Rainbow Electronics MAX17008 - Manual

General Description
The MAX17007A/MAX17008 are dual Quick-PWM™
step-down controllers intended for general power gen-
eration in battery-powered systems. The two switched-
mode power supplies (SMPSs) can also be combined to
operate in a two-phase single-output mode. Constant
on-time Quick-PWM operation provides fast response to
load transients and handles wide input/output (I/O) volt-
age ratios with ease, while maintaining a relatively con-
stant switching frequency. The switching frequency can
be individually adjusted between 200kHz and 600kHz
with external resistors. Differential output current sens-
ing allows output sense-resistor sensing for an accurate
current limit, or lossless inductor direct-current resis-
tance (DCR) current sensing for lower power dissipation
while maintaining 0.7% output accuracy. Overvoltage
(MAX17007A only), undervoltage protection, and accu-
rate user-selectable current limits (15mV, 30mV, 45mV,
and 60mV) ensure robust operations.
The SMPS outputs can operate in skip mode or in ultra-
sonic mode for improved light-load efficiency. The ultra-
sonic mode eliminates audible noises by maintaining a
minimum switching frequency of 25kHz in pulse-
skipping mode.
The output voltage of SMPS1 can be dynamically
adjusted by changing the voltage at the REFIN1 pin.
The device includes a 0.5% accurate reference output
that can be used to set the REFIN1 voltage. An external
5V bias supply is required to power the internal circuitry
and its gate drivers.
Independent on/off controls with well-defined logic thresh-
olds and independent open-drain power-good outputs
provide flexible system configurations. To prevent current
surges at startup, the internal voltage target is slowly
ramped up from zero to the final target with a slew rate of
1.3mV/μs for SMPS1 at CSL1 and 0.65mV/μs for SMPS2
at FB2. To prevent the output from ringing off below
ground in shutdown, the internal voltage target is ramped
down from its previous value to zero with the same
respective slew rates. Integrated bootstrap switches
eliminate the need for external bootstrap diodes.
The MAX17007A/MAX17008 are available in a space-
saving, 28-pin, 4mm x 4mm, thin QFN package with an
exposed backside pad.
Applications
Features
♦ Dual Quick-PWM with Fast Transient Response
♦ Automatic Dynamic REFIN1 Detection and
PGOOD1/Fault Blanking
♦ Fixed and Adjustable Output Voltages
±0.7% Output Accuracy Over Line and Load
OUT1: 0 to 2V Dynamic Output or Preset 1.05V
OUT2: 0.7V to 2V Range or Preset 1.5V
♦ Resistor-Programmable Switching Frequency
♦ Integrated BST Switches
♦ Differential Current-Sense Inputs
Low-Cost DCR Sensing or Accurate Current-
Sense Resistors
Internally Coupled Current-Sense Compensation
♦ Combinable Mode Supports High-Current
Dynamic Output Voltages
♦ Selectable Forced-PWM, Pulse Skip, or Ultrasonic
Mode Operation
♦ 26V Maximum Input Voltage Rating
♦ Independent Enable Inputs
♦ Independent Power-Good Outputs
♦ Overvoltage Protection (MAX17007A Only)
♦ Undervoltage/Thermal Protection
♦ Voltage Soft-Start and Soft-Shutdown
MAX17007A/MAX17008
Dual and Combinable QPWM Graphics
Core Controllers for Notebook Computers
________________________________________________________________ Maxim Integrated Products 1
MAX17007A
MAX17008
18
THIN QFN
(4mm x 4mm)
4
17
5
16
6
15
14 22
7
19
3
20
2
21
13 23
12 24
11 25
10 26
9 27
8 28
1
LX1
DH1
PGOOD1
EN1
CSH1
TOP VIEW
*EP
*EP = EXPOSED PAD.
CSL1
REFIN1
LX2
DH2
PGOOD2
EN2
CSH2
CSL2
FB2
BST2 PGND DL2 V
DD
DL1 GND BST1
REF
ILIM1
(CCI) ILIM2
V CC
SKIP TON1 TON2
+
Pin Configuration
Ordering Information
19-3200; Rev 2; 10/08
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
+ Denotes a lead-free/RoHS-compliant package.
* EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
MAX17007AGTI+ -40°C to +105°C 28 Thin QFN-EP*
MAX17008GTI+ -40°C to +105°C 28 Thin QFN-EP*
Notebook Computers
Low-Power I/O Supplies
GPU Core Supplies
2 to 4 Li+ Cells Battery-
Powered Devices
Quick-PWM is a trademark of Maxim Integrated Products, Inc.