MAX1587AETL Maxim Integrated Products, MAX1587AETL Datasheet - Page 21

• Manufacturer Part Number: MAX1587AETL
• Description: Other Power Management PMICs w/Dynamic Core for PDAs
• Manufacturer: Maxim Integrated Products

where V
and V
V
DBI threshold (1.232V typ).
Alternately, LBI and DBI can be set with separate two-
resistor-dividers. Choose the lower resistor of the divider
chain to be 250kΩ or less (R5 and R7 in Figure 4). The
equations for upper divider-resistors as a function of
each threshold are then:
When resistors are used to set V
is 1.00V. When resistors are used to set V
threshold at DBI is 1.232V. A resistor-set threshold can
also be used for only one of DBI or LBI. The other
threshold can then be factory set by connecting the
appropriate input to IN.
If BKBT is not powered, DBO does not function and is
high impedance. DBO is expected to connect to
nBATT_FAULT on Intel CPUs. If BKBT is not powered,
LBO does not function and is high impedance.
Figure 4. Setting the Low-Battery and Dead-Battery Thresholds
with Separate Resistor-Dividers. The values shown set a DBI
threshold of 3.3V and an LBI threshold of 3.5V (no resistors are
needed for factory-preset thresholds).
LBITH
MAIN BATTERY
DB
is the LBI threshold (1.0V typ) and V
LB
is the desired dead-battery detection voltage.
is the desired low-battery detection voltage
334kΩ
200kΩ
Dynamic Core for PDAs and Smart Phones
R4
R5
R
R
4
6
______________________________________________________________________________________
=
=
500kΩ
200kΩ
R
R
5
7
R6
R7
×
×
⎛
⎜
⎝
⎛
⎜
⎝
V
V
DBITH
LBITH
V
V
DB
LB
IN
DBI (1.232V THRESHOLD)
LBI (1.00V THRESHOLD)
High-Efficiency, Low-I
LB
−
−
MAX1586
, the threshold at LBI
1
1
⎞
⎟
⎠
⎞
⎟
⎠
DBITH
DB
is the
, the
POK is an open-drain output that goes low when any
activated regulator (V1–V6) is below its regulation
threshold. POK does not monitor V7. When all active
output voltages are within 10% of regulation, POK is
high impedance. POK does not flag an out-of-regula-
tion condition while V3 is transitioning between voltages
set by serial programming or when any regulator chan-
nel has been turned off. POK momentarily goes low
when any regulator is turned on, but returns high when
that regulator reaches regulation. When all regulators
(V1–V6) are off, POK is forced low. If the input voltage
is below the UVLO threshold, POK is held low and
maintains a valid low output with V
BKBT is not powered, POK does not function and is
high impedance.
Typical processor connections have only power-control
pins, typically labeled PWR_EN and SYS_EN. The
MAX1586/MAX1587 provide numerous on/off control
pins for maximum flexibility. In a typical application,
many of these pins are connected together. ON1, ON2,
and ON6 typically connect to SYS_EN. ON3, ON4, and
ON5 typically connect to PWR_EN. V7 remains on as long
as the main or backup power is connected. Sequencing
is not performed internally on the MAX1586/MAX1587;
however, all ON_ inputs have hysteresis and can connect
to RC networks to set sequencing. For typical connec-
tions to Intel CPUs, no external sequencing is required.
The backup-battery input (BKBT) provides backup
power for V7 when V1 is disabled. Normally, a primary
or rechargeable backup battery is connected to this
pin. If a backup battery is not used, then BKBT should
connect to IN through a diode or external regulator. See
the Backup-Battery and V7 Configurations section for
information on how to use BKBT and V7.
An I
REG3 on the MAX1587, and REG3 and REG6 on the
MAX1586. The serial interface operates when V
exceeds the 2.40V UVLO threshold and at least one of
ON1–ON6 is asserted. The serial interface is shut down
to minimize off-current drain when no regulators are
enabled.
2
C-compatible, two-wire serial interface controls
Q
Connection to Processor
and Power Sequencing
Backup-Battery Input
PMICs with
Power-OK Output (POK)
Serial Interface
IN
as low as 1V. If
21
IN