Electrical characteristics – Rainbow Electronics MAX1638 User Manual
Page 4
V
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
4
_______________________________________________________________________________________
FREQ = REF
FREQ = V
CC
Falling FB, 1% hysteresis with respect to V
REF
Rising FB, 1% hysteresis with respect to V
REF
FREQ = AGND
Over line and load (Note 1)
V
CC
= V
DD
CONDITIONS
510
600
690
800
1000
1200
Switching Frequency
6
8
10
kHz
240
300
360
%
-8
-6
-4
PWROK Trip Level
%
±2.5
Output Voltage (FB) Accuracy
V
4.5
5.5
Input Voltage Range
UNITS
MIN
TYP
MAX
PARAMETER
BST - LX = 4.5V
FREQ = V
CC
V
DD
= 4.5V
Ω
0.7
2
%
84
90
Ω
0.7
2
Maximum Duty Cycle
DL On-Resistance
DH On-Resistance
FB = 3.5V
Current-Limit Trip Voltage
mV
70
100
130
ELECTRICAL CHARACTERISTICS
(V
DD
= V
CC
= D4 = +5V, PGND = AGND = D0–D3= 0V, FREQ = REF,
T
A
= -40°C to +85°C
, unless otherwise noted.) (Note 3)
Note 1:
FB accuracy is 100% tested at FB = 3.5V (code 10000) with V
CC
= V
DD
= 4.5V to 5.5V and CSH - CSL = 0mV to 80mV. The
other DAC codes are tested with V
CC
= V
DD
= 5V and CSH - CSL = 0.
Note 2:
AC load regulation sets the AC loop gain, to make tradeoffs between output filter capacitor size and transient response,
and has only a slight effect on DC accuracy or DC load-regulation error.
Note 3:
Specifications from 0°C to -40°C are guaranteed by design, not production tested.
No load
V
3.448
3.5
3.553
Reference Voltage
V
CC
rising edge, 1% hysteresis
V
3.9
4.3
Input Undervoltage Lockout
0.4
Operating mode
3
V
CC
Supply Current
V
CC
= V
DD
= 5.5V, FB forced 200mV above
regulation point, operating or shutdown mode
mA
0.2
V
CC
= V
DD
= 5.5V,
FB overdrive =
200mV
V
DD
Supply Current
mA
12
Shutdown
mode
V
REF
= 0V
DAC code = 11111