CDH2D09 View Datasheet(PDF) - Maxim Integrated
Part Name
Description
MFG CO.
'CDH2D09' PDF : 44 Pages View PDF
PMIC with Integrated Charger and
Smart Power Selector for Handheld Devices
USB Power-OK Output (UOK)
As shown Figure 3, the USB power-OK output (UOK) is
an active-low open-drain output. The UOK output pulls
low when the voltage from USB to AGND (VUSB) is
between VUSBH (typically 6.9V) and VUSBL (typically
4.0V).
The USB power-OK circuitry remains active in thermal
overload and USB suspend. If the USB power-OK out-
put feature is not required, connect UOK to ground or
leave unconnected.
USB Suspend (USUS)
As shown in Table 1, driving USUS high suspends the
DC or USB inputs if they are configured as a USB
power input. The suspend current is 110µA when USUS
is driven high allowing the MAX8671X to comply with
the USB 1.1/2.0 specification for USB suspend as well
as the USB OTG specification for an unconfigured
device. If an external input (USB or DC) is connected to
the MAX8671X and suspended, the SYS node is sup-
ported by the battery. The DOK, UOK, and VL circuits
remain active in USB suspend mode.
A common assumption is that REG5 is disabled in USB
suspend. This is not true. REG5 is not affected by the
USB suspend mode. While in suspend, a USB device
must provide the 3.3V termination to the USB trans-
ceivers’ pullup resistors. This 3.3V termination can
come from the MAX8671X’s VL output or REG5. Both
remain enabled in USB suspend.
DC Power Input (DC)
DC is a current-limited power input that supplies the
system (SYS) up to 1A. The DC-to-SYS switch is a lin-
ear regulator designed to operate in dropout. This lin-
ear regulator prevents the SYS voltage from exceeding
5.3V. As shown in Table 1, DC supports four different
current limits that are set with the PEN1, PEN2, and
USUS digital inputs. These current limits are ideally
suited for use with AC-to-DC wall adapters and USB
power. The operating voltage range for DC is 4.1V to
6.6V, but it can tolerate up to 14V without damage.
When the DC input voltage is below the undervoltage
threshold (VDCL, 4V typ), it is considered invalid.
Similarly, if the DC voltage is above the overvoltage
threshold (VDCH, 6.9V typ), it is considered invalid.
When the DC voltage is below the battery voltage, it is
considered invalid. The DC power input is disconnect-
ed when the DC voltage is invalid. As shown in Table 1,
when power is available at the DC input, it has priority
over the USB input. Bypass DC to ground with at least
a 4.7µF capacitor.
USB
VUSBL
4.0V RISING (typ)
500mV HYST
VUSBH
6.9V RISING (typ)
400mV HYST
MAX8671X
USB
UNDERVOLTAGE
UOK
USB
OVERVOLTAGE
AGND
Figure 3. USB Power-OK Logic
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