l6730cqtr STMicroelectronics, l6730cqtr Datasheet - Page 4
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l6730cqtr
Manufacturer Part Number
l6730cqtr
Description
Adjustable Step-down Controller With Synchronous Rectification
Manufacturer
STMicroelectronics
Datasheet
1.L6730CQTR.pdf
(50 pages)
Summary description
1
4/50
Summary description
The controller is an integrated circuit realized in BCD5 (BiCMOS-DMOS, version 5) fabrication
that provides complete control logic and protection for high performance step-down DC-DC and
niPOL converters.
It is designed to drive N-Channel MOSFETs in a synchronous rectified buck topology. The
output voltage of the converter can be precisely regulated down to 600mV with a maximum
tolerance of ±0.8% or to 1.2V, when one of the internal references is used. It is also possible to
use an external reference from 0V to 2.5V. The input voltage can range from 1.8V to 14V, while
the supply voltage can range from 4.5V to 14V. High peak current gate drivers provide for fast
switching to the external power section and the output current can be in excess of 20A,
depending on the number of the external MOSFETs used. The PWM duty cycle can range from
0% to 100% with a minimum on-time (T
with very low duty cycle and very high switching frequency.
The device provides voltage-mode control. It includes a 400KHz free-running oscillator that is
adjustable from 100KHz to 1MHz. The error amplifier features a 10MHz gain-bandwidth-
product and 5V/µs slew-rate that permits to realize high converter bandwidth for fast transient
response. The device monitors the current by using the R
side MOSFET(s), eliminating the need for a current sensing resistor and guaranteeing an
effective over-current-protection in all the application conditions. When necessary, two different
current limit protections can be externally set through two external resistors. A leading edge
adjustable blanking time is also available to avoid false over-current-protection (OCP)
interventions in every application condition. It is possible to select the HICCUP mode or the
constant current protection (L6730D) after the soft-start phase.
During the soft-start phase a constant current protection is provided. It is possible to select
(before the device turn-on) the sink-source or the source-only mode capability by acting on a
multifunction pin (L6730C). The L6730C disables the sink mode capability during the soft-start
in order to allow a proper start-up also in pre-biased output voltage conditions. The L6730D can
always sink current and so it can be used to supply the DDR Memory BUS termination. Other
features are Master-Slave synchronization (with 180° phase shift), Power-Good with adjustable
delay, over-voltage-protection, feed-back disconnection, selectable UVLO threshold (5V and
12V Bus) and thermal shutdown. The HTSSOP20 package allows the realization of really
compact DC/DC converters.
ON
,
MIN
) lower than 100ns making possible conversions
DS(on)
of both the high-side and low-
L6730C - L6730D