_FAULT_RESPONSE
UT_FAULT_RESPONSE
VIN_OV_FAULT_RESPONSE
VIN_UV_FAULT_RESPONSE
IOUT_OC_FAULT_RESPONSE
IOUT_UC_FAULT_RESPONSE
Time setting Commands
TON_DELAY
TON_RISE
TOFF_DELAY
TOFF_FALL
TON_MAX_FAULT_LIMIT
Status Commands (Read Only)
CLEAR_FAULTS
STATUS_BYTE
STATUS_WORD
STATUS_VOUT
STATUS_IOUT
STATUS_INPUT
STATUS_TEMPERATURE
STATUS_CML
STATUS_MFR_SPECIFIC
Monitor Commands (Read Only
READ_VIN
READ_VOUT
READ_IOUT
READ_TEMPERATURE_1
READ_TEMPERATURE_2
READ_FAN_SPEED_1
READ_DUTY_CYCLE
READ_FREQUENCY
Group Commands
INTERLEAVE
PHASE_CONTROL
Cmd
33h
35h
36h
38h
39h
29h
2Ah
30h
Impl
Yes
No
No
Yes
Yes
No
No
No
5Eh
5Fh
40h
42h
43h
44h
46h
4Ah
4Bh
4Fh
51h
52h
53h
55h
57h
58h
59h
Yes
No
Yes
No
No
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
41h
45h
50h
54h
56h
5Ah
47h
4Ch
Yes
Yes
Yes
Yes
Yes
Yes
No
No
60h
61h
64h
65h
62h
Yes
Yes
Yes
Yes
No
03h
78h
79h
7Ah
7Bh
7Ch
7Dh
7Eh
80h
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
88h
8Bh
8Ch
8Dh
8Eh
90h
94h
95h
Yes
Yes
Yes
Yes
No
No
Yes
Yes
37h
F0h
Yes
Yes
Designation
Identiﬁcation Commands
PMBUS_REVISION
MFR_ID
MFR_MODEL
MFR_REVISION
MFR_LOCATION
MFR_DATE
MFR_SERIAL
Supervisory Commands
STORE_DEFAULT_ALL
RESTORE_DEFAULT_ALL
STORE_USER_ALL
RESTORE_USER_ALL
Product Speciﬁc Commands
Output Commands
XTEMP_SCALE
XTEMP_OFFSET
Time Setting Commands
POWER_GOOD_DELAY
Fault limit Commands
IOUT_AVG_OC_FAULT_LIMIT
IOUT_AVG_UC_FAULT_LIMIT
Fault Response Commands
MFR_IOUT_OC_FAULT_RESPONSE
MFR_IOUT_UC_FAULT_RESPONSE
OVUV_CONFIG
Conﬁguration and Control Commands
MFR_CONFIG
USER_CONFIG
MISC_CONFIG
TRACK_CONFIG
PID_TAPS
PID_TAPS_CALC*
INDUCTOR
NLR_CONFIG
TEMPCO_CONFIG
IOUT_OMEGA_OFFSET
DEADTIME
DEADTIME_CONFIG
DEADTIME_MAX
SNAPSHOT
SNAPSHOT_CONTROL
DEVICE_ID
USER_DATA_00
Group Commands
SEQUENCE
GCB_CONFIG
GCB_GROUP
ISHARE_CONFIG
PHASE_CONTROL
Supervisory Commands
PRIVATE_PASSWORD
PUBLIC_PASSWORD
UNPROTECT
SECURITY_LEVEL
Cmd
Impl
98h
99h
9Ah
9Bh
9Ch
9Dh
9Eh
Yes
Yes
Yes
Yes
Yes
Yes
Yes
11h
12h
15h
16h
Yes
Yes
Yes
Yes
D9h
DAh
No
No
D4h
Yes
E7h
E8h
Yes
Yes
E5h
E6h
D8h
Yes
Yes
Yes
D0h
D1h
E9h
E1h
D5h
F2h
D6h
D7h
DCh
BEh
DDh
DEh
BFh
EAh
F3h
E4h
B0h
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
E0h
D3h
E2h
D2h
F0h
Yes
Yes
Yes
Yes
Yes
FBh
FCh
FDh
FAh
Yes
Yes
Yes
Yes
Notes:
Cmd is short for Command.
Impl is short for Implemented.
* These commands are available in products without DLC.
** These commands are available in products with DLC.
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 35 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
MECHANICAL SPECIFICATIONS-THROUGH-HOLE MOUNT
All component placements – whether shown as physical components or symbolical outline – are for reference only and are subject to change throughout the product’s life cycle,
unless explicitly described and dimensioned in this drawing.
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 36 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
MECHANICAL SPECIFICATIONS-SURFACE MOUNT
All component placements – whether shown as physical components or symbolical outline – are for reference only and are subject to change throughout the product’s life
cycle, unless explicitly described and dimensioned in this drawing.
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 37 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
MECHANICAL SPECIFICATIONS-SIP VERSION
All component placements – whether shown as physical components or symbolical outline – are for reference only and are subject to change throughout the product’s life cycle,
unless explicitly described and dimensioned in this drawing.
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 38 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Soldering Information - Surface Mounting and Hole Mount
through Pin in Paste Assembly
The product is intended for forced convection or vapor phase reﬂow soldering
in SnPb or Pb-free processes.
The reﬂow proﬁle should be optimised to avoid excessive heating of the
product. It is recommended to have a sufﬁciently extended preheat time to
ensure an even temperature across the host PWB and it is also recommended
to minimize the time in reﬂow.
Maximum Product Temperature Requirements
Top of the product PWB near pin 10B is chosen as reference location for the
maximum (peak) allowed product temperature (TPRODUCT) since this will likely
be the warmest part of the product during the reﬂow process.
SnPb solder processes
For SnPb solder processes, the product is qualiﬁed for MSL 1 according to
IPC/JEDEC standard J STD 020C.
During reﬂow TPRODUCT must not exceed 225 °C at any time.
A no-clean ﬂux is recommended to avoid entrapment of cleaning ﬂuids in
cavities inside the product or between the product and the host board, since
cleaning residues may affect long time reliability and isolation voltage.
General reflow process specifications
Average ramp-up (TPRODUCT)
Typical solder melting (liquidus)
temperature
Minimum reﬂow time above TL
Minimum pin temperature
Peak product temperature
TL
TPIN
TPRODUCT
Average ramp-down (TPRODUCT)
Maximum time 25°C to peak
SnPb eutectic
3°C/s max
3°C/s max
183°C
221°C
60 s
210°C
225°C
6°C/s max
6 minutes
60 s
235°C
260°C
6°C/s max
8 minutes
Pb-free
Minimum Pin Temperature Recommendations
Pin number 2B is chosen as reference location for the minimum pin temperaTemperature
TPRODUCT maximum
TPIN minimum
For Pb-free solder processes, the product is qualiﬁed for MSL 3 according to
IPC/JEDEC standard J-STD-020C.
During reﬂow TPRODUCT must not exceed 260 °C at any time.
Dry Pack Information
Products intended for Pb-free reﬂow soldering processes are delivered in
standard moisture barrier bags according to IPC/JEDEC standard J STD 033
(Handling, packing, shipping and use of moisture/reﬂow sensitivity surface
mount devices).
Using products in high temperature Pb-free soldering processes requires
dry pack storage and handling. In case the products have been stored in an
uncontrolled environment and no longer can be considered dry, the modules
must be baked according to J STD 033.
Thermocoupler Attachment
Pin
profile
TL
Pb-free solder processes
Product
profile
Pin 2A for measurement of minimum Pin (solder joint)
temperature TPIN
Time in
reflow
Time in preheat
/ soak zone
Time 25°C to peak
Time
ture recommendation since this will likely be the coolest solder joint during
the reﬂow process.
SnPb solder processes
For SnPb solder processes, a pin temperature (TPIN) in excess of the solder
melting temperature, (TL, 183°C for Sn63Pb37) for more than 60 seconds
and a peak temperature of 220°C is recommended to ensure a reliable solder
joint.
Pin 4B for measurement of maximum
Product temperature TPRODUCT
For dry packed products only: depending on the type of solder paste
and ﬂux system used on the host board, up to a recommended maximum
temperature of 245°C could be used, if the products are kept in a controlled
environment (dry pack handling and storage) prior to assembly.
Soldering Information - Hole Mounting
Lead-free (Pb-free) solder processes
A maximum preheat rate of 4°C/s and maximum preheat temperature of
150°C is suggested. When soldering by hand, care should be taken to avoid
direct contact between the hot soldering iron tip and the pins for more than a
few seconds in order to prevent overheating.
For Pb-free solder processes, a pin temperature (TPIN) in excess of the solder
melting temperature (TL, 217 to 221°C for SnAgCu solder alloys) for more
than 60 seconds and a peak temperature of 245°C on all solder joints is
recommended to ensure a reliable solder joint.
The hole mounted product is intended for plated through hole mounting by
wave or manual soldering. The pin temperature is speciﬁed to maximum to
270°C for maximum 10 seconds.
A no-clean ﬂux is recommended to avoid entrapment of cleaning ﬂuids in
cavities inside the product or between the product and the host board. The
cleaning residues may affect long time reliability and isolation voltage.
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 39 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Delivery Package Information
The products are delivered in antistatic carrier tape (EIA 481 standard).
Carrier Tape Specifications
Material
Surface resistance
Bakeability
Tape width, W
Pocket pitch, P1
Pocket depth, K0
Reel diameter
Reel capacity
Reel weight
Antistatic PS
<107 Ohm/square
The tape is not bakable
44 mm [1.73 inch]
24 mm [0.95 inch]
12.4 mm [0.488 inch]
381 mm [15 inch]
200 products /reel
1.7 kg/full reel
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MDC_OKDx-T/25-W12-xxx-C.A06 Page 40 of 41
OKDx-T/25-W12-xxx-C
25A Digital PoL DC-DC Converter Series
Soldering Information - Hole Mounting (SIP version)
The product is intended for plated through hole mounting by wave or manual
soldering. The pin temperature is speciﬁed to maximum to 270°C for maximum 10 seconds.
A maximum preheat rate of 4°C/s and maximum preheat temperature of
150°C is suggested. When soldering by hand, care should be taken to avoid
direct contact between the hot soldering iron tip and the pins for more than a
few seconds in order to prevent overheating.
A no-clean ﬂux is recommended to avoid entrapment of cleaning ﬂuids in
cavities inside the product or between the product and the host board. The
cleaning residues may affect long time reliability and isolation voltage.
Delivery Package Information (SIP version)
The products are delivered in antistatic trays.
Tray Specifications
Material
Surface resistance
Bakability
Tray thickness
Box capacity
Tray weight
Antistatic Polyethylene foam
105< Ohms/square <1011
The trays are not bakeable
15 mm [0.709 inch]
100 products, 2 full trays/box)
35 g empty tray, 549 g full tray
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansﬁeld, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Speciﬁcations are subject to change without
notice.
© 2016 Murata Power Solutions, Inc.
www.murata-ps.com/support
MDC_OKDx-T/25-W12-xxx-C.A06 Page 41 of 41

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