MAX15018/MAX15019
125V/3A, High-Speed,
Half-Bridge MOSFET Drivers
_______________________________________________________________________________________
7
DELAY MATCHING (DH AND DL RISING)
MAX15018 toc18
10ns/div
V
IN_
10V/div
V
DH
AND V
DL
10V/div
C
L
= 0pF
RESPONSE TO V
DD
GLITCH
MAX15018 toc19
40
s/div
V
DH_
V
IN_
V
DL
V
DD
10V/div
10V/div
10V/div
10V/div
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
_______________________________________________________________________________________
7
Pin Description
PIN NAME FUNCTION
1V
DD
Input Supply Voltage. Valid supply voltage ranges from 8V to 12.6V. Bypass V
DD
to GND with a parallel
combination of 0.1µF and 1µF ceramic capacitors as close to the IC as possible.
2 BST
Boost Flying Capacitor Connection. Connect a 0.22µF ceramic capacitor from BST to HS as close to the IC
as possible for the high-side MOSFET driver supply.
3 DH High-Side Gate Driver Output. Driver output for the high-side MOSFET gate.
4 HS Source Connection for High-Side MOSFET. Also serves as the return for the high-side driver.
5 IN_H High-Side Noninverting Logic Input
6 IN_L Low-Side Noninverting (MAX15018A/MAX15019A) or Low-Side Inverting (MAX15018B/MAX15019B) Input
7 GND
Ground. Use GND as a return path to the DL driver output and the IN_H, IN_L inputs. Must be connected to
ground.
8 DL Low-Side Gate Driver Output. Driver output for the low-side MOSFET gate.
—EP
Exposed Pad. Internally connected to GND. Externally connect the exposed pad to a large ground plane to
aid in heat dissipation. Grounding EP does not substitute the requirement to connect GND to ground.
MAX15018/MAX15019
125V/3A, High-Speed,
Half-Bridge MOSFET Drivers
8 _______________________________________________________________________________________
Detailed Description
The MAX15018A/MAX15018B/MAX15019A/MAX15019B
half-bridge, n-channel MOSFET drivers control high-
and low-side MOSFETs in high-voltage, high peak-cur-
rent applications and offer a high 125V voltage range
that allows ample margin above the 100V transient
specification of telecom standards. These drivers oper-
ate with an IC supply voltage of 8V to 12.6V, and con-
sume only 2.75mA of supply current during typical
switching operations. The MAX15018_/MAX15019_ pro-
vide 3A (typ) sink/source peak current per output and
are capable of operating with large capacitive loads
and with switching frequencies near 1MHz.
These drivers are intended to be used to drive the
high-side MOSFET without requiring an isolation device
such as an optocoupler or a drive transformer. The
high-side driver is controlled by a TTL/CMOS logic sig-
nal referenced to ground and is powered by a boot-
strap circuit formed by an integrated diode and an
external capacitor. Undervoltage lockout (UVLO) pro-
tection is provided for both the high- and low-side dri-
ver supplies (BST and V
DD
) and includes a UVLO
hysteresis of 0.5V (typ).
The drivers are independently controlled and feature
exceptionally fast switching times, very short propaga-
tion delays (35ns typ), and matched propagation delay-
times (2ns typ) between drivers, making them ideally
suited for high-frequency applications. Internal logic cir-
cuitry prevents shoot-through during output state
changes and minimizes package power dissipation.
These devices are available with CMOS (V
DD
/2) or TTL
logic-level inputs. The MAX15018A/MAX15018B accept
CMOS input logic levels, while the MAX15019A/
MAX15019B accept TTL input logic levels. For both ver-
sions, the logic inputs are protected against voltage
spikes up to +15V, regardless of V
DD
. See the
Driver
Logic Inputs (IN_H, IN_L)
section.
The MAX15018_/MAX15019_ are available with both
high-side and low-side noninverting logic inputs or with
noninverting high-side and inverting low-side logic inputs.
See the
Functional Diagrams
and
Selector Guide
. The
MAX15018A and MAX15019A are pin-for-pin replace-
ments for the HIP2100IB and HIP2101IB, respectively.
The MAX15018_/MAX15019_ are available in a space-
saving, high-power, 8-pin SO-EP package that can dissi-
pate up to 1.95W at +70°C. All devices operate over the
-40°C to +125°C automotive temperature range.
Undervoltage Lockout
Both the high- and low-side drivers feature separate
UVLO protection that monitors each driver’s input sup-
ply voltage (BST and V
DD
). The low-side driver UVLO
threshold (V
DD_UVLO
) is referenced to GND and pulls
both driver outputs low when V
DD
falls below 7.3V (typ).
The high-side driver UVLO threshold (V
BST_UVLO
) is ref-
erenced to HS, and only pulls DH low when V
BST
falls
below 6.9V (typ) with respect to HS. After the IC is first
energized, and once V
DD
rises above its UVLO thresh-
old, DL starts switching and either follows the IN_L logic
input (MAX15018A/MAX15019A) or is inverted with refer-
ence to the IN_L logic input (MAX15018B/
MAX15019B). At this time, the bootstrap capacitor is not
charged, and DH does not switch since the BST-to-HS
voltage is below V
BST_UVLO
. Within a short time follow-
ing engagement of low-side switching, C
BST
charges
through V
DD
and causes V
BST
to exceed V
BST_UVLO
.
DH then starts switching and follows IN_H. For synchro-
nous buck and half-bridge converter topologies, the
bootstrap capacitor can charge up in one cycle. Normal
operation then begins in a few microseconds after the
BST-to-HS voltage exceeds V
BST_UVLO
. In the two-
switch forward topology, C
BST
takes more time (a few
hundred microseconds) to charge and increase its volt-
age above V
BST_UVLO
. The typical hysteresis for both
UVLO thresholds is 0.5V. The bootstrap capacitor value
should be selected carefully to avoid oscillations during
turn-on and turn-off at the DH output. Choose a capaci-
tor value 20 times greater than the total gate capaci-
tance of the MOSFET. Use a low ESR-type X7R
dielectric ceramic capacitor at BST (typically a 0.1µF
ceramic is adequate) and a parallel combination of 1µF
and 0.1µF ceramic capacitors from V
DD
to GND. The
high-side MOSFET’s continuous on-time is limited due
to the charge loss from the high-side driver’s quiescent
current. The maximum on-time is dependent on the size
of C
BST
, I
BST
(190µA, max), and V
BST_UVLO
.
Output Driver
The MAX15018_/MAX15019_ drivers contain low on-
resistance p-channel and n-channel devices in a totem
pole configuration for the driver output stage. This
allows for rapid turn-on and turn-off of high gate-charge
(Q
g
) external switching MOSFETs.
The drivers exhibit low drain-to-source resistance
(R
DS_ON
), which decreases for higher values of V
DD
and for lower operating temperatures. Lower R
DS_ON
means higher source and sink currents from the IC,
and results in faster switching speeds, since the exter-
nal MOSFET gate capacitance will charge and dis-
charge at a quicker rate. The peak source and sink
current provided by the drivers is typically 3A.
Propagation delay from the logic inputs to the driver
outputs is matched to within 8ns (max) between the
low-side and high-side drivers. Turn-on and turn-off
propagation delays are typically 35ns and 36ns. See
Figure 1. The internal drivers also contain break-before-
make logic to eliminate shoot-through conditions that
would cause unnecessarily high operating supply cur-
rents, efficiency reduction, and voltage spikes at V
DD
.
Voltage at DL is approximately equal to V
DD
when in a
high state, and zero when in a low state. Voltage from
DH to HS is approximately equal to V
DD
minus the
diode drop of the integrated bootstrap diode when in a
high state, and zero when in a low state. The high-side
MOSFET’s continuous on-time is limited due to the
charge loss from the high-side driver’s quiescent cur-
rent. The maximum on-time is dependent on the size of
the bootstrap capacitor (C
BST
), I
BST
(190µA max), and
V
BST_UVLO
.
Integrated Bootstrap Diode
An integrated diode between V
DD
and BST is used in
conjunction with an external bootstrap capacitor (C
BST
)
to provide the voltage required to turn on the high-side
MOSFET (see the
Typical Operating Circuit
). The inter-
nal diode charges the bootstrap capacitor from V
DD
when the low-side switch is on, and isolates V
DD
when
HS is pulled high when the high-side driver turns on.
The internal bootstrap diode has a typical forward volt-
age drop of 0.9V and has a 40ns (typ) turn-off/-on time.
The turn-off time (reverse recovery time) depends on
the reverse-recovery current and can be as low as
10ns. If a lower diode voltage-drop between V
DD
and
BST is needed, connect an external Schottky diode
between V
DD
and BST.
MAX15018/MAX15019
125V/3A, High-Speed,
Half-Bridge MOSFET Drivers
_______________________________________________________________________________________ 9
Figure 1. Timing Characteristics of Logic Inputs (MAX15018A/MAX15019A)
IN_L
DL
t
D_OFF1
IN_H
V
IL
V
IL
DH
90%
10%
90%
10%
V
IH
V
IH
t
R
t
R
t
D_ON1
t
D_OFF1
t
MATCH
= (t
D_ON2
- t
D_ON1
) OR (t
D_OFF2
- t
D_OFF1
)
t
F
t
F
t
D_ON2

MAX15019BASA+T

Mfr. #:
Manufacturer:
Maxim Integrated
Description:
Gate Drivers 125V/3A High-Speed Half-B MOSFET Drvr
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
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