Datasheet

MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
6 _______________________________________________________________________________________
___________________Chip Information
TRANSISTOR COUNT: 386
tion is P = I
OUT
(V
IN
- V
OUT
). The power dissipation at
+70°C ambient is 571mW (see Absolute Maximum
Ratings). The thermal resistance junction-to-case of the
SOT23-5 package is 81°C/W, and the maximum safe
junction temperature is +150°C.
The GND pin performs the dual function of providing an
electrical connection to ground and channeling heat
away. Connect GND to ground using a large pad or
ground plane.
__________Applications Information
Setting the MAX1616 Output Voltage
Set the MAX1616’s output voltage with two resistors, R1
and R2 (Figure 2). Choose R2 = 250kΩ to maintain a
5µA minimum load and calculate R1 using the following
equation:
where V
FBT
= 1.24V (typical).
Capacitor Selection
Use a 0.1µF minimum capacitor on the input. Higher
values will improve line-transient response.
Use 1µF minimum on the output, or 4.7µF for the full
30mA load current (6.8µF, MAX1616). Otherwise, use
1µF plus 0.125µF/mA (0.2µF/µA, MAX1616). For output
voltages less than 3.3V, use 15µF instead of 6.8µF. The
output capacitor’s effective series resistance (ESR) must
be less than 1Ω for stable operation.
Output Voltage Noise
The MAX1615/MAX1616 typically exhibit 5mVp-p of
noise during normal operation. This is negligible in
most applications. In applications that include analog-
to-digital converters (ADCs) of more than 12 bits, con-
sider the ADC’s power-supply-rejection specifications.
Transient Response
The Typical Operating Characteristics show the
MAX1615/MAX1616’s load-transient response. Two of
the output response’s components can be observed on
the load-transient graph: a DC shift from the output
impedance due to the different load currents, and the
transient response. Typical step changes in the load
current from 10mA to 20mA produce 50mV transients.
Increasing the output capacitor’s value attenuates tran-
sient spikes.
R1 = R2
V
V
OUT
FBT
−
⎛
⎝
⎜
⎞
⎠
⎟
1
Table 1. Surface-Mount Capacitor
Manufacturers
MANUFACTURER CAPACITOR
Sprague 593D, 595 series
Electrolytic
AVX TPS series
TYPE
Matsuo 267 series
Ceramic
AVX X7R
Matsuo X7R
Table 2. Component Suppliers
PHONE FAX
[phone]
[phone]
[phone]
AVX [phone]
Sprague
SUPPLIER
Matsuo [phone]
[phone]
IN
OUT
FB
SHDN
GND
6V TO
28V
0.1µF
6.8µF*
R1
R2
OUTPUT
VOLTAGE
MAX1616
*15µF for V
OUT
<3.3V
Figure 2. MAX1616 Typical Application Circuit