Detailed Description
The MAX16984 combines a 5V/2.1A automotive grade
step-down converter, a USB host charger adapter emu-
lator, and USB protection switches. It is designed for
high-power USB ports in automotive radio, navigation,
connectivity, and USB hub applications.
The USB protection switches provide high-ESD and
short-circuit protection for the low-voltage internal data
lines of the multimedia processor’s USB transceiver
and support USB Hi-Speed (480Mbps) and USB Full-
Speed (12Mbps) pass-through operation. The MAX16984
features integrated host-charger port-detection circuitry
adhering to the USB 2.0 Battery Charging Specification
BC1.2 and also includes dedicated bias resistors for iPod/
iPhone 1.0A and iPad 2.1A dedicated charging modes.
The high-efficiency step-down DC-DC converter operates
from a voltage up to 28V and is protected from load dump
transients up to 42V. The device includes resistor-pro-
grammable frequency selection from 220kHz to 2.2MHz
to allow optimization of efficiency, noise, and board space
based on the application requirements. The converter can
deliver up to 2.1A of continuous current at 105NC.
The MAX16984 also includes a high-side current-sense
amplifier and configurable feedback adjustment circuit
designed to provide automatic USB voltage adjustment
to compensate for voltage drops in captive cables associ-
ated with automotive applications.
Power-Up and Enabling
System Enable (IN)
IN is used as the main enable to the MAX16984 and is
also used to clamp the D+ and D- pins during an ESD
and short-to-battery on the HVD+ and HVD- pins. This
clamping protects the downstream USB transceiver. The
IN pin contains an overvoltage lockout that disables the
data switches if IN is above V
IN_OVLO
. Bypass IN with a
1FF capacitor and connect it to the same 3.3V supply as
shared with the multimedia processor’s USB transceiver.
If IN is logic-high, the protection switches are enabled
and the USB switches operate in one of four modes per
the CD0 and CD1 inputs. If IN is at a logic-low level, SUP
power consumption is reduced and the device enters a
standby low quiescent level.
Functional Diagram
MAX16984
FAULT
IN
CD1
CD0
D-
D+
SUPSW
SENSO
FBMAX
FBPER
REF
I LIMIT
BIAS
SUP
I/O
CONTROL AND
DIAGNOSTICS
HVD-
HVD+
GND
BST
LX
PGND
SYNC
FOSC
SENSP
SENSN
FBCAP
2.1A
FPWM
DC-DC
FEEDBACK
ADJUSTMENT
FEEDBACK
CURRENT-
SENSE AMP
BIAS
USB AUTO DCP, CDP,
iPhone, iPad
CHARGER DETECTION
ENBUCK
ENBUCK
MAX16984 Automotive High-Current Step-Down Converter with
USB Protection/Host Charger Adapter Emulator
www.maximintegrated.com
Maxim Integrated
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ABRIDGED DATA SHEET
