L6731B STMicroelectronics, L6731B Datasheet - Page 11

• Manufacturer Part Number: L6731B
• Description: IC CTRLR ADJ STPDN SYNC 16-TSSOP
• Manufacturer: STMicroelectronics

Specifications of L6731B

• 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
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

L6731B
5.3
Figure 4.
5.4
Bypassing the LDO to avoid the voltage drop with low Vcc
If V
maximum LDO output current is about 100mA and so the output voltage drop is 100mV, to
avoid this the LDO can be bypassed.
Internal and external references
It is possible to set the internal/external reference and the switching frequency by setting the
proper voltage at the DDR-IN pin. The maximum value of the external reference is 2.5V (typ.):
●
●
●
Providing an external reference from 0V to 450mV the output voltage will be regulated but
some restrictions must be considered:
●
●
●
To set the resistor divider it must be considered that a 100K pull-down resistor is integrated into
the device (see
pin is captured by the device at the start-up when V
Bypassing the LDO
CC
V
V
V
The minimum OVP threshold is set at 300mV;
The under-voltage-protection doesn't work;
The PGOOD signal remains low;
EAREF
EAREF
EAREF
5V the internal LDO works in dropout with an output resistance of about 1 . The
from 0% to 80% of V
from 80% to 95% of V
from 95% to 100% of V
Figure
5.). Finally it must be taken into account that the voltage at the DDR-IN
CCDR
CCDR
CCDR
-> External reference/F
-> V
-> V
REF
REF
= 0.6V/F
= 0.6V/F
CC
is about 4V.
SW
SW
=500KHz
=250KHz
SW
= 250KHz
Device description
11/24