Rainbow Electronics MAX1636 - Manual

General Description
The MAX1636 is a synchronous, buck, switch-mode,
power-supply controller that generates the CPU supply
voltage in battery-powered systems. It achieves ±1%
output voltage accuracy and offers the excellent load-
transient response needed by upcoming generations of
dynamic-clock CPUs.
Up to 95% efficiency is achieved through synchronous
rectification and Maxim’s proprietary Idle Mode™ con-
trol scheme. Efficiency is greater than 80% over a
1000:1 load-current range, extending battery life in sys-
tem-suspend or standby modes. Excellent dynamic
response corrects output load transients caused by the
latest dynamic-clock CPUs within five 300kHz clock
cycles. Strong, 1A, on-board gate drivers ensure fast,
external N-channel MOSFET switching.
The MAX1636 features a logic-controlled and synchro-
nizable, fixed-frequency, pulse-width-modulation (PWM)
operating mode that reduces noise and RF interference
in sensitive mobile communications and pen-entry appli-
cations. Holding SKIP high forces fixed-frequency mode
for lowest noise under all load conditions.
For a low-cost version that omits the +5V VL linear-
regulator block and comes in a smaller 16-pin QSOP
package, refer to the MAX1637 data sheet.
Applications
Notebook Computers
Subnotebook Computers
Desktop Computers
Bus-Termination Supplies
Features
♦ ±1% DC Accuracy (Adjustable Mode)
♦ Output Overvoltage Crowbar Protection
♦ Output Undervoltage Shutdown
♦ Adjustable Switching Frequency to 340kHz
♦ Low-Dropout Operation
♦ Idle Mode Pulse-Skipping Operation
♦ 1.10V to 5.5V Adjustable Output Voltage
♦ 2.5V/3.3V Dual-Mode Fixed-Output Settings
♦ Internal Digital Soft-Start
♦ 1.1V ±1% Reference Output
♦ 3µA (typ) Shutdown Current
♦ Open-Drain Power-Good Output (R
RE ES SE ET T)
♦ 20-Pin SSOP Package
MAX1636
Low-Voltage, Precision Step-Down
Controller for Portable CPU Power
________________________________________________________________ Maxim Integrated Products 1
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
SKIP
LX
DH
BST SHDN
RESET
CSL
CSH
TOP VIEW
PGND
DL
VL
V+ SYNC
REF
CC
OVP
12
11
9
10
V CC
FB GND
GND
MAX1636
SSOP
19-1268; Rev 2; 2/98
EVALUATION KIT MANUAL
FOLLOW
S DATA SHEET
Idle Mode is a trademark of Maxim Integrated Products.
Pin Configuration
Typical Operating Circuit
Ordering Information
MAX1636
V+ SHDN
GND
V IN
DL
PGND
LX
DH
VL
V
CC
BST
OVP
CSH
CSL
FB
RESET TO µP
CC
SKIP
GND
SYNC
REF
PART
MAX1636EAP -40°C to +85°C
TEMP. RANGE PIN-PACKAGE
20 SSOP
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.