Rainbow Electronics MAX16910 - Manual (Page 11)

200mA, Automotive, Ultra-Low
Quiescent Current, Linear Regulator
MAX16910
______________________________________________________________________________________ 11
ENABLE
ENABLE is an active-high, logic-level enable input that
turns the device on or off. Drive ENABLE high to turn
the device on. An internal 0.65µA pulldown current
keeps the MAX16910 in shutdown mode when driven
by a three-state driver in high-impedance mode, or an
open-drain driver. When in shutdown, the MAX16910
consumes only 1.6µA. ENABLE withstands voltages up
to 45V, allowing it to be driven by high-input level volt-
ages or connected to IN for always-on operation.
Thermal Protection
The MAX16910 features thermal protection. When the
junction temperature exceeds +180°C, an internal ther-
mal sensor turns off the pass transistor, and allows the
device to cool. The thermal sensor turns on the pass
transistor again after the junction temperature cools by
25°C. This results in a cycled output during continuous
thermal-overload conditions. Thermal protection protects
the MAX16910 in the event of fault conditions. For con-
tinuous operation, do not exceed the absolute maximum
junction temperature rating of +150°C.
Output Short-Circuit Current Limit
The MAX16910 features a 330mA current limit. The out-
put can be shorted to GND continuously without dam-
age to the device. During a short circuit, the power dis-
sipated across the pass transistor can quickly heat the
device. When the die temperature reaches +180°C, the
MAX16910 turns off the pass transistor and automatically
restarts after the die temperature has cooled by 25°C.
RESET Output
The MAX16910 features an active-low, open-drain reset
output. Once the monitored output voltage exceeds the
reset threshold voltage, RESET remains low for the reset
timeout period and then goes high. RESET changes from
high to low whenever the monitored output voltage drops
below the reset threshold voltage. RESET also asserts
low when ENABLE is low and during thermal shutdown.
Timeout
The MAX16910 features a reset timeout period adjustable
input. The internal capacitance produces a 60µs default
delay when TIMEOUT is left unconnected. Connect a
capacitor from TIMEOUT to GND to set a higher timeout
period than default. Use the following formula to deter-
mine the reset timeout capacitor:
C TIMEOUT = 0.8 x I TO x T TIMEOUT
where C TIMEOUT is in nF, I TO is in µA, and T TIMEOUT is
in ms.
For example, if I
TO is 1µA, C TIMEOUT needs to be 8nF to
get a 10ms delay.
___________Applications Information
Output-Capacitor Selection and
Regulator Stability
For stable operation over the full temperature range,
with fixed 3.3V and 5.0V output voltages, use a low-ESR
4.7µF capacitor. For resistor-programmed output voltag-
es, a 10µF low-ESR ceramic capacitor is recommended
for stable operation. Use larger output-capacitor values
such as 22µF to reduce noise, improve load-transient
response and power-supply rejection. Some ceramic
dielectrics exhibit large capacitance and ESR variations
with temperature. To improve power-supply rejection
and transient response, use a capacitor larger than the
minimum 1µF capacitor between IN and GND.
Available Output-Current Calculation
The MAX16910 provides up to 200mA of continuous
output current. The input voltage range extends to
30V. Package power dissipation limits the amount of
output current available for a given input/output voltage
and ambient temperature. Figure 1 shows the maxi-
mum allowable power dissipation for these devices to
keep the junction temperature below +150°C. Figure 1
assumes that the exposed metal pad of the MAX16910 is
soldered to a 1in
2 of multilayer copper board. Use Figure
1 to determine the allowable package dissipation for a
given ambient temperature. Alternately, use the following
formulas to calculate the allowable power dissipation P
D .
For the TDFN-EP package:
( )
A
D
A A
1.951W for T 70 C
P W
1.951W 0.0244 T 70 C for 70 C T 125 C
C
 ≤ + ° 
 
=  
− × − ° + ° ≤ < + °  
°  
For the SO-EP package:
( )
A
D
A A
1.861W for T 70 C
P W
1.861W 0.0233 T 70 C for 70 C T 125 C
C
 ≤ + ° 
 
=  
− × − ° + ° ≤ < + °  
°  