Data Sheet

SYNC

RoHS Compliant

Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings

only, functional operation of the device is not implied at these or any other conditions in excess of those given in the operations

sections of the data sheet. Exposure to absolute maximum ratings for extended periods can adversely affect the device reliability.

Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature conditions.

Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature conditions. See

Feature Descriptions for additional information.

voltage of the module. The output voltage follows the

continue operation without interruption as the response to

Please see the Digital Feature Descriptions section.

At input voltages below the input undervoltage lockout limit,

the module operation is disabled. The module will begin to

operate at an input voltage above the undervoltage lockout

turn-on threshold.

Please see the Digital Feature Descriptions section.

Please see the Digital Feature Descriptions section.

The module switching frequency can be synchronized to a

signal with an external frequency within a specified range.

Synchronization can be done by using the external signal

applied to the SYNC pin of the module as shown in Fig. 45,

with the converter being synchronized by the rising edge of

Please see the Digital Feature Descriptions section.

Identical dimensions and pin layout of Analog and Digital

MicroDLynx modules permit migration from one to the other

without needing to change the layout. In both cases the trim

resistor is connected between trim and signal ground. The

output of the analog module cannot be trimmed down to

0.45V

terminal can be connected through a pullup resistor

The module has a feature that optimizes transient response

External capacitors are usually added to the output of the

module for two reasons: to reduce output ripple and noise

(see Figure 38) and to reduce output voltage deviations from

the steady-state value in the presence of dynamic load

current changes. Adding external capacitance however

Larger values of external capacitance could also cause the

and TRIM pins of the module, as shown in Fig. 46. This R-C

allows the user to externally adjust the voltage loop

feedback compensation of the module.

Figure. 46. Circuit diagram showing connection of RTUME

and CTUNE to tune the control loop of the module.

Recommended values of RTUNE and CTUNE for different output

capacitor combinations are given in Tables 2 and 3. Table 3

presence of dynamic current loading, additional output

capacitance will be required. Table 3 lists recommended

values of RTUNE and CTUNE in order to meet 2% output

voltage deviation limits for some common output voltages

in the presence of a 10A to 20A step change (50% of full

load), with an input voltage of 12V.

Please contact your GE technical representative to obtain

more details of this feature as well as for guidelines on how

to select the right value of external R-C to tune the module

Table 2. General recommended values of of RTUNE and

combinations.

Note: The capacitors used in the Tunable Loop tables are

The 20A Digital MicroDLynxTM power modules have a PMBus

interface that supports both communication and control.

The PMBus Power Management Protocol Specification can

be obtained from www.pmbus.org. The modules support a

parameters can be programmed using PMBus and stored as

master must generate the correct PEC byte for all

either address resistor value is outside the range specified in

PU: Sets the default to either operate any time input power

OPERATION command.

used together with the CMD, PU and ON bits to determine

startup.

PMBus. When setting this parameter, make sure that the

charging current for output capacitors can be delivered by

the module in addition to any load current to avoid nuisance

tripping of the overcurrent protection circuitry during

startup. The TON_RISE command sets the rise time in ms,

and allows choosing soft start times between 600μs and

9ms, with possible values listed in Table 5. Note that the

exponent is fixed at -4 (decimal) and the upper two bits of

The VOUT_SCALE_LOOP parameter is important for a

number of PMBus commands related to output voltage

trimming, margining, over/under voltage protection and the

information on the output voltage divider ratio is conveyed

to the module through the VOUT_SCALE_LOOP parameter

which is calculated as follows:

The VOUT_SCALE_LOOP parameter is specified using the

high byte are used to set the exponent which is fixed at –9

(decimal). The remaining three bits of the high byte [2:0] and

When PMBus commands are used to trim or margin the

output voltage, the value of VREF is what is changed inside

the module, which in turn changes the regulated output

voltage of the module.

The nominal output voltage of the module can be adjusted

with a minimum step size of 0.4% over a ±25% range from

nominal using the VOUT_TRIM command over the PMBus.

The VOUT_TRIM command is used to apply a fixed offset

using the “Linear” mode with the exponent fixed at –10

(decimal). The value of the offset voltage is given by

output voltage. The valid range in two’s complement for this

command is –4000h to 3fffh. The high order two bits of

the high byte must both be either 0 or 1. If a value outside of

the +/-25% adjustment range is given with this command,

the module will set it’s output voltage to the nominal value

(as if VOUT_TRIM had been set to 0), assert SMBALRT#, set

the CML bit in STATUS_BYTE and the invalid data bit in

STATUS_CML.

The module can also have its output voltage margined via

PMBus commands. The command VOUT_MARGIN_HIGH

sets the margin high voltage, while the command

or VOUT_MARGIN_LOW and the VOUT_TRIM values as

Note that the sum of the margin and trim voltages cannot

be outside the ±25% window around the nominal output

voltage. The data associated with VOUT_MARGIN_HIGH and

VOUT_MARGIN_LOW can be stored to non-volatile memory

using the STORE_DEFAULT_ALL command.

The module is commanded to go to the margined high or

used to enable margining as follows:

00XX : Margin Off

set using the parameter IOUT_OC_WARN_LIMIT. This

data word where the upper five bits [7:3] of the high byte

represent the exponent and the remaining three bits of the

high byte [2:0] and the eight bits in the low byte represent

the mantissa. The exponent is fixed at –1 (decimal). The

upper five bits of the mantissa are fixed at 0 while the lower

2013, the value for IOUT_OC_WARN_LIMIT will be fixed at

The module can provide information related to temperature

of the module through the STATUS_TEMPERATURE

command. The command returns information about

whether the pre-set over temperature fault threshold and/or

the warning threshold have been exceeded.

The module has output over and under voltage protection

capability. The PMBus command VOUT_OV_FAULT_LIMIT is

used to set the output over voltage threshold from four

possible values: 108%, 110%, 112% or 115% of the

Values within the supported range for over and

undervoltage detection thresholds will be set to the nearest

fixed percentage. Note that the correct value for

response to the fault. Both these commands use a single

The module allows adjustment of the input under voltage

lockout and hysteresis. The command VIN_ON allows setting

the input voltage turn on threshold, while the VIN_OFF

command sets the input voltage turn off threshold. For the

VIN_ON command, possible values are 2.75V, and 3V to 14V

Each threshold is set up symmetrically above and below the

nominal value. The POWER_GOOD_ON command sets the

which the PGOOD command is de-asserted. This command

also sets two thresholds symmetrically placed around the

PGOOD terminal can be connected through a pullup resistor

The READ_IOUT command provides module average output

current information. This command only supports positive or

current sourced from the module. If the converter is sinking

current a reading of 0 is provided. The READ_IOUT

command returns two bytes of data in the linear data

format. The exponent uses the upper five bits [7:3] of the

high data byte in two-s complement format and is fixed at –

The module can provide output voltage information using

the READ_VOUT command. The command returns two bytes