ltc3787gn Linear Technology Corporation, ltc3787gn Datasheet - Page 4

• Manufacturer Part Number: ltc3787gn
• Description: Ltc3787 - Polyphase Synchronous Boost Controller
• Manufacturer: Linear Technology Corporation

LTC3787
elecTrical characTerisTics
SYMBOL
DF
t
INTV
V
VLDO INT
V
VLDO EXT
V
V
Oscillator and Phase-Locked Loop
f
f
f
f
PGOOD Output
V
I
V
t
BOOST1 and BOOST2 Charge Pump
I
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 reliabil-
ity and lifetime.
Note 2: The LTC3787 is tested under pulsed load conditions such that
T
0°C to 85°C 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
LTC3787I is guaranteed over the –40°C to 125°C operating junction temp-
erature range. Note that the maximum ambient temperature consistent
with these specifications is determined by specific operating conditions
in conjunction with board layout, the rated package thermal impedance
and other environmental factors. The junction temperature (T
calculated from the ambient temperature (T
(P
θ
4
junction temperature range, otherwise specifications are at T
ON(MIN)
PROG
LOW
HIGH
SYNC
PGOOD
PGOOD(DELAY)
BOOST1,2
J
JA
INTVCC(VIN)
INTVCC(EXT)
EXTVCC
LDOHYS
PGL
PGOOD
D
BG1,2(MAX)
≈ T
, in Watts) according to the formula: T
= 43°C/W for the QFN package and θ
CC
A
. The LTC3787E is guaranteed to meet specifications from
Linear Regulator
PARAMETER
PGOOD Voltage Low
PGOOD Leakage Current
PGOOD Trip Level
PGOOD Delay
BOOST Charge Pump Available Output
Current
Maximum BG Duty Factor
Minimum BG On-Time
Internal V
INTV
Internal V
INTV
EXTV
EXTV
Programmable Frequency
Lowest Fixed Frequency
Highest Fixed Frequency
Synchronizable Frequency
CC
CC
CC
CC
Load Regulation
Load Regulation
Switchover Voltage
Hysteresis
CC
CC
Voltage
Voltage
JA
J
= T
= 90°C/W for the SSOP package.
A
, in °C) and power dissipation
A
+ (P
D
• θ
JA
), where
J
, in °C) is
CONDITIONS
V
FREQ = 0V, Forced Continuous or
Pulse-Skipping Mode
(Note 7)
6V < V
I
V
I
EXTV
R
R
R
V
V
PLLIN/MODE = External Clock
I
V
V
PGOOD Going High to Low
CC
CC
PGOOD
SW1,2
EXTVCC
FREQ
FREQ
PGOOD
FB
FREQ
FREQ
FREQ
V
Hysteresis
V
Hysteresis
The
= 0mA to 50mA
= 0mA to 40mA, V
with Respect to Set Regulated Voltage
FB
FB
CC
A
= 0V
= INTV
BIAS
= 25k
= 60k
= 100k
Ramping Negative
Ramping Positive
= 12V; V
= 2mA
l
= 25°C, VBIAS = 12V, unless otherwise noted (Note 2).
= 5V
Ramping Positive
= 6V
denotes the specifications which apply over the full operating
< 38V, V
CC
Note 3: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. The maximum
rated junction temperature will be exceeded when this protection is active.
Continuous operation above the specified absolute maximum operating
junction temperature may impair device reliability or permanently damage
the device.
output of the error amplifier while maintaining I
current limit range.
Note 5: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency.
Note 6: Rise and fall times are measured using 10% and 90% levels. Delay
times are measured using 50% levels.
Note 7: see Minimum On-Time Considerations in the Applications
Information section.
BOOST1,2
Note 4: The LTC3787 is tested in a feedback loop that servos V
EXTVCC
EXTVCC
– V
= 0
SW1,2
= 6V
= 4.5V;
l
l
MIN
335
320
488
–12
5.2
5.2
4.5
75
8
TH
TYP
110
250
105
400
760
350
535
–10
5.4
0.5
5.4
0.5
4.8
0.2
2.5
2.5
96
10
25
55
at the midpoint of the
MAX
465
380
585
850
5.6
5.6
0.4
±1
–8
12
2
2
5
FB
to the
UNITS
3787fa
kHz
kHz
kHz
kHz
kHz
kHz
mV
µA
µA
ns
µs
%
%
%
%
%
%
%
V
V
V
V