NQB-D datasheet(21/36 Pages) CUI

21 / 36 page

cui.com

date 11/07/2014

│ page 21 of 36

CUI Inc

│ SERIES: NQB-D │ DESCRIPTION: FULLY REGULATED ADVANCED BUS CONVERTERS

Operating information

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, duty cycle and internal temperature.

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 CUI Power

Modules representative for design support of custom

configurations or appropriate SW tools for design and

down-load of your own configurations.

Power Management Overview

The NQB consists of two different product families

designed for two different input voltage ranges, 36 to 75

Vdc and 40 to 60 Vdc, see ordering information.

The input voltage range 36 to 75 Vdc meets the

requirements of the European Telecom Standard ETS 300

132-2 for normal input voltage range in –48 and –60 Vdc

systems, -40.5 to -57.0 V and –50.0 to -72 V respectively.

At input voltages exceeding 75 V, the power loss will

be higher than at normal input voltage and T

P1 must be

limited to absolute max +125°C. The absolute maximum

continuous input voltage is 80 Vdc.

The input voltage range 40 to 60 Vdc meets the

requirements for normal input voltage range in -48 V

systems, -40.5 to -57.0 V. At input voltages exceeding

60 V, the power loss will be higher than at normal input

voltage and T

P1 must be limited to absolute max +125°C.

The absolute maximum continuous input voltage is 65 Vdc.

Input Voltage

The product monitors the input voltage and will turn

on and turn off at predetermined levels. The minimum

hysteresis between turn on and turn off input voltage is

2 V. The turn on and turn off levels of the product can be

reconfigured using the PMBus interface

Turn-off Input Voltage

The products are fitted with a configurable remote control

function. The primary remote control is referenced to the

primary negative input connection (-In). The RC function

allows the converter to be turned on/off by an external

device like a semiconductor or mechanical switch. The RC

pin has an internal pull up resistor. The remote control

functions can also be configured using the PMBus.

Remote Control (RC)

The device should be capable of sinking 0.7 mA. When the

RC pin is left open, the voltage generated on the RC pin is

max 6 V. The standard product is provided with “negative

logic” remote control and will be off

until the RC pin is connected to the

-In. To turn on the product the

voltage between RC pin and -In

should be less than 1 V.

To turn off the product the RC pin

should be left open for a minimum

of time 150 µs, the same time

requirement applies when the product

shall turn on. In situations where it is

desired to have the product to power up automatically

without the need for control signals or a switch, the RC

pin can be wired directly to –In or disabled via the 0xE3

command. The logic option for the primary remote control is

configured via 0xE3 command using the PMBus.

The CTRL-pin can be configured as remote control via the

PMBus interface. In the default configuration the CTRL-

pin is disabled and floating. The output can be configured

to internal pull-up to 3.3 V using the MFR_MULTI_PIN_

CONFIG (0xF9) PMBus command. The CTRL-pin can be left

open when not used. The logic options for the secondary

remote control can be positive or negative logic. The logic

option for the secondary remote control is configured

via ON_OFF_CONFIG (0x02) command using the PMBus

interface, see also MFR_MULTI_PIN_CONFIG section.

Remote Control (secondary side)

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.

Minimum recommended external input capacitance is 100

µF. The performance in some applications can be enhanced

by addition of external capacitance as described under

External Decoupling Capacitors.

Input and Output Impedance

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 parallel capacitors to lower the

effective ESR. The ceramic capacitors will handle high-

frequency dynamic load changes while the electrolytic

capacitors are used to handle low frequency dynamic load

changes. Ceramic capacitors will also reduce any high

frequency noise at the load. It is equally important to

use low resistance and low inductance PWB layouts and

cabling. External decoupling capacitors will become part

of the product’s control loop. The control loop is optimized

for a wide range of external capacitance and the maximum

recommended value that could be used without any

additional analysis is found in the electrical specification.

The ESR of the capacitors is a very important parameter.

Stable operation is guaranteed with a verified ESR value of

External Decoupling Capacitors

For more information, please visit the product page.

NQB-D Datasheet(PDF) 21 Page - CUI INC

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