cui.com

date 11/07/2014

│ page 8 of 14

CUI Inc

│ MODEL: NDM2Z-12H │ DESCRIPTION: AUTO COMPENSATED, DIGITAL DC-DC POL CONVERTER

OPERATING INFORMATION

The NDM2Z-12 modules are available in different

configurations; not all pins and functions are supported by

each configuration. This document describes all pins and

functions.

The Novum Z Products PMBus Commands application note

defines the available PMBus™ commands.

REQUIRED CONFIGURATIONS

NDM2Z-12 Module Pins

Each NDM2Z-12 module should have a resistor placed

between VSET and PREF to set the output voltage of the

module. The maximum output voltage which can be

configured by PMBus commands can never exceed 110% of

the voltage set by the VSET pin. The SMBus address of each

module is set by either pin-strap configuration or resis-

tor value associated with the SA0 pin. More information

regarding setting the SMBus address for a module can be

found in the section titled “SMBus”.

PCB Layout

Good performance of any point of load voltage regulator

module can only be achieved with careful PCB layout

considerations. Ground planes or very wide traces should

be used for power and ground routing. Input capacitors

should be placed close to the input voltage pins of the

module and output capacitors should be placed close to the

load. The module should also be placed as close as possible

to the load.

INPUT AND OUTPUT CAPACITORS

Input Capacitors

Input capacitors are recommended to be used with the

NDM2Z-12 module in order to minimize input voltage ripple.

A 330 μF POSCAP or electrolytic and 3x 22 μF ceramic

capacitors should be placed as close as possible to the input

pins of the module. Additional input capacitors may be

used if less input voltage ripple is desired.

Output Capacitors

Output capacitors are recommended to be used with the

NDM2Z-12 module in order to improve transient response

and minimize output voltage ripple. A 330 μF POSCAP or

electrolytic and 3x 22 μF ceramic capacitors should be

placed as close as possible to the load. Additional output

capacitors may be used to further improve the output

voltage characteristics.

POWER CONVERSION AND MANAGEMENT

Power Conversion Overview

The NDM2Z-12 module has several features to enable high

power conversion efficiency. Non-linear loop response (NLR)

improves the response time and reduces the output

deviation as a result of load transients. The incorporation

of DFM enhances the performance of CUI modules over that

available from conventional analog POL offerings.

Power Management Overview

The NDM2Z-12 module incorporates a wide range of power

management features. All power management functions

can be configured via the SMBus interface. The NDM2Z-12

can monitor and report many characteristics of the module

including input voltage, output voltage, output current and

internal temperature. Additionally, the NDM2Z-12 includes

circuit protection features that protect the module and load

from damage due to system faults. Monitoring parameters

can also be configured to provide alerts for specific

conditions. The ability of CUI modules to digitally control,

configure and monitor OS features provides significant

benefits over traditional analog POL products.

CONFIGURING THE MODULE

Pin Settings

Pin SA0 is used to set the SMBus address of the NDM2Z-12

module. Details of this feature are discussed in the section

titled “SMBus”. Pin SYNC is used to synchronize the switch-

ing clock of the module to an external clock source. More

information regarding synchronization can be found in the

section titled “SWITCHING FREQUENCY AND SYNCHRONI-

ZATION”.

Pin VSET is used to configure the output voltage of the

module. The voltage established by the VSET pin limits the

maximum output voltage that can be configured by SMBus

commands.

The SA0, SYNC and VSET pin configurations are read by

the module when power is applied or whenever a SMBus

RESTORE command is issued.

The CTRL pin is active high and can be used to enable the

module. Internal connections on the module will drive the

CTRL pin high if it is left floating.

Pins +S and -S are used for remote voltage sensing of the

output voltage.

For more information, please visit the product page.