Owner manual

MAX16999
Ultra-Low Output Voltage, Low-Quiescent-Current
Linear Regulator for High-Temperature Applications
_______________________________________________________________________________________ 9
Undervoltage Lockout (UVLO)
Before the MAX16999 can operate, the input voltage
must exceed the UVLO threshold of 2.2V (max) with a
30mV hysteresis. If the input voltage is below the UVLO
threshold, OUT becomes high impedance and EN is
ignored regardless if it is driven high or low.
Applications Information
Capacitor Selection
Capacitors are required at the MAX16999 input and
output for stable operation over the full temperature
range and with load currents up to 100mA. Connect a
1µF ceramic capacitor between IN and GND and a
4.7µF ceramic capacitor between OUT and GND. The
input capacitor (C
IN
) lowers the source impedance of
the input supply. Use larger output capacitors to
reduce noise and improve stability and power-supply
rejection. The output capacitor’s equivalent series
resistance (ESR) affects stability and output noise. Use
output capacitors with an ESR of 30mΩ or less to
ensure stability and optimize transient response.
Surface-mount ceramic capacitors have very low ESR
and are commonly available in values up to 10µF.
Connect C
IN
and C
OUT
as close to the MAX16999 as
possible to minimize the impact of the PCB trace induc-
tance.
Using MAX16999 in Parallel
with Another Supply
The MAX16999 can be used in parallel with another
supply of equal voltage (see Figure 2). The circuit
shows a typical low-power solution for a µC.
4V TO 36V
3.3V, 1A LOW-IQ
INTERFACE SUPPLY
1.2V, 3A
CORE SUPPLY
TO μC
1.2V LOW-IQ
CORE BYPASS
MAX1745
MAX8693
MAX16999
Figure 2. Low-Quiescent µC Supply Solution
Table 1. Output Currents at T
A
= +125°C
SINGLE-LAYER BOARD
MULTILAYER
BOARD
V
OUT
(V)
V
IN
= 3.3V
(mA)
V
IN
= 5V
(mA)
V
IN
= 5V
(mA)
0.5 92 57 72
0.6 95 59 73
0.7 99 60 75
0.8 100 61 77
0.9 100 63 79
1.0 100 64 81
1.1 100 66 83
1.2 100 68 85
1.5 100 74 92
1.8 100 81 100
2.5 100 100 100
3.3 100 100 100