LT1948
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
FB1
C
T
SW1
GND
1
2
3
4
8
7
6
5
V
ON
VO2
SW2
V
IN
V
IN
Voltage ................................................................ 8V
C
T
Voltage.................................................................. 6V
SW1, SW2 Voltage .................................................. 36V
FB Voltage ................................................................. 3V
V
ON
, VO2 Voltage..................................................... 30V
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LT1948EMS8
MS8 PART
MARKING
LTNR
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 200°C/W
Consult factory for Industrial and Military grade parts.
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 3.3V unless otherwise specified.
SYMBOL
Supply Current
Reference Voltage
Reference Line Reg
C
T
Source Current
C
T
Voltage to Turn On Q3
FB1 Voltage to Begin C
T
Charge
SW1 Current Limit
SW2 Current Limit
SW1 Saturation Voltage
SW2 Saturation Voltage
Oscillator Frequency
Maximum Duty Cycle
0°C
≤
T
A
≤
85°C
–40°C
≤
T
A
≤
0°C
VO2 Pin Resistance
SW1, SW2 Error Amp Gain
SW1, SW2 Error Amp Gm
FB1 Regulation Voltage
q
q
q
ELECTRICAL CHARACTERISTICS
CONDITIONS
Not Switching
2.7V < V
IN
< 8V
V
FB1
= 1.3V
MIN
TYP
7
1.26
0.01
MAX
13
UNITS
mA
V
%/V
4.5
1.25
1.17
5.5
1.28
1.20
1.5
0.8
350
250
6.5
1.30
1.23
(Note 3)
(Note 3)
I
SW1
= 800mA
I
SW2
= 300mA
q
1.2
0.5
410
300
3.6
90
2.4
70
69
67
3.2
75
Measured to Ground
400
100
50
1.240
1.230
22
1.260
0.01
23
200
0.01
0.01
1.280
1.285
0.05
24
260
5
2
µA/V
V
V
V
mV
µA
µA
FB1 Line Regulation
VO2 Regulation Voltage
V
ON
Switch Drop
SW1 Leakage Current
SW2 Leakage Current
2.7V < V
IN
< 8V
VO2 = 25V, 7mA Load from V
ON
, C
T
Voltage >1.30V
Switch Off, SW1 Voltage = 3.3V
Switch Off, SW2 Voltage = 3.3V
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The LT1948 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.
Note 3:
Current limit guaranteed by design and/or correlation to static test.
2
U
µA
V
V
A
A
mV
mV
MHz
%
%
%
kΩ
V/V
W
U
U
W W
W
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
