Manual

MAX1684/MAX1685
Low-Noise, 14V Input, 1A, PWM
Step-Down Converters
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
SHDN
= 6V, STBY = SYNC/PWM = CVL, V
BOOT
= V
OUT
, FB = AGND, circuit of Figure 1, T
A
= 0°C to +85°C, unless otherwise
noted. Typical values are at T
A
= +25°C.)
STBY = low, V
IN
= 2.7V
CONDITIONS
µA230 430
Quiescent Supply Current
in Dropout
UNITSMIN TYP MAXSYMBOLPARAMETER
SHDN = low
µA26Shutdown Supply Current
MAX1684 260 300 340
MAX1684 180 350
V
IN
= 14V, V
LX
= 0 or 14V, SHDN = low
SYNC Capture Range
MAX1685
kHz
520 600 680
f
OSC
Oscillator Frequency
µA20I
LX
LX Leakage Current
%100Maximum Duty Cycle
(Note 3) %
20
MAX1685
Constant-Frequency Minimum
Duty Cycle
10
-1µA < I
REF
< 50µA mV415Reference Load Regulation
V
IN
= 3V to 14V, BOOT = AGND,
I
CVL
= 0 to 5mA
V2.7 3.0 3.15
I
REF
= 0
CVL Regulator Output Voltage
2.7V < V
BOOT
< 5.5V mV0.2 5Reference Supply Regulation
V1.238 1.251 1.264V
REF
Reference Output Voltage
kHz
360 700
MAX1684
MAX1685
BOOT = AGND, I
CVL
= 5mA mV120CVL Dropout Voltage
Typical hysteresis is +10°C (Note 4) °C160Thermal Shutdown Threshold
BOOT falling edge,
typical hysteresis is 0.1V
V2.35 2.5 2.65BOOT Switchover Threshold
I
CVH
= -1mA V-5.0 -4.6 -4.1CVH with Respect to V
IN
SHDN, STBY, SYNC/PWM
V2V
IH
Logic Input High Voltage
V
ILIM/SS
= 1.4V µA3.3 4 4.65ILIM/SS Source Current
High or low period ns500SYNC/PWM Pulse Width
SHDN, STBY, SYNC/PWM
µA-1 1Logic Input Current
0.7V
IL
Logic Input Low Voltage
BOOT = AGND, CVL falling edge,
typical hysteresis is 40mV
V2.35 2.5 2.6
CVL Undervoltage Lockout
Threshold
V