LTC1538CG-AUX Linear Technology, LTC1538CG-AUX Datasheet - Page 7

• Manufacturer Part Number: LTC1538CG-AUX
• Description: IC SW REG STP-DN SYNC DUAL28SSOP
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LTC1538CG-AUX

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 1.19 ~ 9 V
• Current - Output: 50mA
• Frequency - Switching: 125kHz ~ 240kHz
• Voltage - Input: 3.5 ~ 36 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

PIN
TYPICAL PERFORMANCE CHARACTERISTICS
V
IC’s signal ground pin.
INTV
and the EXTV
powered from this voltage. Must be closely decoupled to
power ground with a minimum of 2.2 F tantalum or
electrolytic capacitor. The INTV
when both RUN/SS1 and RUN/SS2 are low. Refer to the
LTC1438/LTC1439 for applications which do not require a
5V standby regulator.
EXTV
switch closes and supplies INTV
low dropout regulator whenever EXTV
Connect this pin to V
output voltage. Do not exceed 10V on this pin. See EXTV
connection in Applications Information section.
BOOST 1, BOOST 2: Supplies to the Topside Floating Drivers.
The bootstrap capacitors are returned to these pins. Voltage
swing at these pins is from INTV
SW1, SW2: Switch Node Connections to Inductors. Volt-
age swing at these pins is from a Schottky diode (external)
voltage drop below ground to V
IN
U
: Main Supply Pin. Must be closely decoupled to the
CC
CC
FUNCTIONS
/5V STANDBY: Output of the Internal 5V Regulator
: External Power Input to an Internal Switch. This
U
20
15
10
5
0
CC
0
Auxiliary Regulator Sink
Current Available
Switch. The driver and control circuits are
2
U
OUT
4
AUX DR VOLTAGE (V)
6
of the controller with the higher
W
8
CC
CC,
10
IN
CC
U
.
to V
regulator remains on
bypassing the internal
12
CC
IN
1538/39 • G19
is higher than 4.8V.
14
+ INTV
16
CC
.
CC
SGND: Small Signal Ground. Common to both controllers,
must be routed separately from high current grounds to
the (–) terminals of the C
PGND: Driver Power Ground. Connects to sources of
bottom N-channel MOSFETs and the (–) terminals of C
SENSE
current comparators. SENSE
the first controllers V
remote output voltage sensing operation. The first con-
troller can only be used as a 3.3V or 5.0V regulator
controlled by the V
set to a 3.3V, 5.0V or an adjustable regulator controlled by
the V
Table 1. Output Voltage Table
CONTROLLER 1
CONTROLLER 2
PROG2
–
1, SENSE
100
pin (see Table 1).
90
80
70
60
50
40
30
20
10
0
10
LTC1538-AUX/LTC1539
Auxiliary Regulator PSRR
PROG1
–
2: Connects to the (–) input for the
5V or 3.3V Only, Secondary Feedback Loop
OUT
Remote Sensing
Adjustable Only
LTC1538-AUX
FREQUENCY (kHz)
pin. The second controller can be
OUT
I
sensing point preventing true
I
L
L
= 10mA
= 100mA
100
–
capacitors.
1 is internally connected to
1538/39 • G20
5V/3.3V/Adjustable
Remote Sensing
POR1 Output
1000
LTC1539
7
IN
.