Datasheet

LTC3856
5
3856f
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Differential Amplifier
A
DA
Gain E-Grade
I-Grade
l
l
0.998
0.997
1
1
1.002
1.003
V/V
V/V
R
IN
Input Resistance Measured at DIFFP Input 80 kΩ
V
OS
Input Offset Voltage V
DIFFP
= V
DIFFOUT
= 1.5V, I
DIFFOUT
= 100µA 2 mV
PSRR Power Supply Rejection Ratio 4.5V < V
IN
< 38V 100 dB
I
CL
Maximum Output Current 2 3 mA
V
OUT(MAX)
Maximum Output Voltage I
DIFFOUT
= 300µA V
INTVCC
–1.4
V
INTVCC
–1.1
V
On-Chip Driver
TG R
UP
TG Pull-Up R
DS(ON)
TG High 2.6 Ω
TG R
DOWN
TG Pull-Down R
DS(ON)
TG Low 1.5 Ω
BG R
UP
BG Pull-Up R
DS(ON)
BG High 2.4 Ω
BG R
DOWN
BG Pull-Down R
DS(ON)
BG Low 1.1 Ω
GBW Gain-Bandwidth Product (Note 8) 3 MHz
SR Slew Rate (Note 8) 2 V/µs
Stage Shedding Mode
I
ISET
Programmable Stage Shedding
Mode Current
6.5 7.5 8.5 µA
AVP (Active Voltage Positioning)
V
AVP
Maximum V
OUT
with AVP 2.5 V
I
SINK
Sink Current of AVP Pin SENSE
+
= 1.2V 250 µA
I
SOURCE
Source Current of AVP Pin SENSE
+
= 1.2V 2 mA
V
AVP
-V
O(MAX)
Maximum Voltage Drop V
AVP
to V
O
SENSE
+
= 1.2V 120 mV
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
junction temperature range, otherwise specifications are at T
A
= 25°C (Note 2). V
IN
= 15V, V
RUN
= 5V, unless otherwise noted.
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC3856 is tested under pulse load conditions such that
T
J
≈ T
A
. The LTC3856E is guaranteed to meet performance specifications
from 0°C to 85°C operating junction temperature. Specifications over
the –40°C to 125°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC3856I is guaranteed to meet performance specifications over the
full –40°C to 125°C operating junction temperature range.
Note 3: T
J
is calculated from the ambient temperature, T
A
, and power
dissipation, P
D
, according to the following formula:
LTC3856UH: T
J
= T
A
+ (P
D
• 34°C/W)
LTC3856FE: T
J
= T
A
+ (P
D
• 25°C/W)
Note 4: The LTC3856 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
FB
.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See the Applications Information
section.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7: The minimum on-time condition corresponds to the on inductor
peak-to-peak ripple current ≥40% of I
MAX
(see Minimum On-Time
Considerations in the Applications Information section).
Note 8: Guaranteed by design.