LTC1778 Linear Technology, LTC1778 Datasheet - Page 3

• Manufacturer Part Number: LTC1778
• Description: Wide Operating Range/ No RSENSE Step-Down Controller
• Manufacturer: Linear Technology

ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are T
SYMBOL
t
V
V
V
V
V
V
I
I
V
V
TG R
TG R
BG R
BG R
TG t
TG t
BG t
BG t
Internal V
V
V
PGOOD Output (LTC1778 Only)
V
Note 1: Absolute Maximum Ratings are those values beyond which the life of
a device may be impaired.
Note 2: T
dissipation P
OFF(MIN)
RUN/SS(C)
RUN/SS(D)
SENSE(MAX)
SENSE(MIN)
FB(UV)
RUN/SS(ON)
RUN/SS(LE)
RUN/SS(LT)
IN(UVLO)
IN(UVLOR)
INTVCC
EXTVCC
PGL
V
V
V
V
V
V
V
FB(OV)
LDO(LOADREG)
EXTVCC
EXTVCC(HYS)
FBH
FBL
FB(HYS)
LTC1778E: T
r
f
r
f
UP
DOWN
UP
DOWN
CC
J
is calculated from the ambient temperature T
Regulator
D
as follows:
J
= T
PARAMETER
Minimum Off-Time
Maximum Current Sense Threshold
V
Minimum Current Sense Threshold
V
Output Overvoltage Fault Threshold
Output Undervoltage Fault Threshold
RUN Pin Start Threshold
RUN Pin Latchoff Enable Threshold
RUN Pin Latchoff Threshold
Soft-Start Charge Current
Soft-Start Discharge Current
Undervoltage Lockout
Undervoltage Lockout Release
TG Driver Pull-Up On Resistance
TG Driver Pull-Down On Resistance
BG Driver Pull-Up On Resistance
BG Driver Pull-Down On Resistance
TG Rise Time
TG Fall Time
BG Rise Time
BG Fall Time
Internal V
Internal V
EXTV
EXTV
EXTV
PGOOD Upper Threshold
PGOOD Lower Threshold
PGOOD Hysteresis
PGOOD Low Voltage
PGND
PGND
A
+ (P
CC
CC
CC
– V
– V
D
Switchover Voltage
Switch Drop Voltage
Switchover Hysteresis
CC
CC
• 130 C/W)
SW
SW
Voltage
Load Regulation
A
= 25 C. V
A
and power
CONDITIONS
I
V
V
V
V
V
V
RUN/SS Pin Rising
RUN/SS Pin Falling
V
V
V
V
TG High
TG Low
BG High
BG Low
C
C
C
C
6V < V
I
I
I
V
V
V
I
ON
CC
CC
CC
PGOOD
RNG
RNG
RNG
RNG
RNG
RNG
RUN/SS
RUN/SS
IN
IN
LOAD
LOAD
LOAD
LOAD
FB
FB
FB
The
= 0mA to 20mA, V
= 20mA, V
= 20mA, V
= 30 A
Falling
Rising
Rising
Falling
Returning
IN
= 1V, V
= 0V, V
= INTV
= 1V, V
= 0V, V
= INTV
IN
= 3300pF
= 3300pF
= 3300pF
= 3300pF
= 5mA
= 15V unless otherwise noted.
= 0V
= 4.5V, V
< 30V, V
denotes specifications which apply over the full operating
CC
CC
FB
FB
FB
FB
EXTVCC
EXTVCC
, V
, V
= 0.76V
= 0.76V
= 0.84V
= 0.84V
Note 3: The LTC1778 is tested in a feedback loop that adjusts V
a specified error amplifier output voltage (I
Note 4: The LTC1778E is guaranteed to meet performance specifications from
0 C to 70 C. Specifications over the –40 C to 85 C operating temperature
range are assured by design, characterization and correlation with statistical
process controls.
FB
FB
EXTVCC
FB
= 0.76V
= 0.84V
= 0V
Rising
= 5V
EXTVCC
= 4V
= 4V
LTC1778/LTC1778-1
– 0.5
– 5.5
MIN
113
158
520
5.5
0.8
0.8
4.7
4.5
5.5
79
TH
).
– 7.5
– 1.2
– 0.1
0.15
TYP
– 67
– 47
– 93
250
133
186
600
150
200
7.5
1.5
3.5
1.8
3.4
3.5
4.7
7.5
20
20
20
20
93
4
2
2
3
1
5
1
MAX
– 9.5
400
153
107
214
680
300
9.5
4.5
4.2
3.9
5.3
9.5
0.4
–3
2
3
4
3
3
4
2
2
2
FB
to achieve
UNITS
1778fa
3
mV
mV
mV
mV
mV
mV
mV
mV
mV
ns
ns
ns
ns
ns
%
%
%
%
%
V
V
V
A
A
V
V
V
V
V