MAX1540 Datasheet, PDF (4/49 Pages) Maxim Integrated Products – Dual Step-Down Controllers with Saturation Protection, Dynamic Output, and Linear Regulator

Dual Step-Down Controllers with Saturation
Protection, Dynamic Output, and Linear Regulator
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 15V, V_CC = V_DD = ON1 = ON2 = 5V, SKIP = GND, LDOIN (MAX1541) = V+, T_A = 0°C to +85°C, unless otherwise noted. Typical
values are at T_A = +25°C.)
PARAMETER
OUT_ Input Resistance
SYMBOL
MAX1540
R_OUT_
MAX1541
CONDITIONS
FB_ = GND
FB_ = V_CC or
adjustable
FB1 = OUT1
FB2 = GND
FB2 = V_CC or
adjustable
MIN TYP MAX UNITS
70
145
350
50
115
220
400
700 1500
kΩ
90
170
350
60
130
270
OUT_ Discharge Mode On-
Resistance
R_DISCHARGE
10
25
Ω
OUT_ Synchronous-Rectifier
Discharge-Mode Turn-On Level
0.2
0.3
0.4
V
Soft-Start Ramp Time
t_SS
Rising edge on ON_ to full current limit
1.7
ms
DH1 On-Time
t_ON1
V+ = 15V,
V_OUT1 = 1.5V
(Note 3)
TON = GND (620kHz) 149
169
190
TON = REF (485kHz) 191
216
242
ns
TON = open (345kHz) 274
304
335
TON = V_CC (235kHz) 402
447
491
DH2 On-Time
t_ON2
V+ = 15V,
V_OUT2 = 1.5V
(Note 3)
TON = GND (460kHz) 201
228
256
TON = REF (355kHz) 260
296
331
ns
TON = open (255kHz) 371
412
453
TON = V_CC (170kHz) 556
618
679
On-Time Tracking
t_ON2 with respect to t_ON1 (Note 3)
120
135
150
%
Minimum Off-Time
t_OFF(MIN) (Note 3)
400
500
ns
LINEAR REGULATOR (LDO) (Note 1)
MAX1540 LDO Output-Voltage
Accuracy
V_LDOOUT
ON1 = ON2 = GND,
V+ = 6V to 28V
0 < I_LDOOUT < 10mA
0 < I_LDOOUT < 100mA
4.85
4.70
5.0
5.10
5.10
V
MAX1541 LDO Output-Voltage
Accuracy (Fixed V_LDOOUT)
FBLDO = ON1 =
0 < I_LDOOUT < 10mA 4.85
5.0
V_LDOOUT ON2 = GND,
V_LDOIN = 6V to 28V ^{0 < I}LDOOUT ^{< 100mA 4.70}
5.10
5.10
V
MAX1541 LDO Feedback
Accuracy (Adjustable V_LDOOUT)
V_FBLDO
FBLDO = LDOOUT,
ON1 = ON2 = GND,
V_LDOIN = 4.5V to
28V
0 < I_LDOOUT < 10mA
0 < I_LDOOUT < 100mA
1.212
1.175
1.25
1.275
1.275
V
MAX1541 LDO Output
Adjust Range
LDOOUT Short-Circuit Current
FBLDO Input Bias Current
Dropout Voltage
1.175
24
V
130
mA
I_FBLDO
-0.1
+0.1
µA
MAX1540: V+ - V_LDOOUT, I_LDOOUT = 50mA
MAX1541: V_LDOIN - V_LDOOUT,
I_LDOOUT = 50mA
500
800
mV
500
800
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