LM3420AM5-4.2 National Semiconductor, LM3420AM5-4.2 Datasheet - Page 11

• Manufacturer Part Number: LM3420AM5-4.2
• Description: IC CTRLR LIION BAT CHRG SOT23-5
• Manufacturer: National Semiconductor
• Type: Battery Chargerr

Specifications of LM3420AM5-4.2

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SC-74A, SOT-753
• Output Current: 15mA
• Output Voltage: 4.2V
• Operating Supply Voltage (max): 20V
• Operating Temp Range: -40C to 85C
• Package Type: SOT-23
• Mounting: Surface Mount
• Pin Count: 5
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM3420AM5-4.2TR; LM3420AM5-4.2; LM3420AM5-4.2TR

Compensation
where R
part, R
16.8V part.
The resistor (R
on the die. Since this resistor value will affect the phase
margin, the worst case maximum and minimum values are
important when analyzing closed loop stability. The minimum
and maximum room temperature values of this resistor are
specified in the Electrical Characteristics section of this data
sheet, and a curve showing the temperature coefficient is
V
The regulation voltage (V
nally trimmed by adding a single resistor from the COMP pin
to the +IN pin or from the COMP pin to the GND pin,
depending on the desired trim direction. Trim adjustments up
to
in the temperature coefficient. (See temperature coefficient
curve shown in Figure 3 below.)
REG
±
10% of V
f
≈ 287 kΩ for the 12.6V part, and R
f
External Voltage Trim
≈ 75 kΩ for the 4.2V part, R
REG
f
) in the formula is an internal resistor located
can be realized, with only a small increase
REG
(Continued)
) of the LM3420 can be exter-
f
≈ 181 kΩ for the 8.4V
f
≈ 392 kΩ for the
FIGURE 2. LM3420 Test Circuit
11
shown in the curves section. Minimum values of R
lower phase margins.
Test Circuit
The test circuit shown in Figure 2 can be used to measure
and verify various LM3420 parameters. Test conditions are
set by forcing the appropriate voltage at the V
point and selecting the appropriate R
the Electrical Characteristics section. Use a DVM at the
“measure” test points to read the data.
Normalized Temperature Drift with
Output Externally Trimmed
FIGURE 3.
01235907
L
or I
OUT
01235908
as specified in
OUT
www.national.com
f
result in
Set test