Ericsson Internal
E
SECSUND
PRODUCT SPECIFICATION
2 (7)
Prepared (also subject responsible if other)
No.
30/1301-BMR 451 0002 Uen
13
Technical Specification
Approved
Checked
Date
Rev
Reference
EN/LZT 146 401 R4A May 2015
BMR 451 Digital PoL Regulators
Input 4.5-14 V, Output up to 40 A / 132 W
2015-05-15
PJ1
© Ericsson AB
Control Loop Compensation
immediately when an appropriate input
The product is configured with a robust control loop
voltage is applied, or turn on/off can be performed with PMBus
commands. Please contact your local Ericsson Power Modules
representative for design support of custom configurations or
appropriate SW tools for design and down-load of new
configurations.
compensation which allows for a wide range operation of input
and output voltages and capacitive loads as defined in the
electrical specification. 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. Please contact your local
Ericsson Power Modules representative for design support of
custom configurations or appropriate SW tools for design and
down-load of new configurations.
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
products are designed for a stable operation (30 degrees
phase margin) without external capacitors connected to the
input or output. The performance in some applications can be
enhanced by addition of external capacitance as described
under External Capacitors. If the input voltage source contains
significant inductance, the addition of a 470 µF capacitor with
low ESR at the input of the product will ensure stable
operation.
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 electrical specification. 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.
Please contact your local Ericsson Power Modules
External Decoupling Capacitors
Input capacitors:
The recommended input capacitor has a minimum capacitance
of 470 µF and a low ESR. The ripple current rating of the
capacitor must be at least 4 A rms. 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.
representative for design support of custom configurations or
appropriate SW tools for design and down-load of new
configurations.
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 PCB
ground layer to reduce noise susceptibility. The remote sense
circuitry will compensate for up to 10% voltage drop between
output pins and the point of load.
Output capacitors:
The recommended output capacitor has a minimum
capacitance of 680 µF and a low ESR. 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 high-frequency 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.
If the remote sense is not needed +S should be connected to
VOUT and −S should be connected to GND.
Output Voltage Adjust Range (default)
With Analog Output Voltage Adjust the output voltage can be
set in the range 0.7 V to 3.3 V at 25 different levels by an
external resistor, RSET, which is applied between the FLEX pin
and the −S pin. The resistor is sensed during boot-up of the
regulator. Changing the resistor 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. If the input voltage is lower, the product
will still deliver power with a lower output voltage than the set
output voltage. The product will turn off at the input turn-off
voltage level, according to Turn-off Input Voltage Range.
It is equally important to use low resistance and low inductance
PCB layouts and cabling.
External decoupling capacitors are a part of the control loop of
the product and may affect the stability margins. The ESR of
the capacitors is a very important parameter. Stable operation
is guaranteed for an ESR value of >5 mΩ and a total
capacitance in the range defined in the electrical specification.
For a total capacitance outside this range or with lower ESR a
re-configuration will be necessary for robust dynamic operation
and stability. Please contact your local Ericsson Power
Modules representative for design support of custom
configurations or appropriate SW tools for design and down-
load of new configurations.
FLEX
R
SET
−S
ERICSSON [ ERICSSON ]
