Datasheet

MAX17499/MAX17500
Current-Mode PWM Controllers with
Programmable Switching Frequency
_______________________________________________________________________________________ 7
Pin Description
PIN
NAME
FUNCTION
1
UVLO/EN
Externally Programmable Undervoltage Lockout. UVLO/EN programs the input start voltage. Connect
UVLO/EN to GND to disable the device. NDRV stops switching approximately 210μs after the UVLO/EN
voltage falls below 1.17V.
2 UFLG
Open-Drain Undervoltage Flag Output. UFLG is asserted low as soon as the UVLO/EN voltage falls below its
threshold.
3 FB Error-Amplifier Inverting Input
4
COMP
Error-Amplifier Output
5CS
Current-Sense Input. Current-sense connection for PWM regulation and cycle-by-cycle current limit.
Connect to the high side of the sense resistor. An RC filter may be necessary to eliminate leading-edge
spikes. Current-limit trip voltage is 1V.
6RT
Oscillator Timing Resistor Input. An RC network may be required to reduce jitter (see the Typical Application
Circuit).
NDRV HIGH-OUTPUT IMPEDANCE
vs. TEMPERATURE
MAX17499/500 toc21
TEMPERATURE (°C)
R
ON
(Ω)
603510-15
3.4
3.8
4.2
4.6
5.0
3.0
-40
85
SOURCING 20mA
ERROR AMPLIFIER OPEN-LOOP GAIN
AND PHASE vs. FREQUENCY
FREQUENCY (Hz)
GAIN (dB)
PHASE (DEGREES)
100
-60
80
60
40
20
0
-20
-40
120
-200
80
40
0
-40
-80
-120
-160
10.1 10 100 1k 10k 100k 1M 10M
100M
MAX17499/500 toc22
GAIN
PHASE
Typical Operating Characteristics (continued)
(V
UVLO/EN
= +1.4V, V
FB
= +1V, COMP = open, V
CS
= 0V, T
A
= +25°C, unless otherwise noted.)
1
2
3
4
5
10
9
8
7
6
IN
+
V
CC
NDRV
GNDCOMP
FB
UFLG
UVLO/EN
MAX17499
MAX17500
μMAX
TOP VIEW
RTCS
Pin Configuration