LT3500EMSE#PBF Linear Technology, LT3500EMSE#PBF Datasheet - Page 7

• Manufacturer Part Number: LT3500EMSE#PBF
• Description: IC REG STEP-DOWN 2A 16-MSOP
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LT3500EMSE#PBF

• Topology: Step-Down (Buck) (1), Linear (LDO) (1)
• Function: Any Function
• Number Of Outputs: 2
• Frequency - Switching: 500kHz ~ 2.4MHz
• Voltage/current - Output 1: 0.8 ~ 38.9 V, 2A
• Voltage/current - Output 2: Adjustable, 13mA
• W/led Driver: No
• W/supervisor: No
• W/sequencer: No
• Voltage - Supply: 3 V ~ 36 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-MSOP Exposed Pad
• Current - Output: 2A
• Voltage - Output: 0.8 ~ 38.9 V
• Voltage - Input: 3 ~ 36 V
• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Primary Input Voltage: 36V
• No. Of Outputs: 2
• Output Current: 2A
• No. Of Pins: 16
• Operating Temperature Range: -40°C To +125°C
• Msl: MSL 1 - Unlimited
• Supply Voltage Range: 2.4V To 36V
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

TYPICAL PERFORMANCE CHARACTERISTICS
PIN FUNCTIONS
V
is monitored by an undervoltage comparator. The V
is also connected to the collectors of the internal power
NPN switch and linear output NPN. The V
dI/dt edges and must be decoupled to ground close to
the pin of the device.
SHDN: The SHDN pin is used to shut down the LT3500
and reduce quiescent current to a typical value of
12μA. The accurate 0.76V threshold and input current
hysteresis can be used as an undervoltage lockout, prevent-
ing the regulator from operating until the input voltage has
reached a predetermined level. Force the SHDN pin above
its threshold or let it fl oat for normal operation.
SS: The SS pin is used to control the slew rate of the
output of both the switching and linear regulators. A
single capacitor from the SS pin to ground determines
the regulators’ ramp rate. For soft-start details see the
Applications Information section.
PG: The power good pin is an open-collector output that
sinks current when the FB or LFB falls below 90% of its
IN
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.00
1.05
: The V
–50
LDRV Dropout Voltage
vs Temperature
I
LDRV
–25
IN
= 5mA
pin powers the internal control circuitry and
0
TEMPERATURE (°C)
25
50
75
100 125 150
3500 G22
IN
pin has high
6
5
4
3
2
1
0
2.5
Switcher Dropout Operation
I
T
VOUT1
A
= 25°C
3.0
IN
= 1A
pin
INPUT VOLTAGE (V)
3.5
4.0
V
nominal regulating voltage. For V
state remains true, although during SHDN, V
lockout, or thermal shutdown, its current sink capability
is reduced
V
input to the peak switch current comparator. It is normally
used for frequency compensation, but can also be used
as a current clamp or control loop override. If the error
amplifi er drives V
level, a voltage clamp activates. This indicates that the
output is overloaded and current to be pulled from the
SS pin reducing the regulation point.
R
the constant switch frequency.
Connecting a resistor from the R
will set the R
resultant switching frequency will be set by the resistor
value. The minimum value of 15kΩ and maximum value
of 200kΩ set the switching frequency to 2.5MHz and
250kHz respectively.
VOUT1
C
T
: The V
/SYNC: This R
4.5
= 5V
V
VOUT1
C
5.0
= 3.3V
pin is the output of the error amplifi er and the
3500 G23
T
5.5
/SYNC pin to a typical value of 1V. The
T
/SYNC pin provides two modes of setting
C
above the maximum switch current
2500
2000
1750
1500
1250
2250
1000
750
500
250
5
Inductor Value for 2A Maximum
Load Current (V
I
RIPPLE
10
L = 1.5μH
= 250mA)
15
INPUT VOLTAGE (V)
IN
T
L = 1μH
/SYNC pin to ground
above 2V, its output
20
OUT1
IN
25
LT3500
= 3.3V,
L = 2.2μH
L = 3.3μH
L = 4.7μH
L = 6.8μH
L = 10μH
undervoltage
30
T
A
= 25°C
35
3500 G24
3500fc
7
40