lt3071 Linear Technology Corporation, lt3071 Datasheet - Page 12

• Manufacturer Part Number: lt3071
• Description: Lt3071 5a, Low Noise, Programmable Output, 85mv Dropout Linear Regulator With Analog Margining Features
• Manufacturer: Linear Technology Corporation

LT3071
pin Functions
I
sources a current typically equal to I
per amp of output current. Terminating this pin with a
resistor to GND produces a voltage proportional to I
For example, at I
With a 1k resistor to GND, this produces 2V. If I
unused, tie this pin to V
MARGA (Pin 22): Analog Margining. This pin margins the
output voltage over a continuous analog range of ±10%.
Tying this pin to GND adjusts output voltage by –10%.
Driving this pin to 1.2V adjusts output voltage by +10%. A
voltage source or a voltage output DAC is ideal for driving
this pin. If the MARGA function is not used, either float
this pin or terminate with a 1nF capacitor to GND.
V
lect. These three-state pins combine to select a nominal
output voltage from 0.8V to 1.8V in increments of 50mV.
Output voltage is limited to 1.8V maximum by an internal
override of V
threshold is less than 250mV referenced to GND and the
logic high threshold is greater than V
range between these two thresholds as set by a window

MON
O0
, V
(Pin 21): Output Current Monitor. The I
O1
and V
O1
O2
when V
OUT
(Pins 23, 24, 25): Output Voltage Se-
= 5A, I
BIAS
O2
= high. The input logic low
.
MON
typically sources 2mA.
+
OUT
BIAS
+
V
BIAS
/2500 or 400µA
– 250mV. The
V
IN
Figure 1. Kelvin Sense Connection
MON
MON
EN
IN
V
V
V
MARGA
VIOC
pin
OUT
O0
O1
O2
is
.
LT3071
BIAS
GND
REF/BYP
PWRGD
comparator defines the logic Hi-Z state. See Table 1 in the
Applications Information section that defines the V
and V
BIAS (Pin 27): Bias Supply. This pin supplies current to
the internal control circuitry and the output stage driving
the pass transistor. The LT3071 requires a minimum 2.2µF
bypass capacitor for stability and proper operation. To
ensure proper operation, the BIAS voltage must satisfy
the following conditions: 2.2V ≤ V
(1.25 • V
voltage is limited to 2.2V.
EN (Pin 28): Enable. This pin enables/disables the
output device only. The internal reference and all sup-
port functions are active if V
threshold. Pulling EN low keeps the reference circuit
active, but disables the output pass transistor and puts
the LT3071 into a low power nap mode. Drive the EN
pin with either a digital logic port or an open-collector
NPN or an open-drain NMOS terminated with a pull-up
resistor to V
35k to meet the V
connect EN to BIAS.
SENSE
I
OUT
MON
O0
R
R
settings versus V
OUT
P
P
+ 1V). For V
BIAS
3071 F01
LOAD
. The pull-up resistor must be less than
IH
condition of the EN pin. If unused,
OUT
OUT
≤ 0.95V, the minimum BIAS
.
BIAS
BIAS
is above its UVLO
≤ 3.6V and V
O2
BIAS
, V
3071fa
O1
≥