MAX1887EEE Maxim Integrated Products, MAX1887EEE Datasheet - Page 10

• Manufacturer Part Number: MAX1887EEE
• Description: Current Mode PWM Controllers
• Manufacturer: Maxim Integrated Products

Specifications of MAX1887EEE

• Number Of Outputs: 1
• Mounting Style: SMD/SMT
• Package / Case: QSOP-16
• Switching Frequency: 550 KHz
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Synchronous Pin: No
• Topology: Boost

Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
10
MAX1887
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10
—
11
—
—
—
1
3
4
5
6
7
8
9
2
PIN
MAX1897
19
20
10
11
12
13
1
2
3
4
5
6
7
8
9
NAME
COMP
PGND
SHDN
TRIG
CM+
GND
TON
CS+
ILIM
CM-
POL
V
V
CS-
DL
DD
CC
Dual-Mode Current-Limit Adjustment and Standby Input. The current-limit threshold
voltage is 1/10 the voltage seen at ILIM (V
drops below 250mV, the slave controller enters a low-power standby mode, forcing
DL high and DH low.
Trigger Input. Connect to the master controller’s low-side gate driver. For the
MAX1887, a rising edge triggers a single cycle. For the MAX1897, the trigger input’s
polarity is pin selectable. POL = V
phase operation), and POL = GND triggers on the falling edge (in-phase operation).
Master Controller’s Positive Current-Sense Input
Master Controller’s Negative Current-Sense Input
On-Time Selection Control Input. This is a three-level input used to determine the DH
on time (see On-Time Control and Active Current Balancing). For the MAX1897,
connect TON as follows for the indicated switching frequencies:
GND = 550kHz
floating = 300kHz
V
For the MAX1887, the switching frequency is internally configured for 300kHz
operation. The slave controller’s switching frequency should be selected to closely
match the frequency of the master PWM controller.
Slave Controller’s Negative Current-Sense Input
Slave Controller’s Positive Current-Sense Input
Current Balance Compensation. Connect a series resistor and capacitor between
COMP and OUT. See the Current Balance Compensation section.
TRIG P ol ar i ty S el ect Inp ut. C onnect P OL to V
TRIG ( out- of- p hase op er ati on) . C onnect P OL to GN D to tr i g g er on the fal l i ng ed g e of TRIG
( i n- p hase op er ati on) . For the M AX 1887, P OL i s i nter nal l y connected to V
Analog Ground. Connect the MAX1897’s exposed pad to analog ground.
Power Ground
Low-Side Gate-Driver Output. DL swings from PGND to V
when the MAX1897 enters standby or shutdown mode.
Supply Voltage Input for the DL Gate Driver. For the MAX1887, V
the analog supply voltage input that powers the PWM core. Connect to the system
supply voltage (4.5V to 5.5V). Bypass to PGND with a 1µF or greater ceramic
capacitor, as close to the IC as possible.
Analog Supply Voltage Input for PWM Core. Connect V
voltage (4.5V to 5.5V) through a series 10Ω resistor. Bypass to GND with a 0.22µF
or greater ceramic capacitor, as close to the MAX1897 as possible.
Active-Low Shutdown Input. A logic low shuts down the MAX1897 slave controller,
immediately pulling DL high and DH low. Connect to V
CC
= 200kHz.
CC
DESCRIPTION
or floating triggers on the rising edge (out-of-
ILIM
C C
or fl oat to tr i g g er on the r i si ng ed g e of
) over a 400mV to 1.5V range. If V
CC
CC
DD
for normal operation.
Pin Description
to the system supply
. DL is forced high
DD
C C
also serves as
.
ILIM