General Description
The MAX8890 is a power-management IC intended for
cellular handsets using a single lithium-ion (Li+) cell
battery with input voltages from +2.5V to +5.5V. The IC
contains three identical, low-noise, low-dropout (LDO)
linear regulators to provide all of the supply voltage
requirements for the RF portion of the handset.
The first LDO is intended to power the transmitter,
receiver, and synthesizer. The second LDO is intended
to power the TCXO, and high-power voltage-controlled
oscillators (VCOs). The third LDO is intended to power
the UHF offset VCO.
Each LDO has its own individual enable (ON/OFF) con-
trol to maximize design flexibility. The reference is pow-
ered on if any of the enable inputs (EN1, EN2, EN3) are
logic high. The high-accuracy output voltage of each
LDO is preset at an internally trimmed voltage (1.8V to
3.3V in 50mV increments). Each LDO is capable of sup-
plying 100mA with a low 50mV dropout and is opti-
mized for low noise and high crosstalk-isolation.
Designed with internal P-channel MOSFET pass transis-
tors, the MAX8890’s low 180µA operating supply cur-
rent is independent of load.
Other features include short-circuit and thermal over-
load protection. The MAX8890 is available in a com-
pact, high-power, 12-pin 4mm ✕4mm QFN package
with a metal pad on the underside.
Applications
Cellular Handsets
Single-Cell Li+ Systems
3-Cell NiMH, NiCD, or Alkaline Systems
Personal Digital Assistants (PDAs)
Features
♦Three 100mA Low-Dropout Linear Regulators
♦Low 50mV Dropout Voltage at 100mA
♦±1% Output Voltage Accuracy Over Temperature
♦Preset 1.8V to 3.3V Output Voltages
(in 50mV Increments)
♦Low 45µVRMS Output Voltage Noise
♦Low 180µA Operating Supply Current
♦2.5V to 5.5V Input Voltage Range
♦67dB PSRR
♦10µVp-p Channel-to-Channel Crosstalk
♦Short-Circuit Protection
♦Thermal Overload Protection
♦0.01µA Shutdown Current
♦Tiny 12-Pin 4mm x 4mm QFN Package
MAX8890
Integrated Cellular RF-Section
Power-Management IC
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-2075; Rev 0; 7/01
Standard Versions table and Pin Configuration appear at
end of data sheet.
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP. RANGE PIN-PACKAGE
MAX8890EGCxyz* -40°C to +85°C 12 (4 x 4) QFN
*Each preset output voltage of these devices is factory
trimmed to one of ten voltages. Replace “xyz” with the letters
corresponding to the desired output voltages (see Standard
Preset Output Voltage Suffixes table), where the three letter
suffix corresponds to the following output voltages: “x” =
VOUT1, “y” = VOUT2, and “z” = VOUT3.
Note: There are five standard versions available (see Standard
Versions table). Sample stock is generally held on standard
versions only. Standard versions have an order increment
requirement of 2500 pieces. Nonstandard versions have an
order increment requirement of 10,000 pieces. Contact the
factory for availability of nonstandard versions.
SUFFIX OUTPUT
VOLTAGE (V) SUFFIX OUTPUT
VOLTAGE (V)
A 3.30 H 2.75
B 3.00 J 2.70
D 2.90 K 2.50
F 2.85 L 2.00
G 2.80 M 1.80
Standard Preset Output
Voltage Suffixes
*Nonstandard output voltages between 1.80V and 3.30V are
available in 50mV increments.
ON
OFF
IN1 OUT1
IN2 OUT2
IN3 OUT3
EN1 BP
EN2
EN3 GND
MAX8890
INPUT
OUTPUT #1
OUTPUT #2
OUTPUT #3
Typical Operating Circuit
MAX8890
Integrated Cellular RF-Section
Power-Management IC
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN_ = 3.6V, EN_ = IN_, CIN = 6.8µF, COUT_ = 2.2µF, CBP = 0.01µF, all ceramic capacitors TA= 0°C to +85°C, unless otherwise
noted. Typical values are at TA= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note A: As long as the maximum continuous power dissipation rating is not exceeded, the output may be shorted indefinitely.
IN_, EN_ to GND.......................................................-0.3V to +6V
OUT_, BP to GND ......................................-0.3V to (VIN_ + 0.3V)
Output Short-Circuit Protection (Note A) .......................indefinite
Continuous Power Dissipation (TA= +70°C)
12-Pin 4 x 4 QFN (derate 16.9mW/°C above +70°C) .......1349mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
GENERAL
Input Voltage VIN_ 2.5 5.5 V
Input Undervoltage Lockout
Threshold VUVLO Rising and falling edge 2.10 2.25 2.45 V
Input Undervoltage Hysteresis 45 mV
SUPPLY CURRENT
Quiescent Supply Current IQIOUT_ = 0 180 330 µA
Shutdown Supply Current EN_ = OUT_ = GND 0.01 10 µA
LINEAR REGULATORS
TA = +85°C-1+1
Output Voltage Accuracy VOUT_
VIN_ = 0.5V + the
highest of
(VOUT1, VOUT2, or
VOUT3),
IOUT_ = 1mA to
100mA
TA = 0°C +85°C-2 +2
%
Current Limit ILIM OUT_ = GND 120 250 500 mA
Output Pulldown Resistance ROUT_ EN_ = GND 3 5 8 kΩ
IOUT_ = 1mA 1
IOUT_ = 50mA 25Dropout Voltage (Note 1) VIN_ -
VOUT_IOUT_ = 100mA 50 100
mV
Line Regulation
VIN_ = (VOUT_+ 0.1V) to 5.5V for VOUT_≥
2.4V, or VIN_ = 2.5V to 5.5V for VOUT_ <
2.4V, IOUT = 1mA
-0.15 +0.15 %/V
Output Voltage Noise 10Hz to 100kHz, COUT_ = 10µF ceramic,
VOUT_ = 2.8V, IOUT_ = 10mA 45 µVRMS
Output Voltage PSRR 100Hz, COUT_ = 2.2µF ceramic,
IOUT_ = 10mA 67 dB
Channel-to-Channel Isolation 10kHz, COUT_ = 2.2µF ceramic,
IOUT_ = 10mA 64 dB
MAX8890
Integrated Cellular RF-Section
Power-Management IC
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS
(VIN_ = 3.6V, EN_ = IN_, CIN = 6.8µF, COUT_ = 2.2µF, CBP = 0.01µF, all ceramic capacitors TA= -40°C to +85°C, unless otherwise
noted.) (Note 2)
ELECTRICAL CHARACTERISTICS (continued)
(VIN_ = 3.6V, EN_ = IN_, CIN = 6.8µF, COUT_ = 2.2µF, CBP = 0.01µF, all ceramic capacitors TA= 0°C to +85°C, unless otherwise
noted. Typical values are at TA= +25°C.)
Note 1: The Dropout Voltage is defined as VIN_ - VOUT_, when VOUT_ is 100mV below the set output voltage (the value of VOUT_ for
VIN_ = VOUT_ + 500mV). Since the minimum input voltage range is 2.5V, this specification is only meaningful when the set
output voltage exceeds 2.7V (VOUT_(NOM) ≥2.7V).
Note 2: Specifications to -40°C are guaranteed by design, not production tested.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ENABLE LOGIC CONTROL
EN_ Input Threshold VEN_ 2.5V ≤ VIN_≤ 5.5V 0.4 1.6 V
EN_ Input Bias Current IEN_V
EN_ = 5.5V or 0, TA = +85°C-1+1µA
THERMAL PROTECTION
Thermal Shutdown Temperature TSHDN Rising temperature 160 °C
Thermal Shutdown Hysteresis ∆TSHDN 15 °C
PARAMETER SYMBOL CONDITIONS MIN MAX UNITS
GENERAL
Input Voltage VIN_ 2.5 5.5 V
Input Undervoltage Lockout
Threshold VUVLO Rising and Falling edge 2.10 2.45 V
SUPPLY CURRENT
Quiescent Supply Current IQIOUT_ = 0 330 µA
Shutdown Supply Current EN_ = OUT_ = GND 10 µA
LINEAR REGULATORS
Output Voltage Accuracy VOUT_VIN_ = 0.5V + the highest of (VOUT1, VOUT2,
or VOUT3), IOUT_ = 1mA to 100mA -2 +2 %
Current Limit ILIM OUT_ = GND 110 500 mA
Output Pulldown Resistance ROUT_ EN_ = GND 3 8 kΩ
Dropout Voltage (Note 1) VIN_ -
VOUT_IOUT_ = 100mA 100 mV
Line Regulation
VIN_ = (VOUT_+ 0.1V) to 5.5V for VOUT_≥
2.4V, or VIN_ = 2.5V to 5.5V for VOUT_ <
2.4V, IOUT = 1mA
-0.15 +0.15 %/V
ENABLE LOGIC CONTROL
EN_ Input Threshold VEN_ 2.5V ≤ VIN_≤ 5.5V 0.4 1.6 V
EN_ Input Bias Current IEN_V
EN_ = 5.5V or 0, TA = +85°C-11µA
MAX8890
Integrated Cellular RF-Section
Power-Management IC
4 _______________________________________________________________________________________
Typical Operating Characteristics
(Circuit of Figure 1, MAX8890EGCGGG, VIN = 3.3V, EN_ = IN_, TA= +25°C, unless otherwise noted.)
0
1.0
0.5
2.0
1.5
2.5
3.0
0231 456
OUTPUT VOLTAGE
vs. INPUT VOLTAGE
MAX8890 toc01
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
IOUT = NO LOAD
2.77
2.79
2.78
2.81
2.80
2.82
2.83
0406020 80 100
OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX8890 toc02
LOAD CURRENT (mA)
OUTPUT VOLTAGE (V)
2.77
2.79
2.78
2.81
2.80
2.82
2.83
-40 10 35-15 60 85
OUTPUT VOLTAGE
vs. TEMPERATURE
MAX8890 toc03
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
IOUT = 100mA
0
20
10
40
30
60
50
70
04020 60 80 100
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX8890 toc04
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
TA = -40°C
TA = +25°C
TA = +85°C
0
60
40
20
80
100
120
140
160
180
200
021 3456
GROUND-PIN CURRENT
vs. INPUT VOLTAGE
MAX8890 toc05
INPUT VOLTAGE (V)
GROUND-PIN CURRENT (µA)
IOUT = NO LOAD
IOUT1 = 100mA
ONLY ONE OUTPUT ENABLED
(EN1 = IN, EN2 = EN3 = GND)
50
65
60
55
70
75
80
85
90
95
100
04020 60 80 100
GROUND-PIN CURRENT
vs. LOAD CURRENT
MAX8890 toc06
LOAD CURRENT (mA)
GROUND-PIN CURRENT (µA)
ONLY ONE OUTPUT ENABLED
(EN1 = IN, EN2 = EN3 = GND)
50
70
60
90
80
110
100
120
-40 10-15 35 60 85
GROUND-PIN CURRENT
vs. TEMPERATURE
MAX8890 toc07
TEMPERATURE (°C)
GROUND-PIN CURRENT (µA)
IOUT1 = 100mA
ONLY ONE OUTPUT ENABLED
(EN1 = IN, EN2 = EN3 = GND)
80
70
60
50
40
30
20
10
0
0.01 1 100.1 100 1000
POWER-SUPPLY REJECTION RATIO
MAX8890 toc08
FREQUENCY (kHz)
PSRR (dB)
CIN = 1µF + 0.1µF
IOUT = 10mA
80
70
60
50
40
30
20
10
0
0.1 10 1001 1000
CHANNEL-TO-CHANNEL ISOLATION
MAX8890 toc09
FREQUENCY (kHz)
ISOLATION (dB)
LOW-IMPEDANCE INPUT
IOUT1 = 100mA SINUSOIDAL LOAD
IOUT3 = 10mA
MAX8890
Integrated Cellular RF-Section
Power-Management IC
_______________________________________________________________________________________ 5
20µs/div
LOAD TRANSIENT
A
B
MAX8890 toc10
A. IOUT_ = 1mA to 100mA, 50mA/div
B. VOUT_ = 2.8V, 20mV/div
VIN = 3.3V (VOUT_ +500mV)
20µs/div
LOAD TRANSIENT NEAR DROPOUT
A
B
MAX8890 toc11
A. IOUT_ = 1mA to 100mA, 50mA/div
B. VOUT_ = 2.8V, 20mV/div
VIN = 2.9V (VOUT_ + 100mV)
40µs/div
LINE TRANSIENT RESPONSE
A
B
MAX8890 toc12
A. VIN = 3.5V to 4.0V, 200mV/div
B. VOUT_ = 2.8V, 2mV/div
IOUT = 100mA
4.0V
3.5V
2.8V
5ms/div
STARTUP WAVEFORM
(CBP = 0.1µF)
A
C
B
MAX8890 toc15
A. VIN = 0 to 3.3V, 5V/div
B. VOUT_ = 2.8V, 2V/div
C. VBP = 1.25V, 1V/div
ROUT_ = 28Ω (100mA)
20µs/div
STARTUP WAVEFORM
(CBP = 0.01µF)
A
C
B
MAX8890 toc14
A. VIN = 0 to 3.3V, 5V/div
B. VOUT_ = 2.8V, 2V/div
C. VBP = 1.25V, 1V/div
ROUT_ = 28Ω (100mA)
1000
1
0.1 10 100 1000
CROSSTALK VOLTAGE
10
100
MAX8890 toc13
FREQUENCY (kHz)
CROSSTALK (µVp-p)
1
LOW-IMPEDANCE INPUT
IOUT1 = 100mA SINUSOIDAL LOAD
IOUT3 = 10mA
Typical Operating Characteristics (continued)
(Circuit of Figure 1, MAX8890EGCGGG, VIN = 3.3V, EN_ = IN_, TA= +25°C, unless otherwise noted.)
MAX8890
Integrated Cellular RF-Section
Power-Management IC
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(Circuit of Figure 1, MAX8890EGCGGG, VIN = 3.3V, EN_ = IN_, TA= +25°C, unless otherwise noted.)
20µs/div
ENABLE WAVEFORM
(1ST OUTPUT)
A
C
D
B
MAX8890 toc16
A. VEN1 = 0 to 3.3V, 5V/div
B. VOUT1 = 2.8V, ROUT1 = 28Ω (100mA), 2V/div
C. VBP = 1.25V, 1V/div
D. IIN, 200mA/div
VIN = 3.3V, EN2 = EN3 = GND, CBP = 0.01µF
20µs/div
ENABLE WAVEFORM
(2ND OUTPUT)
A
C
D
B
MAX8890 toc17
A. VEN2 = 0 to 3.3V, 5V/div
B. VOUT2 = 2.8V, ROUT2 = 28Ω (100mA), 2V/div
C. VBP = 1.25V, 1V/div
D. IIN, 200mA/div
VIN = 3.3V, EN1 = IN, EN3 = GND, CBP = 0.01µF
Pin Description
PIN NAME FUNCTION
1 IN1 Regulator 1 Input. Supply voltage can range from 2.5V to 5.5V. Bypass with a capacitor to GND (see
Capacitor Selection and Regulator Stability).
2 IN2 Regulator 2 Input. Supply voltage can range from 2.5V to VIN1. Bypass with a capacitor to GND (see
Capacitor Selection and Regulator Stability).
3 OUT2 Regulator 2 Output. Sources up to 100mA. Bypass with a 2.2µF ceramic capacitor to GND.
4 EN1 Active-High Enable Input for Regulator 1. A logic low shuts down the first linear regulator. In shutdown,
OUT1 is pulled low through an internal 5kΩ resistor. Connect to IN1 for normal operation.
5 EN2 Active-High Enable Input for Regulator 2. A logic low shuts down the second linear regulator. In
shutdown, OUT2 is pulled low through an internal 5kΩ resistor. Connect to IN2 for normal operation.
6 EN3 Active-High Enable Input for Regulator 3. A logic low shuts down the third linear regulator. In
shutdown, OUT3 is pulled low through an internal 5kΩ resistor. Connect to IN3 for normal operation.
7BP
1.25V Voltage Reference Bypass Pin. Connect a 0.01µF ceramic bypass capacitor from BP to GND to
minimize the output noise. Make no other connection to this pin.
8 GND Ground. Connect both ground pins together externally, as close to the IC as possible.
9 IN3 Regulator 3 Input. Supply voltage can range from 2.5V to VIN1. Bypass with a capacitor to GND (see
Capacitor Selection and Regulator Stability).
10 OUT3 Regulator 3 Output. Sources up to 100mA. Bypass with a 2.2µF ceramic capacitor to GND.
11 GND Ground. Connect both ground pins together externally, as close to the IC as possible.
12 OUT1 Regulator 1 Output. Sources up to 100mA. Bypass with a 2.2µF ceramic capacitor to GND.
EXPOSED
PAD GND
Gr ound .THE EXPO SED PA D A ND A LL F OUR C ORNER T ABS O N T HE Q FN PA CKAGE A RE
IN TER NALLY C ONNEC TED TO G ROUND. The exp osed p ad functi ons as a heatsi nk. S ol der to a l ar ge p ad
or to the ci rcui t b oar d g round p lane to m axi mize p ow er d issi pati on. D o not use as d evi ce g round .
MAX8890
Integrated Cellular RF-Section
Power-Management IC
_______________________________________________________________________________________ 7
Detailed Description
The MAX8890 is an RF power-management IC for a
cellular phone. The MAX8890 contains three low-noise,
low quiescent current, low-dropout, linear regulators for
powering the transmitter, receiver, synthesizer, TCXO,
and voltage controlled oscillators (VCOs). Each low-
dropout linear regulator (LDO) supplies loads up to
100mA and is available with preset output voltages
from 1.8V to 3.3V in 50mV increments. Furthermore, the
MAX8890’s input voltage range of 2.5V to 5.5V is per-
fect for single-cell Li+ battery or 3-cell NiMH battery
applications.
As illustrated in Figure 2, each regulator consists of an
error amplifier, internal feedback resistive-divider, and
P-channel MOSFET pass transistor. The output voltage
feeds back through the internal resistive-divider con-
nected to OUT_. This feedback voltage connects to the
error amplifier, which compares the feedback voltage
with the internal 1.25V reference voltage and amplifies
the difference. If the feedback voltage is lower than the
reference voltage, the pass-transistor gate is pulled
lower, which allows more current to flow to the output
and increases the output voltage. If the feedback volt-
age is too high, the pass-transistor gate is pulled up,
allowing less current to flow to the output.
Clear transmission and reception in a cellular phone
can only be achieved with a low-noise power supply.
Therefore, all three LDOs on the MAX8890 feature low
output voltage noise, high power-supply rejection
ratios, and excellent load and line regulation character-
istics. Designed for single-cell Li+ battery applications
where a pulsed current demand is required from the
battery, each LDO is designed with 45µVRMS noise
from 10Hz to 100kHz and PSRR of 67dB.
The MAX8890 also features output current limiting
(short-circuit protection), a low-power shutdown mode,
and thermal overload protection.
Internal P-Channel Pass MOSFET
Each linear regulator features a 0.5ΩP-channel MOS-
FET pass transistor. Unlike similar designs using PNP
pass transistors, P-channel MOSFETs require no base
drive, which reduces the quiescent current. PNP based
regulators also waste considerable current in dropout
when the pass transistor saturates and use high base-
drive currents under large loads. The MAX8890 does
not suffer from these problems and consumes only
180µA of quiescent current (all 3 regulators enabled).
Current Limit (Short-Circuit Protection)
The MAX8890 contains separate current-limit circuitry
for each linear regulator. The device monitors and con-
trols the gate voltage of each pass transistor, limiting
the regulator’s output current to 250mA (typ). The out-
put can be shorted to ground for an indefinite period of
time without damage to the part as long as the maxi-
mum continuous power dissipation rating is not
exceeded.
Output Voltage Selection
The MAX8890 is supplied with factory-set output volt-
ages from 1.8V to 3.3V in 50mV increments. The three-
letter part number suffix identifies the output voltage for
each regulator. For example, the MAX8890EGCAKM’s
output voltages are preset to 3.3V (VOUT1), 2.5V
(VOUT2), and 1.8V (VOUT3).
ON
OFF
IN1 OUT1
IN2 OUT2
IN3 OUT3
EN1 BP
EN2
EN3 GND
MAX8890
CBP
0.01µF
COUT1
2.2µF
COUT2
2.2µF
COUT3
2.2µF
CIN
4.7µF
INPUT
2.5V TO 5.5V OUTPUT #1
(1.8V TO 3.3V)*
OUTPUT #2
(1.8V TO 3.3V)*
OUTPUT #3
(1.8V TO 3.3V)*
*SEE THE Ordering Information AND
Preset Output Voltage Suffixes SECTIONS
Figure 1. Typical Application Circuit
MAX8890
Integrated Cellular RF-Section
Power-Management IC
8 _______________________________________________________________________________________
IN1
EN1
IN2
EN2
IN3
EN3
OUT1
BP
GND
OUT2
OUT3
LINEAR REGULATOR #1
LINEAR REGULATOR #2
LINEAR REGULATOR #3
STARTUP
CIRCUITRY
CONTROL
LOCIC
REF
1.25V
THERMAL
SHDN
IN1
ERROR
AMPLIFIER
CURRENT
LIMIT
RSENSE
Figure 2. Functional Diagram
Enable
If any one of the three low-dropout linear regulators
(LDOs) is enabled, the internal 1.25V reference powers
up. Therefore, all three LDOs must be disabled to shut
down the internal reference, reducing the supply cur-
rent to 0.01µA.
Pull EN_ low to enter shutdown. When any one of the
linear regulators is shutdown, the corresponding
MAX8890 output disconnects from the corresponding
input, and the output discharges through an internal
5kΩresistor. The capacitance and load determine the
rate at which VOUT_ decays. Do not leave EN_ floating.
Connect EN_ to IN_ for normal operation. EN_ can be
pulled as high as 6V, regardless of the input and output
voltages.
Thermal Overload Protection
Thermal overload protection limits the MAX8890’s total
power dissipation in the event of fault conditions. Each
linear regulator has its own thermal shutdown circuitry.
MAX8890
Integrated Cellular RF-Section
Power-Management IC
_______________________________________________________________________________________ 9
When the junction temperature exceeds TJ= 160°C, a
thermal sensor activates the shutdown logic, disabling
the overheated regulator. The thermal sensor turns the
linear regulator on again after the regulator’s junction
temperature cools by 15°C, resulting in a pulsed output
during continuous thermal-overload conditions. For
continuous operation, do not exceed the absolute maxi-
mum junction-temperature rating of TJ= 150°C.
Applications Information
Capacitor Selection and Regulator
Stability
Capacitors are required at each input and each output
of the MAX8890 for stable operation over the full load
range and full temperature range. Connect a minimum
2.2µF ceramic capacitor between OUT_ and ground to
ensure stability and optimum transient response. Use
larger 10µF ceramic output capacitors for lower noise
requirements.
The input capacitor (CIN_) lowers the source imped-
ance of the input supply, thereby reducing the input
noise and improving transient response. Connect a
minimum 1µF ceramic capacitance between each IN_
and ground. Place all input and output capacitors as
close to the MAX8890 as possible to minimize the
impact of PC board trace impedance. Because IN1
and IN2 are next to each other, they may easily share a
single 2.2µF or larger ceramic capacitor.
Surface-mount ceramic capacitors have very low ESR
and are commonly available in values up to 10µF.
However, note that some ceramic dielectrics exhibit
large capacitance and ESR variation with temperature.
Z5U and Y5V dielectrics may require a minimum 3.3µF
nominal output capacitance, especially with low tem-
perature operation.
Reference Bypass Capacitor
An external bypass capacitor is connected to BP to
reduce the inherent reference noise. The capacitor
forms a lowpass filter in conjunction with an internal
network. Use a 0.01µF or greater ceramic capacitor
connected as close to BP as possible. Capacitance
values greater than 0.01µF will increase the startup
time. (See Typical Operating Characteristics for startup
waveforms.) For the lowest noise, increase the bypass
capacitor to 0.1µF. Values above 0.1µF provide no per-
formance improvement and are therefore not recom-
mended. Do not place any additional loading on this
reference bypass pin.
Noise, PSRR, and Transient Response
The MAX8890 is designed to operate with low dropout
voltages and low quiescent currents in battery-powered
systems while providing low noise, fast transient
response, and high AC rejection. See the Typical
Operating Characteristics for a plot of Power-Supply
Rejection Ratio (PSRR) vs. Frequency. When operating
from noisy sources, improved supply-noise rejection
and transient response can be achieved by increasing
the values of the input and output bypass capacitors
and through passive filtering techniques.
The MAX8890 load-transient response graphs (see
Typical Operating Characteristics) show two compo-
nents of the output response: a DC shift from the output
impedance due to the load current change and the
transient response. Increasing the output capacitor’s
value and decreasing the ESR reduces the transient
under/overshoot.
Input-Output (Dropout) Voltage
A regulator’s minimum input-to-output voltage differen-
tial (dropout voltage) determines the lowest useable
input supply voltage. Once the linear regulator reaches
dropout, the series pass transistor is fully on and regu-
lation ceases. The output voltage tracks the input volt-
age as the input voltage drops lower. Because the
MAX8890 uses P-channel MOSFET pass transistors, its
dropout voltage is a function of the MOSFET’s drain-to-
source on-resistance (RDS(ON)) multiplied by the load
current (see Typical Operating Characteristics):
VDROPOUT = VIN_ - VOUT_ = RDS(ON) ✕IOUT_
MAX8890
Integrated Cellular RF-Section
Power-Management IC
10 ______________________________________________________________________________________
12
OUT1
11
GND
10
OUT3
9IN3
8GND
7BP
4
EN1
5
EN2
6
EN3
1IN1
2IN2
3OUT2
MAX8890
TOP VIEW
4✕ 4 QFN
Pin Configuration
VERSION TOP MARK
MAX8890EGCAAA AAAA
MAX8890EGCDDD AAAC
MAX8890EGCGGG AAAE
MAX8890EGCMMM AAAJ
MAX8890EGCAKM AAAK
Standard Versions
Chip Information
TRANSISTOR COUNT: 1472
PROCESS: BiCMOS
MAX8890
Integrated Cellular RF-Section
Power-Management IC
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Package Information
12, 16,20, 24L QFN.EPS
MAX8890
Integrated Cellular RF-Section
Power-Management IC
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information (continued)
