E-L6919ETR STMicroelectronics, E-L6919ETR Datasheet - Page 13

• Manufacturer Part Number: E-L6919ETR
• Description: IC CTRLR 5BIT PROG 2PHASE 28SOIC
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of E-L6919ETR

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.8 ~ 1.55 V
• Current - Output: 2A
• Frequency - Switching: 150kHz
• Voltage - Input: 5 ~ 12 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Power - Output: 2W
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 6.5 V
• Maximum Operating Temperature: 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-4592-2

Figure 6. Constant Current operation
In this particular situation, the switching frequency results reduced. The ON time is the maximum allowed
(T
Over current is set anyway when I
to work with convenient values for I
age with respect to the load value, it can be simply considered that, for example, to have on OCP threshold
of 170%, this will correspond to I
Integrated Droop Function
The device uses a droop function to satisfy the requirements of high performance microprocessors, reducing
the size and the cost of the output capacitor.
This method "recovers" part of the drop due to the output capacitor ESR in the load transient, introducing a de-
pendence of the output voltage on the load current
As shown in figure 7, the ESR drop is present in any case, but using the droop function the total deviation of the
output voltage is minimized. In practice the droop function introduces a static error (V
and V
FB and COMP has always a capacitor in series (See fig. 8). The voltage regulated is then equal to:
Since I
given by:
I
tional to the output current. Since the device has an average current mode regulation, the information about the
total current delivered is used to implement the Droop Function.
This current (equal to the sum of both I
INFOx
onMAX
OUT
= 20.6 A (I
FB
) while the OFF time depends on the application:
depends on the current information about the two phases, the output characteristic vs. load current is
TonMAX
, the total current information flows only in this resistor because the compensation network between
a) Maximum current for each phase
FB
= 41.1 A).
T
O FF
TonMAX
INFOx
=
INFOx
V
FB
OUT
L
INFOx
. Since the OCP intervention threshold is fixed, to modify the percent-
Ipe ak I
------------------------------------- -
= 35 A (I
reaches 35 A (I
=
) is sourced from the FB pin. Connecting a resistor between this pin
V
VID R
V
OUT
OUT
–
= V
–
OCP x
FB
ID
FB
= 70 A). The full load current will then correspond to
- R
FB
R
--------------------- - I
FB
SENSE
f
= 70 A). The full load value is only a convention
Ipeak
I
I
Rg
MAX
OCPx
· I
=
FB
----------------------------------------- -
T
ONm a x
OUT
1
UVP
Vout
+
b) Output Characteristic
T
(I
FB
O FF
=50 A)
DROOP
Droop effect
I
(I
OCP
FB
=70 A)
=2·I
in figure 8) propor-
OCPx
I
MAX,TOT
Iout
L6919E
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