MAX1638 Datasheet, PDF (4/16 Pages) Maxim Integrated Products – High-Speed Step-Down Controller with Synchronous Rectification for CPU Power

High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
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)
PARAMETER
Input Voltage Range
Input Undervoltage Lockout
V_CC Supply Current
V_DD Supply Current
CONDITIONS
MIN
V_CC = V_DD
4.5
V_CC rising edge, 1% hysteresis
3.9
V_CC = V_DD = 5.5V,
FB overdrive =
200mV
Operating mode
Shutdown
mode
DAC code = 11111
V_REF = 0V
V_CC = V_DD = 5.5V, FB forced 200mV above
regulation point, operating or shutdown mode
TYP
MAX
5.5
4.3
3
0.4
12
0.2
UNITS
V
V
V
mA
mA
Reference Voltage
Output Voltage (FB) Accuracy
PWROK Trip Level
Switching Frequency
Maximum Duty Cycle
DH On-Resistance
DL On-Resistance
Current-Limit Trip Voltage
No load
Over line and load (Note 1)
Rising FB, 1% hysteresis with respect to V_REF
Falling FB, 1% hysteresis with respect to V_REF
FREQ = V_CC
FREQ = REF
FREQ = AGND
FREQ = V_CC
BST - LX = 4.5V
V_DD = 4.5V
FB = 3.5V
3.448 3.5 3.553
V
±2.5
%
-8
-6
-4
%
6
8
10
800 1000 1200
510
600
690
kHz
240
300
360
84
90
%
0.7
2
Ω
0.7
2
Ω
70
100
130
mV
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.
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