LT1510IS#TR Linear Technology, LT1510IS#TR Datasheet - Page 8

• Manufacturer Part Number: LT1510IS#TR
• Description: DP-Battery Charger, 200kHz, 1.5A Stepdn Bat Charger
• Manufacturer: Linear Technology

Specifications of LT1510IS#TR

• Battery Type: Li-Ion/NiCD/NiMH
• Output Current: 1.5A
• Output Voltage: 2 to 20V
• Operating Supply Voltage (min): 7V
• Operating Supply Voltage (max): 30V
• Operating Temp Range: -40C to 85C
• Package Type: SOIC N
• Mounting: Surface Mount
• Pin Count: 16
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Not Compliant

LT1510/LT1510-5
OPERATIO
APPLICATIONS
Application Note 68, the LT1510 design manual, contains
more in depth appications examples.
Input and Output Capacitors
In the chargers in Figures 1 and 2 on the first page of this
data sheet, the input capacitor C
input switching ripple current in the converter, so it must
have adequate ripple current rating. Worst-case RMS
ripple current will be equal to one half of output charging
current. Actual capacitance value is not critical. Solid
8
TEST CIRCUITS
The LT1510 is a current mode PWM step-down (buck)
switcher. The battery DC charging current is programmed
by a resistor R
pin (see Block Diagram). Amplifier CA1 converts the
charging current through R
I
compares the output of CA1 with the programmed current
and drives the PWM loop to force them to be equal. High
DC accuracy is achieved with averaging capacitor C
Note that I
goes through R1 and generates a ramp signal that is fed to
the PWM control comparator C1 through buffer B1 and
PROG
(500 A/A) fed into the PROG pin. Amplifier CA2
PROG
PROG
has both AC and DC components. I
U
U
(or a DAC output current) at the PROG
INFORMATION
U
S1
IN
to a much lower current
is assumed to absorb all
W
0.47 F
I
PROG
R
U
PROG
PROG
10k
PROG
PROG
Test Circuit 2
+
LT1510
.
2.465V
VA
tantalum capacitors such as the AVX TPS and Sprague
593D series have high ripple current rating in a relatively
small surface mount package, but caution must be used
when tantalum capacitors are used for input bypass . High
input surge currents can be created when the adapter is
hot-plugged to the charger and solid tantalum capacitors
have a known failure mechanism when subjected to very
high turn-on surge currents. Highest possible voltage
rating on the capacitor will minimize problems. Consult with
the manufacturer before use. Alternatives include new high
level shift resistors R2 and R3, forming the current mode
inner loop. The Boost pin drives the switch NPN Q
saturation and reduces power loss. For batteries like
lithium-ion that require both constant-current and con-
stant-voltage charging, the 0.5%, 2.465V reference and
the amplifier VA reduce the charging current when battery
voltage reaches the preset level. For NiMH and NiCd, VA
can be used for overvoltage protection. When input volt-
age is not present, the charger goes into low current (3 A
typically) sleep mode as input drops down to 0.7V below
battery voltage. To shut down the charger, simply pull the
V
+
–
C
–
+
pin low with a transistor.
LT1013
V
REF
10k
OVP
1510 TC02
SW
into