L6731BTR STMicroelectronics, L6731BTR Datasheet - Page 3

• Manufacturer Part Number: L6731BTR
• Description: IC CTRLR ADJ STEP DOWN 16-TSSOP
• Manufacturer: STMicroelectronics

Specifications of L6731BTR

• Applications: Controller, DDR
• Voltage - Input: 1.8 ~ 14 V
• Number Of Outputs: 1
• Voltage - Output: Adjustable down to 0.6V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-5099-2

L6731B
1
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%. If an external reference is used, it will be trasferred divided by 2 to the N.I.
input of the error-amplifier, in accordance to the DDR memory specifications.
An internal resistor divider and a voltage buffer allow to achieve an accuracy of 1% on both Vtt
and Vttref. It's possibile to provide an external reference from 0V to 2.5V in order to meet the
specification for DDRI and DDRII. 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.
The PWM duty cycle can range from 0% to 100% with a minimum on-time (T
100ns making possible conversions with very low duty cycle at high switching frequency. The
device provides voltage-mode control that includes a selectable frequency oscillator (250KHz
or 500KHz).
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
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. During the soft-start phase a constant current protection is provided while
after the soft-start the device enters in hiccup mode in case of over-current. The converter can
always sink current. Other features are Power-Good, not latched over-voltage-protection, feed-
back disconnection and thermal shutdown. The HTSSOP16 package allows the realization of
really compact DC/DC converters.
DS(on)
of both the high-side and low-side MOSFET(s), eliminating the need for a
Summary description
ON, MIN
) lower than
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